CAMBREX CORP
SC 14D1, 1997-08-28
INDUSTRIAL ORGANIC CHEMICALS
Previous: BRAZIL FUND INC, NT-NSAR, 1997-08-28
Next: MEDICAL INCOME PROPERTIES 2B LTD PARTNERSHIP, SC 14D1/A, 1997-08-28



<PAGE>   1
 
================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                            ------------------------
 
                                 SCHEDULE 14D-1
                             TENDER OFFER STATEMENT
                          PURSUANT TO SECTION 14(d)(1)
                     OF THE SECURITIES EXCHANGE ACT OF 1934
                                      AND
 
                                  SCHEDULE 13D
                                     UNDER
                      THE SECURITIES EXCHANGE ACT OF 1934
                            ------------------------
 
                               BIOWHITTAKER, INC.
                       (NAME OF SUBJECT COMPANY (ISSUER))
                           BW ACQUISITION CORPORATION
                          A WHOLLY-OWNED SUBSIDIARY OF
 
                              CAMBREX CORPORATION
                                    (BIDDER)
 
<TABLE>
<S>                                       <C>
COMMON STOCK, PAR VALUE $0.01 PER SHARE                    09066T  108
        (AND ASSOCIATED RIGHTS)               (CUSIP NUMBER OF CLASS OF SECURITIES)
     (TITLE OF CLASS OF SECURITIES)
</TABLE>
 
                             PETER E. THAUER, ESQ.
 
                           BW ACQUISITION CORPORATION
                            C/O CAMBREX CORPORATION
                             ONE MEADOWLANDS PLAZA
                       EAST RUTHERFORD, NEW JERSEY 07073
                                 (201) 804-3000
            (NAME, ADDRESS AND TELEPHONE NUMBER OF PERSON AUTHORIZED
           TO RECEIVE NOTICES AND COMMUNICATIONS ON BEHALF OF BIDDER)
                                    COPY TO:
                             ANDREW L. SOMMER, ESQ.
                              DEBEVOISE & PLIMPTON
                                875 THIRD AVENUE
                            NEW YORK, NEW YORK 10022
                           TELEPHONE: (212) 909-6000
                            ------------------------
 
                           CALCULATION OF FILING FEE
 
<TABLE>
<CAPTION>
                       TRANSACTION VALUATION*      AMOUNT OF FILING FEE**
                    --------------------------------------------------------
                    <S>                         <C>
                            $138,948,952                  $27,790
                    --------------------------------------------------------
</TABLE>
 
 * Based on the offer to purchase all of the outstanding shares of Common Stock,
   par value $0.01 per share (the "Shares"), of the Subject Company and the
   associated Rights at $11.625 net per Share. Based on information provided by
   BioWhittaker, Inc., the number of Shares outstanding as of August 27, 1997 is
   assumed to be 10,881,210 and the number of options to purchase shares
   outstanding as of August 27, 1997 is assumed to be 1,071,388.
** 1/50 of 1% of Transaction Valuation.
[ ] Check box if any part of the fee is offset as provided by Rule 0-11(a)(2)
    and identify the filing with which the offsetting fee was previously paid.
    Identify the previous filing by registration statement number, or the Form
    or Schedule and the date of its filing.
 
   Amount Previously Paid:
   -----------------------------------------
 
   Form or Registration No.:
   ----------------------------------------
 
   Filing Party:
   -------------------------------------------------------
 
   Date Filed:
   --------------------------------------------------------
================================================================================
<PAGE>   2
 
<TABLE>
<S>                       <C>                                           <C>
- --------------------------
  CUSIP NO. 09066T  108
- --------------------------
  -----------------------------------------------------------------------------------------------
            NAME OF REPORTING PERSON:
            S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
    1       CAMBREX CORPORATION
            I.R.S. IDENTIFICATION NO. 22-2476135
  -----------------------------------------------------------------------------------------------
            CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
              (SEE INSTRUCTIONS)                                                           (A)  [
              ]
    2       (B)  [ ]
  -----------------------------------------------------------------------------------------------
            SEC USE ONLY
    3
  -----------------------------------------------------------------------------------------------
            SOURCES OF FUNDS (SEE INSTRUCTIONS)
    4
            BK
  -----------------------------------------------------------------------------------------------
            CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
    5       PURSUANT TO ITEMS 2(E) OR 2(F)                                                 [ ]
  -----------------------------------------------------------------------------------------------
            CITIZENSHIP OR PLACE OF ORGANIZATION
    6
            DELAWARE
  -----------------------------------------------------------------------------------------------
            AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
    7
            3,716,443 SHARES*
  -----------------------------------------------------------------------------------------------
            CHECK IF THE AGGREGATE AMOUNT IN ROW (7) EXCLUDES CERTAIN
    8       SHARES (SEE INSTRUCTIONS)                                                      [ ]
  -----------------------------------------------------------------------------------------------
            PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (7)
    9       31.1%
  -----------------------------------------------------------------------------------------------
            TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
    10      CO
  -----------------------------------------------------------------------------------------------
</TABLE>
<PAGE>   3
 
<TABLE>
<S>                       <C>                                           <C>
- --------------------------
  CUSIP NO. 09066T  108
- --------------------------
 -----------------------------------------------------------------------------------------------
           NAME OF REPORTING PERSON:
           S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
   1       BW ACQUISITION CORPORATION
           I.R.S. IDENTIFICATION NO. APPLIED FOR
 -----------------------------------------------------------------------------------------------
           CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
             (SEE INSTRUCTIONS)                                                            (A) [
             ]
   2       (B)  [ ]
 -----------------------------------------------------------------------------------------------
           SEC USE ONLY
   3
 -----------------------------------------------------------------------------------------------
           SOURCES OF FUNDS (SEE INSTRUCTIONS)
   4
           BK
 -----------------------------------------------------------------------------------------------
           CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
   5       PURSUANT TO ITEMS 2(E) OR 2(F)                                                  [ ]
 -----------------------------------------------------------------------------------------------
           CITIZENSHIP OR PLACE OF ORGANIZATION
   6
           DELAWARE
 -----------------------------------------------------------------------------------------------
           AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
   7
           3,716,443*
 -----------------------------------------------------------------------------------------------
           CHECK IF THE AGGREGATE AMOUNT IN ROW (7) EXCLUDES CERTAIN
   8       SHARES (SEE INSTRUCTIONS)                                                       [ ]
 -----------------------------------------------------------------------------------------------
           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (7)
   9       31.1%
 -----------------------------------------------------------------------------------------------
           TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
   10      CO
 -----------------------------------------------------------------------------------------------
</TABLE>
 
* The Purchaser and Parent (each as defined herein) have entered into two
  separate but substantially identical Stockholders Agreements, each dated as of
  August 22, 1997 (collectively, the "Stockholders Agreement"), with Anasco GmbH
  on the one hand, and each of Joseph F. Alibrandi, Noel L. Buterbaugh, Thomas
  R. Winkler, Philip L. Rohrer Jr., Leif Olsen and F. Dudley Staples Jr. on the
  other (collectively, the "Selling Stockholders"), pursuant to which such
  Selling Stockholders have agreed to tender their shares in the Offer and have
  granted to the Purchaser an irrevocable option, exercisable upon the
  occurrence of certain trigger events, to purchase the Shares (as defined
  herein) owned of record by the Selling Stockholders at a price per Share equal
  to the Offer Price (as defined in the Offer to Purchase), in cash. By virtue
  of the Stockholders Agreement, Parent and the Purchaser may be deemed to be
  the beneficial owners of up to 3,716,443 Shares. Parent and the Purchaser
  disclaim any such beneficial ownership.
<PAGE>   4
 
     This Tender Offer Statement on Schedule 14D-1 relates to the offer by BW
Acquisition Corporation, a Delaware corporation (the "Purchaser") and a
wholly-owned subsidiary of Cambrex Corporation, a Delaware corporation
("Parent"), to purchase all of the issued and outstanding shares of Common
Stock, par value $0.01 per share (the "Common Stock") of BioWhittaker, Inc., a
Delaware corporation (the "Company"), together with the associated rights to
purchase Series A Participating Cumulative Preferred Stock (the "Rights"; and
together with the Common Stock the "Shares") at a price of not less than $11.625
per Share net to the seller in cash, upon the terms and subject to the
conditions set forth in the Offer to Purchase dated August 28, 1997 (the "Offer
to Purchase"), and in the related Letter of Transmittal (which, together with
the Offer to Purchase and supplements thereto, collectively constitute the
"Offer"), copies of which are attached as Exhibits (a)(1) and (a)(2),
respectively.
 
     This Tender Offer Statement on Schedule 14D-1 also constitutes a statement
on Schedule 13D with respect to Parent's and the Purchaser's possible beneficial
ownership of Shares pursuant to the Stockholders Agreement. The cover page above
and item numbers and responses thereto below are in accordance with the
requirements of Schedule 14D-1. Parent and the Purchaser disclaim any such
beneficial ownership.
 
ITEM 1.  SECURITY AND SUBJECT COMPANY
 
     (a) The name of the subject company is BioWhittaker, Inc. The principal
executive offices of the Company are located at 8830 Biggs Ford Road,
Walkersville, Maryland 21793-0127.
 
     (b) The exact title of the class of equity securities being sought in the
Offer is Common Stock, par value $0.01 per share, together with the associated
rights to purchase Series A Participating Cumulative Preferred Stock of the
Company. Information regarding the number of Shares outstanding, the amount of
Shares being sought and the consideration being offered therefor is set forth in
the Introduction (the "Introduction") of the Offer to Purchase and is
incorporated herein by reference.
 
     (c) Information concerning the principal market in which the Shares are
traded and the high and low sales prices of the Shares for each quarterly period
during the past two years is set forth in Section 6 ("Price Range of the
Shares") of the Offer to Purchase and is incorporated herein by reference.
 
ITEM 2.  IDENTITY AND BACKGROUND
 
     (a)-(d) and (g) This Statement is filed by the Purchaser and Parent. The
information concerning the name, the state of its organization, its principal
business and address of the principal office of each of the Purchaser and
Parent, and the information regarding the name, business address, present
principal occupation or employment and the name, principal business and address
of any corporation or other organization in which such employment or occupation
is conducted, material occupations, positions, offices or employments during the
last five years and the citizenship of each of the executive officers and
directors of the Purchaser and Parent is set forth in Section 9 ("Certain
Information Concerning the Purchaser and Parent") of the Offer to Purchase and
in Schedule I thereto and is incorporated herein by reference.
 
     (e) and (f) During the last five years, neither the Purchaser nor Parent
nor, to the best knowledge of the Purchaser or Parent, any of the persons listed
in Schedule 1 to the Offer to Purchase (i) has been convicted in a criminal
proceeding (excluding traffic violations or similar misdemeanors) or (ii) was a
party to a civil proceeding of a judicial or administrative body of competent
jurisdiction and as a result of such proceeding was or is subject to a judgment,
decree or final order enjoining future violations of, or prohibiting activities
subject to, federal or state securities laws or finding any violation of such
laws.
 
ITEM 3.  PAST CONTACTS, TRANSACTIONS OR NEGOTIATIONS WITH THE SUBJECT COMPANY
 
     (a) The information set forth in Section 9 ("Certain Information Concerning
the Purchaser and Parent") of the Offer to Purchase is incorporated herein by
reference. Except as set forth in Section 9 of the Offer to Purchase, since
October 31, 1993, there have been no transactions which would be required to be
disclosed under this Item 3(a) between either the Purchaser or Parent or, to the
best knowledge of the
<PAGE>   5
 
Purchaser and Parent, any of the persons listed in Schedule 1 to the Offer to
Purchase and the Company or any of its executive officers, directors or
affiliates.
 
     (b) The information set forth in Section 9 ("Certain Information Concerning
the Purchaser and Parent") and Section 11 ("Contacts and Transactions with the
Company; Background of the Offer") of the Offer to Purchase is incorporated
herein by reference. Except as set forth in Section 9 and Section 11 of the
Offer to Purchase, since October 31, 1993, there have been no contacts,
negotiations or transactions which would be required to be disclosed under this
Item 3(b) between either the Purchaser or Parent or any of their respective
subsidiaries or, to the best knowledge of the Purchaser and Parent, any of those
persons listed in Schedule I to the Offer to Purchase and the Company or its
affiliates concerning a merger, consolidation or acquisition, a tender offer or
other acquisition of securities, an election of directors or a sale or other
transfer of a material amount of assets.
 
ITEM 4.  SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION
 
     (a)-(b) The information set forth in Section 10 ("Source and Amount of
Funds") of the Offer to Purchase is incorporated herein by reference.
 
     (c) Not applicable.
 
ITEM 5.  PURPOSE OF THE TENDER OFFER AND PLANS OR PROPOSALS OF THE BIDDER
 
     (a)-(g) The information set forth in the Introduction, Section 7 ("Purpose
of the Offer; Plans for the Company; Effect of the Offer on the Market for the
Shares; Stock Quotation; Exchange Act Registration; Margin Regulations"),
Section 11 ("Contacts and Transactions with the Company; Background of the
Offer"), Section 12 ("The Merger Agreement; The Stockholders Agreement") and
Section 13 ("Dividends and Distributions") of the Offer to Purchase is
incorporated herein by reference.
 
ITEM 6.  INTEREST IN SECURITIES OF THE SUBJECT COMPANY
 
     (a) The information set forth in the Introduction and Section 9 ("Certain
Information Concerning the Purchaser and Parent") of, and Schedule 1 to, the
Offer to Purchase is incorporated herein by reference.
 
     (b) The information set forth in the Introduction, Section 9 ("Certain
Information Concerning Parent and the Purchaser") and Section 11 ("Contacts and
Transactions with the Company; Background of the Offer") of, and Schedule 1 to,
the Offer to Purchase is incorporated herein by reference.
 
ITEM 7. CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH RESPECT TO
        THE SUBJECT COMPANY'S SECURITIES
 
     The information set forth in the Introduction, Section 9 ("Certain
Information Concerning the Purchaser and Parent"), Section 11 ("Contacts and
Transactions with the Company; Background of the Offer"), Section 10 ("Source
and Amount of Funds"), Section 12 ("The Merger Agreement; The Stockholders
Agreement") and Section 16 ("Fees and Expenses") of the Offer to Purchase is
incorporated herein by reference. Except as set forth in the Introduction and
Sections 9, 10, 11, 12 and 16 of the Offer to Purchase, neither the Purchaser
nor Parent, nor, to the best knowledge of the Purchaser or Parent, any of the
persons listed in Schedule 1 to the Offer to Purchase, has any contract,
arrangement, understanding or relationship with any other person with respect to
any securities of the Company (including, but not limited to, any contract,
arrangement, understanding or relationship concerning the transfer or the voting
of any such securities, joint ventures, loans or option arrangements, puts or
calls, guarantees of loans, guarantee agreements or any giving or withholding of
proxies).
 
ITEM 8.  PERSONS RETAINED, EMPLOYED OR TO BE COMPENSATED
 
     The information set forth in the Introduction and Section 16 ("Fees and
Expenses") of the Offer to Purchase is incorporated herein by reference.
 
                                        2
<PAGE>   6
 
ITEM 9.  FINANCIAL STATEMENTS OF CERTAIN BIDDERS
 
     The information set forth in Section 9 ("Certain Information Concerning
Parent and the Purchaser") of the Offer to Purchase, including the financial
statements and related notes thereto incorporated by reference in Section 9, is
incorporated herein by reference.
 
     The incorporation by reference herein of the above-referenced financial
information does not constitute an admission that such information is material
to a decision by a stockholder of the Company whether to sell, tender or hold
Shares being sought in the Offer.
 
ITEM 10.  ADDITIONAL INFORMATION
 
     (a) The information set forth in the Introduction, in Section 9 ("Certain
Information Concerning the Purchaser and Parent"), in Section 11 ("Contacts and
Transactions with the Company; Background of the Offer") and in Section 12 ("The
Merger Agreement; The Stockholder Agreement") of the Offer to Purchase is
incorporated herein by reference.
 
     (b) and (c) The information set forth in the Introduction, Section 12 ("The
Merger Agreement; The Stockholder Agreement") and Section 15 ("Certain Legal
Matters") of the Offer to Purchase is incorporated herein by reference.
 
     (d) The information set forth in Section 7 ("Purpose of the Offer; Plans
for the Company; Effect of the Offer on the Market for the Shares; Stock
Quotation; Exchange Act Registration; Margin Regulations") and Section 15
("Certain Legal Matters") of the Offer to Purchase is incorporated herein by
reference.
 
     (e) The information set forth in Section 11 ("Contacts and Transactions
with the Company; Background of the Offer") and Section 15 ("Certain Legal
Matters") of the Offer to Purchase is incorporated herein by reference.
 
     (f) The information set forth in the Offer to Purchase and the Letter of
Transmittal is incorporated herein by reference.
 
                                        3
<PAGE>   7
 
ITEM 11.  MATERIAL TO BE FILED AS EXHIBITS
 
<TABLE>
<S>      <C>
(a)(1)   Offer to Purchase dated August 28, 1997.
(a)(2)   Letter of Transmittal.
(a)(3)   Notice of Guaranteed Delivery.
(a)(4)   Letter from the Dealer Manager to Brokers, Dealers, Commercial Banks, Trust
         Companies and Nominees.
(a)(5)   Letter to clients for use by Brokers, Dealers, Commercial Banks, Trust
         Companies and Nominees.
(a)(6)   Guidelines for Certification of Taxpayer Identification Number on Substitute
         Form W-9.
(a)(7)   Summary Advertisement as published on August 28, 1997.
(a)(8)   Joint Press Release issued by Parent and the Company on August 25, 1997.
(b)(1)   Commitment Letter, dated as of August 20, 1997, as amended, by and among
         Parent and the financial institutions listed therein.
(c)(1)   Agreement and Plan of Merger, dated as of August 22, 1997, among Parent, the
         Purchaser and the Company.
(c)(2)   Stockholders Agreement, dated as of August 22, 1997, between Parent and
         Anasco GmbH.
(c)(3)   Management Stockholders Agreement, dated as of August 22, 1997, among Parent
         and the stockholders named therein.
(c)(4)   Form of Employment Letter, dated August 22, 1997, among Parent, the
         Purchaser and certain executives of the Company.
(c)(5)   Form of Employment Letter, dated August 22, 1997, among Parent, the
         Purchaser and Noel L. Buterbaugh.
(c)(6)   Form of Assumption Agreement, dated as of August 22, 1997, among Parent, the
         Purchaser and the Company.
(d)      None.
(e)      Not applicable.
(f)      None.
</TABLE>
 
                                        4
<PAGE>   8
 
                                   SIGNATURE
 
     After due inquiry and to the best of our knowledge and belief, we certify
that the information set forth in this Statement is true, complete and correct.
 
                                          BW ACQUISITION CORPORATION
 
                                          By: /s/ PETER E. THAUER
 
                                          --------------------------------------
                                          Name: Peter E. Thauer
                                          Title: Vice President
 
                                          CAMBREX CORPORATION
 
                                          By: /s/ PETER E. THAUER
 
                                          --------------------------------------
                                          Name: Peter E. Thauer
                                          Title: Vice President
 
Date: August 28, 1997
 
                                        5
<PAGE>   9
 
                                 EXHIBIT INDEX
 
<TABLE>
<CAPTION>
EXHIBIT
  NO.                                     DESCRIPTION                                 PAGE NO.
- --------   -------------------------------------------------------------------------  --------
<C>        <S>                                                                        <C>
11(a)(1)   Offer to Purchase dated August 28, 1997..................................
11(a)(2)   Letter of Transmittal....................................................
11(a)(3)   Notice of Guaranteed Delivery............................................
11(a)(4)   Letter from the Dealer Manager to Brokers, Dealers, Commercial Banks,
           Trust Companies and Nominees.............................................
11(a)(5)   Letter to clients for use by Brokers, Dealers, Commercial Banks, Trust
           Companies and Nominees...................................................
11(a)(6)   Guidelines for Certification of Taxpayer Identification Number on
           Substitute Form W-9......................................................
11(a)(7)   Summary Advertisement as published on August 28, 1997....................
11(a)(8)   Joint Press Release issued by Parent and the Company on August 25,
           1997.....................................................................
11(b)(1)   Commitment Letter, dated as of August 20, 1997, as amended, by and among
           Parent and the financial institutions listed therein.....................
11(c)(1)   Agreement and Plan of Merger, dated as of August 22, 1997, among Parent,
           the Purchaser and the Company.
11(c)(2)   Stockholders Agreement, dated as of August 22, 1997, between Parent and
           Anasco GmbH..............................................................
11(c)(3)   Management Stockholders Agreement, dated as of August 22, 1997, among
           Parent and the stockholders named therein................................
11(c)(4)   Form of Employment Letter dated, August 22, 1997, among Parent, the
           Purchaser and certain executives of the Company.
11(c)(5)   Form of Employment Letter, dated August 22, 1997, among Parent, the
           Purchaser and Noel L. Buterbaugh.
11(c)(6)   Form of Assumption Agreement, dated as of August 22, 1997, among Parent,
           the Purchaser and the Company.
</TABLE>
 
                                        6

<PAGE>   1
 
                           Offer to Purchase for Cash
                     All Outstanding Shares of Common Stock
                            (and Associated Rights)
 
                                       of
 
                               BIOWHITTAKER, INC.
 
                                       at
                             $11.625 NET PER SHARE
 
                                       by
                           BW ACQUISITION CORPORATION
                        a wholly-owned subsidiary of the
                              CAMBREX CORPORATION
                            ------------------------
 
     THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK
CITY TIME, ON THURSDAY, SEPTEMBER 25, 1997, UNLESS THE OFFER IS EXTENDED.
                            ------------------------
 
  THE BOARD OF DIRECTORS OF BIOWHITTAKER, INC. (THE "COMPANY") HAS UNANIMOUSLY
    APPROVED THE MAKING OF THE OFFER AND THE MERGER (AS DEFINED HEREIN) AND
 DETERMINED THAT THE TERMS OF THE OFFER AND THE MERGER ARE FAIR TO, AND IN THE
 BEST INTERESTS OF, THE STOCKHOLDERS OF THE COMPANY AND UNANIMOUSLY RECOMMENDS
 THAT STOCKHOLDERS OF THE COMPANY ACCEPT THE OFFER AND TENDER THEIR SHARES (AS
                                DEFINED HEREIN).
                            ------------------------
 
     THE OFFER IS CONDITIONED UPON, AMONG OTHER THINGS, (1) THERE BEING VALIDLY
TENDERED AND NOT WITHDRAWN PRIOR TO THE EXPIRATION OF THE OFFER AT LEAST THAT
NUMBER OF SHARES WHICH, TOGETHER WITH THE OPTION SHARES (AS DEFINED HEREIN)
WHICH ARE SUBJECT TO THE STOCKHOLDERS AGREEMENT (AS DEFINED HEREIN), WOULD
REPRESENT IN EXCESS OF 50% OF ALL OUTSTANDING SHARES ON A FULLY DILUTED BASIS ON
THE DATE OF PURCHASE AND (2) ANY WAITING PERIOD UNDER THE HART-SCOTT-RODINO
ANTITRUST IMPROVEMENTS ACT OF 1976, AS AMENDED, AND THE REGULATIONS THEREUNDER
APPLICABLE TO THE PURCHASE OF SHARES PURSUANT TO THE OFFER HAVING EXPIRED OR
BEEN TERMINATED.
                            ------------------------
 
                                   IMPORTANT
 
    Any stockholder desiring to tender all or any portion of such stockholder's
shares of common stock of the Company, par value $0.01 per share (the "Common
Stock"), and associated rights to purchase Series A Participating Cumulative
Preferred Stock, par value $0.01 per share (together with the Common Stock, the
"Shares") issued pursuant to the Stockholder Protection Rights Agreement dated
as of January 20, 1995 between the Company and Bank of Boston, as Rights Agent,
as amended, should either (1) complete and sign the Letter of Transmittal or a
facsimile copy thereof in accordance with the instructions in the Letter of
Transmittal, have such stockholder's signature thereon guaranteed if required by
Instruction 1 to the Letter of Transmittal, mail or deliver the Letter of
Transmittal (or such facsimile), or, in the case of a book-entry transfer
effected pursuant to the procedure set forth in Section 2, an Agent's Message
(as defined herein), and any other required documents to the Depositary and
either deliver the certificates for such Shares to the Depositary along with the
Letter of Transmittal (or facsimile) or deliver such Shares pursuant to the
procedure for book-entry transfer set forth in Section 2 prior to the expiration
of the Offer or (2) request such stockholder's broker, dealer, bank, trust
company or other nominee to effect the transaction for such stockholder. A
stockholder having Shares registered in the name of a broker, dealer, bank,
trust company or other nominee must contact such broker, dealer, bank, trust
company or other nominee if such stockholder desires to tender such Shares.
 
    A stockholder who desires to tender Shares and whose certificates for such
Shares are not immediately available or who cannot comply in a timely manner
with the procedure for book-entry transfer, or who cannot deliver all required
documents to the Depositary prior to the expiration of the Offer, may tender
such Shares by following the procedure for guaranteed delivery set forth in
Section 2.
 
    Questions and requests for assistance or for additional copies of this Offer
to Purchase, the Letter of Transmittal and the Notice of Guaranteed Delivery may
be directed to the Information Agent or to the Dealer Manager at their
respective addresses and telephone numbers set forth on the back cover of this
Offer to Purchase.
 
                            ------------------------
                      THE DEALER MANAGER FOR THE OFFER IS:
                              SCHRODER & CO. INC.
AUGUST 28, 1997
<PAGE>   2
 
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                                                                        PAGE
                                                                                        ----
<S>                                                                                     <C>
INTRODUCTION..........................................................................    1
THE TENDER OFFER......................................................................    3
 1. Terms of the Offer................................................................    3
 2. Procedure for Tendering Shares....................................................    4
 3. Withdrawal Rights.................................................................    7
 4. Acceptance for Payment and Payment................................................    7
 5. Certain Federal Income Tax Consequences...........................................    9
 6. Price Range of the Shares.........................................................    9
 7. Purpose of the Offer; Plans for the Company; Effect of the Offer on the Market for
    the Shares; Stock Quotation; Exchange Act Registration; Margin Regulations .......   10
 8. Certain Information Concerning the Company........................................   11
 9. Certain Information Concerning the Purchaser and Parent...........................   13
10. Source and Amount of Funds........................................................   15
11. Contacts and Transactions with the Company; Background of the Offer...............   15
12. The Merger Agreement; The Stockholders Agreement..................................   19
13. Dividends and Distributions.......................................................   26
14. Certain Conditions of the Offer...................................................   27
15. Certain Legal Matters.............................................................   29
16. Fees and Expenses.................................................................   31
17. Miscellaneous.....................................................................   32
Schedule 1 -- Directors and Executive Officers of Parent and the Purchaser............  S-1
</TABLE>
 
                                        i
<PAGE>   3
 
To the Holders of Common Stock
  of BioWhittaker, Inc.:
 
                                  INTRODUCTION
 
     BW Acquisition Corporation, a Delaware corporation (the "Purchaser"), which
is a wholly owned subsidiary of the Cambrex Corporation, a Delaware corporation
("Parent"), hereby offers to purchase all outstanding shares of Common Stock,
par value $0.01 per share (the "Common Stock"), and associated rights to
purchase Series A Participating Cumulative Preferred Stock, par value $0.01 per
share (the "Rights" and, together with the Common Stock, the "Shares"), issued
pursuant to the Stockholder Protection Rights Agreement dated as of January 20,
1995, between BioWhittaker, Inc., a Delaware corporation (the "Company") and
Bank of Boston, as Rights Agent, as amended (the "Rights Agreement"), of the
Company, at a price of $11.625 per Share, net to the seller in cash, without
interest thereon (the "Offer Price"), upon the terms and subject to the
conditions set forth in this Offer to Purchase and in the related Letter of
Transmittal (which, together with any amendments or supplements hereto or
thereto, collectively constitute the "Offer"). The Offer is being made pursuant
to the Agreement and Plan of Merger dated as of August 22, 1997 (the "Merger
Agreement"), among Parent, the Purchaser and the Company.
 
     Tendering stockholders will not be obligated to pay brokerage fees or
commissions or, except as set forth in Instruction 6 of the Letter of
Transmittal, transfer taxes on the purchase of Shares pursuant to the Offer. The
Purchaser will pay all fees and expenses of Schroder & Co. Inc. ("Schroders"),
which is acting as Dealer Manager (the "Dealer Manager"), ChaseMellon
Shareholder Services L.L.C., which is acting as the Depositary (the
"Depositary"), and D.F. King & Co., Inc., which is acting as Information Agent
(the "Information Agent"), incurred in connection with the Offer. See Section
16.
 
     THE BOARD OF DIRECTORS OF THE COMPANY HAS UNANIMOUSLY APPROVED THE MAKING
OF THE OFFER AND THE MERGER (AS DEFINED BELOW) AND DETERMINED THAT THE TERMS OF
THE OFFER AND THE MERGER ARE FAIR TO, AND IN THE BEST INTERESTS OF, THE
STOCKHOLDERS OF THE COMPANY AND UNANIMOUSLY RECOMMENDS THAT STOCKHOLDERS OF THE
COMPANY ACCEPT THE OFFER AND TENDER THEIR SHARES. THE FACTORS CONSIDERED BY THE
BOARD OF DIRECTORS OF THE COMPANY IN ARRIVING AT ITS DECISION TO APPROVE THE
MAKING OF THE OFFER AND THE MERGER AND TO RECOMMEND THAT STOCKHOLDERS OF THE
COMPANY ACCEPT THE OFFER AND TENDER THEIR SHARES ARE DESCRIBED IN THE COMPANY'S
SOLICITATION/RECOMMENDATION STATEMENT ON SCHEDULE 14D-9.
 
     ALEX. BROWN & SONS INCORPORATED, THE COMPANY'S FINANCIAL ADVISOR, HAS
DELIVERED TO THE BOARD OF DIRECTORS OF THE COMPANY A WRITTEN OPINION DATED
AUGUST 22, 1997 TO THE EFFECT THAT, AS OF THE DATE OF SUCH OPINION AND BASED
UPON AND SUBJECT TO CERTAIN MATTERS STATED THEREIN, THE $11.625 PER SHARE CASH
CONSIDERATION TO BE RECEIVED BY HOLDERS OF SHARES (OTHER THAN CAMBREX AND ITS
AFFILIATES) IN THE OFFER AND THE MERGER WAS FAIR, FROM A FINANCIAL POINT OF
VIEW, TO SUCH HOLDERS. SUCH OPINION IS SET FORTH IN FULL AS AN EXHIBIT TO THE
SCHEDULE 14D-9, WHICH IS BEING MAILED TO STOCKHOLDERS OF THE COMPANY HEREWITH
AND SHOULD BE READ CAREFULLY IN ITS ENTIRETY. THE OPINION OF ALEX. BROWN IS
DIRECTED TO THE BOARD OF DIRECTORS OF THE COMPANY AND RELATES TO THE FAIRNESS OF
THE CASH CONSIDERATION TO BE RECEIVED IN THE OFFER AND THE MERGER BY HOLDERS OF
SHARES (OTHER THAN CAMBREX AND ITS AFFILIATES) FROM A FINANCIAL POINT OF VIEW,
DOES NOT ADDRESS ANY OTHER ASPECT OF THE OFFER OR THE MERGER OR RELATED
TRANSACTIONS, AND IS NOT INTENDED TO CONSTITUTE, AND DOES NOT CONSTITUTE, A
RECOMMENDATION TO ANY STOCKHOLDER AS TO WHETHER SUCH STOCKHOLDER SHOULD TENDER
SHARES IN THE OFFER.
 
     THE OFFER IS CONDITIONED UPON, AMONG OTHER THINGS, (I) THERE BEING VALIDLY
TENDERED AND NOT WITHDRAWN PRIOR TO THE EXPIRATION DATE (AS DEFINED IN SECTION
1) AT LEAST THAT NUMBER OF SHARES WHICH, TOGETHER WITH THE OPTION SHARES (AS
DEFINED HEREIN) WHICH ARE SUBJECT TO THE STOCKHOLDERS AGREEMENT (AS DEFINED
HEREIN), WOULD REPRESENT IN EXCESS OF 50% OF ALL OUTSTANDING SHARES DETERMINED
ON A FULLY DILUTED BASIS ON THE DATE OF PURCHASE (THE "MINIMUM CONDITION") AND
(II) ANY WAITING PERIOD UNDER THE HART-SCOTT-RODINO ANTITRUST IMPROVEMENTS ACT
OF 1976, AS AMENDED, AND THE REGULATIONS THEREUNDER (THE "HSR ACT") APPLICABLE
TO THE PURCHASE OF SHARES PURSUANT TO THE OFFER HAVING EXPIRED OR BEEN
TERMINATED (THE "HSR CONDITION"). THE PURCHASER RESERVES THE RIGHT (SUBJECT TO
THE APPLICABLE RULES AND REGULATIONS OF THE SECURITIES AND EXCHANGE COMMISSION
(THE "COMMISSION")), WHICH IT PRESENTLY HAS NO INTENTION OF EXERCISING (AND
WHICH IT MAY NOT EXERCISE WITHOUT THE COMPANY'S WRITTEN CONSENT), TO WAIVE OR
REDUCE THE MINIMUM CONDITION AND TO ELECT TO PURCHASE, PURSUANT TO THE OFFER,
LESS THAN THE MINIMUM NUMBER OF SHARES WHICH WOULD OTHERWISE BE REQUIRED TO
SATISFY THE MINIMUM CONDITION. SEE SECTIONS 1 AND 14.
<PAGE>   4
 
     The Company has informed the Purchaser that, as of August 27, 1997, there
were 10,881,210 Shares issued and outstanding and 1,071,388 Shares reserved for
issuance upon the exercise of outstanding options to purchase Shares ("Stock
Options"). As described below, there are 910,928 Option Shares (as defined
below) which are subject to the Stockholders Agreement. Accordingly, based on
the foregoing assumptions, the Minimum Condition will be satisfied if at least
5,065,372 Shares, or approximately 46.6% of the outstanding Shares as of August
27, 1997 are validly tendered and not withdrawn prior to the Expiration Date. If
the Minimum Condition is satisfied and the Purchaser accepts for payment Shares
tendered pursuant to the Offer, the Purchaser will be able to elect a majority
of the members of the Company's Board of Directors and to effect the Merger
without the affirmative vote of any other stockholder of the Company.
 
THE MERGER
 
     Pursuant to the Merger Agreement, following the consummation of the Offer
and the satisfaction or waiver of certain conditions, the Purchaser will be
merged with and into the Company (the "Merger"), with the Company surviving the
Merger (as such, the "Surviving Corporation") as a wholly owned subsidiary of
Parent. In the Merger, each outstanding Share (other than Shares owned by the
Company, any subsidiary of the Company, Parent, the Purchaser or any other
subsidiary of Parent or by stockholders, if any, who are entitled to and who
properly exercise appraisal rights under Delaware law) will be converted into
the right to receive from the Surviving Corporation the Offer Price in cash,
without interest (the "Merger Consideration"). The Merger is subject to a number
of conditions, including approval by stockholders of the Company, if such
approval is required by applicable law. See Section 12.
 
THE RIGHTS
 
     The Board of Directors of the Company has made all determinations and taken
all actions that are required so that the Rights will not become exercisable as
a result of the Offer and the Merger.
 
THE STOCKHOLDERS AGREEMENT
 
     In connection with the execution of the Merger Agreement, the Purchaser and
Parent entered into two separate but substantially identical Stockholders
Agreements, each dated as of August 22, 1997 (collectively, the "Stockholders
Agreement"), with Anasco GmbH ("Anasco") on the one hand, and each of Joseph F.
Alibrandi, Noel L. Buterbaugh, Thomas R. Winkler, Philip L. Rohrer Jr., Leif
Olsen and F. Dudley Staples Jr. on the other (collectively, the "Selling
Stockholders"). Anasco is the Company's largest stockholder and the other
Selling Stockholders are directors and officers of the Company. Pursuant to the
Stockholders Agreement, the Selling Stockholders have agreed to tender their
shares in the Offer and have granted to the Purchaser an irrevocable option,
exercisable upon the occurrence of certain trigger events, to purchase the
Shares owned of record by the Selling Stockholders (including, in some cases
Shares underlying Stock Options (such Shares, the "Option Shares")) at a price
per Share equal to the Offer Price, in cash. Pursuant to the Stockholders
Agreement, the Selling Stockholders have also agreed that, among other things,
until the applicable termination date set forth in the Stockholders Agreement,
such Selling Stockholders will not transfer the Shares subject to the
Stockholders Agreement and will vote such Shares in favor of the Merger and
against certain competing transactions. An aggregate of 3,716,443 Shares are
subject to the Stockholders Agreement including 910,928 Option Shares,
representing 31.1% of the Shares that, as of August 27, 1997, were issued and
outstanding on a fully diluted basis according to the Company.
 
INTENTION OF COMPANY OFFICERS AND DIRECTORS TO TENDER
 
     The Company has informed Parent and the Purchaser that, to the best
knowledge of the Company, all of the Company's officers and directors currently
intend to tender all Shares owned by them into the Offer. As described above,
certain of the Company's officers and directors are required under the
Stockholders Agreement to tender all Shares owned by them into the Offer.
 
     The Merger Agreement and the Stockholders Agreement are more fully
described in Section 12.
 
     Certain Federal income tax consequences of the sale of Shares pursuant to
the Offer and the conversion of Shares pursuant to the Merger are described in
Section 5.
 
                                        2
<PAGE>   5
 
     THIS OFFER TO PURCHASE AND THE RELATED LETTER OF TRANSMITTAL CONTAIN
IMPORTANT INFORMATION THAT SHOULD BE READ BEFORE ANY DECISION IS MADE WITH
RESPECT TO THE OFFER.
 
                                THE TENDER OFFER
 
1.  TERMS OF THE OFFER
 
     Upon the terms and subject to the conditions of the Offer, the Purchaser
will accept for payment and pay for all Shares validly tendered prior to the
Expiration Date and not theretofore withdrawn in accordance with Section 3. The
term "Expiration Date" means 12:00 midnight, New York City time, on Thursday,
September 25, 1997, unless and until the Purchaser shall have extended the
period of time during which the Offer is open, in which event the term
"Expiration Date" shall mean the latest time and date at which the Offer, as so
extended by the Purchaser, will expire.
 
     In addition, the Purchaser has agreed in the Merger Agreement that it will
not, without the written consent of the Company, (a) reduce the number of Shares
subject to the Offer, (b) reduce the Offer Price, (c) add to the conditions set
forth in Section 14 (the "Offer Conditions"), (d) modify the form of
consideration payable in the Offer, (e) increase the Minimum Condition or (f)
amend the Offer Conditions or any other term of the Offer in any manner
materially adverse to the holders of Shares.
 
     Subject to the terms of the Merger Agreement and the applicable rules and
regulations of the Commission, the Purchaser reserves the right (but shall not
be obligated), at any time and from time to time, and regardless of whether or
not any of the events or facts set forth in Section 14 hereof shall have
occurred, (a) to extend the period of time during which the Offer is open, and
thereby delay acceptance for payment of and the payment for any Shares, by
giving oral or written notice of such extension to the Depositary and (b) to
amend the Offer in any other respect by giving oral or written notice of such
amendment to the Depositary. UNDER NO CIRCUMSTANCES WILL INTEREST BE PAID ON THE
PURCHASE PRICE FOR TENDERED SHARES, WHETHER OR NOT THE PURCHASER EXERCISES ITS
RIGHT TO EXTEND THE OFFER.
 
     If by 12:00 midnight, New York City time, on Thursday, September 25, 1997
(or any date or time then set as the Expiration Date), any or all of the Offer
Conditions have not been satisfied or waived, the Purchaser reserves the right
(but shall not be obligated), subject to the terms and conditions contained in
the Merger Agreement and to the applicable rules and regulations of the
Commission, (a) to terminate the Offer and not accept for payment or pay for any
Shares and return all tendered Shares to tendering stockholders, (b) to waive
all the unsatisfied conditions and accept for payment and pay for all Shares
validly tendered prior to the Expiration Date and not theretofore withdrawn, (c)
to extend the Offer and, subject to the right of stockholders to withdraw Shares
until the Expiration Date, retain the Shares that have been tendered during the
period or periods for which the Offer is extended or (d) to amend the Offer.
 
     There can be no assurance that the Purchaser will exercise its right to
extend the Offer. Any extension, waiver, amendment or termination will be
followed as promptly as practicable by a public announcement of such event. In
the case of an extension, Rule 14e-l(d) under the Exchange Act, requires that
the announcement be issued no later than 9:00 a.m., New York City time, on the
next business day after the previously scheduled Expiration Date in accordance
with the public announcement requirements of Rule 14d-4(c) under the Exchange
Act. Subject to applicable law (including Rules 14d-4(c) and 14d-6(d) under the
Exchange Act, which require that any material change in the information
published, sent or given to stockholders in connection with the Offer be
promptly disseminated to stockholders in a manner reasonably designed to inform
stockholders of such change) and without limiting the manner in which the
Purchaser may choose to make any public announcement, the Purchaser will not
have any obligation to publish, advertise or otherwise communicate any such
public announcement other than by making a release to the Dow Jones News
Service.
 
     If the Purchaser extends the Offer or if the Purchaser is delayed in its
acceptance for payment of or payment (whether before or after its acceptance for
payment of Shares) for Shares or it is unable to pay for
 
                                        3
<PAGE>   6
 
Shares pursuant to the Offer for any reason, then, without prejudice to the
Purchaser's rights under the Offer, the Depositary may retain tendered Shares on
behalf of the Purchaser, and such Shares may not be withdrawn except to the
extent tendering stockholders are entitled to withdrawal rights as described in
Section 3. However, the ability of the Purchaser to delay the payment for Shares
that the Purchaser has accepted for payment is limited by Rule 14e-l(c) under
the Exchange Act, which requires that a bidder pay the consideration offered or
return the securities deposited by or on behalf of holders of securities
promptly after the termination or withdrawal of such bidder's offer, and by the
terms of the Merger Agreement, which requires that the Purchaser pay for Shares
accepted for payment as soon as legally permissible.
 
     If the Purchaser makes a material change in the terms of the Offer or the
information concerning the Offer or waives a material condition of the Offer
(including a waiver of the Minimum Condition), the Purchaser will disseminate
additional tender offer materials and extend the Offer to the extent required by
Rules 14d-4(c), 14d-6(d) and 14e-1 under the Exchange Act. The minimum period
during which an offer must remain open following material changes in the terms
of the offer or information concerning the offer, other than a change in price
or a change in the percentage of securities sought, will depend upon the facts
and circumstances then existing, including the relative materiality of the
changed terms or information. With respect to a change in price or a change in
the percentage of securities sought, a minimum period of 10 business days is
generally required to allow for adequate dissemination to stockholders.
 
     Consummation of the Offer is conditioned upon satisfaction of the Minimum
Condition, the HSR Condition and the other Offer Conditions. Subject to the
terms and conditions contained in the Merger Agreement, the Purchaser reserves
the right (but shall not be obligated) to waive any or all such conditions.
However, if the Purchaser waives or amends the Minimum Condition during the last
five business days during which the Offer is open, the Purchaser will be
required to extend the Expiration Date so that the Offer will remain open for at
least five business days after the announcement of such waiver or amendment is
first published, sent or given to holders of Shares and may also be required to
extend the Offer if other conditions are waived, depending upon the materiality
of the waiver.
 
     The Company has provided the Purchaser with the Company's stockholder lists
and security position listings for the purpose of disseminating the Offer to
holders of Shares. This Offer to Purchase, the related Letter of Transmittal and
other relevant materials will be mailed by the Purchaser to record holders of
Shares, and will be furnished to brokers, dealers, banks, trust companies and
similar persons whose names, or the names of whose nominees, appear on the
stockholder lists, or, if applicable, who are listed as participants in a
clearing agency's security position listing, for subsequent transmittal to
beneficial owners of Shares.
 
2.  PROCEDURE FOR TENDERING SHARES
 
     Valid Tender.  For a stockholder validly to tender Shares pursuant to the
Offer, either (a) a Letter of Transmittal (or facsimile thereof), properly
completed and duly executed, together with any required signature guarantees,
or, in the case of a book-entry transfer, an Agent's Message (as defined below),
and any other required documents, must be received by the Depositary at one of
its addresses set forth on the back cover of this Offer to Purchase prior to the
Expiration Date and either certificates for tendered Shares must be received by
the Depositary at one of such addresses or such Shares must be delivered
pursuant to the procedures for book-entry transfer set forth below (and a
Book-Entry Confirmation (as defined below) received by the Depositary), in each
case prior to the Expiration Date, or (b) the tendering stockholder must comply
with the guaranteed delivery procedures set forth below.
 
     The Depositary will establish accounts with respect to the Shares at The
Depository Trust Company, the Midwest Securities Trust Company and the
Philadelphia Depository Trust Company (the "Book-Entry Transfer Facilities") for
purposes of the Offer within two business days after the date of this Offer to
Purchase. Any financial institution that is a participant in any of the
Book-Entry Transfer Facilities' systems may make book-entry delivery of Shares
by causing a Book-Entry Transfer Facility to transfer such Shares into the
Depositary's account in accordance with such Book-Entry Transfer Facility's
procedures for such transfer. However, although delivery of Shares may be
effected through bookentry transfer into the Depositary's account at a
Book-Entry Transfer Facility, the Letter of Transmittal (or facsimile thereof),
 
                                        4
<PAGE>   7
 
properly completed and duly executed, with any required signature guarantees, or
an Agent's Message, and any other required documents, must, in any case, be
transmitted to, and received by, the Depositary at one of its addresses set
forth on the back cover of this Offer to Purchase prior to the Expiration Date,
or the tendering stockholder must comply with the guaranteed delivery procedures
described below. The confirmation of a book-entry transfer of Shares into the
Depositary's account at a Book-Entry Transfer Facility as described above is
referred to herein as a "Book-Entry Confirmation". DELIVERY OF DOCUMENTS TO A
BOOK-ENTRY TRANSFER FACILITY IN ACCORDANCE WITH SUCH BOOK-ENTRY TRANSFER
FACILITY'S PROCEDURES DOES NOT CONSTITUTE DELIVERY TO THE DEPOSITARY.
 
     The term "Agent's Message" means a message transmitted by a Book-Entry
Transfer Facility to, and received by, the Depositary and forming a part of a
Book-Entry Confirmation, which states that such Book-Entry Transfer Facility has
received an express acknowledgment from the participant in such Book-Entry
Transfer Facility tendering the Shares that such participant has received and
agrees to be bound by the terms of the Letter of Transmittal and that the
Purchaser may enforce such agreement against the participant.
 
     THE METHOD OF DELIVERY OF SHARES, THE LETTER OF TRANSMITTAL AND ALL OTHER
REQUIRED DOCUMENTS, INCLUDING DELIVERY THROUGH ANY BOOK-ENTRY TRANSFER FACILITY,
IS AT THE ELECTION AND RISK OF THE TENDERING STOCKHOLDER. SHARES WILL BE DEEMED
DELIVERED ONLY WHEN ACTUALLY RECEIVED BY THE DEPOSITARY (INCLUDING, IN THE CASE
OF A BOOK-ENTRY TRANSFER, BY BOOK-ENTRY CONFIRMATION). IF DELIVERY IS BY MAIL,
REGISTERED MAIL WITH RETURN RECEIPT REQUESTED, PROPERLY INSURED, IS RECOMMENDED.
IN ALL CASES, SUFFICIENT TIME SHOULD BE ALLOWED TO ENSURE TIMELY DELIVERY.
 
     Signature Guarantees.  No signature guarantee is required on the Letter of
Transmittal (a) if the Letter of Transmittal is signed by the registered
holder(s) (which term, for purposes of this Section, includes any participant in
any of the Book-Entry Transfer Facilities' systems whose name appears on a
security position listing as the owner of the Shares) of Shares tendered
therewith and such registered holder has not completed either the box entitled
"Special Delivery Instructions" or the box entitled "Special Payment
Instructions" on the Letter of Transmittal or (b) if such Shares are tendered
for the account of a financial institution (including most commercial banks,
savings and loan associations and brokerage houses) that is a participant in the
Security Transfer Agents Medallion Program, the New York Stock Exchange
Medallion Signature Guarantee Program or the Stock Exchange Medallion Program
(such participant, an "Eligible Institution"). In all other cases, all
signatures on the Letter of Transmittal must be guaranteed by an Eligible
Institution. See Instructions 1 and 5 to the Letter of Transmittal. If the
certificates for Shares are registered in the name of a person other than the
signer of the Letter of Transmittal, or if payment is to be made or certificates
for Shares not tendered or not accepted for payment are to be returned to a
person other than the registered holder of the certificates surrendered, the
tendered certificates must be endorsed or accompanied by appropriate stock
powers, in either case signed exactly as the name or names of the registered
holders or owners appear on the certificates, with the signatures on the
certificates or stock powers guaranteed as aforesaid. See Instructions 1 and 5
to the Letter of Transmittal.
 
     Guaranteed Delivery.  If a stockholder desires to tender Shares pursuant to
the Offer and such stockholder's certificates for Shares are not immediately
available or the procedure for book-entry transfer cannot be completed on a
timely basis or time will not permit all required documents to reach the
Depositary prior to the Expiration Date, such stockholder's tender may be
effected if all the following conditions are met:
 
          (i) such tender is made by or through an Eligible Institution;
 
          (ii) a properly completed and duly executed Notice of Guaranteed
     Delivery, substantially in the form provided by the Purchaser, is received
     by the Depositary, as provided below, prior to the Expiration Date; and
 
          (iii) the certificates for all tendered Shares, in proper form for
     transfer (or a Book-Entry Confirmation with respect to all such Shares),
     together with a Letter of Transmittal (or facsimile thereof), properly
     completed and duly executed, with any required signature guarantees, or, in
     the case of a book-entry transfer, an Agent's Message, and any other
     required documents are received by the Depositary within three trading days
     after the date of execution of such Notice of Guaranteed Delivery. A
 
                                        5
<PAGE>   8
 
     "trading day" is any day on which the New York Stock Exchange, Inc. (the
     "NYSE") is open for business.
 
     The Notice of Guaranteed Delivery may be delivered by hand to the
Depositary or transmitted by telegram, facsimile transmission or mail to the
Depositary and must include a guarantee by an Eligible Institution in the form
set forth in such Notice of Guaranteed Delivery.
 
     Notwithstanding any other provision hereof, payment for Shares accepted for
payment pursuant to the Offer will in all cases be made only after timely
receipt by the Depositary of (a) certificates for (or a timely Book-Entry
Confirmation with respect to) such Shares, (b) a Letter of Transmittal (or
facsimile thereof), properly completed and duly executed, with any required
signature guarantees, or, in the case of a book-entry transfer, an Agent's
Message, and (c) any other documents required by the Letter of Transmittal.
Accordingly, tendering stockholders may be paid at different times depending
upon when certificates for Shares or Book-Entry Confirmations with respect to
Shares are actually received by the Depositary. UNDER NO CIRCUMSTANCES WILL
INTEREST BE PAID ON THE PURCHASE PRICE OF THE SHARES TO BE PAID BY THE
PURCHASER, REGARDLESS OF ANY EXTENSION OF THE OFFER OR ANY DELAY IN MAKING SUCH
PAYMENT.
 
     The valid tender of Shares pursuant to one of the procedures described
above will constitute a binding agreement between the tendering stockholder and
the Purchaser upon the terms and subject to the conditions of the Offer.
 
     Appointment.  By executing a Letter of Transmittal as set forth above, the
tendering stockholder will irrevocably appoint designees of the Purchaser as
such stockholder's attorneys-in-fact and proxies in the manner set forth in the
Letter of Transmittal, each with full power of substitution, to the full extent
of such stockholder's rights with respect to the Shares tendered by such
stockholder and accepted for payment by the Purchaser and with respect to any
and all other Shares or other securities or rights issued or issuable in respect
of such Shares on or after August 22, 1997. All such proxies will be considered
coupled with an interest in the tendered Shares. Such appointment will be
effective when, and only to the extent that, the Purchaser accepts for payment
Shares tendered by such stockholder as provided herein. Upon such appointment,
all prior powers of attorney, proxies and consents given by such stockholder
with respect to such Shares or other securities or rights will, without further
action, be revoked and no subsequent powers of attorney, proxies, consents or
revocations may be given (and, if given, will not be deemed effective). The
designees of the Purchaser will thereby be empowered to exercise all voting and
other rights with respect to such Shares and other securities or rights in
respect of any annual, special or adjourned meeting of the Company's
stockholders, actions by written consent in lieu of any such meeting or
otherwise, as they in their sole discretion deem proper. The Purchaser reserves
the right to require that, in order for Shares to be deemed validly tendered,
immediately upon the Purchaser's acceptance for payment of such Shares, the
Purchaser must be able to exercise full voting, consent and other rights with
respect to such Shares and other securities or rights, including voting at any
meeting of stockholders.
 
     Determination of Validity.  All questions as to the validity, form,
eligibility (including time of receipt) and acceptance of any tender of Shares
will be determined by the Purchaser in its sole discretion, which determination
will be final and binding. The Purchaser reserves the absolute right to reject
any or all tenders determined by it not to be in proper form or the acceptance
for payment of or payment for which may, in the opinion of the Purchaser's
counsel, be unlawful. The Purchaser also reserves the absolute right to waive
any defect or irregularity in the tender of any Shares of any particular
stockholder whether or not similar defects or irregularities are waived in the
case of other stockholders. No tender of Shares will be deemed to have been
validly made until all defects or irregularities relating thereto have been
cured or waived. None of the Purchaser, Parent, the Depositary, the Information
Agent, the Dealer Manager or any other person will be under any duty to give
notification of any defects or irregularities in tenders or incur any liability
for failure to give any such notification. The Purchaser's interpretation of the
terms and conditions of the Offer (including the Letter of Transmittal and the
instructions thereto) will be final and binding.
 
     Backup Withholding.  In order to avoid "backup withholding" of Federal
income tax on payments of cash pursuant to the Offer, a stockholder surrendering
Shares in the Offer must, unless an exemption applies, provide the Depositary
with such stockholder's correct taxpayer identification number ("TIN") on a
 
                                        6
<PAGE>   9
 
Substitute Form W-9 and certify under penalties of perjury that such TIN is
correct and that such stockholder is not subject to backup withholding. If a
stockholder does not provide such stockholder's correct TIN or fails to provide
the certifications described above, the Internal Revenue Service (the "IRS") may
impose a penalty on such stockholder and any payment of cash to such stockholder
pursuant to the Offer may be subject to backup withholding of 31%. All
stockholders surrendering Shares pursuant to the Offer should complete and sign
the main signature form and the Substitute Form W-9 included as part of the
Letter of Transmittal to provide the information and certification necessary to
avoid backup withholding (unless an applicable exemption exists and is proved in
a manner satisfactory to the Purchaser and the Depositary). Certain stockholders
(including, among others, all corporations and certain foreign individuals and
entities) are not subject to backup withholding. Noncorporate foreign
stockholders should complete and sign the main signature form and a Form W-8,
Certificate of Foreign Status, a copy of which may be obtained from the
Depositary, in order to avoid backup withholding. See Instruction 9 to the
Letter of Transmittal.
 
3.  WITHDRAWAL RIGHTS
 
     Except as otherwise provided in this Section 3, tenders of Shares are
irrevocable. Shares tendered pursuant to the Offer may be withdrawn pursuant to
the procedures set forth below at any time prior to the Expiration Date and,
unless theretofore accepted for payment and paid for by the Purchaser pursuant
to the Offer, may also be withdrawn at any time after Monday, October 27, 1997.
 
     For a withdrawal to be effective, a written, telegraphic or facsimile
transmission notice of withdrawal must be timely received by the Depositary at
one of its addresses set forth on the back cover of this Offer to Purchase and
must specify the name of the person having tendered the Shares to be withdrawn,
the number of Shares to be withdrawn and the name of the registered holder of
the Shares to be withdrawn, if different from the name of the person who
tendered the Shares. If certificates for Shares have been delivered or otherwise
identified to the Depositary, then, prior to the physical release of such
certificates, the serial numbers shown on such certificates must be submitted to
the Depositary and, unless such Shares have been tendered by an Eligible
Institution, the signatures on the notice of withdrawal must be guaranteed by an
Eligible Institution. If Shares have been delivered pursuant to the procedure
for book-entry transfer as set forth in Section 2, any notice of withdrawal must
also specify the name and number of the account at the appropriate Book-Entry
Transfer Facility to be credited with the withdrawn Shares and otherwise comply
with such Book-Entry Transfer Facility's procedures. Withdrawals of tenders of
Shares may not be rescinded, and any Shares properly withdrawn will thereafter
be deemed not validly tendered for purposes of the Offer. However, withdrawn
Shares may be retendered by again following one of the procedures described in
Section 2 at any time prior to the Expiration Date.
 
     All questions as to the form and validity (including time of receipt) of
notices of withdrawal will be determined by the Purchaser in its sole
discretion, which determination will be final and binding. None of the
Purchaser, Parent, the Depositary, the Information Agent, the Dealer Manager or
any other person will be under any duty to give notification of any defects or
irregularities in any notice of withdrawal or incur any liability for failure to
give any such notification.
 
4.  ACCEPTANCE FOR PAYMENT AND PAYMENT
 
     Upon the terms and subject to the conditions of the Offer (including, if
the Offer is extended or amended, the terms and conditions of any such extension
or amendment), the Purchaser will accept for payment and will pay for all Shares
validly tendered prior to the Expiration Date and not properly withdrawn in
accordance with Section 3 promptly after the Expiration Date. All determinations
concerning the satisfaction of such terms and conditions will be within the
Purchaser's discretion, which determinations will be final and binding. See
Sections 1 and 14. The Purchaser expressly reserves the right to delay
acceptance for payment of or payment for Shares in order to comply in whole or
in part with any applicable law, including, without limitation, the HSR Act. Any
such delays will be effected in compliance with Rule 14e-l(c) under the Exchange
Act (relating to a bidder's obligation to pay for or return tendered securities
promptly after the termination or withdrawal of such bidder's offer).
 
                                        7
<PAGE>   10
 
     The Company expects to file soon their Premerger Notification and Report
Forms with respect to the Offer under the HSR Act. The waiting period under the
HSR Act with respect to the Offer will expire at 11:59 p.m., New York City time,
on the 15th day after the date the Company's form is filed unless early
termination of the waiting period is granted. However, the Antitrust Division of
the Department of Justice (the "Antitrust Division") or the Federal Trade
Commission (the "FTC") may extend the waiting period by requesting additional
information or documentary material from the Company. If such a request is made,
such waiting period will expire at 11:59 p.m., New York City time, on the 10th
day after substantial compliance by the Company with such request. Thereafter,
the waiting period may only be extended by court order. The waiting period under
the HSR Act may be terminated prior to its expiration by the FTC and the
Antitrust Division. Purchaser will request early termination of the waiting
period, although there can be no assurance that this request will be granted.
Pursuant to the Merger Agreement, Purchaser may, but need not, extend the Offer
until the applicable waiting period under the HSR Act shall have expired or been
terminated. See Section 15 hereof for additional information concerning the HSR
Act and the applicability of the antitrust laws to the Offer.
 
     In all cases, payment for Shares accepted for payment pursuant to the Offer
will be made only after timely receipt by the Depositary of (a) certificates for
(or a timely Book-Entry Confirmation with respect to) such Shares, (b) a Letter
of Transmittal (or facsimile thereof), properly completed and duly executed,
with any required signature guarantees, or, in the case of a book-entry
transfer, an Agent's Message, and (c) any other documents required by the Letter
of Transmittal. The per Share consideration paid to any stockholder pursuant to
the Offer will be the highest per Share consideration paid to any other
stockholder pursuant to the Offer.
 
     For purposes of the Offer, the Purchaser will be deemed to have accepted
for payment, and thereby purchased, Shares properly tendered to the Purchaser
and not withdrawn as, if and when the Purchaser gives oral or written notice to
the Depositary of the Purchaser's acceptance for payment of such Shares. Payment
for Shares accepted for payment pursuant to the Offer will be made by deposit of
the purchase price therefor with the Depositary, which will act as agent for
tendering stockholders for the purpose of receiving payment from the Purchaser
and transmitting payment to tendering stockholders. UNDER NO CIRCUMSTANCES WILL
INTEREST BE PAID ON THE PURCHASE PRICE OF THE SHARES TO BE PAID BY THE
PURCHASER, REGARDLESS OF ANY EXTENSION OF THE OFFER OR ANY DELAY IN MAKING SUCH
PAYMENT.
 
     If the Purchaser is delayed in its acceptance for payment of or payment for
Shares or is unable to accept for payment or pay for Shares pursuant to the
Offer for any reason, then, without prejudice to the Purchaser's rights under
the Offer (but subject to compliance with Rule 14e-l(c) under the Exchange Act,
which requires that a tender offeror pay the consideration offered or return the
tendered securities promptly after termination or withdrawal of a tender offer,
and the terms of the Merger Agreement), the Depositary may, nevertheless, on
behalf of the Purchaser, retain tendered Shares, and such Shares may not be
withdrawn except to the extent tendering stockholders are entitled to exercise,
and duly exercise, withdrawal rights as described in Section 3.
 
     If any tendered Shares are not purchased pursuant to the Offer for any
reason, certificates for any such Shares will be returned, without expense to
the tendering stockholder (or, in the case of Shares delivered by book-entry
transfer of such Shares into the Depositary's account at a Book-Entry Transfer
Facility pursuant to the procedure set forth in Section 2, such Shares will be
credited to an account maintained at the appropriate Book-Entry Transfer
Facility), as promptly as practicable after the expiration or termination of the
Offer.
 
     The Purchaser reserves the right to transfer or assign, in whole or from
time to time in part, to Parent, or to one or more direct or indirect wholly
owned subsidiaries of Parent, the right to purchase Shares tendered pursuant to
the Offer, but any such transfer or assignment will not relieve the Purchaser of
its obligations under the Offer and will in no way prejudice the rights of
tendering stockholders to receive payment for Shares validly tendered and
accepted for payment pursuant to the Offer.
 
                                        8
<PAGE>   11
 
5.  CERTAIN FEDERAL INCOME TAX CONSEQUENCES
 
     The receipt of cash in exchange for Shares pursuant to the Offer or the
Merger (and the receipt of cash by a stockholder that exercises appraisal rights
in connection with the Merger under Delaware law) will be a taxable transaction
for Federal income tax purposes under the Internal Revenue Code of 1986, as
amended (the "Code"), and may also be a taxable transaction under applicable
state, local or foreign income or other tax laws. Generally, for Federal income
tax purposes, a tendering stockholder will recognize gain or loss equal to the
difference between the amount of cash received by the stockholder pursuant to
the Offer or the Merger (other than amounts received pursuant to a stockholder's
exercise of appraisal rights that are denominated as interest, which amounts
would be taxable as ordinary income) and the aggregate tax basis in the Shares
tendered by the stockholder and purchased pursuant to the Offer or converted in
the Merger, as the case may be. Gain or loss will be calculated separately for
each block of Shares tendered and purchased pursuant to the Offer or converted
in the Merger, as the case may be.
 
     If Shares are held by a stockholder as capital assets, gain or loss
recognized by the stockholder will be capital gain or loss. Such capital gain or
loss will be long-term if such stockholder's holding period for the Shares
exceeds one year and short-term in all other cases. Individual stockholders will
generally be taxed on capital gain at a maximum Federal marginal rate of 20% if
such stockholder's holding period for the Shares exceeds eighteen months, 28% if
the holding period exceeds one year (but does not exceed eighteen months), and
39.6% if the holding period does not exceed one year. Corporate stockholders
will generally be taxed at a maximum Federal marginal rate of 35% with respect
to long-term capital gains. The ability of a stockholder (whether corporate or
individual) to use capital losses to offset ordinary income is limited.
 
     A stockholder that tenders Shares may be subject to 31% backup withholding
unless the stockholder provides its TIN and certifies that such number is
correct or properly certifies that it is awaiting a TIN, or unless an exemption
applies. Exemptions are available for stockholders that are corporations and for
certain foreign individuals and entities. A stockholder that does not furnish a
required TIN may be subject to a penalty imposed by the IRS. See "Backup
Withholding" under Section 2.
 
     If backup withholding applies to a stockholder, the Depositary is required
to withhold 31% from payments to such stockholder. Backup withholding is not an
additional tax. Rather, the amount of the backup withholding can be credited
against the Federal income tax liability of the person subject to the backup
withholding, provided that the required information is given to the IRS. If
backup withholding results in an overpayment of tax, a refund can be obtained by
the stockholder upon filing an income tax return.
 
     THE FOREGOING DISCUSSION MAY NOT BE APPLICABLE WITH RESPECT TO SHARES
RECEIVED PURSUANT TO THE EXERCISE OF EMPLOYEE STOCK OPTIONS OR OTHERWISE AS
COMPENSATION OR WITH RESPECT TO HOLDERS OF SHARES WHO ARE SUBJECT TO SPECIAL TAX
TREATMENT UNDER THE CODE, SUCH AS NON-U.S. PERSONS, LIFE INSURANCE COMPANIES,
TAX-EXEMPT ORGANIZATIONS AND FINANCIAL INSTITUTIONS, AND MAY NOT APPLY TO OTHER
HOLDERS OF SHARES IN LIGHT OF THEIR INDIVIDUAL CIRCUMSTANCES. STOCKHOLDERS ARE
URGED TO CONSULT THEIR OWN TAX ADVISORS TO DETERMINE THE PARTICULAR TAX
CONSEQUENCES TO THEM (INCLUDING THE APPLICATION AND EFFECT OF ANY STATE, LOCAL
OR FOREIGN INCOME AND OTHER TAX LAWS) OF THE OFFER AND THE MERGER.
 
6.  PRICE RANGE OF THE SHARES
 
     The Shares are traded on the NYSE under the symbol BWI. The following table
sets forth, for each of the periods indicated, the high and low sales prices per
Share as reported by the NYSE and the Dow Jones News Retrieval Service.
 
                                        9
<PAGE>   12
 
                               BIOWHITTAKER, INC.
 
<TABLE>
<CAPTION>
                                                                                SALES PRICES
                                                                               --------------
                                                                               HIGH       LOW
                                                                               ----       ---
<S>                                                                            <C>        <C>
PERIOD ENDING
1995
  First Quarter..............................................................  $ 8  1/8   $ 6 1/4
  Second Quarter.............................................................    8  1/2     7 1/8
  Third Quarter..............................................................    8          7
  Fourth Quarter.............................................................    8  1/8     6 3/8
1996
  First Quarter..............................................................    8  1/2     7 1/4
  Second Quarter.............................................................    8  7/8     7 3/4
  Third Quarter..............................................................    8  3/4     6 1/2
  Fourth Quarter.............................................................    8  3/8     6 5/8
1997
  First Quarter..............................................................    9  1/2     7 7/8
  Second Quarter.............................................................   11 7/16     7 3/4
  Third Quarter (through August 27, 1997)....................................   11 9/16    10 1/8
</TABLE>
 
     On August 22, 1997, the last full trading day before the public
announcement of the execution of the Merger Agreement, the last reported sales
price of the Shares on the NYSE was $10 3/8 per Share. On August 27, 1997, the
last full trading day before commencement of the Offer, the last reported sales
price of the Shares on the NYSE was $11 1/2 per Share. STOCKHOLDERS ARE URGED TO
OBTAIN CURRENT MARKET QUOTATIONS FOR THE SHARES.
 
7.  PURPOSE OF THE OFFER; PLANS FOR THE COMPANY; EFFECT OF THE OFFER ON THE
    MARKET FOR THE SHARES; STOCK QUOTATION; EXCHANGE ACT REGISTRATION; MARGIN
    REGULATIONS
 
     Purpose.  The purpose of the Offer is to enable Parent to acquire control
of, and the entire equity interest in, the Company. The Offer, as the first step
in the acquisition of the Company, is intended to facilitate the acquisition of
all the Shares and to provide the stockholders of the Company with cash
consideration of $11.625 per Share for all of their shares at the earliest
possible time. The purpose of the Merger is to acquire all Shares not tendered
and purchased pursuant to the Offer.
 
     Plans for the Company.  It is expected that after consummation of the
Offer, no change will be made in the executive officers of the Company, but that
Parent will designate certain additional directors of the Company. Upon request
by Parent, the Company shall use its best efforts promptly, at the Company's
election, either to increase the size of its board or to secure the resignation
of such number of directors as is necessary to enable Parent's designees to be
elected to its board, and to cause Parent's designees to be so elected. Parent
has designated Peter Tracey, Peter E. Thauer, Douglas H. MacMillan, Ronald
Pizzo, Salvatore J. Guccione and Mary Fletcher to fill such vacancies. After the
Offer has been consummated, subject to the conditions set forth in the Merger
Agreement, it is anticipated that the Merger Agreement will be submitted to the
stockholders of the Company for approval. In the Merger Agreement, Parent and
the Purchaser have agreed to vote or cause to be voted all Shares owned by them
in favor of approval and adoption of the Merger Agreement. If after consummation
of the Offer the Purchaser holds 90% or more of the outstanding Shares, the
Purchaser intends to effect a "short-term merger" under the DGCL without a
meeting of, or action by, the stockholders of the Company.
 
     Market for the Shares.  The purchase of Shares pursuant to the Offer will
reduce the number of holders of Shares and the number of Shares that might
otherwise trade publicly and could adversely affect the liquidity and market
value of the remaining Shares held by the public.
 
                                       10
<PAGE>   13
 
     Stock Quotation.  Depending upon the number of Shares purchased pursuant to
the Offer, the Shares may no longer meet the requirements of the NYSE for
continued listing. According to the NYSE's published guidelines, the NYSE would
consider delisting the Shares if, among other things, the number of record
holders of at least 100 Shares were to fall below 1,200, the number of publicly
held Shares (exclusive of management or other concentrated holdings) were to
fall below 600,000 or the aggregate market value of publicly held Shares were to
not exceed $5 million. According to the Company, as of August 27, 1997, there
were 10,881,210 Shares outstanding. If, as a result of the purchase of Shares
pursuant to the Offer or otherwise, the Shares no longer meet the requirements
of the NYSE for continued listing and the Shares are no longer listed, the
market for Shares could be adversely affected.
 
     If the NYSE was to delist the Shares, it is possible that the Shares would
continue to trade on other securities exchanges or in the over-the-counter
market and that price quotations would be reported by such exchanges or through
the Nasdaq Stock Market or other sources. The extent of the public market for
the Shares and the availability of such quotations would, however, depend upon
the number of holders of Shares remaining at such time, the interests in
maintaining a market in Shares on the part of securities firms, the possible
termination of registration of the Shares under the Exchange Act, as described
below, and other factors.
 
     Exchange Act Registration.  The Shares are currently registered under the
Exchange Act. Registration of the Shares under the Exchange Act may be
terminated upon application of the Company to the Commission if the Shares are
neither listed on a national securities exchange nor held by 300 or more holders
of record. Termination of registration of the Shares under the Exchange Act
would substantially reduce the information required to be furnished by the
Company to its stockholders and to the Commission and would make certain
provisions of the Exchange Act no longer applicable to the Company, such as the
short-swing profit recovery provisions of Section 16(b) of the Exchange Act, the
requirement of furnishing a proxy statement pursuant to Section 14(a) of the
Exchange Act in connection with stockholders' meetings and the related
requirement of furnishing an annual report to stockholders and the requirements
of Rule 13e-3 under the Exchange Act with respect to "going private"
transactions. Furthermore, the ability of "affiliates" of the Company and
persons holding "restricted securities" of the Company to dispose of such
securities pursuant to Rule 144 or 144A promulgated under the Securities Act of
1933 may be impaired or eliminated. The Purchaser intends to seek to cause the
Company to apply for termination of registration of the Shares under the
Exchange Act as soon after the completion of the Offer as the requirements for
such termination are met.
 
     If registration of the Shares is not terminated prior to the Merger, then
the Shares will be delisted from all stock exchanges and the registration of the
Shares under the Exchange Act will be terminated following the consummation of
the Merger.
 
     Margin Regulations.  The Shares are currently "margin securities" under the
regulations of the Board of Governors of the Federal Reserve System (the
"Federal Reserve Board"), which has the effect, among other things, of allowing
brokers to extend credit on the collateral of the Shares. Depending upon factors
similar to those described above regarding listing and market quotations, it is
possible that, following the Offer, the Shares would no longer constitute
"margin securities" for the purposes of the margin regulations of the Federal
Reserve Board and therefore could no longer be used as collateral for loans made
by brokers.
 
8.  CERTAIN INFORMATION CONCERNING THE COMPANY
 
     The Company is a Delaware corporation with its principal offices at 8830
Biggs Ford Road, Walkersville, Maryland 21793. The Company is a successor to a
Florida corporation founded in 1947. The Company was acquired by Whittaker
Corporation ("Whittaker") in 1969 and was reincorporated in Delaware in 1991.
Also in 1991, Whittaker distributed all of its interest in the Company, which
then represented 80.1% of the Common Stock of the Company, to its stockholders.
 
     The Company is primarily engaged in the development, manufacture, and
marketing of cell culture and endotoxin detection products. The Company also
manufactures and sells a proprietary line of products used to diagnose allergies
and certain other clinical diagnostic testing products.
 
                                       11
<PAGE>   14
 
     Set forth below is certain selected consolidated financial information with
respect to the Company and its subsidiaries excerpted from the information
contained in the Company's Annual Report on Form 10-K for the fiscal year ended
October 31, 1996 (the "Company 1996 10-K"), and the Company's Quarterly Report
on Form 10-Q for the six-month period ended April 30, 1997 (the "Company 1997
10-Q"). More comprehensive financial information is included in the Company 1996
10-K, the Company 1997 10-Q and other documents filed by the Company with the
Commission, and the following summary is qualified in its entirety by reference
to the Company 1996 10-K, the Company 1997 10-Q and such other documents and all
the financial information (including any related notes) contained therein. The
Company 1996 10-K, the Company 1997 10-Q and such other documents should be
available for inspection and copies thereof should be obtainable in the manner
set forth below under "Available Information".
 
                               BIOWHITTAKER, INC.
 
                  SELECTED CONSOLIDATED FINANCIAL INFORMATION
                (IN THOUSANDS, EXCEPT PER SHARE AND SHARE DATA)
 
<TABLE>
<CAPTION>
                                                                                 SIX MONTHS ENDED
                                                     YEARS ENDED OCTOBER 31,         APRIL 30,
                                                   ---------------------------   -----------------
                                                    1996      1995      1994      1997      1996
                                                   -------   -------   -------   -------   -------
                                                                                    (UNAUDITED)
<S>                                                <C>       <C>       <C>       <C>       <C>
Consolidated Statements of Income:
  Sales..........................................  $51,459   $55,797   $54,651   $27,932   $25,471
  Cost and expenses..............................   43,330    47,249    46,815    23,360    21,930
  Net income.....................................      833     6,986     3,534     2,967      (592)
  Net income per share(1)........................     0.08      0.64      0.32      0.27     (0.05)
Consolidated Balance Sheets:(2)
  Total current assets...........................  $33,477   $39,056   $30,556   $36,553   $34,372
  Total assets...................................   61,155    59,801    60,248    64,602    64,091
  Total current liabilities......................   11,252    10,175    12,620    11,780    14,072
  Total liabilities..............................   14,364    13,843    21,127    14,835    18,729
  Total stockholders' equity.....................   46,791    45,958    39,121    49,767    45,362
</TABLE>
 
- ---------------
(1) The per Share information was on the basis of 11,042,000, 10,971,000,
    10,895,000, 10,920,000, and 10,759,000 Shares issued and outstanding as of
    October 31, 1994, October 31, 1995, October 31, 1996, April 30, 1997 and
    April 30, 1996, respectively. As of the date hereof, Parent and the
    Purchaser understand from the Company that there are 10,881,210 Shares
    issued and outstanding and 1,071,388 Shares reserved for issuance upon the
    exercise of outstanding options to purchase Shares.
 
(2) As of end of period.
 
     Certain Company Projections.  During the course of discussions between
Parent and the Company, the Company provided Parent with certain non-public
business and financial information about the Company. This information included
forecasts (prepared during the spring of 1997) for the fiscal years ending
October 1997 and 1998 of (i) net sales of $56.7 million and $67.6 million,
respectively, (ii) earnings before interest and taxes of $10.0 million and $12.5
million, respectively, (iii) net earnings of $6.3 million and $8.1 million,
respectively, and (iv) net earnings per share of $0.60 and $0.73, respectively.
These forecasts have not been updated since July, 1997.
 
     The projections do not give effect to the Offer or the Merger and were
predicated on certain assumptions, including the following: (i) the assumption
that the Company would continue as an independent, "stand alone" enterprise
during the entire period covered by the projections; (ii) assumptions relating
to anticipated levels of sales, including the introduction and market
penetration of various new and anticipated products, the expected number and
terms of new contracts and the renewal or termination of existing contracts,
anticipated selling prices for the Company's products, and access to markets and
distribution channels; (iii) assumptions
 
                                       12
<PAGE>   15
 
relating to the Company's costs and expenses, including the availability and
cost of raw materials, levels of expenditures on capital items, selling, general
and administrative expenses and for research and development activities, and
effective tax rates; (iv) assumptions relating to the impact of governmental
regulation on the Company, including the timing of approval of the Company's
products and the continuation of current governmental regulation without changes
adverse to the Company's business; and (v) general economic factors such as
inflation, foreign currency rates and interest rates.
 
     The Company does not as a matter of course make public any projections as
to future performance or earnings, and the projections set forth above are
included in this Offer to Purchase only because the information was provided to
Parent. The projections were not prepared with a view to public disclosure or
compliance with the published guidelines of the Commission or the guidelines
established by the American Institute of Certified Public Accountants regarding
projections or forecasts. The Company's internal operating projections are, in
general, prepared solely for internal use and capital budgeting and other
management decisions and are subjective in many respects and thus susceptible to
various interpretations and periodic revision based on actual experience and
business developments. The projections were based on a number of assumptions
that are beyond the control of the Company, the Purchaser or Parent or their
respective financial advisors, including economic forecasting (both general and
specific to the Company's business), which is inherently uncertain and
subjective. None of the Company, the Purchaser or Parent or their respective
financial advisors assumes any responsibility for the accuracy of any of the
projections. The inclusion of the foregoing projections should not be regarded
as an indication that the Company, the Purchaser or Parent or any other person
who received such information considers it an accurate prediction of future
events. Accordingly, there can be no assurance that the projected results will
be realized or that actual results will not be significantly higher or lower
than those reflected in the projections. Neither the Company nor Parent intends
to update, revise or correct such projections if they become inaccurate (even in
the short term).
 
     Available Information.  The Company is subject to the informational
requirements of the Exchange Act and, in accordance therewith, is required to
file reports relating to its business, financial condition and other matters.
Information as of particular dates concerning the Company's directors and
officers, their remuneration, stock options and other matters, the principal
holders of the Company's securities and any material interest of such persons in
transactions with the Company is disclosed in the Company's proxy statement
dated February 12, 1997, and filed with the Commission. Such information should
be available for inspection at the public reference facilities of the Commission
at 450 Fifth Street, N.W., Washington, DC 20549, and at the regional offices of
the Commission located at Seven World Trade Center, 13th Floor, New York, NY
10048 and Citicorp Center, 500 West Madison Street (Suite 1400), Chicago, IL
60661. Copies of such information should be obtainable, by mail, upon payment of
the Commission's customary charges, by writing to the Commission's principal
office at 450 Fifth Street, N.W., Washington, DC 20549. Such material should
also be available for inspection at the library of the NYSE, 20 Broad Street,
New York, NY 10005.
 
     Except as otherwise stated in this Offer to Purchase, the information
concerning the Company contained herein has been taken from or based upon
publicly available documents on file with the Commission and other publicly
available information. Although the Purchaser and Parent do not have any
knowledge that any such information is untrue, neither the Purchaser nor Parent
takes any responsibility for the accuracy or completeness of such information or
for any failure by the Company to disclose events that may have occurred and may
affect the significance or accuracy of any such information.
 
9.  CERTAIN INFORMATION CONCERNING THE PURCHASER AND PARENT
 
     The Purchaser, a Delaware corporation, which is a wholly owned subsidiary
of Parent, was organized to acquire the Company and has not conducted any
unrelated activities since its organization. The principal office of the
Purchaser is located at the principal office of Parent. All outstanding shares
of capital stock of the Purchaser are owned by Parent.
 
     Parent, a Delaware corporation, with its principal executive office located
at One Meadowlands Plaza, East Rutherford, NJ 07073, manufactures and markets a
broad line of specialty chemicals and commodity chemical intermediates and also
manufactures chemicals to customer specifications. There are five product
 
                                       13
<PAGE>   16
 
categories: pharmaceutical bulk actives; pharmaceutical intermediates; organic
intermediates; performance enhancers; and polymer systems. Currently Parent's
overall strategy for these categories is to focus on niche markets that have
global opportunities, build on strong customer relations to fill Parent's new
products' pipeline, and support the capital and state-of-the-art technology,
while being leaders in environmental, health and safety performance.
 
     Set forth below is certain selected consolidated financial information with
respect to Parent and its subsidiaries excerpted from the information contained
in Parent's Annual Report on Form 10-K for the fiscal year ended December 31,
1996 (the "Parent 1996 10-K"), and Parent's Quarterly Report on Form 10-Q for
the six-month period ended June 30, 1997 (the "Parent 1997 10-Q"). More
comprehensive financial information is included in the Parent 1996 10-K, the
Parent 1997 10-Q and other documents filed by Parent with the Commission, and
the following summary is qualified in its entirety by reference to the Parent
1996 10-K, the Parent 1997 10-Q and such other documents and all the financial
information (including any related notes) contained therein. The Parent 1996
10-K, the Parent 1997 10-Q and such other documents should be available for
inspection and copies thereof should be obtainable in the manner set forth below
under "Available Information".
 
                              CAMBREX CORPORATION
 
                  SELECTED CONSOLIDATED FINANCIAL INFORMATION
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
 
<TABLE>
<CAPTION>
                                                                               SIX MONTHS ENDED
                                           YEAR ENDED DECEMBER 31,                 JUNE 30,
                                      ----------------------------------     ---------------------
                                        1996         1995         1994         1997         1996
                                      --------     --------     --------     --------     --------
                                                                                  (UNAUDITED)
<S>                                   <C>          <C>          <C>          <C>          <C>
Consolidated Statements of Income:
  Gross Sales.......................  $369,479     $368,070     $249,683     $193,914     $189,686
  Operating expenses................   313,111      312,673      220,658      164,024      159,480
  Net earnings......................    28,225       19,670       11,126       16,300       13,725
  Net earnings per share (fully
     diluted).......................      2.37         1.95         1.30         1.36         1.16
Consolidated Balance Sheets:(1)
  Total current assets..............  $136,862     $144,136     $130,698     $139,494     $146,985
  Total assets......................   404,444      402,553      360,477      393,139      409,450
  Total current liabilities.........    73,950       74,269      110,773       61,599       73,985
  Total liabilities.................   175,399      213,069      258,511      167,032      200,881
  Total stockholders' equity........   229,045      189,484      101,966      226,107      208,573
</TABLE>
 
- ---------------
(1) At period end.
 
     Available Information.  Parent is subject to the informational requirements
of the Exchange Act and, in accordance therewith, is required to file reports
relating to its business, financial condition and other matters. Information as
of particular dates concerning Parent's directors and officers, their
remuneration, stock options and other matters, the principal holders of Parent's
securities and any material interest of such persons in transactions with Parent
is disclosed in Parent's proxy statement dated March 24, 1997, and filed with
the Commission. Such information may be inspected at the public reference
facilities of the Commission at 450 Fifth Street, N.W., Washington, DC 20549,
and at the regional offices of the Commission located at Seven World Trade
Center, 13th Floor, New York, NY 10048 and Citicorp Center, 500 West Madison
Street (Suite 1400), Chicago, IL 60661. Copies of such information should be
obtainable, by mail, upon payment of the Commission's customary charges, by
writing to the Commission's principal office at 450 Fifth Street, N.W.,
Washington, DC 20549. Such material should also be available for inspection at
the library of the NYSE, 20 Broad Street, New York, NY 10005.
 
                                       14
<PAGE>   17
 
10.  SOURCE AND AMOUNT OF FUNDS
 
     The Purchaser estimates that the total amount of funds required to purchase
pursuant to the Offer the Shares that are outstanding on a fully diluted basis
and to consummate the Merger under the Merger Agreement and to pay fees and
expenses related to the Offer and the Merger will be approximately $141,000,000.
The Purchaser plans to obtain all funds needed for the Offer and the Merger from
the proceeds of a new revolving credit facility (the "Credit Facility")
consisting of up to $400,000,000 of senior financing for which Purchaser has
received a commitment from The Chase Manhattan Bank ("Chase") pursuant to a
commitment letter (the "Commitment Letter") dated August 20, 1997 among Chase,
Chase Securities, Inc., as advisor and arranger, and Parent. The Credit Facility
may also be used for the general corporate and working needs of Parent and its
Subsidiaries, to refinance certain indebtedness of Parent, and to fund future
acquisitions.
 
     The obligation of Chase to provide the Credit Facility and the initial
extension of credit is subject to certain conditions, including, but not limited
to, there not occurring or becoming known to Chase any material adverse
condition or material adverse change in or affecting the business, operations,
property, condition (financial or otherwise) or prospects of Parent and its
subsidiaries, taken as a whole. The definitive credit agreement for the Credit
Facility is expected to provide for customary representations, warranties and
affirmative covenants. The definitive credit agreement will also provide for
customary negative and financial covenants including (a) limitations on
additional indebtedness, (b) limitations on dividends and similar distributions,
(c) limitations on liens and encumbrances, (d) limitations on asset dispositions
and similar transfers, (e) limitations on investments, loans and advances, (f)
limitations on mergers, consolidations and similar combinations, (g) limitations
on transactions with affiliates, (h) limitations on negative pledge clauses, (i)
limitations on sale and leasebacks, (j) limitations on changes in fiscal year,
(k) limitations on changes in lines of business, and (l) compliance with
financial ratios.
 
     The loans under the Credit Facility will bear interest at Parent's option
either at (a) Chase's alternative base rate or (b) a reserve-adjusted LIBO rate,
plus, in each case, a margin determined by Parent's leverage ratio. The Credit
Facility will (a) be secured by a lien on 65% of the capital stock of Parent's
first-time foreign subsidiaries and (b) be guaranteed by Parent's domestic
subsidiaries.
 
     Although Purchaser expects that the Credit Facility will be available to
provide funds in accordance with their respective terms, there can be no
assurance that the Credit Facility will be consummated. Nonetheless,
consummation of the Credit Facility is not a condition to consummation of the
transactions contemplated by the Merger Agreement.
 
     A copy of the Commitment Letter has been filed as an Exhibit to the
Schedule 14D-1 and the foregoing summary is qualified in its entirety by
reference to such Exhibit.
 
11.  CONTACTS AND TRANSACTIONS WITH THE COMPANY; BACKGROUND OF THE OFFER
 
  Background of the Offer
 
     In March, 1997, Parent was contacted by Alex. Brown & Sons Incorporated
("Alex. Brown"), the investment bankers for the Company, as to whether Parent
would be interested in exploring the possibility of acquiring the Company. At
that time, Parent was advised that it was one of several parties that was being
contacted as part of the Company's previously announced decision to consider
various strategic alternatives. On March 20, 1997, following Parent's expression
of interest in participating in such process, Parent executed a confidentiality
and standstill agreement with the Company. Parent was then provided with certain
confidential information concerning the Company and was asked to indicate, by
mid-May 1997, its level of interest in pursuing an acquisition of the Company.
 
     On April 17, 1997, Parent indicated to Alex. Brown in writing that it was
making a non-binding offer in the range of $100 million to $120 million (or
$9.00 to $11.25 per Share) to purchase the Company subject, among other things,
to negotiation of definitive agreements relating to the proposed transaction and
satisfactory completion of due diligence. Thereafter, representatives of Parent
visited the Company's offices on May 19, 1997, and received a presentation about
the Company from the Company's senior management.
 
                                       15
<PAGE>   18
 
     In May, 1997, Parent was notified by the Company that based on such
preliminary indication of interest, it was one of several parties that had been
invited to conduct further due diligence of the Company. Parent was also advised
that it should submit its final expression of interest by no later than July 1,
1997.
 
     On June 10, 1997, the Company's Chief Executive Officer met informally with
the Chairman of the Board and the Chief Executive Officer of Parent and
discussed whether the two companies were strategically compatible. On June 12
and June 24, 1997, representatives of Parent visited the Company's headquarters
to conduct further due diligence.
 
     On July 1, 1997, Parent made a proposal to acquire the Company for $120
million subject, among other things, to negotiation and execution of definitive
agreements relating to the proposed acquisition and requested that the Company
enter into an exclusive negotiating period through August 31, 1997. Although the
Company refused to grant Parent's request for an exclusive negotiating period,
discussions concerning Parent's proposal continued during the early part of
July.
 
     On July 11, 1997, the Company's Chief Executive Officer and a
representative of Alex. Brown met with the President and other members of senior
management of Parent and representatives of Schroders, Parent's investment
banking firm. As a result of those negotiations, Parent notified the Company
that it was prepared to negotiate to acquire the Company at a price of $11.625
per share, subject to completing due diligence, negotiating the terms of an
acceptable agreement and satisfactory discussions with certain key executives of
the Company concerning their role with the Company following any such
acquisition.
 
     On July 22, 1997, the Company received from Parent's counsel an initial
draft of the Merger Agreement, which contemplated, among other things, the
receipt of stockholder agreements from Anasco (which is an affiliate of
Boehringer Ingelheim GmbH ("Boehringer Ingelheim")) and certain directors and
officers of the Company. Counsel for the companies then began negotiating the
terms of the proposed Merger Agreement and related documents.
 
     On July 24, 1997, Parent's Board of Directors met to consider Parent's
acquisition of the Company. Representatives of the Company attended a portion of
such meeting and made a presentation about, and answered questions from the
Board concerning, the Company. At such meeting, Parent also received an opinion
from Schroders to the effect that, as of the date of such opinion and based on
certain matters stated therein, the consideration to be paid by Parent was fair,
from a financial point of view, to the stockholders of the Parent. After
discussions, the Board of Parent then unanimously approved Parent's acquisition
of the Company on substantially the terms presented at the meeting and reflected
in the Merger Agreement, with such changes thereto as might thereafter be
negotiated by Parent's senior management team.
 
     On July 25, 1997, a representative of Boehringer Ingelheim wrote a letter
to Parent stating that Boehringer Ingelheim would not be able to respond
immediately to Parent's request for a stockholder agreement binding on Anasco
until after it had reviewed the implications of such an agreement with its legal
and financial advisors. The letter stated that Boehringer Ingelheim was also
considering the suitability of Parent as a partner in light of the commercial
arrangements between the Company and a European company in which the Company
previously owned a 50% interest (the "BI Joint Venture") and Parent's future
intentions in this regard.
 
     Counsel for the Company and for Parent continued to negotiate provisions of
the proposed Merger Agreement, including the conditions for termination by
Parent; the effect of any such termination, including the size of any
termination fee and the payment of Parent's expenses; and the circumstances
under which the Company could entertain alternative acquisition proposals.
During the course of these negotiations, Parent converted the structure of the
transaction to a tender offer, followed by a merger, and provided a new draft of
the agreement reflecting such changes for the Company and its counsel to
consider.
 
     During the early part of the week of July 28th, Parent and its
representatives were advised that the Company's Board of Directors would meet on
the afternoon of July 30th to consider Parent's proposal, including the terms of
the proposed Merger Agreement.
 
                                       16
<PAGE>   19
 
     On July 30, 1997, following the conclusion of the Company's Board meeting,
Debevoise & Plimpton, Parent's legal advisers, were contacted by the Company's
legal and financial advisers. They were told that although the Company's Board
viewed favorably a transaction with Parent at $11.625 per share, the Board was
not prepared to go forward unless several issues were resolved to its
satisfaction. These included whether the Company would be obligated to reimburse
Parent's expenses in the event of termination of the Merger Agreement, the
treatment of certain employee benefit plans, including confirmation of Parent's
express assumption of the Company's existing Change of Control Agreements with
certain of its senior employees; the conditions to consummation of the Merger
and the tender offer; the scope of the proposed stockholder agreements; the
duration of non-compete agreements to be signed by certain of the Company's
executive officers in connection with the acquisition of the Company by Parent;
and the circumstances under which the Company could entertain an alternative
acquisition proposal following execution of the Merger Agreement. Following
discussions with its legal and financial advisors, the Executive Vice President
of Parent telephoned the Chief Executive Officer of the Company to state that
Parent was unwilling to accede to the Company's position on these issues and
that Parent was therefore deferring further negotiations. Counsel for the
Company sent a revised draft of the agreement to counsel for Parent that
evening, reflecting among other things, the Board's position on these issues.
 
     Thereafter, Parent authorized Schroders to contact Alex. Brown to further
clarify Parent's position with respect to the various issues raised by the
Company. In discussions with Alex. Brown, Schroders stated that Parent would not
pursue the transaction without stockholder agreements from Anasco and certain
officers and directors of the Company in order to assure these parties' support
of the transaction and reiterated that Parent was unwilling to accede to the
other requests for modification of the proposed transaction made by the Company.
 
     During the next week, in conversations between management of the Company
and Parent and their respective legal and financial advisors, the Company
indicated that the officers and directors identified by Parent would be willing
to execute stockholder agreements and that the management stockholders would be
willing to execute non-competition agreements on substantially the terms sought
by Parent. They further indicated that although Anasco continued to object to
certain terms of the proposed stockholder agreement, including the proposed
trigger events and the conditions to termination of the agreement, Anasco would
agree to participate in additional discussions to reach agreement regarding
these issues.
 
     Following these discussions, Parent authorized its financial and legal
advisors to begin negotiations with the Company's advisors. In a conference call
on August 11, 1997, Schroders and Debevoise informed the Company's legal and
financial advisors that Parent would be willing to modify its positions with
respect to certain of the open issues, but would not go forward without a
stockholder agreement from Anasco on the terms previously proposed by Parent.
 
     Over the next several days, representatives of Parent and the Company held
a number of discussions with representatives of Boehringer Ingelheim concerning
the terms of the stockholder agreement, including the proposed trigger events
and whether Parent would receive the spread between a superior proposal and
Parent's proposed purchase price for the Shares in the event a superior
transaction was consummated by a third party.
 
     During the course of discussions with Boehringer Ingelheim concerning the
stockholder agreement, Parent, the Company and their advisors continued
negotiation of the terms of the Merger Agreement. On August 14, 1997 Boehringer
Ingelheim indicated its tentative agreement to the terms of the stockholder
agreement proposed by Parent and authorized its counsel to finalize the
definitive agreement with counsel for Parent.
 
     Over the next few days, counsel for the parties continued negotiations and
preparation of the Merger Agreement and related documents. On August 21, 1997,
Parent was advised by representatives of the Company that the Company's Board
had approved the proposed transaction subject to resolution of certain remaining
issues in the Merger Agreement and receipt of a fairness opinion of Alex. Brown,
the substance of which had been reviewed with the Board.
 
                                       17
<PAGE>   20
 
     Following resolution of the outstanding issues during the course of the
following day, the parties executed and delivered the Merger Agreement, the
stockholders agreements and the related agreements.
 
Employment Letters
 
     Certain senior executives of the Company and Noel L. Buterbaugh, the
President and Chief Executive Officer of the Company (each, a "Senior Executive"
and, collectively, the "Senior Executives"), have entered into letter agreements
(each an "Employment Letter" and, collectively, the "Employment Letters") with
Parent concerning their respective employment relationships following completion
of the acquisition of the Company by Parent. Each of the Employment Letters
provides for (i) annual salary at a stated rate, subject to annual review; (ii)
participation in, and receipt of bonuses through, Parent's Earnings Improvement
Program, with 1998 bonuses at least equal to the Senior Executive's bonus target
award under the Company's 1997 Management Incentive Compensation Plan; (iii) the
grant of options pursuant to Parent's 1996 Performance Stock Option Plan; (iv)
continued participation in and receipt of benefits under existing welfare
benefit plans (including medical, prescription, dental, disability, life
insurance and similar plans) or similar plans of Parent which, in the aggregate
will not be less favorable than existing plans; (v) continued accrual of
benefits under the Company's defined contribution plans; and (vi) continuation
of reasonable fringe benefits. In addition, each of the Employment Letters also
provides that upon any termination of the Senior Executive's employment by
Parent (not including death or disability) other than for cause, the Senior
Executive is entitled to a severance payment equal to his monthly base salary
for up to 12 months from the date of separation or until he secures other
employment, whichever occurs first.
 
     The Employment Letters also contain certain non-competition and
non-solicitation provisions applicable for a period of two years following the
date of termination of each Senior Executive's employment by the Parent for any
reason.
 
     Forms of the Employment Letters have been filed as Exhibits to the Schedule
14D-1 and the foregoing summary is qualified in its entirety by reference to
such Exhibit.
 
Other Arrangements
 
     Except as described in this Offer to Purchase (including Schedule 1
hereto), neither the Purchaser nor Parent nor, to the best knowledge of the
Purchaser and Parent, any of the persons listed in Schedule 1 hereto, nor any
associate or majority-owned subsidiary of the Purchaser, Parent nor any of the
persons so listed, beneficially owns any equity security of the Company, and
neither the Purchaser nor Parent, nor, to the best knowledge of the Purchaser
and Parent, any of the other persons referred to above, or any of the respective
directors, executive officers or subsidiaries of any of the foregoing, has
effected any transaction in any equity security of the Company during the past
60 days.
 
     Except as described in this Offer to Purchase, as of the date hereof (a)
there have not been any contacts, transactions or negotiations between the
Purchaser and Parent, any of Parent's subsidiaries or, to the best knowledge of
the Purchaser and Parent, any of the persons listed in Schedule 1 hereto, on the
one hand, and the Company or any of its directors, officers or affiliates, on
the other hand, that are required to be disclosed pursuant to the rules and
regulations of the Commission and (b) neither the Purchaser nor Parent nor, to
the best knowledge of the Purchaser and Parent, any of the persons listed in
Schedule 1 hereto has any contract, arrangement, understanding or relationship
with any person with respect to any securities of the Company.
 
                                       18
<PAGE>   21
 
12.  THE MERGER AGREEMENT; THE STOCKHOLDERS AGREEMENT
 
     The following is a summary of certain provisions of the Merger Agreement
and other agreements, copies of which have been filed with the Commission as
Exhibits to the Schedule 14D-1 relating to the Offer and are incorporated herein
by reference. Such summaries are qualified in their entirety by reference to the
text of such agreements.
 
  The Merger Agreement
 
     The Merger Agreement provides that following the satisfaction or waiver of
the conditions described below under "Conditions to the Merger", the Purchaser
will be merged with and into the Company, and each then outstanding Share (other
than Shares owned by the Company, any subsidiary of the Company, Parent, the
Purchaser, any other subsidiary of Parent or by stockholders, if any, who are
entitled to and who properly exercise appraisal rights under Delaware law) will
be converted into the right to receive an amount in cash equal to the price per
Share paid pursuant to the Offer.
 
     Vote Required To Approve Merger.  The Delaware General Corporation Law (the
"DGCL") requires, among other things, that the adoption of any plan of merger or
consolidation of the Company must be approved by the Board of Directors and
generally by the holders of the Company's outstanding voting securities. The
Board of Directors of the Company has approved the making of the Offer and the
Merger; consequently, the only additional action of the Company that may be
necessary to effect the Merger is approval by the Company's stockholders if the
"short-form" merger procedure described below is not available. Under the DGCL,
the affirmative vote of holders of a majority of the voting power of the then
outstanding Shares (including any Shares owned by the Purchaser) is generally
required to approve the Merger. If the Purchaser acquires, through the Offer,
the Stockholders Agreement or otherwise, a majority of the voting power of the
outstanding Shares (which would be the case if the Minimum Condition were
satisfied and the Purchaser were to accept for payment Shares tendered pursuant
to the Offer and to exercise its option under the Stockholders Agreement to
acquire the Option Shares), it would have sufficient voting power to effect the
Merger without the vote of any other stockholder of the Company.
 
     Under the DGCL, if a corporation owns 90% or more of each outstanding class
of capital stock of another corporation, it can effect a "short-form" merger
with such corporation without prior notice to, or any other action by, any other
stockholder of such corporation. As a result, assuming no Stock Options are
exercised following August 22, 1997, if the Purchaser were to acquire ownership
of 9,793,089 Shares pursuant to the Offer, the Purchaser would own more than 90%
of the only class of capital stock of the Company then outstanding and would be
able to effect the Merger pursuant to the "short-form" merger provisions of the
DGCL. See Section 15.
 
     Conditions to the Merger.  The Merger Agreement provides that the
obligations of Parent, the Purchaser and the Company to consummate the Merger
are subject to the satisfaction of certain conditions, including the following:
(a) the Purchaser shall have purchased all Shares duly tendered and not
withdrawn pursuant to the terms of the Offer and subject to the terms thereof;
provided that the obligation of the Parent and the Purchaser to effect the
Merger shall not be conditioned on the fulfillment of such condition if the
failure of the Purchaser to purchase the Shares pursuant to the Offer shall have
constituted a breach of the Offer or of the Merger Agreement; (b) the
consummation of the Merger shall not be precluded by any order, decree or
injunction of a court of competent jurisdiction (each party having agreed to use
its best efforts to have any such order reversed or injunction lifted), and
there shall not have been any action taken or any law enacted, promulgated or
deemed applicable to the Merger by any court, governmental agency or regulatory
or administrative authority, foreign or domestic (each, a "Governmental Entity")
that makes consummation of the Merger illegal; (c) if required by Certificate of
Incorporation and By-Laws of the Company and the DGCL, the Merger Agreement
shall have been approved and adopted by the affirmative vote of the holders of
the requisite number of Shares in accordance with the Certificate of
Incorporation and By-Laws of the Company and the DGCL; and (d) any applicable
waiting period under the HSR Act shall have expired or been terminated. The
Merger Agreement also provides that the obligations of Parent and the Purchaser
to consummate the Merger are subject to the following additional conditions: (a)
the Company shall have
 
                                       19
<PAGE>   22
 
performed all of its material agreements and covenants contained in the Merger
Agreement required to be performed on or prior to the Effective Time and the
representations and warranties of the Company contained in the Merger Agreement
shall be true and correct in all material respects on and as of (i) the date
made and (ii) except in the case of representations and warranties expressly
made solely with reference to a particular date, the effective time of the
Merger and (b) the Company shall not have received notice from the holder or
holders of more than 10% of the outstanding Shares, determined on a fully
diluted basis, that such holder or holders have exercised or intend to exercise
its or their appraisal rights under Section 262 of the DGCL.
 
     As used herein, "Material Adverse Effect" means, with respect to any person
or entity, a material adverse effect on the business, assets, liabilities,
operations or condition (financial or otherwise) of such person or entity and
its subsidiaries, taken as a whole.
 
     Termination of the Merger Agreement.  The Merger Agreement may be
terminated at any time prior to the effective time of the Merger, whether prior
to or after approval of the terms of the Merger Agreement by the stockholders of
the Company:
 
          (1) by the mutual written consent of Parent, the Purchaser and the
     Company;
 
          (2) by either the Parent or the Company if, on or before October 31,
     1997 and without fault of such terminating party, Purchaser shall not have
     purchased in the Offer such number of Shares which, together with the
     number of Option Shares subject to the Stockholders Agreement, represents
     in excess of 50% of the Shares on a fully diluted basis, or the Merger
     shall not have been consummated on or before November 30, 1997, provided,
     however, that the right to terminate the Merger Agreement is not available
     to any party whose failure to fulfill any obligation under the Merger
     Agreement has been the cause of, or resulted in, the failure of the Offer
     or the Merger to have occurred on or before the aforesaid date;
 
          (3) by either Parent or the Company if the Offer shall expire or
     terminate in accordance with its terms without any Shares having been
     purchased thereunder and, in the case of termination by the Parent, the
     Purchaser shall not have been required by the terms of the Offer or the
     Merger Agreement to purchase any Shares pursuant to the Offer;
 
          (4) by the Company if the Purchaser shall not timely commence the
     Offer as provided in the Merger Agreement;
 
          (5) if approval by the Company's stockholders is required by law, by
     either the Purchaser or the Company if, upon a vote of the Company's
     stockholders, such stockholder approval shall not have been obtained;
 
          (6) unilaterally by the Purchaser or the Company (i) if the other
     fails to perform any material covenant or agreement in any material respect
     in the Merger Agreement, and does not cure the failure in all material
     respects within 30 business days after the terminating party delivers
     written notice of the alleged failure or (ii) if any condition to the
     obligations of that party is not satisfied (other than by reason of a
     breach by that party of its obligations hereunder), and it reasonably
     appears that the condition cannot be satisfied prior to November 30, 1997;
 
          (7) by either the Purchaser or the Company if either is prohibited by
     an order or injunction (other than an order or injunction on a temporary or
     preliminary basis) of a court of competent jurisdiction or other
     Governmental Entity from consummating the Offer or the Merger and all means
     of appeal and all appeals from such order or injunction have been finally
     exhausted;
 
          (8) by the Purchaser if the Board of Directors of the Company shall
     have withdrawn or modified, or resolved to withdraw or modify, in any
     manner which is adverse to Parent or the Purchaser, its recommendation or
     approval of the Merger or the Merger Agreement; provided, however, that
     such a termination shall not become effective if, as a result of the
     Company's receipt of a proposal for an Acquisition Transaction (as defined
     under "Takeover Proposals") from a third party, the Company, in accordance
     with the Merger Agreement, withdraws or modifies, or resolves to withdraw
     or modify, in any manner which is adverse to Parent or the Purchaser, its
     recommendation or approval of the Merger or the
 
                                       20
<PAGE>   23
 
     Merger Agreement and if within ten business days of taking and disclosing
     to its stockholders the aforementioned position the Company publicly
     reconfirms its recommendation of the transactions contemplated by the
     Merger Agreement; or
 
          (9) by the Company if (i) the Board of Directors of the Company shall
     have determined in good faith, based on the advice of outside counsel, that
     it is necessary, in order to comply with its fiduciary duties to the
     Company's stockholders under applicable law, to terminate the Merger
     Agreement to enter into an agreement with respect to or to consummate a
     transaction constituting a Superior Proposal (as defined under "Takeover
     Proposals"), (ii) the Company shall have given notice to the Purchaser
     advising the Purchaser that the Company has received a Superior Proposal
     from a third party, specifying the material terms and conditions (including
     the identity of the third party) and that the Company intends to terminate
     the Merger Agreement, (iii) either (A) the Purchaser shall not have revised
     its proposal for an Acquisition Transaction within two business days from
     the time on which such notice is deemed to have been given to Parent, or
     (B) if the Purchaser within such period shall have revised its proposal for
     an Acquisition Transaction, the Board of Directors of the Company, after
     receiving advice from the Company's financial advisor, shall have
     determined in its good faith reasonable judgment that the third party's
     proposal for an Acquisition Transaction is superior to Parent's revised
     proposal for an Acquisition Transaction and (iv) the Company, at the time
     of such termination, pays the Expenses and the Termination Fee (each as
     defined under "Fees and Expenses" below).
 
     Takeover Proposals.  The Merger Agreement provides that the Company shall
not, shall not permit any of its subsidiaries to, and shall not authorize or
permit any officer, director or employee or any investment banker, attorney,
accountant or other advisor or representative of the Company or any of its
subsidiaries to, directly or indirectly, except as otherwise described in this
Section or "Takeover Proposals" (i) initiate, solicit, negotiate, encourage, or
provide confidential information to facilitate any proposal or offer to acquire
all or any substantial part of the business and properties of the Company and
its subsidiaries, taken as a whole, or beneficial ownership (as determined
pursuant to Rule 13d-3 promulgated under the Exchange Act) of 20% or more of the
capital stock of the Company, whether by merger, purchase of assets, tender
offer or otherwise, whether for cash, securities or any other consideration or
combination thereof (such transactions being referred to herein as "Acquisition
Transactions"), (ii) enter into any agreement with respect to any Acquisition
Transaction or give any approval of the type referred to in the next paragraph
below with respect to any Acquisition Transaction or (iii) participate in any
discussions regarding, or take any other action to facilitate any inquiries or
the making of any proposal that constitutes or may reasonably be expected to
lead to any Acquisition Transaction. Notwithstanding the immediately preceding
sentence, the Company and its subsidiaries may, prior to the approval of the
Merger Agreement by the Company's stockholders, in response to any unsolicited
proposal for an Acquisition Transaction, furnish information concerning its
business, properties or assets to the corporation, partnership, person or other
entity or group (a "Potential Acquiror") making such proposal for an Acquisition
Transaction and participate in negotiations with the Potential Acquiror if (x)
the Company's Board of Directors after consultation with one or more of its
independent financial advisors, is of the reasonable belief that such Potential
Acquiror has the financial wherewithal to consummate such an Acquisition
Transaction, (y) the Company's Board of Directors reasonably determines, after
receiving advice from the Company's financial advisor, that such Potential
Acquiror has submitted a proposal for an Acquisition Transaction that involves
consideration to the Company's stockholders and other terms that taken as a
whole are superior to the Merger, and (z) based upon advice of counsel to such
effect, the Company's Board of Directors determines in good faith that it is
necessary to so furnish information and negotiate in order to comply with its
fiduciary duty to stockholders of the Company. The Merger Agreement provides
that in the event the Company shall determine to provide any information as
described above, or shall receive any offer of the type referred to in this
subsection or shall receive or become aware of any other proposal to acquire a
substantial part of the business and properties of the Company and its
subsidiaries, taken as a whole, or to acquire a substantial amount of capital
stock of the Company, it shall promptly inform Parent orally as to the fact that
information is to be provided and shall furnish to Parent the identity of the
recipient of such information and/or the proponent of such offer or proposal and
a description of the material terms thereof. The Company is also obligated to
keep Parent fully informed of the status and material details of any
 
                                       21
<PAGE>   24
 
such proposed Acquisition Transaction or other transaction (including any
material amendments or material proposed amendments of any such proposed
Acquisition Transaction or other transaction).
 
     The Merger Agreement also provides that neither the Board of Directors of
the Company nor any committee thereof (x) shall withdraw or modify or propose to
withdraw or modify, in any manner adverse to Parent, the approval of
recommendation of such Board of Directors or such committee of the Merger or (y)
approve or recommend, or propose to approve or recommend, any proposal for an
Acquisition Transaction except, in each case, in connection with a Superior
Proposal. As used herein, the term "Superior Proposal" means a bona fide
proposal to acquire, directly or indirectly, for consideration consisting of
cash and/or securities, more than 50% of the Shares then outstanding or all or
substantially all the assets of the Company, provided (i) such proposed
transaction satisfies the tests set forth in clauses (x), (y) and (z) of the
second sentence of the immediately preceding paragraph and (ii) the Board of
Directors determines, in its good faith reasonable judgment, that such proposed
transaction is reasonably likely to be consummated without undue delay.
 
     Fees and Expenses.  The Merger Agreement provides that the Company will
pay, or cause to be paid, in same day funds to Parent the sum of (x) Parent's
Expenses (as defined below) and (y) $4,125,000 (the "Termination Fee") upon
demand if (i) the Company terminates the Merger Agreement in accordance with the
provision described in paragraph (9) under "Termination of Merger Agreement". In
addition, the Company will pay or cause to be paid in same day funds to Parent,
the sum of Parent's Expenses and the Termination Fee upon demand if (i) the
Purchaser terminates the Merger Agreement in accordance with the provisions
described in paragraphs (6) or (8) under "Termination of Merger Agreement" at
any time after a proposal for an Acquisition Transaction has been made, (ii) the
Company or the Purchaser terminates the Merger Agreement in accordance with the
provisions described in paragraphs (2), (3) or (5) under "Termination of Merger
Agreement" at any time after a proposal for an Acquisition Transaction has been
made, or (iii) the Purchaser terminates the Merger Agreement in accordance with
the provision described in paragraph (6)(ii) under "Termination of Merger
Agreement" at any time after a proposal for an Acquisition Transaction has been
made and, within nine months after any termination referred to in the
immediately preceding clauses (i), (ii) or (iii) of this sentence, the person
that made the proposal for an Acquisition Transaction (or an affiliate thereof)
completes a merger, consolidation or other business combination with the Company
or a subsidiary of the Company, or the purchase from the Company or from a
subsidiary of the Company of 30% or more (in voting power) of the voting
securities of the Company or of 30% or more (in market value) of the assets of
the Company and its subsidiaries, on a consolidated basis; provided that the
Company will not have any such obligations if the Purchaser terminates the
Merger Agreement in accordance with the provision described in paragraph (6)(ii)
under "Termination of Merger Agreement" as a result of the failure of a
condition to be satisfied unless the reason for the failure of such condition to
be satisfied is reasonably related to the making of such proposal for an
Acquisition Transaction by the person that ultimately consummated a transaction
with the Company. "Expenses" shall mean reasonable and reasonably documented
out-of-pocket fees and expenses incurred or paid by or on behalf of Parent in
connection with the Offer and the Merger or the consummation of any of the
transactions contemplated by the Merger Agreement (including, without
limitation, the fees and expenses of one counsel representing the financial
institutions providing financing to the Purchaser and all fees and expenses of
Parent's investment banking firm), provided that all such Expenses for this
purpose shall not exceed $1.2 million in the aggregate.
 
     Conduct of Business by the Company.  The Merger Agreement provides that,
except as otherwise expressly contemplated by the Merger Agreement (including
exceptions on the disclosure schedule thereto) or to the extent that the
Purchaser shall otherwise consent in writing, during the period from the date of
the Merger Agreement to the effective time of the Merger the Company shall not
and shall cause its subsidiaries not to: (a) declare, set aside or pay any
dividends on, or make any other distributions in respect of, any of its capital
stock, other than dividends and distributions by a direct or indirect wholly
owned subsidiary of the Company to its parent; (b) split, combine or reclassify
any of its capital stock or issue or authorize the issuance of any other
securities in respect of, in lieu of or in substitution for shares of its
capital stock; (c) purchase, redeem or otherwise acquire any shares of capital
stock of the Company or any of its subsidiaries or any other securities thereof
or any rights, warrants or options to acquire any such shares or other
securities; (d) issue, deliver, sell,
 
                                       22
<PAGE>   25
 
pledge or otherwise encumber any shares of its capital stock, any other voting
securities or any securities convertible into, or any rights, warrants or
options to acquire, any such shares, voting securities or convertible securities
except upon exercise of any Stock Option; (e) amend its certificate of
incorporation, by-laws or other comparable organizational documents; (f) acquire
or agree to acquire (x) by merging or consolidating with, or by purchasing a
substantial portion of the assets of, or by any other manner, any business or
any corporation, limited liability company, partnership, joint venture,
association or other business organization or division thereof or (y) any assets
that individually or in the aggregate are material to the Company and its
subsidiaries taken as a whole; (g) sell, lease, license, mortgage or otherwise
encumber or subject to any lien or otherwise dispose of any of its properties or
assets, other than in the ordinary course of business consistent with past
practice, that are material to the Company and its subsidiaries taken as a
whole; (h) incur any indebtedness, except for borrowings for working capital
purposes not in excess of $500,000 at any one time outstanding incurred in the
ordinary course of business consistent with past practice and except for
intercompany indebtedness between the Company and any of its wholly-owned
subsidiaries or between such wholly-owned subsidiaries, or make any loans,
advances or capital contributions to, or investments in, any other person, other
than to the Company or any direct or indirect wholly owned subsidiary of the
Company; (i) make or agree to make any new capital expenditure or capital
expenditures which in the aggregate are in excess of $250,000; (j) make any tax
election that could reasonably be expected to have a Material Adverse Effect on
the Company or settle or compromise any material income tax liability; (k)
except in the ordinary course of business or except as would not reasonably be
expected to have a Material Adverse Effect on the Company, modify, amend or
terminate any material contract or agreement to which the Company or any
subsidiary is a party or waive, release or assign any material rights or claims
thereunder; (l) make any material change to its accounting methods, principles
or practices, except as may be required by generally accepted accounting
principles; or (m) authorize, or commit or agree to take, any of the foregoing
actions.
 
     In addition to the foregoing, the Company has agreed that, except as
expressly contemplated or permitted by the Merger Agreement, it will not take
any action, or permit any of its subsidiaries to take any action, that would, or
that could reasonably be expected to, result in (a) any of the representations
and warranties of the Company set forth in the Merger Agreement that are
qualified as to materiality becoming untrue, (b) any of such representations and
warranties that are not so qualified becoming untrue in any material respect or
(c) any of the conditions to the Merger not being satisfied.
 
     Board of Directors.  The Merger Agreement provides that promptly upon the
purchase by the Purchaser of the Shares pursuant to the Offer and from time to
time thereafter, the Purchaser shall be entitled to designate up to the minimum
number of directors of the Company necessary in order for the result (expressed
as a fraction) derived by dividing the number of directors so designated by the
total number of directors to be at least equal to the result (expressed as a
fraction) derived by dividing the Shares then held by the Purchaser by the total
number of Shares then outstanding, provided, however, that until the
consummation of the Merger, the Board of Directors of the Company will have at
least two Independent Directors. Subject to applicable law, the Company has
agreed to take all action requested by Parent necessary to effect any such
election, including mailing to its stockholders the Information Statement
containing the information required by Section 14(f) of the Exchange Act and
Rule 14f-1 promulgated thereunder, which Information Statement is attached as
Schedule I to the Schedule 14D-9. The term "Independent Director" means a
director of the Company who is (i) not designated by the Purchaser nor otherwise
affiliated with Parent or the Purchaser, (ii) not an employee or the Chairman of
the Company or any of its subsidiaries and (iii) is not affiliated with Anasco.
 
     Stock Options.  Pursuant to the Merger Agreement, immediately prior to the
effective time of the Merger, each then outstanding Stock Option, shall be
canceled by the Company in exchange for a payment in cash by the Purchaser (the
"Option Consideration") equal to the product of (i) the number of Shares
previously subject to the Stock Option and (ii) the excess, if any, of the Offer
Price over the aggregate exercise price for such Shares under such Stock Option.
As of the effective time of the Merger, each holder of an Stock Option will be
entitled to receive only an amount equal to the Option Consideration. All Stock
Option amounts payable shall be subject to any required withholding of taxes and
shall be paid without interest. Pursuant to the Merger Agreement, the Company
shall thereafter cause each stock option or other equity based plan maintained
with respect to any Shares (or rights in respect thereof) (other than the
 
                                       23
<PAGE>   26
 
BioWhittaker, Inc. Savings and Stock Investment Plan and the BioWhittaker, Inc.
Supplemental Executive Retirement Plan) to be terminated.
 
     Indemnification and Insurance.  In the Merger Agreement, Parent and the
Purchaser have agreed that all rights to indemnification and exculpation from
liabilities for acts or omissions occurring at or prior to the effective time of
the Merger now existing in favor of the current or former directors or officers
of the Company and its subsidiaries as provided in their respective certificates
of incorporation, by-laws (or comparable organizational documents) and
indemnification agreements shall survive the Merger and shall continue in full
force and effect in accordance with their terms for a period of not less than
six years from the Effective Time. Pursuant to the Merger Agreement, Parent will
cause to be maintained for a period of not less than six years from the
effective time of the Merger the Company's current directors' and officers'
insurance and indemnification policy to the extent that it provides coverage for
events occurring prior to such effective time ("D&O Insurance") for all persons
who are directors and officers of the Company on the date of the Merger
Agreement, so long as the annual premium therefor would not be in excess of 200%
of the last annual premium paid prior to the date of the Merger Agreement;
provided, however, that Parent may, in lieu of maintaining such existing D&O
Insurance as provided above, cause coverage to be provided under any policy
maintained for the benefit of Parent or any of its subsidiaries or any policy
specifically obtained for this purpose, so long as the terms thereof are no less
advantageous to the intended beneficiaries thereof than the existing D&O
Insurance. If the existing D&O Insurance expires, is terminated or canceled
during such six-year period, Parent has agreed to use all reasonable efforts to
cause to be obtained as much D&O Insurance as can be obtained for the remainder
of such period, on terms and conditions no less advantageous to the covered
persons than the existing D&O Insurance.
 
     Reasonable Efforts.  The Merger Agreement provides that, except as
otherwise contemplated therein, Parent, the Purchaser and the Company shall use
their reasonable best efforts to take promptly, or cause to be taken, all
actions and to do promptly, or cause to be done, all things necessary, proper or
advisable to consummate and make effective the transactions contemplated by the
Merger Agreement, including using their reasonable best efforts (i) to obtain
all necessary waivers, consents and approvals, and (ii) to effect all necessary
registrations and filings, subject to approval by the Company's stockholders. In
case at any time after the effective time of the Merger any further action is
necessary or desirable to carry out the obligations of the parties under the
Merger Agreement, the proper officers and/or directors of Parent, the Purchaser
and the Company, as the case may be, shall take the necessary action.
 
     Specifically, Parent, Purchaser and the Company have agreed to use their
reasonable best efforts to make promptly any required submissions under the HSR
Act with respect to the Merger and the transactions contemplated by the Merger
Agreement. The Company has agreed to use its reasonable best efforts to obtain
all consents, approvals, permits or authorizations as are required to be
obtained from other parties to loan agreements or other contracts material to
the Company's business in connection with the consummation of the Merger.
 
     Amendment to the Rights Agreement.  In connection with the Company's
entering into the Merger Agreement, on August 22, 1997, the Company amended the
Rights Agreement by entering into Amendment No.1 thereto (the "Amendment"). The
Amendment has been effected to ensure that (i) the respective transactions
contemplated by the Offer, the Merger Agreement and the Stockholders Agreement
are exempt from the Rights Agreement's operation and (ii) neither the Purchaser
nor Parent, nor any of their affiliates shall be deemed an Acquiring Person (as
defined in the Rights Agreement) as a result of consummation of such
transactions. Should either the Offer or the Merger Agreement or any of the
transactions contemplated thereby have resulted in Parent or the Purchaser being
deemed Acquiring Persons, the Company could have effected a distribution of
Rights to the Company's stockholders pursuant to the Rights Agreement.
 
     Representations and Warranties.  The Merger Agreement contains various
customary representations and warranties.
 
  The Stockholders Agreement
 
     Pursuant to the terms and conditions of the Stockholders Agreement, each
Selling Stockholder has agreed to tender his Shares in the Offer. In the
Stockholders Agreement, each Selling Stockholder has further
 
                                       24
<PAGE>   27
 
agreed that, until the Termination Date (as defined below), such Selling
Stockholder will vote his Shares (i) in favor of the Merger, the execution and
delivery by the Company of the Merger Agreement and the approval of the terms
thereof and each of the other actions contemplated by the Merger Agreement and
the Stockholders Agreement and any actions required in furtherance thereof; (ii)
against any action or agreement that would result in a breach of any covenant,
representation or warranty or any other obligation or agreement of the Company
under the Merger Agreement, the Offer or the Stockholders Agreement; and (iii)
except as specifically requested in writing by Parent in advance, against the
following actions (other than the Merger and the transactions contemplated by
the Merger Agreement): (A) any extraordinary corporate transaction, such as a
merger, consolidation or other business combination involving the Company or its
subsidiaries; (B) a sale, lease or transfer of a material amount of assets of
the Company or its subsidiaries or a reorganization, recapitalization,
dissolution, liquidation or winding up of the Company or any of its
subsidiaries; (C) any change in the majority of the Board of Directors of the
Company; (D) any material change in the present capitalization of the Company or
any amendment of the Company's Certificate of Incorporation; (E) any other
material change in the Company's corporate structure or business; and (F) any
other action which is intended or could reasonably be expected to impede,
interfere with, delay, postpone, discourage or materially adversely affect the
Merger, the transactions contemplated by the Merger Agreement or the
Stockholders Agreement or the contemplated economic benefits of any of the
foregoing.
 
     In addition, subject to his obligations as a director or officer of the
Company, to the extent permitted by the Merger Agreement, each Selling
Stockholder has agreed that he shall not, directly or indirectly (including
through advisors, agents or other intermediaries), initiate, solicit, negotiate,
encourage or provide confidential information to facilitate any proposal or
offer by any person that constitutes or could reasonably be expected to lead to
an Acquisition Transaction. If any Selling Stockholder receives any such inquiry
or proposal, then such Selling Stockholder shall promptly inform Parent of the
material terms and conditions, if any, of such inquiry or proposal and the
identity of the person making it. The Selling Stockholders have also agreed to
immediately cease and cause to be terminated any existing activities,
discussions or negotiations with any parties conducted heretofore with respect
to any of the foregoing.
 
     Under the Stockholders Agreement, each Selling Stockholder has also granted
the Purchaser an irrevocable option to purchase all of such Selling
Stockholder's Shares, including all Shares subject to all Stock Options owned by
such Selling Stockholder, in each case at the Offer Price per Share. In the case
of all Shares underlying all such Stock Options (the "Option Shares"), such
option may be exercised by the Purchaser at any time following its purchase of
any Shares pursuant to the Offer and prior to the Termination Date. Among other
things, this option may facilitate the Purchaser's ability to acquire 50% of the
outstanding Shares. In the case of all other Shares held by the Selling
Stockholders, such option may be exercisable by the Purchaser at any time, and
from time to time, following any time when the Merger Agreement has been
terminated in accordance with its terms and prior to the Termination Date. Among
other things, such option will enable the Purchaser to sell all of such Shares
to any person who has made and consummates a Superior Proposal.
 
     For purposes of the Stockholders Agreement, the term "Termination Date"
means the earlier of (a) twelve months from the date of the Stockholders
Agreement and (b) the consummation of the Merger, provided, however, that if the
Company is not in breach of its obligations under the Merger Agreement and none
of the Selling Stockholders are in breach of their obligations under the
Stockholders Agreement, the Termination Date shall be the date that: (i) the
Merger Agreement shall have terminated in accordance with the provisions
described in paragraphs (1), (4), (6)(i) or (7) under "Termination of the Merger
Agreement" above, (ii) the Merger Agreement shall have terminated in accordance
with the provisions described in paragraphs (2), (3) or (5) under "Termination
of the Merger Agreement" above and no proposal for an Acquisition Transaction
has been made, (iii) the Merger Agreement shall have terminated in accordance
with the provisions described in paragraph (6)(ii) under "Termination of the
Merger Agreement" above unless a proposal for an Acquisition Transaction has
been made. The Stockholders Agreement shall terminate on the Termination Date.
 
     A Copy of the Stockholders Agreement has been filed as an Exhibit to the
Schedule 14D-1 and the foregoing summary is qualified in its entirety by
reference to such Exhibit.
 
                                       25
<PAGE>   28
 
     Except as otherwise described in this Offer to Purchase, the Purchaser and
Parent have no current plans or proposals that would relate to, or result in,
any extraordinary corporate transaction involving the Company, such as a merger,
reorganization or liquidation involving the Company or any of its subsidiaries,
a sale or transfer of a material amount of assets of the Company or any of its
subsidiaries to any unaffiliated third party, any change in the Company's
capitalization or dividend policy or any other material change in the Company's
business or corporate structure.
 
  Appraisal Rights
 
     Holders of Shares do not have appraisal rights as a result of the Offer.
However, if the Merger is consummated, holders of Shares at the effective time
of the Merger will have certain rights pursuant to the provisions of Section 262
of the DGCL ("Section 262") to dissent and demand appraisal of their Shares.
Under Section 262, dissenting stockholders who comply with the applicable
statutory procedures will be entitled to receive a judicial determination of the
fair value of their Shares (exclusive of any element of value arising from the
accomplishment or expectation of the Merger) and to receive payment of such fair
value in cash, together with a fair rate of interest, if any. Any such judicial
determination of the fair value of Shares could be based upon factors other
than, or in addition to, the price per Share to be paid in the Merger or the
market value of the Shares. The value so determined could be more or less than
the price per Share to be paid in the Merger.
 
     The foregoing summary of Section 262 does not purport to be complete and is
qualified in its entirety by reference to Section 262. FAILURE TO FOLLOW THE
STEPS REQUIRED BY SECTION 262 FOR PERFECTING APPRAISAL RIGHTS MAY RESULT IN THE
LOSS OF SUCH RIGHTS.
 
  Going Private Transactions
 
     The Commission has adopted Rule 13e-3 under the Exchange Act, which is
applicable to certain "going private" transactions. The Purchaser does not
believe that Rule 13e-3 will be applicable to the Merger unless the Merger is
consummated more than one year after the termination of the Offer. If
applicable, Rule 13e-3 requires, among other things, that certain financial
information concerning the fairness of the Merger and the consideration offered
to minority stockholders in such transaction be filed with the Commission and
disclosed to stockholders prior to the consummation of the Merger.
 
13.  DIVIDENDS AND DISTRIBUTIONS
 
     Pursuant to the terms of the Merger Agreement, the Company is prohibited
from taking any of the actions described in the two succeeding paragraphs, and
nothing herein shall constitute a waiver by the Purchaser or Parent of any of
its rights under the Merger Agreement or a limitation of remedies available to
the Purchaser or Parent for any breach of the Merger Agreement, including
termination thereof.
 
     If, on or after August 22, 1997, the Company should (a) split, combine or
otherwise change the Shares, or its capitalization, (b) acquire or otherwise
cause a reduction in the number of outstanding Shares, or other securities or
(c) issue or sell additional Shares or shares of any other class of capital
stock, other voting securities or any securities convertible into, or rights,
warrants or options, conditional or otherwise, to acquire any of the foregoing,
other than Shares issued pursuant to the exercise of outstanding stock options,
then, subject to the provisions of Section 14, the Purchaser, in its sole
discretion, may make such adjustments as it deems appropriate in the Offer Price
and other terms of the Offer, including, without limitation, the number or type
of securities offered to be purchased.
 
     If, on or after August 22, 1997, the Company should declare or pay any cash
dividend on the Shares or other distribution on the Shares, or issue with
respect to the Shares any additional Shares, shares of any other class of
capital stock, other voting securities or any securities convertible into, or
rights, warrants or options, conditional or otherwise, to acquire, any of the
foregoing, payable or distributable to stockholders of record on a date prior to
the transfer of the Shares purchased pursuant to the Offer to the Purchaser or
its nominee or transferee on the Company's stock transfer records, then, subject
to the provisions of Section 14, (a) the Offer Price may, in the sole discretion
of the Purchaser, be reduced by the amount of any such cash dividend or cash
 
                                       26
<PAGE>   29
 
distribution and (b) the whole of any such noncash dividend, distribution or
issuance to be received by the tendering stockholders will (i) be received and
held by the tendering stockholders for the account of the Purchaser and will be
required to be promptly remitted and transferred by each tendering stockholder
to the Depositary for the account of the Purchaser, accompanied by appropriate
documentation of transfer, or (ii) at the direction of the Purchaser, be
exercised for the benefit of the Purchaser, in which case the proceeds of such
exercise will promptly be remitted to the Purchaser. Pending such remittance and
subject to applicable law, the Purchaser will be entitled to all rights and
privileges as owner of any such noncash dividend, distribution, issuance or
proceeds and may withhold the entire Offer Price or deduct from the Offer Price
the amount or value thereof, as determined by the Purchaser in its sole
discretion.
 
14.  CERTAIN CONDITIONS OF THE OFFER
 
     Notwithstanding any other term of the Offer or the Merger Agreement, the
Purchaser shall not be required to accept for payment, or, subject to any
applicable rules and regulations of the Commission, including Rule 14e-1(c)
under the Exchange Act (relating to the Purchaser's obligation to pay for or
return tendered shares after the termination or withdrawal of the Offer), to pay
for any Shares tendered pursuant to the Offer, and (subject to the terms of the
Merger Agreement) may amend or terminate the Offer or postpone the acceptance
for payment, the purchase of, and/or (subject to any such applicable rules and
regulations of the Commission) payment for, Shares tendered, (i) unless there
are validly tendered and not properly withdrawn prior to the expiration of the
Offer at least that number of Shares which, together with the Option Shares
which are subject to the Stockholders Agreement, represents in excess of 50% of
the Shares on a fully-diluted basis, or (ii) if at any time on or after the date
of the Merger Agreement and at or before the time of payment for any such Shares
(whether or not any Shares shall theretofore have been accepted for payment or
paid pursuant to the Offer) any of the following conditions exists:
 
          (a) there shall have been any action or proceeding brought by any
     governmental authority before any federal or state court, or any order or
     preliminary or permanent injunction entered in any action or proceeding
     before any federal or state court or governmental, administrative or
     regulatory authority or agency, located or having jurisdiction within the
     United States or any country or economic region in which either the Company
     or Parent, directly or indirectly, has material assets or operations, or
     any other action taken, proposed or threatened, or statute, rule,
     regulation, legislation, interpretation, judgment or order proposed,
     sought, enacted, entered, enforced, promulgated, amended, issued or deemed
     applicable to Purchaser, the Company or any subsidiary or affiliate of
     Purchaser or the Company or the Offer or the Merger, by any legislative
     body, court, government or governmental, administrative or regulatory
     authority or agency located or having jurisdiction within the United States
     or any country or economic region in which either the Company or Parent,
     directly or indirectly, has material assets or operations, which could
     reasonably be expected to have the effect of: (i) making illegal, or
     otherwise restraining or prohibiting or making materially more costly, the
     making of the Offer, the acceptance for payment of, payment for, or
     ownership, directly or indirectly, of some of or all the Shares by Parent
     or Purchaser, the consummation of any of the transactions contemplated by
     the Merger Agreement or materially delaying the Merger; (ii) prohibiting or
     materially limiting the ownership or operation by the Company or any of its
     subsidiaries, or by Parent, Purchaser or any of Parent's subsidiaries of
     all or any material portion of the business or assets of the Company and
     its subsidiaries taken as a whole or Parent or any of its subsidiaries, or
     compelling Purchaser, Parent or any of Parent's subsidiaries to dispose of
     or hold separate all or any material portion of the business or assets of
     the Company and its subsidiaries taken as a whole or Parent or any of its
     subsidiaries, in each case as a result of the transactions contemplated by
     the Offer or the Merger Agreement; (iii) imposing or confirming material
     limitations on the ability of Purchaser, Parent or any of Parent's
     subsidiaries effectively to acquire or hold or to exercise full rights of
     ownership of Shares including, without limitation, the right to vote any
     Shares acquired or owned by Parent or Purchaser or any of Parent's
     subsidiaries on all matters properly presented to the stockholders of the
     Company, including, without limitation, the adoption and approval of the
     Merger Agreement and the Merger or the right to vote any shares of capital
     stock of any subsidiary directly or indirectly owned by the Company; (iv)
     requiring divestiture by Parent or Purchaser, directly or indirectly, of
     any Shares; or (v) which could reasonably be expected to materially
     adversely affect the business, financial condition or
 
                                       27
<PAGE>   30
 
     results of operations of the Company and its subsidiaries taken as a whole
     or the value of the Shares or of the Offer to Purchaser or Parent;
 
          (b) there shall have occurred (i) any general suspension of trading
     in, or limitation on prices for, securities on any national securities
     exchange or in the over-the-counter market in the United States, (ii) a
     declaration of a banking moratorium or any suspension of payments in
     respect of banks in the United States, (iii) any limitation (whether or not
     mandatory) by any U.S. government or governmental, administrative or
     regulatory authority or agency, on, or any other event that materially
     adversely affects, the extension of credit by banks or other lending
     institutions, (iv) a commencement of a war or armed hostilities or other
     national or international calamity directly or indirectly involving the
     United States which would reasonably be expected to have a Material Adverse
     Effect or materially adversely affect (or materially delay) the
     consummation of the Offer or (v) in the case of any of the foregoing
     existing at the time of the execution of the Merger Agreement, a material
     acceleration or worsening thereof which acceleration or worsening is
     reasonably expected to have a Material Adverse Effect on the Company or to
     materially adversely affect the consummation of the Offer;
 
          (c)(i) it shall have been publicly disclosed that beneficial ownership
     (determined for the purposes of this paragraph as set forth in Rule 13d-3
     promulgated under the Exchange Act) of 20% or more of the outstanding
     Shares has been acquired by any corporation (including the Company or any
     of its subsidiaries or affiliates), partnership, person or other entity or
     group (as defined in Section 13(d)(3) of the Exchange Act), other than
     Parent or any of its affiliates, or (ii) (A) the Board of Directors of the
     Company or any committee thereof shall have withdrawn or modified in a
     manner adverse to Parent or Purchaser the approval or recommendation of the
     Offer, the Merger or the Merger Agreement, or approved or recommended any
     takeover proposal or any other acquisition of Shares other than the Offer
     and the Merger, (B) any such corporation, partnership, person or other
     entity or group shall have entered into a definitive agreement or an
     agreement in principle with the Company with respect to a tender offer or
     exchange offer for any Shares or a merger, consolidation or other business
     combination with or involving the Company or any of its subsidiaries or (C)
     the Board of Directors of the Company or any committee thereof shall have
     resolved to do any of the foregoing;
 
          (d) any of the representations and warranties of the Company set forth
     in the Merger Agreement that are qualified as to materiality shall not be
     true and correct or any such representations and warranties that are not so
     qualified shall not be true and correct in any material respect, in each
     case as if such representations and warranties were made at the time of
     such determination, except with respect to representations and warranties
     made as of an earlier time;
 
          (e) the Company shall have failed to perform any material obligation
     or to comply with any material agreement or material covenant of the
     Company to be performed or complied with by it under the Merger Agreement;
 
          (f) the Merger Agreement shall have been terminated in accordance with
     its terms or the Offer shall have been terminated with the consent of the
     Company; or
 
          (g) any waiting periods under the HSR Act applicable to the purchase
     of Shares pursuant to the Offer shall not have expired or been terminated
     or any material approval, permit, authorization, consent or waiting period
     of any domestic, foreign or supranational governmental, administrative or
     regulatory agency (federal, state, local, provincial or otherwise) located
     or having jurisdiction within the United States or any country or economic
     region in which either the Company or Parent, directly or indirectly, has
     material assets or operations, shall not have been obtained and such
     failure to obtain could reasonably be expected to have a Material Adverse
     Effect on the Company or the value of the Shares or the Offer to the
     Purchaser;
 
which, in the good faith sole judgment of Purchaser makes it inadvisable to
proceed with the Offer or with such acceptance for payment of or payment for
Shares or to proceed with the Merger.
 
     The foregoing conditions are for the sole benefit of Purchaser and may be
asserted by Purchaser regardless of the circumstances giving rise to any such
condition or may be waived by Purchaser in whole or in
 
                                       28
<PAGE>   31
 
part at any time and from time to time in its sole discretion (subject to the
terms of the Merger Agreement). The failure by Purchaser at any time to exercise
any of the foregoing rights shall not be deemed a waiver of any such right, the
waiver of any such right with respect to particular facts and other
circumstances shall not be deemed a waiver with respect to any other facts and
circumstances, and each such right shall be deemed an ongoing right that may be
asserted at any time and from time to time.
 
15.  CERTAIN LEGAL MATTERS
 
     Except as described in this Section 15, based on a review of publicly
available filings made by the Company with the Commission and other publicly
available information concerning the Company and discussions of representatives
of Parent with representatives of the Company, neither the Purchaser nor Parent
is aware of any license or regulatory permit that appears to be material to the
business of the Company and its subsidiaries, taken as a whole, that might be
adversely affected by the Purchaser's acquisition of Shares (and the indirect
acquisition of the stock of the Company's subsidiaries) as contemplated herein
or of any approval or other action by any Governmental Entity that would be
required or desirable for the acquisition or ownership of Shares by the
Purchaser as contemplated herein. Should any such approval or other action be
required or desirable, the Purchaser and Parent currently contemplate that such
approval or other action will be sought, except as described below under "State
Takeover Laws". While, except as otherwise expressly described in this Section
15, the Purchaser does not presently intend to delay the acceptance for payment
of or payment for Shares tendered pursuant to the Offer pending the outcome of
any such matter, there can be no assurance that any such approval or other
action, if needed, would be obtained or would be obtained without substantial
conditions or that failure to obtain any such approval or other action might not
result in consequences adverse to the Company's business or that certain parts
of the Company's business might not have to be disposed of if such approvals
were not obtained or such other actions were not taken or in order to obtain any
such approval or other action. If certain types of adverse action are taken with
respect to the matters discussed below, the Purchaser could decline to accept
for payment or pay for any Shares tendered. See Section 14.
 
     State Takeover Laws.  A number of states throughout the United States have
enacted takeover statutes that purport, in varying degrees, to be applicable to
attempts to acquire securities of corporations that are incorporated or have
assets, stockholders, executive offices or places of business in such states. In
Edgar v. MITE Corp., the Supreme Court of the United States held that the
Illinois Business Takeover Act, which involved state securities laws that made
the takeover of certain corporations more difficult, imposed a substantial
burden on interstate commerce and therefore was unconstitutional. In CTS Corp.
v. Dynamics Corp. of America, however, the Supreme Court of the United States
held that a state may, as a matter of corporate law and, in particular, those
laws concerning corporate governance, constitutionally disqualify a potential
acquiror from voting on the affairs of a target corporation without prior
approval of the remaining stockholders, provided that such laws were applicable
only under certain conditions. Subsequently, a number of Federal courts ruled
that various state takeover statutes were unconstitutional insofar as they apply
to corporations incorporated outside the state of enactment.
 
     Section 203 of the DGCL.  Section 203 of the DGCL, in general, prohibits a
Delaware corporation such as the Company from engaging in a "Business
Combination" (defined as a variety of transactions, including mergers, as set
forth below) with an "Interested Stockholder" (defined generally as a person
that is the beneficial owner of 15% or more of a corporation's outstanding
voting stock) for a period of three years following the date that such person
became an Interested Stockholder unless, among other things, prior to the time
such person became an Interested Stockholder, the board of directors of the
corporation approved either the Business Combination or the transaction that
resulted in the stockholder becoming an Interested Stockholder. The Company's
Board of Directors has approved the Merger Agreement, the Stockholders Agreement
and the Purchaser's acquisition of Shares pursuant to the Offer and the
Stockholders Agreement. Therefore, Section 203 of the DGCL is inapplicable to
the Merger.
 
     Based on information supplied by the Company, the Purchaser does not
believe that any other state takeover statutes purport to apply to the Offer or
the Merger. Neither the Purchaser nor Parent has currently complied with any
state takeover statute or regulation. The Purchaser reserves the right to
challenge the
 
                                       29
<PAGE>   32
 
applicability or validity of any state law purportedly applicable to the Offer
or the Merger and nothing in this Offer to Purchase or any action taken in
connection with the Offer or the Merger is intended as a waiver of such right.
If it is asserted that any state takeover statute is applicable to the Offer or
the Merger and an appropriate court does not determine that it is inapplicable
or invalid as applied to the Offer or the Merger, the Purchaser might be
required to file certain information with, or to receive approvals from, the
relevant state authorities, and the Purchaser might be unable to accept for
payment or pay for Shares tendered pursuant to the Offer, or be delayed in
consummating the Offer or the Merger. In such case, the Purchaser may not be
obligated to accept payment or pay for any Shares tendered pursuant to the
Offer. See Section 14.
 
     Antitrust.  Under the provisions of the HSR Act applicable to the Offer,
the acquisition of Shares under the Offer may be consummated following the
expiration of a 15-calendar day waiting period following the filing by Parent of
a Notification and Report Form with respect to the Offer, unless Parent or the
Company receives a request for additional information or documentary material
from the Antitrust Division or the FTC or unless early termination of the
waiting period is granted. Parent and the Company expect to file Notification
and Report Forms with respect to the Offer soon. If, within the initial 15-day
waiting period, either the Antitrust Division or the FTC requests additional
information or material from Parent or the Company concerning the Offer, the
waiting period will be extended and would expire at 11:59 p.m., New York City
time, on the tenth calendar day after the date of substantial compliance by
Parent or the Company with such request. Only one extension of the waiting
period pursuant to a request for additional information is authorized by the HSR
Act. Thereafter, such waiting period may be extended only by court order or with
the consent of Parent and the Company. In practice, complying with a request for
additional information or material can take a significant amount of time. In
addition, if the Antitrust Division or the FTC raises substantive issues in
connection with a proposed transaction, the parties frequently engage in
negotiations with the relevant governmental agency concerning possible means of
addressing those issues and may agree to delay consummation of the transaction
while such negotiations continue. Expiration or termination of the applicable
waiting period under the HSR Act is a condition to the Purchaser's obligation to
accept for payment and pay for Shares tendered pursuant to the Offer.
 
     The Merger would not require an additional filing under the HSR Act if the
Purchaser owns 50% or more of the outstanding Shares at the time of the Merger
or if the Merger occurs within one year after the HSR Act waiting period
applicable to the Offer expires or is terminated.
 
     The Antitrust Division and the FTC frequently scrutinize the legality under
the antitrust laws of transactions such as the Purchaser's proposed acquisition
of the Company. At any time before or after the Purchaser's acquisition of
Shares pursuant to the Offer, the Antitrust Division or the FTC could take such
action under the antitrust laws as it deems necessary or desirable in the public
interest, including seeking to enjoin the purchase of Shares pursuant to the
Offer or the consummation of the Merger or seeking the divestiture of Shares
acquired by the Purchaser or the divestiture of substantial assets of the
Company or its subsidiaries or Parent or its subsidiaries. Private parties may
also bring legal action under the antitrust laws under certain circumstances.
There can be no assurance that a challenge to the Offer on antitrust grounds
will not be made or, if such a challenge is made, of the result thereof.
 
     EEA and National Merger Regulation.  According to the Company 1996 10-K,
the Company conducts substantial operations in the European Economic Area (the
"EEA"). EEC Regulation 4064/89 (the "Merger Regulation") and Article 57 of the
European Economic Area Agreement require that concentrations with a "Community
dimension" be notified in prescribed form to the Commission of the European
Communities (the "European Commission") for review and approval prior to being
put into effect. In such cases, the European Commission will, with certain
exceptions, have exclusive jurisdiction to review the concentration as opposed
to the individual countries within the EEA.
 
     The Offer will be deemed to have a "Community dimension" if the combined
aggregate worldwide annual revenues of both Parent and the Company exceed ECU 5
billion, if the Community-wide annual revenues of each of Parent and the Company
exceed ECU 250 million and if both Parent and the Company do not receive more
than two-thirds of their respective Community-wide revenues from one and the
same country. Concentrations that are found not to be subject to the Merger
Regulation may be subject to the
 
                                       30
<PAGE>   33
 
various national merger control regimes of the countries of the EEA, resulting
in the possibility that it may be necessary or desirable to obtain approvals
from the various national authorities.
 
     Based upon information contained in the Company 1996 10-K, the Purchaser
currently believes that the Offer should not be considered to have a "Community
dimension," as the Community-wide revenues of the Company for 1995 appear not to
exceed ECU 250 million. Therefore, the Purchaser does not currently intend to
file a notification with the European Commission.
 
     In EEA countries where it may be necessary to obtain approvals, mandatory
notification obligations may also apply to the Offer and the Merger. In certain
other jurisdictions, although filing may not be mandatory, the Purchaser may
consider it to be desirable to obtain clearance from the relevant national
authority. The period within which the relevant national authority must or may
reach a preliminary decision on the Offer and the Merger, and the length of time
available to such national authority if it decides to commence a full
investigation of the transaction, varies from jurisdiction to jurisdiction. In
most cases a decision at the preliminary inquiry phase can be expected within
one to two months of notification; where a full inquiry into a transaction is
undertaken, the detailed investigations may take several months.
 
     There can be no assurance that a challenge to the Offer will not be made
pursuant to the merger control regimes of one or more of various countries (or
alternatively, if applicable, pursuant to the Merger Regulation) or by legal
action brought by private parties or, if such a challenge is made, what the
outcome would be. See Section 14.
 
     Other Foreign Laws.  The Company and certain of its subsidiaries conduct
business in several foreign countries where regulatory filings or approvals may
be required or desirable in connection with the consummation of the Offer.
Certain of such filings or approvals, if required or desirable, may not be made
or obtained prior to the expiration of the Offer. The Purchaser is seeking
further information regarding the applicability of any such laws and currently
intends to take such action as may be required or desirable. If any foreign
Governmental Entity takes any action prior to the completion of the Offer that
might have certain adverse effects, the Purchaser will not be obligated to
accept for payment or pay for any Shares tendered. See Section 14.
 
16.  FEES AND EXPENSES
 
     Schroders is acting as Dealer Manager in connection with the Offer and is
providing certain financial advisory services to the Purchaser and Parent in
connection with the Offer. Parent is paying to Schroders a fee of $150,000 upon
the commencement of the Offer, which fee shall be credited against a fee of
$750,000, payable upon the closing of the Merger. Parent has paid an additional
fee to Schroders of $250,000 in connection with Schroders' delivery to the Board
of Directors of Parent of a fairness opinion with respect to the consideration
to be paid by Parent under the Merger Agreement. In addition, Parent has agreed
to reimburse Schroders for reasonable out-of-pocket expenses related to their
engagement, including the reasonable fees and expenses of its legal counsel, and
has agreed to indemnify each of Schroders and certain affiliated persons against
certain liabilities and expenses in connection with its services, including,
without limitation, certain liabilities under the federal securities laws.
 
     In the ordinary course of its business, Schroders engages in securities
trading, market-making and brokerage activities and may, at any time, hold long
or short positions and may trade or otherwise effect transactions in securities
of the Company. As of August 27, 1997, Schroders had no long or short positions
with respect to Shares held for its own accounts. Ilan Kaufthal, a director of
Parent, is also Managing Director and Vice Chairman of Schroders.
 
     The Purchaser and Parent have retained D.F. King & Co., Inc. to act as the
Information Agent and ChaseMellon Shareholder Services L.L.C., to serve as the
Depositary in connection with the Offer. The Information Agent and the
Depositary each will receive reasonable and customary compensation for their
services, be reimbursed for certain reasonable out-of-pocket expenses and be
indemnified against certain liabilities and expenses in connection therewith,
including certain liabilities and expenses under the Federal securities laws.
 
                                       31
<PAGE>   34
 
     Neither the Purchaser nor Parent will pay any fees or commissions to any
broker or dealer or other person (other than the Dealer Manager and the
Information Agent) in connection with the solicitation of tenders of Shares
pursuant to the Offer. Brokers, dealers, banks and trust companies will be
reimbursed by the Purchaser upon request for customary mailing and handling
expenses incurred by them in forwarding material to their customers.
 
17.  MISCELLANEOUS
 
     The Offer is not being made to (nor will tenders be accepted from or on
behalf of) holders of Shares in any jurisdiction in which the making of the
Offer or the acceptance thereof would not be in compliance with the laws of such
jurisdiction. Neither the Purchaser nor Parent is aware of any jurisdiction in
which the making of the Offer or the acceptance thereof would not be in
compliance with the laws of such jurisdiction. To the extent the Purchaser or
Parent becomes aware of any state law that would limit the class of offerees in
the Offer, the Purchaser will amend the Offer and, depending on the timing of
such amendment, if any, will extend the Offer to provide adequate dissemination
of such information to holders of Shares prior to the expiration of the Offer.
In any jurisdiction the securities, blue sky or other laws of which require the
Offer to be made by a licensed broker or dealer, the Offer is being made on
behalf of the Purchaser by the Dealer Manager or one or more registered brokers
or dealers licensed under the laws of such jurisdiction.
 
     NO PERSON HAS BEEN AUTHORIZED TO GIVE ANY INFORMATION OR TO MAKE ANY
REPRESENTATION ON BEHALF OF THE PURCHASER OR PARENT NOT CONTAINED HEREIN OR IN
THE LETTER OF TRANSMITTAL AND, IF GIVEN OR MADE, SUCH INFORMATION OR
REPRESENTATION MUST NOT BE RELIED UPON AS HAVING BEEN AUTHORIZED.
 
     The Purchaser and Parent have filed with the Commission the Schedule 14D-1
pursuant to Rule 14d-3 under the Exchange Act, together with exhibits,
furnishing certain additional information with respect to the Offer, and may
file amendments thereto. In addition, the Company has filed the Schedule 14D-9
pursuant to Rule 14d-9 under the Exchange Act, together with exhibits, setting
forth its recommendation with respect to the Offer and the reasons for such
recommendation and furnishing certain additional related information. Such
Schedules and any amendments thereto, including exhibits, should be available
for inspection and copies should be obtainable in the manner set forth in
Sections 8 and 9 (except that such material will not be available at the
regional offices of the Commission).
 
                                          BW ACQUISITION CORPORATION
 
August 28, 1997
 
                                       32
<PAGE>   35
 
                                                                      SCHEDULE 1
 
                      DIRECTORS AND EXECUTIVE OFFICERS OF
                            PARENT AND THE PURCHASER
 
     1.  DIRECTORS AND EXECUTIVE OFFICERS OF PARENT.  The following table sets
forth the name and current principal occupation or employment of the directors
and executive officers of Parent. Unless otherwise indicated, all occupations,
offices or positions of employment listed opposite an individual's name were
held by such individual during the last five years. The business address of each
such director and executive officer is Cambrex Corporation, One Meadowlands
Plaza, East Rutherford, NJ 07073. Unless otherwise indicated, all such directors
and executive officers listed below are citizens of the United States. None of
the persons listed below are directors unless indicated by an asterisk.
 
<TABLE>
<CAPTION>
                                                       PRESENT PRINCIPAL OCCUPATION
                                                        OR EMPLOYMENT AND FIVE-YEAR
            NAME AND CITIZENSHIP                            EMPLOYMENT HISTORY
- ---------------------------------------------  ---------------------------------------------
<S>                                            <C>
Cyril C. Baldwin, Jr.* ......................  President of Cambrex Corp. from 1981 to early
                                               1990, CEO from 1984 to April 1995, Chairman
                                               of the Board since 1991; Director of Church &
                                               Dwight Co., Inc. and Congoleum Corp; Member
                                               of NewsBank Advisory Board.
George J.W. Goodman*.........................  President, Chairman, and CEO of Continental
                                               Fidelity, Inc.; Director, US Airways Group,
                                               Inc. and New England Life; Member of Advisory
                                               Council of Princeton University Center for
                                               International Studies.
 
Kathryn Rudie Harrigan*......................  Professor, Management of Organizations
                                               Division of Columbia University Business
                                               School since 1981; Henry L. Kravis Professor
                                               of Business Leadership at Columbia University
                                               Business School since 1993; Academic Director
                                               of Jerome A. Chazen Institute for
                                               International Business at Columbia University
                                               since 1995; Member of the Boards of Schuller
                                               Corp. and Technical Chemicals and Products.
 
Robert LeBuhn*...............................  Chairman, Investor International (U.S.), Inc.
                                               from 1984 to 1994, President from 1984 to
                                               1993; Director of US Airways Group, Inc.,
                                               Acceptance Insurance Companies, Inc., New
                                               Jersey Steel Corp., and Enzon, Inc.
 
Rosina B. Dixon, M.D.*.......................  Consultant to the pharmaceutical industry
                                               since May 1986; Vice President, Secretary,
                                               and Member of the Board of Directors of
                                               Medical Market Specialties Inc. from 1984 to
                                               1986; Medical Director, Schering
                                               Laboratories, Schering-Plough Corp. from 1981
                                               to 1984; Executive Director Biodevelopment,
                                               Pharmaceuticals Division, CIBA-GEIGY Corp.
                                               until 1981; Member of Board of Directors of
                                               Church & Dwight Co., Inc. and Enzon, Inc.
</TABLE>
 
                                       S-1
<PAGE>   36
 
<TABLE>
<CAPTION>
                                                       PRESENT PRINCIPAL OCCUPATION
                                                        OR EMPLOYMENT AND FIVE-YEAR
            NAME AND CITIZENSHIP                            EMPLOYMENT HISTORY
- ---------------------------------------------  ---------------------------------------------
<S>                                            <C>
 
Leon J. Hendrix, Jr.*........................  Principal of Clayton, Dubilier & Rice, Inc.
                                               since 1994; Various positions at Reliance
                                               Electric Co. since 1973, including COO and
                                               Member of Board of Directors since 1992;
                                               Member of Board of Directors of Keithley
                                               Instruments, Inc., National City Bank of
                                               Cleveland, NAACO Industries, Inc., Wesco
                                               Distribution, Inc., Remington Arms Co., and
                                               Riverwood International Inc.; Member of
                                               Clemson University Board of Trustees; Past
                                               Member of Board of Governors of National
                                               Electrical Manufacturers Assoc. and Board of
                                               Directors of Cleveland Chapter of the
                                               American Red Cross.
 
Ilan Kaufthal*...............................  Managing Director of Schroder & Co. Inc.
                                               since 1987 and Vice Chairman of Schroder &
                                               Co. Inc. since May 1997; Various positions at
                                               NL Industries, Inc., including Senior Vice
                                               President and CFO since 1983; Director of
                                               United Retail Group, Inc., Russ Berrie & Co.,
                                               and ASI Solutions, Inc.
 
Francis X. Dwyer*............................  President of Nuodex Inc. from 1982 to 1985;
                                               Chairman of Board of Huls America Inc. from
                                               1985 to 1991; Advisory Chairman and Director
                                               of International Dioxide, Inc. since May
                                               1991.
 
James A. Mack*...............................  President and COO of Cambrex Corp. since
                                               February 1990, CEO since April 1995; Vice
                                               President, Specialty Chemicals and then Vice
                                               President, Performance Chemicals, Olin Corp.
                                               from 1984 to 1990; Executive Vice President,
                                               Oakite Products, Inc. from 1982 to 1984;
                                               Various positions at The Sherwin-Williams
                                               Co., including President and General Manager
                                               of the Chemicals Division from 1977 to 1981;
                                               Past Chairman of Board of Governors of
                                               Synthetic Organic Chemical Manufacturing
                                               Association; Past Member of Board of Trustees
                                               of Michigan Tech Alumni Fund; Member of Board
                                               of Directors of Chemical Manufacturing Assoc.
 
Dean P. Phypers*.............................  Various positions at IBM from 1955 to 1987,
                                               including Senior Vice President, Director,
                                               and CFO; Director of American International
                                               Group, Inc., Bethlehem Steel Corp., and
                                               Church & Dwight Co., Inc.
 
Claes Glassell...............................  Vice President of Cambrex Corp. since 1994;
                                               Senior Vice President, Akzo Nobel AB from
                                               1993 to 1994; Senior Vice President, Nobel
                                               Industries AB from 1992 to 1993.
 
Salvatore J. Guccione........................  Vice President, Commercial Development of
                                               Cambrex Corp. since 1996; Vice President and
                                               General Manager, International Specialty
                                               Products from 1993 to 1995.
</TABLE>
 
                                       S-2
<PAGE>   37
 
<TABLE>
<CAPTION>
                                                       PRESENT PRINCIPAL OCCUPATION
                                                        OR EMPLOYMENT AND FIVE-YEAR
            NAME AND CITIZENSHIP                            EMPLOYMENT HISTORY
- ---------------------------------------------  ---------------------------------------------
<S>                                            <C>
 
Steven M. Klosk..............................  Executive Vice President, Administration of
                                               Cambrex Corp. since 1996; Vice President,
                                               Administration of Cambrex Corp. from 1992 to
                                               1996.
 
Douglas H. MacMillan.........................  Vice President and CFO of Cambrex Corp. since
                                               April 1997; Vice President and CFO of Morgan
                                               Products Ltd. from 1991 to April 1997.
 
Susan M. Sorblum.............................  Treasurer of Cambrex Corp. since 1993;
                                               Various other positions at Cambrex Corp.
                                               since 1990.
 
Peter Thauer.................................  Vice President of Cambrex Corp. since 1992;
                                               General Counsel and Secretary of Cambrex
                                               Corp. since 1989.
 
Peter Tracey.................................  Executive Vice President, Corporate
                                               Development of Cambrex Corp. since March
                                               1997; CFO and Vice President of Finance of
                                               Cambrex Corp. from 1990 to March 1997.
</TABLE>
 
     2. DIRECTORS AND EXECUTIVE OFFICERS OF THE PURCHASER.  The following table
sets forth the name and current principal occupation or employment of the
directors and executive officers of the Purchaser. The business address of each
such director and executive officer is BW Acquisition Corporation in care of
Cambrex Corporation, One Meadowlands Plaza, East Rutherford, NJ 07073. Unless
otherwise indicated, all such directors and executive officers listed below are
citizens of the United States.
 
<TABLE>
<CAPTION>
                                                       PRESENT PRINCIPAL OCCUPATION
                                                        OR EMPLOYMENT AND FIVE-YEAR
            NAME AND CITIZENSHIP                            EMPLOYMENT HISTORY
- ---------------------------------------------  ---------------------------------------------
<S>                                            <C>
Peter Tracey.................................  President of BW Acquisition Corp.; Executive
                                               Vice President, Corporate Development of
                                               Cambrex Corp. since March 1997; CFO and Vice
                                               President of Finance of Cambrex Corp. from
                                               1990 to March 1997.
Peter Thauer.................................  Vice President and Secretary of BW
                                               Acquisition Corp.; Vice President of Cambrex
                                               Corp. since 1992; General Counsel and
                                               Secretary of Cambrex Corp. since 1989.
Douglas H. MacMillan.........................  Vice President, CFO, and Assistant Secretary
                                               of BW Acquisition Corp.; Vice President and
                                               CFO of Cambrex Corp. since April 1997; Vice
                                               President and CFO of Morgan Products Ltd.
                                               from 1991 to April 1997.
</TABLE>
 
                                       S-3
<PAGE>   38
 
     Manually signed facsimile copies of the Letter of Transmittal will be
accepted. The Letter of Transmittal, certificates for Shares and any other
required documents should be sent or delivered by each stockholder of the
Company or such stockholder's broker, dealer, bank, trust company or other
nominee to the Depositary at one of its addresses set forth below.
 
                        The Depositary for the Offer is:
 
                    CHASEMELLON SHAREHOLDER SERVICES, L.L.C.
 
<TABLE>
<S>                                           <C>
                   By Mail:                                      By Hand:
   ChaseMellon Shareholder Services, L.L.C.      ChaseMellon Shareholder Services, L.L.C.
          Reorganization Department                     Reorganization Department
                P.O. Box 3305                                  120 Broadway
          South Hackensack, NJ 07606                            13th Floor
                                                            New York, NY 10271
            By Overnight Courier:                       By Facsimile Transmission
   ChaseMellon Shareholder Services, L.L.C.         (for eligible institutions only):
          Reorganization Department                           (201) 329-8936
     85 Challenger Road, Mail Drop-Reorg
          Ridgefield Park, NJ 07660                Confirm by Telephone: (201) 296-4860
</TABLE>
 
     Questions and requests for assistance or for additional copies of this
Offer to Purchase, the Letter of Transmittal and the Notice of Guaranteed
Delivery may be directed to the Information Agent or the Dealer Manager at their
respective telephone numbers and locations listed below. You may also contact
your broker, dealer, bank, trust company or other nominee for assistance
concerning the Offer.
 
                    The Information Agent for the Offer is:
 
                             D.F. KING & CO., INC.
 
                                77 Water Street
                               New York, NY 10005
                         (212) 269-5550 (call collect)
                            Toll Free (800) 290-6426
 
                      The Dealer Manager for the Offer is:
 
                              SCHRODER & CO. INC.
 
                                Equitable Center
                               787 Seventh Avenue
                               New York, NY 10019
                         (212) 492-6000 (call collect)

<PAGE>   1
 
          STOCKHOLDERS WISHING TO TENDER THEIR SHARES SHOULD USE THIS
                             LETTER OF TRANSMITTAL.
 
                             LETTER OF TRANSMITTAL
                        TO TENDER SHARES OF COMMON STOCK
                            (AND ASSOCIATED RIGHTS)
 
                                       OF
 
                               BIOWHITTAKER, INC.
                                       AT
 
                             $11.625 NET PER SHARE
 
            PURSUANT TO THE OFFER TO PURCHASE DATED AUGUST 28, 1997
 
                                       BY
 
                           BW ACQUISITION CORPORATION
                          A WHOLLY-OWNED SUBSIDIARY OF
 
                              CAMBREX CORPORATION
 
         THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT,
                   NEW YORK CITY TIME, ON SEPTEMBER 25, 1997
                         UNLESS THE OFFER IS EXTENDED.
 
                        The Depositary for the Offer is:
 
                    CHASEMELLON SHAREHOLDER SERVICES, L.L.C.
 
<TABLE>
<S>                                           <C>
                   By Mail:                                      By Hand:
   ChaseMellon Shareholder Services, L.L.C.      ChaseMellon Shareholder Services, L.L.C.
          Reorganization Department                     Reorganization Department
                P.O. Box 3305                                  120 Broadway
          South Hackensack, NJ 07606                            13th Floor
                                                            New York, NY 10271
            By Overnight Courier:                       By Facsimile Transmission
   ChaseMellon Shareholder Services, L.L.C.         (for eligible institutions only):
          Reorganization Department                           (201) 329-8936
     85 Challenger Road, Mail Drop-Reorg
          Ridgefield Park, NJ 07660                Confirm by Telephone: (201) 296-4860
</TABLE>
 
    DELIVERY OF THIS LETTER OF TRANSMITTAL TO AN ADDRESS OTHER THAN AS SET FORTH
ABOVE, OR TRANSMISSIONS OF INSTRUCTIONS VIA A FACSIMILE NUMBER OTHER THAN AS SET
FORTH ABOVE, WILL NOT CONSTITUTE A VALID DELIVERY.
 
    SIGNATURES MUST BE PROVIDED ON THE INSIDE AND REVERSE BACK COVER. PLEASE
READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY.
 
     This BLUE Letter of Transmittal is to be completed by holders of Shares (as
defined below) either if certificates are to be forwarded herewith or, unless an
Agent's Message (as defined in Section 2 of the Offer to Purchase (as defined
below)) is utilized, if a tender of Shares are to be made by book-entry transfer
into the account of ChaseMellon Shareholder Services, L.L.C. as Depositary (the
"Depositary"), at The Depository Trust Company ("DTC"), the Midwest Securities
Trust Company ("MSTC") or the Philadelphia Depository Trust Company ("PDTC")
(each a "Book-Entry Transfer Facility" and collectively the "Book-Entry Transfer
Facilities") pursuant to the procedures set forth in Section 2 of the Offer to
Purchase (as defined below).
<PAGE>   2
 
     Holders of Shares whose certificates for such Shares (the "Share
Certificates") are not immediately available or who cannot deliver their Share
Certificates and all other required documents to the Depositary prior to the
Expiration Date (as defined in Section 1 of the Offer to Purchase), or who
cannot complete the procedure for book-entry transfer on a timely basis, must
tender their Shares according to the guaranteed delivery procedure set forth in
Section 2 of the Offer to Purchase. See Instruction 2. Delivery of documents to
a Book-Entry Transfer Facility does not constitute delivery to the Depositary.
 
[ ] CHECK HERE IF SHARES ARE BEING DELIVERED BY BOOK-ENTRY TRANSFER MADE TO AN
    ACCOUNT MAINTAINED BY THE DEPOSITARY WITH A BOOK-ENTRY TRANSFER FACILITY AND
    COMPLETE THE FOLLOWING:
 
  Name of Tendering Institution:
  ------------------------------------------------------------------------------
 
  Check Box of Book-Entry Transfer Facility:
 
    [ ] DTC                  [ ] MSTC                  [ ] PDTC
 
  Account Number:
  ----------------------- Transaction Code Number:
  -----------------------------------------
 
[ ] CHECK HERE IF SHARES ARE BEING DELIVERED PURSUANT TO A NOTICE OF GUARANTEED
    DELIVERY PREVIOUSLY SENT TO THE DEPOSITARY AND COMPLETE THE FOLLOWING.
    PLEASE ENCLOSE A PHOTOCOPY OF SUCH NOTICE OF GUARANTEED DELIVERY.
 
  Name(s) of Registered Holder(s):
  ---------------------------------------------------------------------------
 
  Window Ticket Number (if any):
  ----------------------------------------------------------------------------
 
  Date of Execution of Notice of Guaranteed Delivery:
  -------------------------------------------------------
 
  Name of Institution which Guaranteed Delivery:
  ------------------------------------------------------------
- --------------------------------------------------------------------------------
                         DESCRIPTION OF SHARES TENDERED
 
<TABLE>
<CAPTION>
<S>                                                <C>                   <C>                   <C>
- ------------------------------------------------------------------------------------------------------------------
  NAME(S) AND ADDRESS(ES) OF REGISTERED HOLDER(S)                       SHARE CERTIFICATE(S) AND
   (PLEASE FILL IN, IF BLANK, EXACTLY AS NAME(S)                           SHARE(S) TENDERED
        APPEAR(S) ON SHARE CERTIFICATE(S))                       (ATTACH ADDITIONAL LIST, IF NECESSARY)
 ------------------------------------------------------------------------------------------------------------------
                                                                              TOTAL NUMBER
                                                           SHARE               OF SHARES               NUMBER
                                                        CERTIFICATE          REPRESENTED BY          OF SHARES
                                                         NUMBER(S)*         CERTIFICATE(S)*          TENDERED**
                                                    ---------------------------------------------------------------
 
                                                    ---------------------------------------------------------------
 
                                                    ---------------------------------------------------------------
 
                                                    ---------------------------------------------------------------
 
                                                    ---------------------------------------------------------------
 
                                                    ---------------------------------------------------------------
                                                        Total Shares
 ------------------------------------------------------------------------------------------------------------------
</TABLE>
 
  * Need not be completed by Book-Entry Stockholders.
 
 ** Unless otherwise indicated, it will be assumed that all Shares represented
    by certificates delivered to the Depositary are being tendered. See
    Instruction 4.
================================================================================
<PAGE>   3
 
Ladies and Gentlemen:
 
     The undersigned hereby tenders to BW Acquisition Corporation, a Delaware
corporation ("Purchaser") and a wholly-owned subsidiary of Cambrex Corporation,
a Delaware corporation, the above-described shares of Common Stock, par value
$0.01 per Share (the "Common Stock"), of BioWhittaker, Inc., a Delaware
corporation (the "Company"), and the associated rights to purchase Series A
Participating Cumulative Preferred Stock (together with the Common Stock, the
"Shares") issued pursuant to the Stockholder Protection Rights Agreement, dated
as of January 20, 1995, as amended, between the Company and Bank of Boston, as
Rights Agent, at a purchase price of $11.625 per Share, net to the seller in
cash without interest thereon, upon the terms and subject to the conditions set
forth in the Offer to Purchase, dated August 28, 1997 (the "Offer to Purchase")
and in this BLUE Letter of Transmittal (which together with the Offer to
Purchase, constitutes the "Offer"). The undersigned understands that Purchaser
reserves the right to transfer or assign, in whole or from time to time in part,
to one or more of its affiliates, the right to purchase all or any portion of
the Shares tendered pursuant to the Offer.
 
     Subject to, and effective upon, acceptance for payment of the Shares
tendered herewith in accordance with the terms and subject to the conditions of
the Offer, the undersigned hereby sells, assigns and transfers to, or upon the
order of, Purchaser all right, title and interest in and to all of the Shares
that are being tendered hereby and any and all dividends, distributions
(including additional Shares) and rights declared, paid or issued with respect
to the tendered Shares on or after August 22, 1997 and payable or distributable
to the undersigned on a date prior to the transfer to the name of Purchaser (or
nominee or transferee of Purchaser) on the Company's stock transfer records of
the Shares tendered herewith (collectively, a "Distribution"), and irrevocably
constitutes and appoints the Depositary the true and lawful agent and
attorney-in-fact of the undersigned with respect to such Shares (and any
Distributions) with full power of substitution (such power of attorney being
deemed to be an irrevocable power coupled with an interest) to (a) deliver
certificates for such Shares (and any Distributions) or transfer ownership of
such Shares (and any Distributions) on the account books maintained by a
Book-Entry Transfer Facility, together in either case with appropriate evidences
of transfer, to the Depositary for the account of Purchaser, (b) present such
Shares (and any Distributions) for transfer on the books of the Company and (c)
receive all benefits and otherwise exercise all rights of beneficial ownership
of such Shares (and any Distributions), all in accordance with the terms and
subject to the conditions of the Offer.
 
     The undersigned irrevocably appoints Peter Thauer and Peter Tracey, and
each of them, or any other designees of Purchaser, as such stockholder's
attorneys-in-fact and proxies, each with full power of substitution, to the full
extent of such stockholder's rights with respect to the Shares tendered by such
stockholder and accepted for payment by Purchaser and with respect to any and
all other shares or other securities issued or issuable in respect of such
Shares on or after August 22, 1997. Such appointment will be effective upon the
acceptance for payment of such Shares by Purchaser in accordance with the terms
of the Offer. Upon such acceptance for payment, all prior powers of attorney and
proxies given by such stockholder with respect to such Shares (and such other
shares and securities) will be revoked without further action, and no subsequent
proxies may be given nor any subsequent written consents executed (and, if given
or executed, will not be deemed effective). The proxies (or other designees of
Purchaser) will be empowered to exercise all voting and other rights of such
stockholder as they in their sole discretion may deem proper at any annual or
special meeting of the Company's stockholders or any adjournment or postponement
thereof, by consent in lieu of any such meeting or otherwise. Purchaser reserves
the right to require that, in order for Shares to be deemed validly tendered,
immediately upon Purchaser's payment for such Shares Purchaser must be able to
exercise full voting rights with respect to such Shares.
 
     The undersigned hereby represents and warrants that (a) the undersigned has
full power and authority to tender, sell, assign and transfer the Shares (and
any Distributions) tendered hereby and (b) when the Shares are accepted for
payment by Purchaser, Purchaser will acquire good, marketable and unencumbered
title to the Shares (and any Distributions), free and clear of all liens,
restrictions, charges and encumbrances, and the same will not be subject to any
adverse claim. The undersigned, upon request, shall execute and deliver any
signature guarantee or additional documents deemed by the Depositary or
Purchaser to be necessary or desirable to complete the sale, assignment and
transfer of the Shares (and any Distributions) tendered hereby.
<PAGE>   4
 
In addition, the undersigned shall promptly remit and transfer to the Depositary
for the account of Purchaser any and all Distributions in respect of the Shares
tendered hereby, accompanied by appropriate documentation of transfer, and
pending such remittance or appropriate assurance thereof, Purchaser will be,
subject to applicable law, entitled to all rights and privileges as owner of any
such Distribution and may withhold the entire purchase price or deduct from the
purchase price the amount or value thereof, as determined by Purchaser in its
sole discretion.
 
     No authority herein conferred or agreed to be conferred by this Letter of
Transmittal shall be affected by, and all such authority shall survive the death
or incapacity of the undersigned. All obligations of the undersigned hereunder
shall be binding upon the heirs, executors, administrators, trustees in
bankruptcy, personal and legal representatives, successors and assigns of the
undersigned.
 
     Tenders of Shares made pursuant to the Offer are irrevocable, except that
Shares tendered pursuant to the Offer may be withdrawn at any time prior to the
Expiration Date (as defined in Section 1 of the Offer to Purchase) and, unless
theretofore accepted for payment by Purchaser pursuant to the Offer, may also be
withdrawn at any time after October 27, 1997. See Section 3 of the Offer to
Purchase.
 
     The undersigned understands that tenders of Shares pursuant to any of the
procedures described in Section 2 of the Offer to Purchase and in the
instructions hereto will constitute a binding agreement between the undersigned
and Purchaser upon the terms and subject to the conditions set forth in the
Offer, including the undersigned's representation and warranty that the
undersigned owns the Shares being tendered.
 
     Unless otherwise indicated herein under "Special Payment Instructions,"
please issue the check for the purchase price and/or return any certificate(s)
for Shares not tendered or not accepted for payment in the name(s) of the
registered holder(s) appearing under "Description of Shares Tendered."
Similarly, unless otherwise indicated herein under "Special Delivery
Instructions," please mail the check for the purchase price and/or any
certificate(s) for Shares not tendered or not accepted for payment (and
accompanying documents, as appropriate) to the address(es) of the registered
holder(s) appearing under "Description of Shares Tendered." In the event that
both the Special Delivery Instructions and the Special Payment Instructions are
completed, please issue the check for the purchase price and/or any
certificate(s) for Shares not tendered or accepted for payment in the name of,
and deliver such check and/or such certificates to, the person or persons so
indicated. Unless otherwise indicated herein under "Special Payment
Instructions," please credit any Shares tendered herewith by book-entry transfer
that are not accepted for payment by crediting the account at the Book-Entry
Transfer Facility designated above. The undersigned recognizes that Purchaser
has no obligation, pursuant to the Special Payment Instructions, to transfer any
Shares from the name(s) of the registered holder(s) thereof if Purchaser does
not accept for payment any of the Shares so tendered.
<PAGE>   5
 
[ ] CHECK HERE IF ANY OF THE CERTIFICATES REPRESENTING THE SHARES THAT YOU OWN
    HAVE BEEN LOST OR DESTROYED AND SEE INSTRUCTION 11.
 
  Number of shares represented by the lost or destroyed certificates:
  --------------
 
  Please fill in the remainder of this Letter of Transmittal.
 
          ------------------------------------------------------------
 
                          SPECIAL PAYMENT INSTRUCTIONS
                        (SEE INSTRUCTIONS 1, 5, 6 AND 7)
 
        To be completed ONLY if certificate(s) for Shares not tendered or not
   accepted for payment and/or the check for the purchase price of Shares
   accepted for payment are to be issued in the name of someone other than
   the undersigned or if Shares tendered by book-entry transfer which are not
   accepted for payment are to be returned by credit to an account maintained
   at a Book-Entry Transfer Facility.
 
   Issue:  [ ] Check   [ ] Certificates to:
 
   Name:
   ----------------------------------------------------
                                    (PLEASE PRINT)
 
   Address:
   --------------------------------------------------
 
          ------------------------------------------------------------
 
          ------------------------------------------------------------
                               (INCLUDE ZIP CODE)
 
          ------------------------------------------------------------
                (TAXPAYER IDENTIFICATION OR SOCIAL SECURITY NO.)
                    (SEE SUBSTITUTE FORM W-9 ON BACK COVER)
 
   [ ] Credit Shares tendered by book-entry transfer that are not accepted
       for payment to (Check One):
 
   [ ] DTC                          [ ] MSTC                         [ ] PDTC
 
          ------------------------------------------------------------
                                (ACCOUNT NUMBER)
          ============================================================
 
                          SPECIAL PAYMENT INSTRUCTIONS
                        (SEE INSTRUCTIONS 1, 5, 6 AND 7)
 
        To be completed ONLY if certificate(s) for Shares not tendered or not
   accepted for payment and/or the check for the purchase price of Shares
   accepted for payment are to be sent to someone other than the undersigned
   or to the undersigned at an address other than that shown above.
 
   Mail:  [ ] Check  [ ] Certificates to:
 
   Name:  -----------------------------------------------------------
                                    (PLEASE PRINT)
 
   Address:
   --------------------------------------------------
 
          ------------------------------------------------------------
 
          ------------------------------------------------------------
                               (INCLUDE ZIP CODE)
 
          ------------------------------------------------------------
                (TAXPAYER IDENTIFICATION OR SOCIAL SECURITY NO.)
                    (SEE SUBSTITUTE FORM W-9 ON BACK COVER)
 
          ------------------------------------------------------------
<PAGE>   6
 
- --------------------------------------------------------------------------------
                                   IMPORTANT:
                             STOCKHOLDERS SIGN HERE
              (ALSO COMPLETE SUBSTITUTE FORM W-9 ON REVERSE SIDE)
            X
 
            --------------------------------------------------------
            X
 
            --------------------------------------------------------
                           Signature(s) of Holder(s)
 
            Dated:
            --------------------------------------------------------
 
            (Must be signed by the registered holder(s) exactly as
            name(s) appear(s) on Share Certificate(s) or on a
            security position listing or by person(s) authorized to
            become registered holders(s) by certificates and
            document transmitted herewith. If signature is by
            trustees, executors, administrators, guardians,
            attorneys-in-fact, officers of corporations or others
            acting in a fiduciary or representative capacity, please
            provide the following information and see Instruction
            5.)
 
            Name(s):
            --------------------------------------------------------
 
                    ------------------------------------------------
                                     (Please Print)
 
            Capacity (Full Title):
                            ----------------------------------------
 
            Address:
                  --------------------------------------------------
 
                  --------------------------------------------------
 
                  --------------------------------------------------
                               (Include Zip Code)
 
            Daytime Telephone Number: (   )
                                     -------------------------------
                                          (Area Code)
 
            Tax Identification or Social Security No.:
                                        ----------------------------
                   (See Substitute Form W-9 on Reverse Side)
 
                           GUARANTEE OF SIGNATURE(S))
                   (IF REQUIRED -- SEE INSTRUCTIONS 1 AND 5)
 
            Authorized Signature:
                            ----------------------------------------
 
            Name:---------------------------------------------------
 
            Name of Firm:
                       ---------------------------------------------
 
            Address:
                  --------------------------------------------------
 
                  --------------------------------------------------
 
                  --------------------------------------------------
                               (Include Zip Code)
 
            Daytime Telephone Number: (   )
                                     -------------------------------
                                          (Area Code)
            Dated:
            --------------------------------------------------- ,
            1997
- --------------------------------------------------------------------------------
                                                             SIGN
                                                             HERE
                                        
<PAGE>   7
 
                                  INSTRUCTIONS
 
             FORMING PART OF THE TERMS AND CONDITIONS OF THE OFFER
 
     1.  GUARANTEE OF SIGNATURES.  No signature guarantee is required on this
Letter of Transmittal (a) if this Letter of Transmittal is signed by the
registered holder(s) of Shares (which term, for purposes of this document, shall
include any participant in a Book-Entry Transfer Facility whose name appears on
a security position listing as the owner of Shares) tendered herewith, unless
such holder(s) has completed either the box entitled "Special Payment
Instructions" or the box entitled "Special Delivery Instructions" above, or (b)
if such Shares are tendered for the account of a firm which is a bank, broker,
dealer, credit union, savings association or other entity which is a member in
good standing of a recognized Medallion Program approved by the Securities
Transfer Association (each of the foregoing being referred to as an "Eligible
Institution"). In all other cases, all signatures on this Letter of Transmittal
must be guaranteed by an Eligible Institution. See Instruction 5 of this Letter
of Transmittal.
 
     2.  REQUIREMENTS OF TENDER.  This Letter of Transmittal is to be completed
by stockholders either if certificates are to be forwarded herewith or, unless
an Agent's Message is utilized, if tenders are to be made pursuant to the
procedure for tender by book-entry transfer set forth in Section 2 of the Offer
to Purchase. Certificates for all physically tendered Shares or timely
confirmation (a "Book-Entry Confirmation") of a book-entry transfer of such
Shares into the Depositary's account at a Book-Entry Transfer Facility, as well
as a properly completed and duly executed Letter of Transmittal (or a facsimile
hereof), with any required signature guarantees, or an Agent's Message in
connection with a book-entry transfer, and any other documents required by this
Letter of Transmittal, must be received by the Depositary at one of its
addresses set forth herein prior to the Expiration Date (as defined in Section 1
of the Offer to Purchase).
 
     Stockholders whose certificates for Shares are not immediately available or
who cannot deliver their certificates for Shares and all other required
documents to the Depositary prior to the Expiration Date or who cannot complete
the procedure for delivery by book-entry transfer on a timely basis may tender
their Shares by properly completing and duly executing a Notice of Guaranteed
Delivery pursuant to the guaranteed delivery procedure set forth in Section 2 of
the Offer to Purchase. Pursuant to such procedure: (i) such tender must be made
by or through an Eligible Institution; (ii) a properly completed and duly
executed Notice of Guaranteed Delivery, substantially in the form made available
by the Purchaser, must be received by the Depositary on or prior to the
Expiration Date; and (iii) the certificates (or a Book-Entry Confirmation)
representing all tendered Shares, in proper form for transfer, in each case
together with the Letter of Transmittal (or a facsimile thereof), properly
completed and duly executed, with any required signature guarantees (or, in the
case of a book-entry delivery, an Agent's Message) and any other documents
required by this Letter of Transmittal, must be received by the Depositary
within three New York Stock Exchange, Inc. trading days after the date of
execution of such Notice of Guaranteed Delivery.
 
     TENDERING STOCKHOLDERS SHOULD USE THIS BLUE LETTER OF TRANSMITTAL AND THE
GRAY NOTICE OF GUARANTEED DELIVERY PROVIDED WITH THE OFFER TO PURCHASE.
STOCKHOLDERS WILL BE ABLE TO TENDER (OR WITHDRAW) THEIR SHARES PURSUANT TO THE
OFFER UNTIL 12:00 MIDNIGHT, NEW YORK CITY TIME, ON SEPTEMBER 25, 1997 (OR SUCH
LATER DATE TO WHICH THE OFFER MAY BE EXTENDED).
 
     THE METHOD OF DELIVERY OF STOCK CERTIFICATES AND ALL OTHER REQUIRED
DOCUMENTS, INCLUDING DELIVERY THROUGH ANY BOOK-ENTRY TRANSFER FACILITY, IS AT
THE OPTION AND RISK OF THE TENDERING STOCKHOLDER. IF DELIVERY IS BY MAIL,
REGISTERED MAIL WITH RETURN RECEIPT REQUESTED, PROPERLY INSURED, IS RECOMMENDED.
IN ALL CASES, SUFFICIENT TIME SHOULD BE ALLOWED TO ENSURE TIMELY DELIVERY.
 
     No alternative, conditional or contingent tenders will be accepted and no
fractional Shares will be purchased. All tendering stockholders, by execution of
this Letter of Transmittal (or a facsimile hereof), waive any right to receive
any notice of the acceptance of their Shares for payment.
<PAGE>   8
 
     3.  INADEQUATE SPACE.  If the space provided herein is inadequate, the
certificate numbers and/or the number of Shares and any other required
information should be listed on a separate signed schedule attached hereto.
 
     4.  PARTIAL TENDERS.  (Not applicable to stockholders who tender by
book-entry transfer). If fewer than all the Shares evidenced by any certificate
submitted are to be tendered, fill in the number of Shares which are to be
tendered in the box entitled "Number of Shares Tendered." In such cases, new
certificates for the Shares that were evidenced by your old certificates, but
which were not tendered by you, will be sent to you, unless otherwise provided
in the appropriate box on this Letter of Transmittal, as soon as practicable
after the Expiration Date. All Shares represented by certificates delivered to
the Depositary will be deemed to have been tendered unless otherwise indicated.
 
     5.  SIGNATURES ON LETTER OF TRANSMITTAL, STOCK POWERS AND ENDORSEMENTS.  If
this Letter of Transmittal is signed by the registered holder(s) of the Shares
tendered hereby, the signature(s) must correspond with the name(s) as written on
the face of the certificate(s) without alteration, enlargement or any change
whatsoever.
 
     If any of the Shares tendered hereby are owned of record by two or more
joint owners, all such owners must sign this Letter of Transmittal.
 
     If any of the tendered Shares are registered in different names on several
certificates, it will be necessary to complete, sign and submit as many separate
Letters of Transmittal as there are different registrations of certificates.
 
     If this Letter of Transmittal or any certificates or stock powers are
signed by trustees, executors, administrators, guardians, attorneys-in-fact,
officers of corporations or others acting in a fiduciary or representative
capacity, such persons should so indicate when signing, and proper evidence
satisfactory to Purchaser of their authority to so act must be submitted.
 
     When this Letter of Transmittal is signed by the registered owner(s) of the
Shares listed and transmitted hereby, no endorsements of certificates or
separate stock powers are required unless payment is to be made to, or
certificates for Shares not tendered or not purchased are to be issued in the
name of, a person other than the registered holder(s). Signatures on such
certificates or stock powers must be guaranteed by an Eligible Institution.
 
     If this Letter of Transmittal is signed by a person other than the
registered owner(s) of the certificate(s) listed, the certificate(s) must be
endorsed or accompanied by appropriate stock powers, in either case signed
exactly as the name(s) of the registered holder(s) appear on the certificate(s).
Signatures on such certificates and stock powers must be guaranteed by an
Eligible Institution, unless the signature is that of an Eligible Institution.
 
     6.  STOCK TRANSFER TAXES.  Except as otherwise provided in this Instruction
6, Purchaser will pay any stock transfer taxes with respect to the purchase of
Shares pursuant to the Offer. If, however, payment of the purchase price is to
be made to, or if certificate(s) for Shares not tendered or accepted for payment
are to be registered in the name of, any person other than the registered
owner(s), or if tendered certificate(s) are registered in the name of any person
other than the person(s) signing this Letter of Transmittal, the amount of any
stock transfer taxes (whether imposed on the registered owner(s) or such person)
payable on account of the transfer to such person will be deducted from the
purchase price unless satisfactory evidence of the payment of such taxes, or an
exemption therefrom, is submitted.
 
     7.  SPECIAL PAYMENT AND DELIVERY INSTRUCTIONS.  If a check is to be issued
in the name of, and/or certificates for Shares not tendered or not accepted for
payment are to be issued or returned to, a person other than the signer of this
Letter of Transmittal or if a check and/or such certificates are to be returned
to a person other than the person(s) signing this Letter of Transmittal or to an
address other than that shown in this Letter of Transmittal, the appropriate
boxes on this Letter of Transmittal must be completed. A stockholder who tenders
by book-entry transfer may request that Shares not accepted for payment be
credited to such account maintained at a Book-Entry Transfer Facility as such
stockholder may designate under "Special Payment Instructions." If no such
instructions are given, such Shares not accepted for payment will be returned by
crediting the account at the Book-Entry Transfer Facility designated above.
<PAGE>   9
 
     8.  WAIVER OF CONDITIONS.  The conditions of the Offer may be waived by
Purchaser in whole or in part at any time and from time to time in its sole
discretion, subject to the terms of the Agreement and Plan of Merger, dated as
of August 22, 1997, among BioWhittaker, Inc., BW Acquisition Corporation and
Cambrex Corporation.
 
     9.  BACKUP WITHHOLDING; SUBSTITUTE FORM W-9.  Under U.S. federal income tax
law, a stockholder whose tendered Shares are accepted for payment is required to
provide the Depositary with such stockholder's correct taxpayer identification
number ("TIN"), generally the stockholder's social security or federal employer
identification number, and certain other information, on Substitute Form W-9
below. If the Depositary is not provided with the correct TIN, the Internal
Revenue Service may subject the stockholder or other payee to a $50 penalty. In
addition, payments that are made to such stockholder or other payee with respect
to Shares purchased pursuant to the Offer may be subject to 31% backup
withholding.
 
     Certain stockholders (including, among others, all corporations and certain
foreign individuals) are not subject to these backup withholding and reporting
requirements. In order for a foreign individual to qualify as an exempt
recipient, the stockholder must submit a Form W-8, signed under penalties of
perjury, attesting to that individual's exempt status. A Form W-8 can be
obtained from the Depositary. See the enclosed "Guidelines for Certification of
Taxpayer Identification Number on Substitute Form W-9" for more instructions.
 
     If backup withholding applies, the Depositary is required to withhold 31%
of any such payments made to the stockholder or other payee. Backup withholding
is not an additional tax. Rather, the tax liability of persons subject to backup
withholding will be reduced by the amount of tax withheld. If withholding
results in an overpayment of taxes, a refund may be obtained from the Internal
Revenue Service.
 
     If the tendering stockholder has not been issued a TIN and has applied for
a TIN or intends to apply for a TIN in the near future, the tendering
stockholder should write "Applied For" in Part 1 of the Substitute Form W-9.
Notwithstanding that "Applied For" is written in Part 1, the Depositary will
withhold 31% of all payments made prior to the time a properly certified TIN is
provided to the Depositary.
 
     The stockholder is required to give the Depositary the TIN (e.g., social
security number or employer identification number) of the record owner of the
Shares or of the last transferee appearing on the transfers attached to, or
endorsed on, the Shares. If the Shares are in more than one name or are not in
the name of the actual owner, consult the enclosed "Guidelines for Certification
of Taxpayer Identification Number on Substitute Form W-9" for additional
guidance on which number to report.
 
     10.  REQUESTS FOR ASSISTANCE OR ADDITIONAL COPIES.  Questions or requests
for assistance may be directed to the Dealer Manager or the Information Agent at
their respective addresses and telephone numbers set forth below. Additional
copies of the Offer to Purchase, the Supplement, this Letter of Transmittal and
the Notice of Guaranteed Delivery may also be obtained from the Information
Agent or from brokers, dealers, commercial banks or trust companies.
 
     11.  LOST, DESTROYED OR STOLEN CERTIFICATES.  If any certificate
representing Shares has been lost, destroyed or stolen, the stockholder should
promptly notify the Depositary by checking the box immediately preceding special
payment/special delivery instructions and indicating the number of Shares lost.
The stockholder will then be instructed as to the steps that must be taken in
order to replace the certificate. This Letter of Transmittal and related
documents cannot be processed until the procedures for replacing lost or
destroyed certificates have been followed.
 
     IMPORTANT: THIS LETTER OF TRANSMITTAL (OR A FACSIMILE HEREOF), TOGETHER
WITH STOCK CERTIFICATES OR CONFIRMATION OF BOOK-ENTRY TRANSFER OR THE NOTICE OF
GUARANTEED DELIVERY, AND ALL OTHER REQUIRED DOCUMENTS, MUST BE RECEIVED BY THE
DEPOSITARY PRIOR TO THE EXPIRATION DATE.
<PAGE>   10
 
     Questions and requests for assistance may be directed to the Information
Agent or the Dealer Manager at their respective addresses and telephone numbers
listed below. Additional copies of the Offer to Purchase, the Letter of
Transmittal and other tender offer materials may be obtained from the
Information Agent as set forth below, and will be furnished promptly at the
Purchaser's expense. You may also contact your broker, dealer, commercial bank,
trust company or other nominee for assistance concerning the Offer.
 
                    The Information Agent for the Offer is:
 
                             D.F. KING & CO., INC.
 
                                77 Water Street
                            New York, New York 10005
                         (212) 269-5550 (Call Collect)
                               or (800) 290-6426
 
                      The Dealer Manager for the Offer is:
 
                              SCHRODER & CO. INC.
 
                                Equitable Center
                               787 Seventh Avenue
                            New York, New York 10019
                         (212) 492-6000 (Call Collect)
<PAGE>   11
 
<TABLE>
<S>                              <C>                                          <C>
- ---------------------------------------------------------------------------------------------------------
PAYER'S NAME: CHASEMELLON SHAREHOLDER SERVICES, L.L.C., AS DEPOSITARY
- ---------------------------------------------------------------------------------------------------------
 SUBSTITUTE                      Part I-PLEASE PROVIDE YOUR TIN IN THE BOX    Social Security Number OR
 FORM W-9                        AT RIGHT AND CERTIFY BY SIGNING AND DATING   ---------/ ---------/
 DEPARTMENT OF THE TREASURY      BELOW.                                       ---------
 INTERNAL REVENUE SERVICE                                                     Employee Identification
                                                                              Number
                                                                              (if awaiting TIN write
                                                                              "Applied For")
                                 ------------------------------------------------------------------------
                                 Part II-For Payees Exempt From Backup Withholding, see the enclosed
                                 Guidelines and complete as instructed therein. CERTIFICATION-Under
 PAYER'S REQUEST FOR TAXPAYER    penalties of perjury, I certify that:
 IDENTIFICATION NUMBER ("TIN")   (1) The number shown on this form is my correct Taxpayer Identification
                                 Number (or a Taxpayer Identification Number has not been issued to me
                                     and either (a) I have mailed or delivered an application to receive
                                     a Taxpayer Identification Number to the appropriate Internal Revenue
                                     Service ("IRS") or Social Security Administration office or (b) I
                                     intend to mail or deliver an application in the near future. I
                                     understand that if I do not provide a Taxpayer Identification Number
                                     within sixty (60) days, 31% of all reportable payments made to me
                                     thereafter will be withheld until I provide a number), and
                                 (2) I am not subject to backup withholding either because I have not
                                 been notified by the IRS that I am subject to backup withholding as a
                                     result of failure to report all interest or dividends, or the IRS
                                     has notified me that I am no longer subject to backup withholding.
                                 ------------------------------------------------------------------------
                                 CERTIFICATION INSTRUCTIONS-You must cross out item (2) above if you have
                                 been notified by the IRS that you are subject to backup withholding
                                 because of underreporting interest or dividends on your tax return.
                                 However, if after being notified by the IRS that you were subject to
                                 backup withholding you received another notification from the IRS that
                                 you are no longer subject to backup withholding, do not cross out item
                                 (2). (Also see instructions in the enclosed Guidelines.)
                                 SIGNATURE                                    DATE , 1997
- ---------------------------------------------------------------------------------------------------------
</TABLE>
 
NOTE: FAILURE TO COMPLETE AND RETURN THIS FORM MAY RESULT IN BACKUP WITHHOLDING
      OF 31% OF ANY PAYMENTS MADE TO YOU PURSUANT TO THE OFFER. PLEASE REVIEW
      THE ENCLOSED GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION
      NUMBER ON SUBSTITUTE FORM W-9 FOR ADDITIONAL DETAILS.

<PAGE>   1
 
                       NOTICE OF GUARANTEED DELIVERY FOR
                      TENDER OF SHARES OF COMMON STOCK AND
                    ASSOCIATED RIGHTS OF BIOWHITTAKER, INC.
                   (NOT TO BE USED FOR SIGNATURE GUARANTEES)
 
     This Notice of Guaranteed Delivery, or one substantially in the form
hereof, must be used to accept the Offer (as defined below) (i) if certificates
("Share Certificates") evidencing shares of common stock par value $0.01 per
Share (the "Common Stock") of BioWhittaker, Inc., and associated rights to
purchase Series A Participating Cumulative Preferred Stock ("Rights"; and
together with the Common Stock, the "Shares"), are not immediately available,
(ii) if Share Certificates and all other required documents cannot be delivered
to ChaseMellon Shareholder Services, L.L.C., as Depositary (the "Depositary"),
prior to the Expiration Date (as defined in Section 1 of the Offer to Purchase
(as defined below)) or (iii) if the procedure for delivery by book-entry
transfer cannot be completed on a timely basis. This Notice of Guaranteed
Delivery may be delivered by hand or mail or transmitted by facsimile
transmission to the Depositary. See Section 2 of the Offer to Purchase.
 
     The Depositary for the Offer is:
 
                    CHASEMELLON SHAREHOLDER SERVICES, L.L.C.
 
<TABLE>
<S>                                                <C>
                     By Mail:                                           By Hand:
     ChaseMellon Shareholder Services, L.L.C.           ChaseMellon Shareholder Services, L.L.C.
             Reorganization Department                          Reorganization Department
                    PO Box 3305                                       120 Broadway
            South Hackensack, NJ 07606                                 13th Floor
                                                                   New York, NY 10271
               By Overnight Courier:                            By Facsimile Transmission
     ChaseMellon Shareholder Services, L.L.C.               (for eligible institutions only):
             Reorganization Department                               (201) 329-8936
        85 Challenger Road, Mail Drop-Reorg
             Ridgefield Park, NJ 07660                    Confirm by Telephone: (201) 296-4860
</TABLE>
 
     DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY TO AN ADDRESS OTHER THAN AS
SET FORTH ABOVE, OR TRANSMISSION OF INSTRUCTIONS VIA FACSIMILE TRANSMISSION
OTHER THAN AS SET FORTH ABOVE, WILL NOT CONSTITUTE A VALID DELIVERY.
 
     This form is not to be used to guarantee signatures. If a signature on a
Letter of Transmittal is required to be guaranteed by an "Eligible Institution"
under the instructions thereto, such signature guarantee must appear in the
applicable space provided in the signature box on the Letter of Transmittal.
<PAGE>   2
 
LADIES AND GENTLEMEN:
 
     The undersigned hereby tenders to BW Acquisition Corporation, a Delaware
corporation and a wholly-owned subsidiary of Cambrex Corporation, upon the terms
and subject to the conditions set forth in the Offer to Purchase, dated August
28, 1997 (the "Offer to Purchase"), and the related Letter of Transmittal
(which, amended from time to time, together constitute the "Offer"), receipt of
each of which is hereby acknowledged, the number of Shares specified below
pursuant to the guaranteed delivery procedure described in Section 2 of the
Offer to Purchase.
 
Number of Shares:
- --------------------------------------------------------------------------------
Certificate Nos. (If Available):
- -------------------------------------------------------------------------------
Check one box if Shares will be delivered by book-entry transfer:
[ ] The Depository Trust Company
[ ] Philadelphia Depository Trust Company
[ ] Midwest Securities Trust Company
 
Name of Tendering Institution:
- -------------------------------------------------------------------------------
Account No.:
- --------------------------------------------------------------------------------
Signature(s) of Holder(s):
 
- --------------------------------------------------------------------------------
 
- --------------------------------------------------------------------------------
Dated:
- ------------------------------------, 1997
Name(s) of Holders:
 
- --------------------------------------------------------------------------------
 
- --------------------------------------------------------------------------------
Please Type or Print
Address:
- --------------------------------------------------------------------------------
                                                         Zip Code
Area Code and Telephone No.:
- -------------------------------------------------------------------------------
 
                                        2
<PAGE>   3
 
                                   GUARANTEE
                    (NOT TO BE USED FOR SIGNATURE GUARANTEE)
 
     The undersigned, a firm which is a member of a registered national
securities exchange or of the National Association of Securities Dealers, Inc.
or which is a commercial bank or trust company having an office or correspondent
in the United States that is a member in good standing of the Securities
Transfer Agents Medallion Program, the New York Stock Exchange Medallion
Signature Guarantee Program or the Stock Exchange Medallion Program, guarantees
to deliver to the Depositary, at one of its addresses set forth above, Share
Certificates evidencing the Shares tendered hereby, in proper form for transfer,
or confirmation of book-entry transfer of such Shares into the Depositary's
account at The Depository Trust Company, the Philadelphia Depository Trust
Company or the Midwest Securities Trust Company, in each case with delivery of a
Letter of Transmittal (or facsimile thereof) properly completed and duly
executed, with any required signature guarantees or an Agent's Message (as
defined in the Offer to Purchase) in the case of a book-entry delivery, and any
other required documents, all within three New York Stock Exchange trading days
of the date hereof.
 
PLEASE TYPE OR PRINT
 
<TABLE>
<S>                                             <C>
Name of Firm:
  --------------------------------------        ---------------------------------------------
                                                AUTHORIZED SIGNATURE:
Address:                                        Name:
- ---------------------------------------------   ---------------------------------------------
                                                Title:
- ---------------------------------------------   ---------------------------------------------
Area Code and
Telephone No.:
  --------------------------------------        Dated:
                                                -----------------------------------------, 1997
</TABLE>
 
DO NOT SEND STOCK CERTIFICATES WITH THIS NOTICE. STOCK CERTIFICATES SHOULD BE
SENT WITH YOUR LETTER OF TRANSMITTAL.
 
                                        3

<PAGE>   1
 
                           OFFER TO PURCHASE FOR CASH
 
                     ALL OUTSTANDING SHARES OF COMMON STOCK
                  AND ASSOCIATED RIGHTS OF BIOWHITTAKER, INC.
                                       AT
                             $11.625 NET PER SHARE
                                       BY
                           BW ACQUISITION CORPORATION
 
    THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK
        CITY TIME, ON SEPTEMBER 25, 1997, UNLESS THE OFFER IS EXTENDED.
 
August 28, 1997
 
To Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees:
 
     We have been appointed by BW Acquisition Corporation, a Delaware
corporation (the "Purchaser") and a wholly-owned subsidiary of Cambrex
Corporation, a Delaware corporation, to act as Dealer Manager in connection with
Purchaser's offer to purchase all outstanding shares of common stock, par value
$0.01 per share (the "Common Stock"), of BioWhittaker, Inc., a Delaware
corporation (the "Company"), and the associated rights to purchase Series A
Participating Cumulative Preferred Stock (the "Rights", and together with the
Common Stock, the "Shares"), at a price of $11.625 per Share, net to the seller
in cash, without interest thereon, upon the terms and subject to the conditions
set forth in Purchaser's Offer to Purchase, dated August 28, 1997 (the "Offer to
Purchase"), and the related Letter of Transmittal (which, as amended from time
to time, together constitute the "Offer") enclosed herewith. Please furnish
copies of the enclosed materials to those of your clients for whose accounts you
hold Shares registered in your name or in the name of your nominee.
 
     THE OFFER IS CONDITIONED UPON, AMONG OTHER THINGS, (I) THERE BEING VALIDLY
TENDERED AND NOT WITHDRAWN PRIOR TO THE EXPIRATION OF THE OFFER AT LEAST THE
NUMBER OF SHARES WHICH, TOGETHER WITH THE OPTION SHARES (AS DEFINED IN THE OFFER
TO PURCHASE) WHICH ARE SUBJECT TO THE STOCKHOLDERS AGREEMENT (AS DEFINED IN THE
OFFER TO PURCHASE), SHALL CONSTITUTE IN EXCESS OF FIFTY PERCENT (50%) OF THE
THEN OUTSTANDING SHARES ON A FULLY-DILUTED BASIS, AND (II) THE EXPIRATION OR
TERMINATION OF ANY APPLICABLE ANTITRUST WAITING PERIODS.
 
     Enclosed for your information and use are copies of the following
documents:
 
          1. Offer to Purchase, dated August 28, 1997;
 
          2. Letter of Transmittal to be used by holders of Shares in accepting
     the Offer and tendering Shares;
 
          3. Notice of Guaranteed Delivery to be used to accept the Offer if the
     Shares and all other required documents are not immediately available or
     cannot be delivered to ChaseMellon Shareholder Services, L.L.C. (the
     "Depositary") by the Expiration Date (as defined in the Offer to Purchase)
     or if the procedure for book-entry transfer cannot be completed by the
     Expiration Date;
 
          4. A letter to stockholders of the Company from Joseph F. Alibrandi of
     the Company, together with a Solicitation/Recommendation Statement on
     Schedule 14D-9 filed with the Securities and Exchange Commission by the
     Company;
 
          5. A letter which may be sent to your clients for whose accounts you
     hold Shares registered in your name or in the name of your nominee, with
     space provided for obtaining such clients' instructions with regard to the
     Offer; and
 
          6. Guidelines for Certification of Taxpayer Identification Number on
     Substitute Form W-9.
<PAGE>   2
 
     WE URGE YOU TO CONTACT YOUR CLIENTS AS PROMPTLY AS POSSIBLE. PLEASE NOTE
THAT THE OFFER AND WITHDRAWAL RIGHTS EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY
TIME, ON SEPTEMBER 25, 1997, UNLESS THE OFFER IS EXTENDED.
 
     In all cases, payment for Shares accepted for payment pursuant to the Offer
will be made only after timely receipt by the Depositary of (i) certificates
evidencing such Shares (the "Share Certificates") or, timely confirmation of a
book-entry transfer of such Shares into the Depositary's account at one of the
Book-Entry Transfer Facilities (as defined in the Offer to Purchase)), (ii) a
Letter of Transmittal (or facsimile thereof) properly completed and duly
executed or an Agent's Message (as defined in the Offer to Purchase) in
connection with a book-entry transfer and (iii) any other required documents in
accordance with the instructions contained in the Letter of Transmittal.
 
     If a holder of Shares wishes to tender Shares, but such Stockholders's
Share Certificates are not immediately available or such Stockholder cannot
deliver the Share Certificates and all other required documents, or cannot
complete the procedure for book-entry transfer, prior to the expiration of the
Offer, a tender of Shares may be effected by following the guaranteed delivery
procedure described in Section 2 of the Offer to Purchase.
 
     Purchaser will not pay any fees or commissions to any broker, dealer or
other person (other than the Dealer Manager, the Depositary and the Information
Agent as described in the Offer) in connection with the solicitation of tenders
of Shares pursuant to the Offer. However, Purchaser will reimburse you for
customary mailing and handling expenses incurred by you in forwarding any of the
enclosed materials to your clients. Purchaser will pay or cause to be paid any
stock transfer taxes payable with respect to the transfer of Shares to it,
except as otherwise provided in Instruction 6 of the Letter of Transmittal.
 
     Any inquiries you may have with respect to the Offer should be addressed to
D. F. King & Co., Inc. (the "Information Agent") at its address and telephone
number set forth on the back cover page of the Offer to Purchase.
 
     Additional copies of the enclosed material may be obtained from the
Information Agent, at the address and telephone numbers set forth on the back
cover page of the Offer to Purchase.
 
                                          Very truly yours,
 
                                          Schroder & Co. Inc.
 
     NOTHING CONTAINED HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL AUTHORIZE YOU
OR ANY OTHER PERSON TO ACT ON BEHALF OF OR AS THE AGENT OF PURCHASER, THE
COMPANY, THE DEALER MANAGER, THE INFORMATION AGENT OR THE DEPOSITARY, OR OF ANY
AFFILIATE OF ANY OF THEM, OR AUTHORIZE YOU OR ANY OTHER PERSON TO USE ANY
DOCUMENT OR TO MAKE ANY STATEMENT ON BEHALF OF ANY OF THEM IN CONNECTION WITH
THE OFFER OTHER THAN THE ENCLOSED DOCUMENTS AND THE STATEMENTS CONTAINED
THEREIN.
 
                                        2

<PAGE>   1
 
                           OFFER TO PURCHASE FOR CASH
 
                     ALL OUTSTANDING SHARES OF COMMON STOCK
                             AND ASSOCIATED RIGHTS
                                       OF
 
                               BIOWHITTAKER, INC.
                           FOR $11.625 NET PER SHARE
                                       BY
 
                           BW ACQUISITION CORPORATION
 
  THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY
      TIME, ON THURSDAY, SEPTEMBER 25, 1997, UNLESS THE OFFER IS EXTENDED.
 
To Our Clients:
 
     Enclosed for your consideration are an Offer to Purchase, dated August 28,
1997 (the "Offer to Purchase"), and a related Letter of Transmittal (which, as
amended from time to time, together constitute the "Offer") in connection with
the offer to purchase by BW Acquisition Corporation, a Delaware corporation (the
"Purchaser") and a wholly-owned subsidiary of Cambrex Corporation, a Delaware
corporation, all outstanding shares of common stock, par value $0.01 per share
(the "Common Stock"), of BioWhittaker, Inc., a Delaware corporation (the
"Company"), and the associated rights to purchase Series A Participating
Cumulative Preferred Stock (the "Rights", and together with the Common Stock,
the "Shares"), at a price of $11.625 per Share, net to the seller in cash,
without interest thereon, upon the terms and subject to the conditions set forth
in the Offer.
 
     WE ARE (OR OUR NOMINEE IS) THE HOLDER OF RECORD OF SHARES HELD BY US FOR
YOUR ACCOUNT. A TENDER OF SUCH SHARES CAN BE MADE ONLY BY US AS THE HOLDER OF
RECORD AND PURSUANT TO YOUR INSTRUCTIONS. THE LETTER OF TRANSMITTAL IS FURNISHED
TO YOU FOR YOUR INFORMATION ONLY AND CANNOT BE USED BY YOU TO TENDER SHARES HELD
BY US FOR YOUR ACCOUNT.
 
     We request instructions as to whether you wish to have us tender on your
behalf any or all of the Shares held by us for your account, upon the terms and
subject to the conditions set forth in the Offer.
 
     Your attention is directed to the following:
 
          1. The tender price is $11.625 per Share, net to the seller in cash
     without interest thereon.
 
          2. The Offer is being made for all outstanding Shares.
 
          3. The Board of Directors of the Company has unanimously determined
     that the Offer is fair to and in the best interests of the Company and its
     stockholders, and recommends that stockholders accept the Offer and tender
     their Shares pursuant to the Offer.
 
          4. The Offer and withdrawal rights will expire at 12:00 Midnight, New
     York City time, on Thursday, September 25, 1997, unless the Offer is
     extended.
 
          5. The Offer is conditioned upon, among other things, (i) there being
     validly tendered and not withdrawn prior to the expiration of the Offer at
     least the number of Shares which, together with the option shares (as
     defined in the Offer to Purchase) which are subject to the Stockholders
     Agreement (as defined in the Offer to Purchase), shall constitute in excess
     of fifty percent (50%) of the Shares then outstanding and (ii) the
     expiration or termination of any applicable antitrust waiting periods.
 
          6. Tendering stockholders will not be obligated to pay brokerage fees
     or commissions or, except as otherwise provided in Instruction 6 of the
     Letter of Transmittal, stock transfer taxes with respect to the purchase of
     Shares by Purchaser pursuant to the Offer.
<PAGE>   2
 
     If you wish to have us tender any or all of your Shares, please so instruct
us by completing, executing and returning to us the instruction form contained
in this letter. An envelope in which to return your instructions to us is
enclosed. If you authorize the tender of your Shares, all such Shares will be
tendered unless otherwise specified in your instructions. YOUR INSTRUCTIONS
SHOULD BE FORWARDED TO US IN AMPLE TIME TO PERMIT US TO SUBMIT A TENDER ON YOUR
BEHALF PRIOR TO THE EXPIRATION OF THE OFFER.
 
     The Offer is made only by the Offer to Purchase and the related Letter of
Transmittal and is not being made to (nor will tenders be accepted from or on
behalf of) holders of Shares in any jurisdiction in which the Offer or the
acceptance thereof would not be in compliance with the securities, blue sky or
other laws of such jurisdiction. However, Purchaser may, in its discretion, take
such action as it may deem necessary to make the Offer in any jurisdiction and
extend the Offer to holders of Shares in such jurisdiction. In those
jurisdictions where the securities laws require the Offer to be made by a
licensed broker or dealer, the Offer shall be deemed to be made on behalf of
Purchaser by Schroder & Co. Inc. or one or more registered brokers or dealers
licensed under the laws of such jurisdiction.
 
                                        2
<PAGE>   3
 
                   INSTRUCTIONS WITH RESPECT TO THE OFFER TO
                       PURCHASE FOR CASH ALL OUTSTANDING
                  SHARES OF COMMON STOCK AND ASSOCIATED RIGHTS
              OF BIOWHITTAKER, INC. BY BW ACQUISITION CORPORATION
 
     The undersigned acknowledge(s) receipt of your letter and the enclosed
Offer to Purchase, dated August 28, 1997, and the related Letter of Transmittal
(which, as amended from time to time, together constitute the "Offer"), in
connection with the offer to purchase by BW Acquisition Corporation, a Delaware
corporation and a wholly-owned subsidiary of Cambrex Corporation, a Delaware
corporation all outstanding shares of common stock, par value $0.01 per share
(the "Common Stock"), of BioWhittaker, Inc., a Delaware corporation, and the
associated rights to purchase Series A Participating Cumulative Preferred Stock
(the "Rights", and together with the Common Stock, the "Shares"), at a price of
$11.625 per Share, net to the seller in cash, without interest thereon, upon the
terms and subject to the conditions set forth in the Offer. This will instruct
you to tender the number of Shares indicated below (or, if no number is
indicated below, all Shares) that are held by you for the account of the
undersigned, upon the terms and subject to the conditions set forth in the
Offer.
 
Number of Shares to Be Tendered*:
 
Date:
 
SIGN HERE
 
- --------------------------------------------------------------------------------
Signature(s):
 
- --------------------------------------------------------------------------------
(Print Name(s))
 
- --------------------------------------------------------------------------------
(Print Addresse(s))
 
- --------------------------------------------------------------------------------
(Area Code and Telephone Number(s))
 
- --------------------------------------------------------------------------------
(Taxpayer Identification or Social Security Number(s))
- ---------------
* Unless otherwise indicated, it will be assumed that all Shares held by us for
  your account are to be tendered.
 
                                        3

<PAGE>   1
 
            GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION
                         NUMBER ON SUBSTITUTE FORM W-9
 
GUIDELINES FOR DETERMINING THE PROPER IDENTIFICATION NUMBER TO GIVE THE
PAYER. -- Social Security numbers have nine digits separated by two hyphens:
i.e. 000-00-0000. Employer identification numbers have nine digits separated by
only one hyphen: i.e. 00-0000000. The table below will help determine the number
to give the payer.
<TABLE>
<CAPTION>
   ------------------------------------------------------------
                                                GIVE THE TAXPAYER
                                                 IDENTIFICATION
        FOR THIS TYPE OF ACCOUNT:                  NUMBER OF -
   ------------------------------------------------------------
<S>                                           <C>
 1. An individual's account                   The individual
 
 2. Two or more individuals (joint            The actual owner of
   account)                                   the account or, if
                                              combined funds, any
                                              one of the
                                              individuals(1)
 
 3. Husband and wife (joint account)          The actual owner of
                                              the account or, if
                                              joint funds, either
                                              person(1)
 
 4. Custodian account of a minor (Uniform     The minor(2)
    Gift to Minors Act)
 
 5. Adult and minor (joint account)           The adult or, if the
                                              minor is the only
                                              contributor, the
                                              minor(1)
 
 6. Account in the name of guardian or        The ward, minor, or
    committee for a designated ward,          incompetent person(3)
    minor, or incompetent person
 
 7. a. The usual revocable savings trust      The grantor-
       account (grantor is also trustee)      trustee(1)
 
   b. So-called trust account that is not     The actual owner(1)
      a legal or valid trust under State
      law
 
 8. Sole proprietorship account               The owner(4)
 
<CAPTION>
   ------------------------------------------------------------
                                                GIVE THE TAXPAYER
                                                 IDENTIFICATION
        FOR THIS TYPE OF ACCOUNT:                  NUMBER OF -
   ------------------------------------------------------------
<S>                                           <C>
 
 9. A valid trust, estate or pension trust    The Legal entity (Do
                                              not furnish the
                                              identifying number of
                                              the personal
                                              representative or
                                              trustee unless the
                                              legal entity itself
                                              is not designated in
                                              the account
                                              title.)(5)
 
10. Corporate account                         The corporation
 
11. Religious, charitable, or educational     The organization
    organization account
 
12. Partnership account held in the name      The partnership
    of the business
 
13. Association, club, or other tax-exempt    The organization
    organization
 
14. A broker or registered nominee            The broker or nominee
 
15. Account with the Department of            The public entity
    Agriculture in the name of a public
    entity (such as a State or local
    government, school district, or
    prison) that receives agricultural
    program payments
</TABLE>
 
============================================================
 
(1) List first and circle the name of the person whose number you furnish.
 
(2) Circle the minor's name and furnish the minor's social security number.
 
(3) Circle the ward's, minor's or incompetent person's name and furnish such
    person's social security number.
 
(4) Show the name of the owner.
 
(5) List first and circle the name of the legal trust, estate, or pension trust.
 
NOTE: If no name is circled when there is more than one name, the number will be
      considered to be that of the first name listed.
<PAGE>   2
 
            GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION
                         NUMBER ON SUBSTITUTE FORM W-9
                                     PAGE 2
 
OBTAINING A NUMBER
 
If you do not have a taxpayer identification number or you do not know your
number, obtain Form SS-5, Application for a Social Security Number Card, or Form
SS-4, Application for Employer Identification Number, at the local office of the
Social Security Administration or the Internal Revenue Service and apply for a
number.
 
PAYEES EXEMPT FROM BACKUP WITHHOLDING
 
Payees specifically exempted from backup withholding on ALL payments include the
following:
 
   - A corporation.
   - A financial institution.
   - An organization exempt from tax under section 501(a), or an individual
     retirement plan.
   - The United States or any agency or instrumentality thereof.
   - A State, the District of Columbia, a possession of the United States, or
     any subdivision or instrumentality thereof.
   - A foreign government, a political subdivision of a foreign government, or
     any agency or instrumentality thereof.
   - An international organization or any agency, or instrumentality thereof.
   - A registered dealer in securities or commodities registered in the U.S. or
     a possession of the U.S.
   - A real estate investment trust.
   - A common trust fund operated by a bank under section 584(a).
   - An exempt charitable remainder trust, or a non-exempt trust described in
     section 4947(a)(1).
   - An entity registered at all times under the Investment Company Act of 1940.
   - A foreign central bank of issue.
 
Payments of dividends and patronage dividends not generally subject to backup
withholding include the following:
 
   - Payments to nonresident aliens subject to withholding under section 1441.
   - Payments to partnerships not engaged in a trade or business in the U.S. and
     which have at least one nonresident partner.
   - Payments of patronage dividends where the amount received is not paid in
     money.
   - Payments made by certain foreign organizations.
   - Payments made to a nominee.
 
Payments of interest generally subject to backup withholding include the
following:
 
   - Payments of interest on obligations issued by individuals. Note: You may be
     subject to backup withholding if this interest is $600 or more and is paid
     in the course of the payer's trade or business and you have not provided
     your correct taxpayer identification number to the payer.
   - Payments of tax-exempt interest (including exempt-interest dividends under
     section 852).
   - Payments described in section 6049(b)(5) to nonresident aliens.
   - Payments on tax-free covenant bonds under section 1451.
   - Payments made by certain foreign organizations.
   - Payments made to a nominee.
 
Exempt payees described above should file Form W-9 to avoid possible erroneous
backup withholding. FILE THIS FORM WITH THE PAYER. FURNISH YOUR TAXPAYER
IDENTIFICATION NUMBER, WRITE "EXEMPT" ON THE FACE OF THE FORM, AND RETURN IT TO
THE PAYER. IF THE PAYMENTS ARE INTEREST, DIVIDENDS, OR PATRONAGE DIVIDENDS, ALSO
SIGN AND DATE THE FORM.
 
Certain payments other than interest, dividends, and patronage dividends, that
are not subject to information reporting are also not subject to backup
withholding. For details, see the regulations under sections 6041, 6041A(a),
6045, and 6050A.
 
PRIVACY ACT NOTICE. -- Section 6109 requires most recipients of dividend,
interest, or other payments to give taxpayer identification numbers to payers
who must report the payments to the IRS. The IRS uses the numbers for
identification purposes. Payers must be given the numbers whether or not
recipients are required to file a tax return. Payers must generally withhold 31%
of taxable interest, dividend, and certain other payments to a payee who does
not furnish a taxpayer identification number to a payer. Certain penalties may
also apply.
 
PENALTIES
 
(1) PENALTY FOR FAILURE TO FURNISH TAXPAYER IDENTIFICATION NUMBER. -- If you
fail to furnish your taxpayer identification number to a payer, you are subject
to a penalty of $50 for each such failure unless your failure is due to
reasonable cause and not to willful neglect.
 
(2) FAILURE TO REPORT CERTAIN DIVIDEND AND INTEREST PAYMENTS. -- If you fail to
include any portion of an includible payment for interest, dividends, or
patronage dividends in gross income, such failure will generally be treated as
being due to negligence and will be subject to a penalty of 20% on any portion
of an underpayment attributable to that failure.
 
(3) CIVIL PENALTY FOR FALSE INFORMATION WITH RESPECT TO WITHHOLDING. -- if you
make a false statement with no reasonable basis which results in no imposition
of backup withholding, you are subject to a penalty of $500.
 
(4) CRIMINAL PENALTY FOR FALSIFYING INFORMATION. -- Falsifying certifications or
affirmations may subject you to criminal penalties including fines and/or
imprisonment.
 
FOR ADDITIONAL INFORMATION CONTACT YOUR TAX
CONSULTANT OR THE INTERNAL REVENUE SERVICE

<PAGE>   1
This announcement is neither an offer to purchase nor a solicitation of an
offer to sell Shares. The Offer is made solely by the Offer to Purchase dated
August 28, 1997 and the related Letter of Transmittal and is not being made to,
nor will tenders be accepted from, or on behalf of, holders of Shares in any
jurisdiction in which the Offer or the acceptance thereof would not be in
compliance with the securities, blue sky or other laws of such jurisdiction.
However, Purchaser may, in its discretion, take such action as it may deem
necessary to make the Offer in any jurisdiction and extend the Offer to holders
of Shares in any such jurisdiction. In those jurisdictions where securities
laws require the Offer to be made by a licensed broker or dealer, the Offer
shall be deemed to be made on behalf of Purchaser by Schroder & Co. Inc. or one
or more registered brokers or dealers licensed under the laws of such
jurisdictions. 

                      Notice of Offer to Purchase for Cash

                     All Outstanding Shares of Common Stock
                            (and Associated Rights)

                                  
                                       of


                               BioWhittaker, Inc.


                                       at


                             $11.625 Net Per Share


                                       by


                           BW Acquisition Corporation


        BW Acquisition Corporation, A Delaware corporation ("Purchaser") and a
wholly-owned subsidiary of Cambrex Corporation, a Delaware corporation
("Parent"), is offering to purchase for cash all the outstanding shares of
Common Stock, par value $0.01 per share (the "Common Stock"), of BioWhittaker,
Inc., a Delaware corporation (the "Company"), and each associated right to
purchase shares of the Company's Series A Participating Cumulative Preferred
Stock (the "Right", and, together with the Common Stock, the "Shares") issued
pursuant to the Stockholder Protection Rights Agreement, dated as of January
20, 1995 (as amended, the "Rights Agreement"), between the Company and Bank of
Boston, at a purchase price of $11.625 per Share, net to the seller in cash,
without interest thereon, upon the terms and subject to the conditions set
forth in the Offer to Purchase dated August 28, 1997 (the "Offer to Purchase"),
and in the related Letter of Transmittal (which, as amended from time to time,
together constitute the "Offer"). Holders of Shares whose certificates for such
Shares ("Share Certificates") are not immediately available or who cannot
deliver their Share Certificates and all other required documents to the
Depositary (as defined below) prior to the Expiration Date (as defined below),
or who cannot complete the procedure for book-entry transfer on a timely basis,
may nevertheless tender their Shares by following the procedure for guaranteed
delivery set forth in Section 2 of the Offer to Purchase. Unless the context
otherwise requires, all references to Shares shall include the associated
Rights. The holders of the Shares are sometimes referred to as "stockholders".

        The purpose of the Offer is for Purchaser to acquire control of the
Company and to purchase as many Shares as are tendered in the Offer.

    THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK
   CITY TIME, ON THURSDAY, SEPTEMBER 25, 1997, UNLESS THE OFFER IS EXTENDED.

        The Offer is conditioned upon, among other things, (i) there being
validly tendered and not withdrawn prior to the expiration of the Offer at
least the number of Shares that, together with the 910,928 Shares that
Purchaser has an option to purchase pursuant to an existing agreement with
certain officers and directors of the Company, shall constitute in excess of
fifty percent (50%) of the Shares then outstanding, and (ii) the expiration or
termination of any applicable antitrust waiting periods. The Offer is also
subject to other terms and conditions.

        For purposes of the Offer, Purchaser shall be deemed to have accepted
for payment, and thereby purchased Shares validly tendered and not withdrawn
as, if and when Purchaser gives oral or written notice to ChaseMellon
Shareholder Services, L.L.C. (the "Depositary") of Purchaser's acceptance for
payment of such Shares pursuant to the Offer. Upon the terms and subject to the
conditions of the Offer, payment for Shares accepted for payment pursuant to
the Offer will be made by deposit of the purchase price therefor with the
Depositary, which will act as agent for tendering stockholders for the purpose
of receiving payments from Purchaser and transmitting such payments to
tendering stockholders whose Shares have been accepted for payment. In all
cases, payment for Shares tendered and accepted for payment pursuant to the
Offer will be made only after timely receipt by the Depositary of (i) the Share
Certificates evidencing such Shares or timely confirmation of a book-entry
transfer of such Shares into the Depositary's account at The Depository Trust
Company, the Midwest Securities Trust Company or the Philadelphia Depository
Trust Company (collectively, the "Book-Entry Transfer Facilities") pursuant to
the procedures set forth in Section 2 of the Offer to Purchase, (ii) a properly
completed and duly executed Letter of Transmittal (or a facsimile thereof) with
any required signature guarantees, or an Agent's Message (as defined in Section
2 of the Offer to Purchase) in connection with a book-entry transfer and (iii)
any other documents required by the Letter of Transmittal.

        Purchaser expressly reserves the right, in its sole discretion (but
subject to the terms and conditions of the Agreement and Plan of Merger among
Parent, the Purchaser and the Company, dated as of August 22, 1997), to extend
the period of time during which the Offer is open by giving oral or written
notice of such extension to the Depositary. Any such extension will be followed
as promptly as practicable by public announcement thereof to be made no later
than 9:00 a.m., New York City time, on the next business day after the
previously scheduled Expiration Date.

        Except as otherwise provided below, tenders of Shares made pursuant to
the Offer are irrevocable except that such Shares may be withdrawn by the
tendering stockholder at any time prior to the Expiration Date (as defined
below) and, unless theretofore accepted for payment and paid for by Purchaser
pursuant to the Offer, may also be withdrawn by such stockholder at any time
after October 27, 1997. The term "Expiration Date" means 12:00 Midnight, New
York City time, on Thursday, September 25, 1997 unless and until Purchaser
shall have extended the period of time during which the Offer is open, in which
event the term "Expiration Date" shall refer to the latest time and date at
which the Offer, as so extended by Purchaser, shall expire. For a withdrawal to
be effective, a written, telegraphic or facsimile transmission notice of
withdrawal must be timely received by the Depositary at one of its addresses
set forth on the back cover of the Offer to Purchase. Any such notice of
withdrawal must specify the name of the person having tendered the Shares to
be withdrawn, the number of Shares to be withdrawn and the name of the
registered holder of such Shares, if different from that of the person who
tendered such Shares. If Share Certificates evidencing Shares to be withdrawn
have been delivered or otherwise identified to the Depositary, then, prior to
the physical release of such Share Certificates, the serial numbers shown on
such Share Certificates must be submitted to the Depositary and the
signature(s) on the notice of withdrawal must be guaranteed by an Eligible
Institution (as defined in Section 2 of the Offer to Purchase), unless such
Shares have been tendered for the account of an Eligible Institution. If Shares
have been tendered pursuant to the procedure for book-entry transfer as set
forth in Section 2 of the Offer to Purchase, any notice of withdrawal must also
specify the name and number of the account of the Book-Entry Transfer Facility
to be credited with the withdrawn Shares.

        The Board of Directors of the Company has unanimously determined that
the Offer is fair to and in the best interests of the Company and the
stockholders, and recommends that the stockholders accept the Offer and tender
their Shares pursuant to the Offer.

        The information required to be disclosed by Rule 14d-6(e)(1)(vii) of
the General Rules and Regulations under the Securities Exchange Act of 1934, as
amended, is contained in the Offer to Purchase and is incorporated by
reference. 

        Purchaser has received stockholder lists and security position listings
from the Company, and the Offer to Purchase and the related Letter of
Transmittal and other tender offer materials will be mailed to record
stockholders and will be furnished to brokers, banks, and similar persons whose
names, or the names of whose nominees, appear on the Company's list of
stockholders or, if applicable, who are listed as participants in a clearing
agency's security position listing, for subsequent transmittal to beneficial
owners of Shares.

     The Offer to Purchase and the related Letter of Transmittal contain
important information which should be read before any decision is made with
respect to the Offer.

     Requests for copies of the Offer to Purchase and the related Letters of
Transmittal and all other tender offer materials may be directed to the
Information Agent of the Dealer Manager as set forth below, and copies will be
furnished promptly at Purchaser's expense. No fees or commissions will be
payable to brokers, dealers or other persons, other than the Dealer Manager,
the Information Agent and the Depositary for soliciting tenders of Shares
pursuant to the Offer. The fees and commissions payable to the Dealer Manager
are described in the Offer to Purchase.

                    The Information Agent for the Offer is:

                             D.F. King & Co., Inc.
                          77 Water Street, 20th Floor
                            New York, New York 10005
                         (212) 269-5550 (Call Collect)

                                       or

                         CALL TOLL FREE: (800) 290-6426


                      The Dealer Manager for the Offer is:

                              Schroder & Co. Inc.
                              The Equitable Center
                               787 Seventh Avenue
                         New York, New York 10019-6016
                         (212) 492-6000 (Call Collect)

August 28, 1997

<PAGE>   1
 
     CAMBREX AND BIOWHITTAKER AGREE TO CAMBREX ACQUISITION OF BIOWHITTAKER
 
     EAST RUTHERFORD, N.J. and WALKERSVILLE, Md., Aug.
25 /PRNewswire/ -- Cambrex Corporation (Amex: CBM), and BioWhittaker, Inc.
(NYSE: BWI) today announced a definitive merger agreement pursuant to which
Cambrex will acquire BioWhittaker for $11.625 per share. Under the merger
agreement, Cambrex will commence a cash tender offer for all of the outstanding
common stock of BioWhittaker. Any shares not tendered will be cashed out for
$11.625 per share in a statutory merger, giving the transaction a total value of
$130.9 million.
 
     The Board of Directors of BioWhittaker unanimously approved the transaction
and certain directors and officers of BioWhittaker, together with Anasco GmbH,
the holder of 19.9% of BioWhittaker's shares, have agreed to tender their shares
to Cambrex. Alex. Brown & Sons Incorporated, BioWhittaker's financial advisor,
has delivered to the Board of Directors a written opinion to the effect that, as
of the date of such opinion and based upon and subject to certain matters stated
therein, the $11.625 per share cash consideration to be received in the tender
offer and the merger by holders of BioWhittaker common stock (other than Cambrex
and its affiliates) was fair, from a financial point of view, to such holders.
 
     The tender offer will be conditioned upon, among other things, the tender
of at least 50% of the outstanding BioWhittaker Common Stock, on a fully diluted
basis, and the termination or expiration of the waiting period under the
Hart-Scott-Rodino Act. In the event of termination of the Merger Agreement,
under certain circumstances Cambrex would be entitled to a termination fee of
$4.125 million and the reimbursement of certain expenses.
 
     BioWhittaker, Inc. develops, produces and sells cell culture products to
the biotechnology and pharmaceutical industries for research and for the rapidly
expanding commercial manufacture of biopharmaceutical products. More information
on BioWhittaker is included in the Q & A below.
 
     "The purchase of BioWhittaker meets all of Cambrex's acquisition criteria,"
said Jim Mack, Cambrex CEO. "Beyond the transition cost, it will be
non-dilutive, and we expect that it will contribute substantially to Cambrex's
worldwide growth in the coming years. It will offer additional opportunities to
existing Cambrex subsidiaries for supplying products into the biopharmaceutical
area. Most important, it represents another strategic step for Cambrex in its
goal to offer pharmaceutical companies a more complete line of innovative
products and cGMP manufacturing capabilities."
 
     Noel L. Buterbaugh, BioWhittaker CEO, commented, "My management team and I
look forward to joining Cambrex. We see synergy and compatibility in our two
companies and believe both companies will benefit by working together."
 
     Mr. Mack will discuss the transaction further during a telephone conference
call at 1:00 p.m. today (EST). Those wishing to participate should call the MCI
Conference Coordinator at 1-800-369-1969, Password: Mack, approximately 10
minutes before 1:00 p.m.
 
     This news release includes forward-looking statements that involve a number
of risks and uncertainties regarding the consummation of this transaction. These
include, among others, satisfaction of conditions to closing the transaction,
including determinations by regulatory authorities, and the risk factors set
forth from time to time in Cambrex's and BioWhittaker's filings with the United
States Securities and Exchange Commission, including their respective Reports on
Form 10-K for their most recently completed fiscal years and their respective
Reports on Form 10-Q for their most recent fiscal quarters for which such
reports were required to be filed. Any of these uncertainties may cause actual
results or future circumstances to differ materially from the forward-looking
statements contained in this news release.
 
<PAGE>   2
 
                             QUESTIONS AND ANSWERS
 
WHAT DOES BIOWHITTAKER DO?
 
     BioWhittaker is a leading supplier of biological tools to the
biotechnology, pharmaceutical and life science research markets. Major products
include cell cultures, cell culture media and endotoxin detection products.
 
WHAT DO THEIR CUSTOMERS DO WITH THESE PRODUCTS?
 
     Cell culture products including living cell cultures, chemically defined
nutrient media necessary for growing cell cultures, and sera used to supplement
the media. These products are used in biotechnology research and
biopharmaceutical applications including the production of drugs and vaccines,
cancer therapy, stem cell therapy, genetic therapy, and tissue repair and
transplantation. In addition, they are used by clinical laboratories for the
isolation and identification of viruses in patient specimens.
 
     Endotoxin detection products include a range of tests that identify the
presence of endotoxin, a bacterial substance that can be fatal to humans.
Pharmaceutical and medical device manufacturers use these products as part of
the quality control process to ensure that injectable drugs and implantable
medical devices are safe for human use.
 
WHAT ARE BIOWHITTAKER'S REVENUES?
 
     Sales revenues in 1996 were $51.5 million. Estimated sales for 1997 (fiscal
year-end October 31st) are approximately $57 million.
 
ARE REVENUES GROWING?
 
     In December 1995 the Company sold part of its clinical diagnostics business
with sales of approximately $11 million. While total sales have increased 12%
for the first nine months of fiscal 1997, sales of the company's core cell
culture and endotoxin detection products have grown over 25% for the same
period. Sales are expected to continue to increase because of the anticipated
growth of the biotechnology industry in the coming years.
 
IS BIOWHITTAKER'S SUCCESS DEPENDENT ON A PARTICULAR CUSTOMER OR PRODUCT?
 
     BioWhittaker has over 5,000 customers worldwide and over 1,500 products to
serve this diverse market. Its success is not dependent on a particular customer
or product. Over 30% of its sales are outside of the United States.
 
HAS BIOWHITTAKER BEEN PROFITABLE?
 
     BioWhittaker has historically been profitable with Net Income currently
averaging over 10% of sales.
 
WHY IS CAMBREX INTERESTED IN THIS COMPANY?
 
     There are several reasons Cambrex is interested in BioWhittaker:
 
          - The number of approved therapeutic products made from biotechnology
            has doubled in the last 2 to 3 years.
 
          - BioWhittaker's core products have grown over 20% per year and they
            have consistent record of profitability.
 
          - Cambrex's strategy is to offer our pharmaceutical customer base a
            full complement of products and cGMP manufacturing services.
            Biotechnology is the fast growing sector of this industry and is an
            essential component of that strategy.
 
          - Biotechnology manufacturing is a logical extension of existing
            Cambrex capabilities in supplying the pharmaceutical industry. This
            purchase gives Cambrex access to valuable technology.
 
<PAGE>   3
 
CAN WE EXPECT CAMBREX TO PURCHASE OTHER BIOTECH COMPANIES?
 
     Most biotech companies are involved in development of specific
biopharmaceutical products. This requires heavy investment in R&D over long
periods of time. Cambrex is not operating in these areas. BioWhittaker is
different in that it is a producer and supplier of critical, high technology
products to a wide array of biotech customers. Therefore, it has more consistent
growth and stable profitability.
 
     The availability of contract biotechnology manufacturing services to the
pharmaceutical industry is limited and the company plans to develop that
capability within new cGMP facilities.
 

<PAGE>   1
                                                               EXHIBIT 11(b) (i)

                                  [CHASE LOGO]

Chase Securities Inc.
270 Park Avenue
New York, NY 10017-2070
                                                                 August 20, 1997

                               Cambrex Corporation
                            Senior Credit Facilities
                                Commitment Letter
Cambrex Corporation
One Meadowlands Plaza
East Rutherford, New Jersey 07073

Attention: Mr. Douglas H. MacMillan
           Vice President-Chief Financial Officer


Ladies and Gentlemen:

         You have advised The Chase Manhattan Bank ("CHASE") and Chase
Securities Inc. ("CSI") that Cambrex Corporation, a Delaware corporation
("CAMBREX" or the "Company") is seeking senior bank financing of up to
$400,000,000 (a) to refinance certain existing indebtedness and (b) for the
purpose of consummating an acquisition identified by you in discussions with us,
which acquisition will be affected through a tender offer for all of the
outstanding common stock (and associated share purchase rights) of the
acquisition target followed by a merger of a wholly owned acquisition subsidiary
of Cambrex with and into the acquisition target (the "Acquisition"), and for
working and other general corporate purposes including future acquisitions. In
that connection, you have requested that CSI agree to structure, arrange and
syndicate senior credit facilities in an aggregate amount of up to $400,000,000
(the "SENIOR FACILITIES") and that Chase commit to provide up to $200,000,000
and to serve as administrative agent for the Senior Facilities.

         CSI is pleased to advise you that it is willing to act as exclusive
advisor and arranger for the Senior Facilities. Furthermore, Chase is pleased to
advise you of (a) its commitment to provide up to $200,000,000 of the Senior
Facilities (which commitment is not conditioned by the completion of the primary
syndication of the $400 million Senior Facilities) and (b) its agreement to use
commercially reasonable efforts to assemble a syndicate of financial
institutions identified by CS1 and Chase in consultation with you (together with
Chase, the "LENDERS") to provide the balance of the necessary commitments for
the Senior Facilities (and to assume a portion of Chase's commitment hereunder),
in each case, upon the terms and subject to the conditions set forth or referred
to in this commitment letter (the "COMMITMENT LETTER") and in the Summary of
Terms and Conditions attached hereto as Exhibit A (the "TERM SHEET").
<PAGE>   2
Cambrex Corporation.               - 2 -                         August 20, 1997


         CSI intends to commence syndication efforts promptly upon the execution
of this Commitment Letter, and you agree actively to assist CSI in completing a
syndication satisfactory to it. Such assistance shall include (a) your using
commercially reasonable efforts to ensure that the syndication efforts benefit
materially from your existing lending relationships, (b) direct contact between
senior management and advisors of the Borrower and the proposed Lenders, (c)
assistance in the preparation of a Confidential Information Memorandum and other
marketing materials to be used in connection with the syndication and (d) the
hosting, with CSI, of one or more meetings of prospective Lenders.

         It is agreed that Chase will act as the sole and exclusive
Administrative Agent, and that CSI will act as the sole and exclusive advisor
and arranger, for the Senior Facilities, and each will, in such capacities,
perform the duties and exercise the authority customarily performed and
exercised by it in such roles. You agree that no other agents, co-agents or
arrangers will be appointed, no other titles will be awarded and no compensation
(other than that expressly contemplated by the Term Sheet and the Fee Letter
referred to below) will be paid in connection with the Senior Facilities unless
you and we shall so agree.

         CSI will manage all aspects of the syndication, including decisions as
to the selection of institutions to be approached and when they will be
approached, when their commitments will be accepted, which institutions will
participate, the allocations of the commitments among the Lenders and the amount
and distribution of fees among the Lenders. To assist CSI in its syndication
efforts, you agree promptly to prepare and provide to CSI and Chase all
information with respect to the Borrower and its subsidiaries, and the other
transactions contemplated hereby, including all financial information and
projections and any budgets, forecasts or pro forma data (the "PROJECTIONS"),
as we may reasonably request in connection with the arrangement and syndication
of the Senior Facilities. You hereby represent and covenant that (a) all
information other than the Projections (the "INFORMATION") that has been or
will be made available to Chase or CSI by you or any of your representatives is
or will be, when furnished, complete and correct in all material respects and
does not or will not, when furnished, contain any untrue statement of a material
fact or omit to state a material fact necessary in order to make the statements
contained therein not materially misleading in light of the circumstances under
which such statements are made and (b) the Projections that have been or will be
made available to Chase or CSI by you or any of your representatives have been
or will be prepared in good faith based upon reasonable assumptions. You
understand that in arranging and syndicating the Senior Facilities we may use
and rely on the Information and Projections without independent verification
thereof.

         As consideration for Chase's commitment hereunder and CSI's agreement
to perform the services described herein, you agree to pay to Chase the
non-refundable fees set forth in Annex I to the Term Sheet and in the Fee Letter
dated the date hereof and delivered herewith (the "FEE LETTER").

Chase's commitment hereunder and CSI's agreement to perform the services
described herein are subject to (a) there not occurring or becoming known to us
any material adverse condition or material adverse change in or affecting the
business, operations, property, condition (financial or
<PAGE>   3
Cambrex Corporation.                    - 3 -                    August 20, 1997


otherwise) or prospects of the Borrower and its subsidiaries, taken as a whole,
(b) our not becoming aware after the date hereof of any information or other
matter affecting the Borrower and its subsidiaries, or the transactions
contemplated hereby which is inconsistent in a material and adverse manner with
any such information or other matter disclosed to us prior to the date hereof,
(c) there not having occurred a material disruption of or material adverse
change in financial, banking or capital market conditions that, in our judgment,
could materially impair the syndication of the Senior Facilities, (d) our
satisfaction that prior to and during the syndication of the Senior Facilities
there shall be no competing offering, placement or arrangement of any debt
securities or bank financing by or on behalf of the Borrower or any of its
affiliates, (e) the negotiation, execution and delivery on or before September
30, 1991 of definitive documentation with respect to the Senior Facilities
satisfactory to Chase and its counsel and (f) the other conditions set forth or
referred to in the Term Sheet. The terms and conditions of Chase's commitment
hereunder and of the Senior Facilities are not limited to those set forth herein
and in the Term Sheet. Those matters that are not covered by the provisions
hereof and of the Term Sheet are subject to the approval and agreement of Chase,
CSI and the Borrower.

         You agree (a) to indemnify and hold harmless Chase, CSI, their
affiliates and their respective officers, directors, employees, advisors, and
agents (each, an "INDEMNIFIED PERSON") from and against any and all losses,
claims, damages and liabilities to which any such indemnified person may become
subject arising out of or in connection with this Commitment Letter, the Senior
Facilities, the use of the proceeds thereof, or any related transaction or any
claim, litigation, investigation or proceeding relating to any of the foregoing,
regardless of whether any indemnified person is a party thereto, and to
reimburse each indemnified person upon demand for any legal or other expenses
incurred in connection with investigating or defending any of the foregoing,
provided that the foregoing indemnity will not, as to any indemnified person,
apply to losses, claims, damages, liabilities or related expenses to the extent
they are found by a final, non-appealable judgment of a court to arise from the
willful misconduct or gross negligence of such indemnified person, and (b) to
reimburse Chase, CSI and their affiliates on demand for all out-of-pocket
expenses (including due diligence expenses, syndication expenses, travel
expenses, and reasonable fees charges and disbursements of counsel) incurred in
connection with the Senior Facilities and any related documentation (including
this Commitment Letter, the Term Sheet, the Fee Letter and the definitive
financing documentation) or the administration, amendment, modification or
waiver thereof. No indemnified person shall be liable for any indirect or
consequential damages in connection with its activities related to the Senior
Facilities.

This Commitment Letter shall not be assignable by you without the prior written
consent of Chase and CSI (and any purported assignment without such consent
shall be null and void), is intended to be solely for the benefit of the parties
hereto and is not intended to confer any benefits upon, or create any rights in
favor of, any person other than the parties hereto. This Commitment Letter may
not be amended or waived except by an instrument in writing signed by you, Chase
and CSI. This Commitment Letter may be executed in any number of counterparts,
each of which shall be an original, and all of which, when taken together, shall
constitute one agreement. Delivery of an executed signature page of this
Commitment Letter by facsimile transmission shall be effective as delivery of a
manually executed counterpart hereof. This
<PAGE>   4
Cambrex Corporation.                - 4 -                        August 20, 1997


Commitment Letter and the Fee Letter are the only agreements that have been
entered into among us with respect to the Senior Facilities and will replace any
previously accepted Commitment Letter and Fee Letter and set forth the entire
understanding of the parties with respect thereto. This Commitment Letter shall
be governed by, and construed in accordance with, the laws of the State of New
York.

         This Commitment Letter is delivered to you on the understanding that
neither this Commitment Letter, nor the Term Sheet nor any of their terms or
substance shall be disclosed, directly or indirectly, to any other person except
(a) to your officers, agents and advisors who are directly involved in the
consideration of this matter or (b) as may be compelled in a judicial or
administrative proceeding or as otherwise required by law (in which case you
agree to inform us promptly thereof), provided that the foregoing restrictions
shall cease to apply after this Commitment Letter has been accepted by you.

         The compensation, reimbursement, indemnification and confidentiality
provisions contained herein and in the Fee Letter shall remain in full force and
effect regardless of whether definitive financing documentation shall be
executed and delivered and notwithstanding the termination of this Commitment
Letter or Chase's commitment hereunder.

         If the foregoing correctly sets forth our agreement, please indicate
your acceptance of the terms hereof and of the Term Sheet and the Fee Letter by
returning to us executed counterparts hereof and of the Fee Letter not later
than 5:00 p.m., New York City time, on August 22, 1997. Chase's commitment and
CSI's agreements herein will expire at such time in the event Chase has not
received such executed counterparts in accordance with the immediately preceding
sentence.
<PAGE>   5
     Cambrex Corporation.                 - 5 -                  August 20, 1997


         Chase and CSI are pleased to have been given the opportunity to assist
you in connection with this important financing.

                                            Very truly yours,

                                            THE CHASE MANHATTAN BANK



                                            By: /s/ James McNimara
                                                ---------------------------
                                                Name:  James McNimara
                                                Title: Vice President


                                            CHASE SECURITIES INC.


                                            By: /s/ Robert W. Mathews
                                                -------------------------
                                                Name:  Robert W. Mathews
                                                Title: Vice President


Accepted and agreed to as of the date first written above by:

CAMBREX CORPORATION




By:  /s/ Douglas H. MacMillan
     ------------------------------------------
     Name:  Douglas H. MacMillan
     Title: Vice President-Chief Financial Officer
<PAGE>   6
                                                                       Exhibit A

                            SENIOR CREDIT FACILITIES
                         Summary of Terms and Conditions
                                 August 20, 1997

I.         Parties

           Borrower:                       Cambrex Corporation (the "BORROWER").
                                           Subsidiaries of Cambrex Corporation
                                           may be designated as borrower on
                                           terms acceptable to Chase.



           Guarantors:                     Each of the Borrower's direct and
                                           indirect domestic subsidiaries (the
                                           "GUARANTORS"; the Borrower and the
                                           Guarantors, collectively, the "CREDIT
                                           PARTIES"). No foreign subsidiary of
                                           the Borrower will be a guarantor, but
                                           in lieu thereof the Borrower will
                                           grant a first priority security
                                           interest in 66% of the capital stock
                                           of each first-tier foreign
                                           subsidiary.



           Advisor and Arranger:           Chase Securities Inc. (in such
                                           capacity, the "ARRANGER").



           Administrative Agent:           The Chase Manhattan Bank ("CHASE"
                                           and, in such capacity, the
                                           "ADMINISTRATIVE AGENT").



           Co-agent:                       The First National Bank of Chicago

           Lenders:                        A syndicate of banks, financial
                                           institutions and other entities,
                                           including Chase, arranged by the
                                           Arranger (collectively, the
                                           "LENDERS").


   II.     Revolving Credit Facility

           Amount of Facility:             Five-year revolving credit facility
                                           (the "REVOLVING CREDIT FACILITY" in
                                           the amount of up to $400,000,000 (or
                                           equivalent) available on a
                                           multi-currency basis with currencies
                                           to be agreed (the loans thereunder,
                                           the "REVOLVING CREDIT LOANS ").



           Availability:                   The Revolving Credit Facility shall
                                           be available on a revolving basis
                                           during the period commencing on the
                                           Closing Date and ending on the fifth
                                           anniversary thereof (the "REVOLVING
                                           CREDIT TERMINATION DATE").
<PAGE>   7
Cambrex Corporation                 - 2 -                        August 20, 1997
Summary of Terms and Conditions

                  Letters of Credit:       A portion of the Revolving Credit
                                           Facility in an amount to be
                                           determined shall be available for the
                                           issuance of standby and/or commercial
                                           letters of credit (the "LETTERS OF
                                           CREDIT" by Chase (in such capacity,
                                           the "ISSUING LENDER"). No Letter of
                                           Credit shall have an expiration date
                                           after the earlier of (a) one year
                                           after the date of issuance and (b)
                                           five business days prior to the
                                           Revolving Credit Termination Date,
                                           provided that any Letter of Credit
                                           with a one-year tenor may provide for
                                           the renewal thereof for additional
                                           one-year periods (which shall in no
                                           event extend beyond the date referred
                                           to in clause (b) above).

                                           Drawings under any Letter of Credit
                                           shall be reimbursed by the Borrower
                                           (whether with its own funds or with
                                           the proceeds of Revolving Credit
                                           Loans) on the same business day. To
                                           the extent that the Borrower does not
                                           so reimburse the Issuing Lender, the
                                           Lenders under the Revolving Credit
                                           Facility shall be irrevocably and
                                           unconditionally obligated to
                                           reimburse the Issuing Lender on a pro
                                           rata basis.



                  Swing Line Loans:        A portion of the Revolving Credit
                                           Facility not in excess of $10,000,000
                                           shall be available for swing line
                                           loans (the "SWING LINE LOANS") from
                                           Chase (in such capacity, the "SWING
                                           LINE LENDER") on same-day notice. Any
                                           such Swing Line Loans will reduce
                                           availability under the Revolving
                                           Credit Facility on a
                                           dollar-for-dollar basis. Each Lender
                                           under the Revolving Credit Facility
                                           shall acquire, under certain
                                           circumstances, an irrevocable and
                                           unconditional pro rata participation
                                           in each Swing Line Loan.



                  Competitive Loans:       The Borrower shall have the option to
                                           request that the Lenders bid for
                                           loans ("COMPETITIVE LOANS") bearing
                                           interest at an absolute rate or a
                                           margin over the eurodollar rate, with
                                           specified maturities ranging from 7
                                           to 360 days. Each Lender shall have
                                           the right, but not the obligation, to
                                           submit bids at its discretion. The
                                           Borrower, by notice given four
                                           business days in advance in the case
                                           of eurodollar rate bids and one
                                           business day in advance in the case
                                           of absolute rate bids, shall specify
                                           the proposed date of borrowing, the
                                           interest period, the amount of the
                                           Competitive Loan and the maturity
                                           date thereof, the interest rate basis
                                           to be used by the Lenders in bidding
                                           and such other terms as the Borrower
                                           may specify. The Administrative Agent
                                           shall advise the Lenders of the terms
<PAGE>   8
Cambrex Corporation                 - 3 -                        August 20, 1997
Summary of Terms and Conditions

                                           of the Borrower's notice, and,
                                           subject to acceptance by the
                                           Borrower, bids shall be allocated to
                                           each Lender in ascending order from
                                           the lowest bid to the highest bid
                                           acceptable to the Borrower. While
                                           Competitive Loans are outstanding,
                                           the available commitments under the
                                           Revolving Credit Facility shall be
                                           reduced by the aggregate amount of
                                           such Competitive Loans.

      Maturity:                            The Revolving Credit Termination
                                           Date.



      Purpose:                             The proceeds of the Revolving Credit
                                           Loans shall be used (i) to refinance
                                           the outstanding loans under the
                                           Company's existing senior bank credit
                                           facilities and, (ii) for working
                                           capital and other general corporate
                                           purposes of the Borrower and its
                                           subsidiaries, (iii) to fund
                                           acquisitions, including the
                                           Acquisition.



III.  Certain Payment Provisions      As set forth on Annex 1.

      Fees and Interest Rates:

      Optional Prepayments and
      Commitment Reductions:               Loans may be prepaid and commitments
                                           may be reduced by the Borrower in
                                           minimum amounts to be agreed upon,
                                           provided that Competitive Loans may
                                           not be prepaid without the consent of
                                           the relevant Lender.



IV.   Certain Conditions

      Initial Conditions:                  The availability of the Credit
                                           Facilities shall be conditioned upon
                                           satisfaction of, among other things,
                                           the following conditions precedent
                                           (the date upon which all such
                                           conditions precedent shall be
                                           satisfied, the "CLOSING DATE") on or
                                           before September 30, 1997:

                                           (a) Each Credit Party shall have
                                           executed and delivered reasonably
                                           satisfactory definitive financing
                                           documentation with respect to the
                                           Credit Facilities (the "CREDIT
                                           DOCUMENTATION").

                                           (b) All governmental and third party
                                           approvals necessary or reasonably
                                           advisable in connection with the
                                           financing contemplated hereby and the
                                           continuing operations of the Borrower
                                           and its subsidiaries shall have been
                                           obtained and be in full force and
                                           effect.


<PAGE>   9
Cambrex Corporation                      - 4 -                   August 20, 1997
Summary of Terms and Conditions

                                           (c) The Lenders shall have received
                                           (i) satisfactory audited consolidated
                                           financial statements of the Borrower
                                           for the two most recent fiscal years
                                           ended prior to the Closing Date as to
                                           which such financial statements are
                                           available and (ii) reasonably
                                           satisfactory unaudited interim
                                           consolidated financial statements of
                                           the Borrower for each quarterly
                                           period ended subsequent to the date
                                           of the latest financial statements
                                           delivered pursuant to clause (i) of
                                           this paragraph as to which such
                                           financial statements are available.

                                           (d) The Lenders, the Administrative
                                           Agent and the Arranger shall have
                                           received all fees required to be
                                           paid, and all expenses for which
                                           invoices have been presented, on or
                                           before the Closing Date.

                                           (e) The Lenders shall have received
                                           such legal opinions, documents and
                                           other instruments as are customary
                                           for transactions of this type or as
                                           they may reasonably request.

      On-Going Conditions:                 The making of each extension of
                                           credit shall be conditioned upon (a)
                                           the accuracy of all representations
                                           and warranties in the Credit
                                           Documentation (including, without
                                           limitation, the material adverse
                                           change and litigation
                                           representations) and (b) there being
                                           no default or event of default in
                                           existence at the time of, or after
                                           giving effect to the making of, such
                                           extension of credit. As used herein
                                           and in the Credit Documentation a
                                           "material adverse change" shall mean
                                           any event, development or
                                           circumstance that has had or could
                                           reasonably be expected to have a
                                           material adverse effect on (a) the
                                           business, assets, property, condition
                                           (financial or otherwise) or prospects
                                           of the Borrower and its subsidiaries
                                           taken as a whole, or (b) the validity
                                           or enforceability of any of the
                                           Credit Documentation, taken as a
                                           whole, or the rights and remedies of
                                           the Administrative Agent and the
                                           Lenders thereunder, taken as a whole.

      V. Certain Documentation Matters     The Credit Documentation shall
                                           contain representations, warranties,
                                           covenants and events of default
                                           customary for


<PAGE>   10
Cambrex Corporation                     - 5 -                    August 20, 1997
Summary of Terms and Conditions

                                           financings of this type and other
                                           terms reasonably deemed appropriate
                                           by the Lenders, including, without
                                           limitation:

      Representations and
      Warranties:                          Financial statements; absence of
                                           undisclosed liabilities; no material
                                           adverse change; corporate existence;
                                           compliance with law; corporate power
                                           and authority; enforceability of
                                           Credit Documentation; no conflict
                                           with law or contractual obligations;
                                           no material litigation; no default;
                                           ownership of property; liens;
                                           intellectual property; no burdensome
                                           restrictions; taxes; Federal Reserve
                                           regulations; ERISA; Investment
                                           Company Act; subsidiaries;
                                           environmental matters; solvency; and
                                           accuracy of disclosure.



      Affirmative Covenants:               Delivery of financial statements,
                                           reports, accountants' letters,
                                           officers' certificates and other
                                           information reasonably requested by
                                           the Lenders; payment of other
                                           obligations; continuation of business
                                           and maintenance of existence and
                                           material rights and privileges;
                                           compliance with laws and material
                                           contractual obligations; maintenance
                                           of property and insurance;
                                           maintenance of books and records;
                                           right of the Lenders to inspect
                                           property and books and records;
                                           notices of defaults, litigation and
                                           other material events; and compliance
                                           with environmental laws.



      Financial Covenants:                 Financial covenants will include:

                                           1. ratio of (i) Funded Debt as of the
                                           end of each quarter to (ii) Cash Flow
                                           for the period of four consecutive
                                           quarters of not more than 4.0:1.

                                           Funded Debt is defined as all
                                           indebtedness including capital lease
                                           obligations and subordinated debt.

                                           Cash Flow is defined as earnings
                                           before interest, taxes, depreciation
                                           and amortization. Cash Flow will be
                                           subject to adjustments to be
                                           determined for any acquisition during
                                           the relevant period.

                                           2. Cash Flow Coverage Ratio (defined
                                           as the ratio of (I) Cash Flow (as
                                           defined above) to (ii) interest
                                           expense of not less than 3.0:1
                                           measured on a rolling four quarter
                                           trailing basis; and


<PAGE>   11
Cambrex Corporation                 - 6 -                        August 20, 1997
Summary of Terms and Conditions

                                          3. Minimum Net Worth (defined as
                                          stockholders' common equity,
                                          preferred stock and minority
                                          interests, less treasury stock) of at
                                          least $200,000,000, increasing
                                          annually by 50% of net income and
                                          100% of the proceeds of any equity
                                          offering.

      Negative Covenants:                 Limitations on: indebtedness
                                          (including preferred stock of
                                          subsidiaries); liens; guarantee
                                          obligations; mergers, consolidations,
                                          liquidations and dissolutions; sales
                                          of assets; leases; dividends and
                                          other payments in respect of capital
                                          stock; investments, loans and
                                          advances; transactions with
                                          affiliates; sale and leasebacks;
                                          changes in fiscal year; negative
                                          pledge clauses; and changes in lines
                                          of business. Acquisitions, including
                                          the Acquisition, will be permitted
                                          provided that, after giving effect
                                          thereto, the Borrower would be in pro
                                          forma compliance with financial
                                          covenants.



      Events of Default:                  Nonpayment of principal when due;
                                          nonpayment of interest, fees or other
                                          amount; material inaccuracy of
                                          representations and warranties;
                                          violation of covenants (subject, in
                                          the case of certain affirmative
                                          covenants, to a grace period to be
                                          agreed upon); cross-default;
                                          bankruptcy events; certain ERISA
                                          events; material judgments; material
                                          environmental liabilities or claims;
                                          and actual or asserted invalidity of
                                          any guarantee or security document or
                                          security interest.



      Voting:                             Amendments and waivers with respect
                                          to the Credit Documentation shall
                                          require the approval of Lenders
                                          holding not less than a majority of
                                          the aggregate amount of the Revolving
                                          Credit Loans (including
                                          participations in Letters of Credit
                                          and Swingline Loans) and unused
                                          commitments under the Credit
                                          Facilities, except that (a) the
                                          consent of each Lender directly
                                          affected thereby shall be required
                                          with respect to (i) reductions in the
                                          amount or extensions of the scheduled
                                          maturity of any Loan, (ii) reductions
                                          in the rate of interest or any fee or
                                          extensions of any due date thereof,
                                          (iii) increases in the amount or
                                          extensions of the expiry date of any
                                          Lender's commitment and (iv)
                                          modifications to the pro rata
                                          provisions of the Credit
                                          Documentation and (b) the consent of
                                          100% of the Lenders shall be required
                                          with respect to (i) modifications to
                                          any of the voting percentages and
                                          (ii)


<PAGE>   12
Cambrex Corporation                     - 7 -                    August 20, 1997
Summary of Terms and Conditions

                                          releases of significantly all or
                                          substantially all of the Guarantors
                                          or all or substantially all of the
                                          pledged collateral.

      Assignments and
      Participations:                     The Lenders shall be permitted to
                                          assign and sell participations in
                                          their Loans and commitments, subject,
                                          in the case of assignments (other
                                          than to another Lender or to an
                                          affiliate of a Lender), to the
                                          consent of the Administrative Agent,
                                          the Issuing Lender, the Swing Line
                                          Lender and the Borrower (which
                                          consent in each case shall not be
                                          unreasonably withheld). In the case
                                          of partial assignments (other than to
                                          another Lender or to an affiliate of
                                          a Lender), the minimum assignment
                                          amount shall be $5,000,000 unless
                                          otherwise agreed by the Borrower and
                                          the Administrative Agent.
                                          Participants shall have the same
                                          benefits as the Lenders with respect
                                          to yield protection and increased
                                          cost provisions. Voting rights of
                                          participants shall be limited to
                                          those matters with respect to which
                                          the affirmative vote of the Lender
                                          from which it purchased its
                                          participation would be required as
                                          described under "Voting" above.
                                          Pledges of Loans in accordance with
                                          applicable law shall be permitted
                                          without restriction. Promissory notes
                                          shall be issued under the Credit
                                          Facilities only upon request.



      Yield Protection:                   The Credit Documentation shall
                                          contain customary provisions (a)
                                          protecting the Lenders against
                                          increased costs or loss of yield
                                          resulting from changes in reserve,
                                          tax, capital adequacy and other
                                          requirements of law and from the
                                          imposition of or changes in
                                          withholding or other taxes and (b)
                                          indemnifying the Lenders for
                                          "breakage costs" incurred in
                                          connection with, among other things,
                                          any prepayment of a Eurodollar Loan
                                          (as defined in Annex 1) on a day
                                          other than the last day of an
                                          interest period with respect thereto
                                          and any prepayment of a Competitive
                                          Loan.



      Expenses and
      Indemnification:                    The Borrower shall pay (a) all
                                          reasonable out-of-pocket expenses of
                                          the Administrative Agent and the
                                          Arranger associated with the
                                          syndication of the Credit Facilities
                                          and the preparation, execution,
                                          delivery and administration of the
                                          Credit Documentation and any
                                          amendment or waiver with respect
                                          thereto (including the reasonable
                                          fees, disbursements and other charges
                                          of counsel) and (b) all out-


<PAGE>   13
Cambrex Corporation                   - 8 -                      August 20, 1997
Summary of Terms and Conditions

                                           of-pocket expenses of the
                                           Administrative Agent and the Lenders
                                           (including the fees, disbursements
                                           and other charges of counsel) in
                                           connection with the enforcement of
                                           the Credit Documentation.

                                           The Administrative Agent, the
                                           Arranger and the Lenders (and their
                                           affiliates and their respective
                                           officers, directors, employees,
                                           advisors and agents) will have no
                                           liability for, and will be
                                           indemnified and held harmless
                                           against, any loss, liability, cost or
                                           expense incurred in respect of the
                                           financing contemplated hereby or the
                                           use or the proposed use of proceeds
                                           thereof (except to the extent
                                           resulting from the gross negligence
                                           or willful misconduct of the
                                           indemnified party).

      Governing Law and Forum:             State of New York.



      Counsel to the
      Administrative Agent and
      the Arranger:                        Milbank, Tweed, Hadley & McCloy


<PAGE>   14
                                                                         Annex I

                                           Interest and Certain Fees


      Interest Rate Options:               The Borrower may elect that the Loans
                                           (other than Competitive Loans)
                                           comprising each borrowing bear
                                           interest at a rate per annum equal
                                           to:

                                                the ABR plus the Applicable
                                                Margin; or

                                                the Eurodollar Rate plus the
                                                Applicable Margin.

                                           provided that all Swing Line Loans
                                           shall bear interest based upon the
                                           ABR.

                                           As used herein:

                                           "ABR" means the higher of (i) the
                                           rate of interest publicly announced
                                           by Chase as its prime rate in effect
                                           at its principal office in New York
                                           City (the "PRIME RATE") and (ii) the
                                           federal funds effective rate from
                                           time to time plus 0.5%.

                                           "APPLICABLE MARGIN" means a
                                           percentage determined in accordance
                                           with the pricing grid below.

                                           "EURODOLLAR RATE" means the rate
                                           (adjusted for statutory reserve
                                           requirements for eurocurrency
                                           liabilities) for eurodollar deposits
                                           for one, two, three or six months (as
                                           selected by the Borrower) appearing
                                           on page 3750 of the Dow Jones Markets
                                           Service.




      Interest Payment Dates:              In the case of Loans bearing interest
                                           based upon the ABR ("ABR LOANS"),
                                           quarterly in arrears.

                                           In the case of Loans bearing interest
                                           based upon the Eurodollar Rate
                                           ("EURODOLLAR LOANS"), on the last day
                                           of each relevant interest period and,
                                           in the case of any interest period
                                           longer than three months, on each
                                           successive date three months after
                                           the first day of such interest
                                           period.


<PAGE>   15
Cambrex Corporation                       - 2 -               August 20, 1997
Summary of Terms and Conditions

      Facility Fees:                       The Borrower shall pay a facility fee
                                           calculated at the rate determined by
                                           reference to the pricing grid below
                                           on the aggregate amount of the
                                           Revolving Credit Facility (whether or
                                           not utilized), payable quarterly in
                                           arrears.



      Letter of Credit Fees:               The Borrower shall pay a commission
                                           on all outstanding Letters of Credit
                                           at a per annum rate equal to the
                                           Applicable Margin then in effect with
                                           respect to Eurodollar Loans on the
                                           face amount of each such Letter of
                                           Credit. Such commission shall be
                                           shared ratably among the Lenders
                                           participating in the Revolving Credit
                                           Facility and shall be payable
                                           quarterly in arrears.

                                           A fronting fee in a per annum amount
                                           to be determined on the face amount
                                           of each Letter of Credit shall be
                                           payable quarterly in arrears to the
                                           Issuing Lender for its own account.
                                           In addition, customary
                                           administrative, issuance, amendment,
                                           payment and negotiation charges shall
                                           be payable to the Issuing Lender for
                                           its own account.



      Default Rate:                        At any time when the Borrower is in
                                           default in the payment of any amount
                                           of principal due under the Credit
                                           Facilities, such overdue principal
                                           amount shall bear interest at 2%
                                           above the rate otherwise applicable
                                           thereto. Overdue interest, fees and
                                           other amounts shall bear interest at
                                           2% above the rate applicable to ABR
                                           Loans.



      Rate and Fee Basis:                  All per annum rates shall be
                                           calculated on the basis of a year of
                                           360 days (or 365/366 days, in the
                                           case of ABR Loans the interest rate
                                           payable on which is then based on the
                                           Prime Rate) for actual days elapsed.


<TABLE>
<CAPTION>
                                                                      Applicable Margin
- ----------------------------------------------------------------------------------------------------------------
Funded Debt to Cash
       Flow                                      ABR                       LIBOR                    Facility Fee
- ----------------------------------------------------------------------------------------------------------------
<S>                                              <C>                       <C>                      <C>
smaller than 2.0:1.0                              0                         22.5                        1 5
- ----------------------------------------------------------------------------------------------------------------
greater than 2.0: 1.0 less than 3.0: 1.0          0                         32.5                       17.5
- ----------------------------------------------------------------------------------------------------------------
greater than 3.0: 1.0 less than 3.5: 1.0          0                         42.5                        20
- ----------------------------------------------------------------------------------------------------------------
greater than 3.5: 1.0                             0                         50.0                        25
- ----------------------------------------------------------------------------------------------------------------
</TABLE>

<PAGE>   1
                                                               EXHIBIT 11 (c)(1)




================================================================================


                          AGREEMENT AND PLAN OF MERGER



                                      AMONG


                               CAMBREX CORPORATION

                           BW ACQUISITION CORPORATION

                               BIOWHITTAKER, INC.








                           Dated as of August 22, 1997




================================================================================
<PAGE>   2
                                TABLE OF CONTENTS


                                                                    Page

1.  THE OFFER..........................................................2

2.  THE MERGER.........................................................4
    2.1    Merger......................................................4
    2.2    Effect of Merger............................................5
    2.3    Conversion of Shares........................................5
    2.4    Stock Options...............................................5
    2.5    Consummation of the Merger..................................6
    2.6    Dissenters' Rights..........................................6
    2.7    Payment for Shares and Options..............................7
    2.8    Closing of the Company's Transfer Books.....................8

3.  REPRESENTATIONS AND WARRANTIES.....................................9
    3.1    Representations and Warranties of Parent and the Purchaser..9
    3.2    Representations and Warranties of the Company..............11

4.  COVENANTS.........................................................22
    4.1    Acquisition Transactions...................................22
    4.2    Interim Operations.........................................24
    4.3    Access and Information.....................................26
    4.4    Certain Filings, Consents and Arrangements.................26
    4.5    Reasonable Best Efforts....................................26
    4.6    Public Statements..........................................27
    4.7    Stockholder Approval.......................................27
    4.8    Stockholder Litigation.....................................29
    4.9    Indemnification, Exculpation and Insurance.................29
    4.10   Amendment of Rights Agreement..............................30
    4.11   Borrowings under the Loan Agreement........................30

5.  CONDITIONS........................................................30
    5.1    Conditions to the Obligations of Parent, the Purchaser and 
           the Company ...............................................30
    5.2    Conditions to the Obligations of Parent and the Purchaser..31
    5.3    Conditions to the Obligations of the Company...............31
<PAGE>   3
6.  MISCELLANEOUS.....................................................32
    6.1    Termination................................................32
    6.2    Non-Survival of Representations, Warranties and Agreements.34
    6.3    Amendment and Waiver.......................................34
    6.4    Entire Agreement...........................................34
    6.5    Definitions................................................35
    6.6    Applicable Law.............................................35
    6.7    Headings...................................................35
    6.8    Notices....................................................35
    6.9    Counterparts...............................................36
    6.10   Severability...............................................36
    6.11   Parties in Interest; Assignment............................37
    6.12   Fees and Expenses..........................................37
    6.13   Specific Performance.......................................38


Annex A           Certain Conditions of the Offer

Exhibit A         Persons Party to the Stockholder Agreement

Schedule 2.2      Offices of the Surviving Corporation


                                       ii
<PAGE>   4
                          AGREEMENT AND PLAN OF MERGER


        AGREEMENT AND PLAN OF MERGER dated as of August 22, 1997 by and among
Cambrex Corporation, a Delaware corporation ("Parent"), BW Acquisition
Corporation, a Delaware corporation and a wholly-owned subsidiary of Parent (the
"Purchaser"), and BioWhittaker, Inc., a Delaware corporation (the "Company").

        WHEREAS, the respective Boards of Directors of the Parent, the Purchaser
and the Company each has determined that it is fair to, and in the best
interests of, their respective stockholders for Parent to acquire the Company
pursuant to a merger (the "Merger") in which the Purchaser shall be merged with
and into the Company pursuant to this Agreement;

        WHEREAS, as a condition of the willingness of the Parent to enter into
this Agreement, those Persons (as defined in Section 6.5) set forth on Exhibit A
hereto, as the holders of shares of the Company's Common Stock, par value $.01
per share (the "Common Stock"), have entered into two separate but substantially
identical Stockholder Agreements, each dated as of the date hereof
(collectively, the "Stockholder Agreement") with the Parent, which provide,
among other things, that, subject to the terms and conditions thereof, each such
Person will tender such Person's shares of Common Stock in the Offer (as defined
below) and vote such shares of Common Stock in favor of the Merger and the
approval and adoption of this Agreement;

        WHEREAS, as a condition of the willingness of the Parent to enter into
this Agreement (i) the participants of the BioWhittaker, Inc. Supplemental
Executive Retirement Plan (the "SERP") have executed an agreement consenting to
the termination of the rabbi trust established under the SERP (the "Trust")
prior to the payment of any benefits under such Trust and the establishment of a
new rabbi trust which was funded prior to execution to this Agreement by the
Company with 120,344 shares of Common Stock, (ii) pursuant to that agreement,
the other 179,656 shares of Common Stock previously held by the Trust will be
returned to the Company and will be canceled and (iii) all other amounts accrued
or contributed to the Trust pursuant to Article V of the SERP will be
transferred to the new rabbi trust;

        WHEREAS, in furtherance thereof, the Parent proposes that the Purchaser
make an offer to purchase for cash all of the issued and outstanding shares of
Common Stock of the Company, and all associated rights, at a price of $11.625
per share net to the seller;
<PAGE>   5
        WHEREAS, the Boards of Directors of the Parent, the Purchaser and the
Company have approved the Merger following the expiration of such offer, upon
the terms and subject to the conditions set forth herein;

        NOW THEREFORE, in consideration of the mutual covenants and agreements
set forth herein, the parties agree as follows:


                                  1. THE OFFER

        1.1 The Offer. (a) As promptly as practicable, but in no event later
than five business days after the public announcement of the execution of this
Agreement, the Purchaser shall, and the Parent shall cause the Purchaser to,
commence a tender offer (the "Offer") to purchase for cash all of the issued and
outstanding shares of Common Stock (the "Shares"), together with the associated
rights, if any, to purchase Series A participating Cumulative Preferred Stock,
par value $.01 per share ("Series A Shares"; and together with the Shares, the
"Securities") at a price of not less than $11.625 per Security net to the seller
in cash; it being understood that the Offer will not apply to the 179,656 Shares
(or associated rights) previously held by the Trust which are being returned to
the Company and canceled as described in the third recital to this Agreement.
The obligations of the Purchaser and the Parent to consummate the Offer and to
accept for payment and purchase the Securities tendered shall be subject only to
the conditions set forth in Annex A hereto. The Purchaser shall not without the
Company's prior written consent reduce the price per Security or the number of
Securities sought to be purchased or modify the form of consideration to be
received by holders of the Securities in the Offer, increase the condition (the
"Minimum Condition") set forth in clause (i) of the first sentence of Annex A
hereto, impose additional conditions to the Offer or amend any term of the Offer
in a manner materially adverse to the holders of the Securities. Subject only to
the conditions of the Offer set forth in Annex A, the Purchaser shall, and the
Parent shall cause the Purchaser to, pay for all of the Securities validly
tendered and not withdrawn pursuant to the Offer as soon as legally permissible.

        (b) As soon as practicable on the date the Offer is commenced, the
Parent and the Purchaser will file with the Securities and Exchange Commission
(the "Commission") a Tender Offer Statement on Schedule 14D-1 (together with
all supplements or amendments thereto, and including all exhibits, the "Offer
Documents"). The Parent and the Purchaser shall give the Company and its counsel
a reasonable opportunity to review the Offer Documents prior to the filing of
the Offer Documents with the Commission or to the dissemination of the Offer
Documents to the stockholders of the


                                       2
<PAGE>   6
Company. The Parent and the Purchaser will furnish the Company and its counsel
in writing with any comments that the Parent, the Purchaser or their counsel may
receive from the Commission or its staff with respect to the Offer Documents,
promptly after receipt of such comments.

        1.2 Company Action. (a) In connection with the Offer, the Company shall
cause its transfer agent to furnish the Purchaser with mailing labels, security
position listings and any available listings or computer files containing the
names and addresses of record holders of the Shares as of a recent date, and
shall furnish to the Purchaser such information and assistance as the Parent or
the Purchaser may reasonably request in communicating the Offer to the Company's
stockholders. Except for such steps as are necessary to disseminate the Offer
Documents, Parent and the Purchaser shall hold in confidence the information
contained in such labels, listings and filings, will use such information only
in connection with the Offer and, if this Agreement is terminated, will, upon
the request of the Company deliver or cause to be delivered to the Company all
copies of such information then in its possession or in the possession of its
agents or representatives.

        (b) The Company hereby consents to the Offer and represents that the
Board of Directors of the Company (at a meeting duly called and held at which a
quorum was present) as part of its approval of this Agreement has (i) approved
the making of the Offer, (ii) determined that each of the Offer and the Merger
is fair to and in the best interests of the stockholders of the Company and
(iii) resolved to recommend acceptance of the Offer and approval and adoption of
this Agreement by the stockholders of the Company (to the extent such approval
and adoption is required by applicable law). Promptly after the commencement of
the Offer, the Company shall file a Tender Offer Solicitation/Recommendation
Statement on Schedule 14D-9 (together with any amendments or supplements
thereto, and including all exhibits, the "Schedule 14D-9") with respect to the
Offer which shall contain the recommendations of the Board of Directors in favor
of the Offer, the Merger and the Agreement, except to the extent that the Board
of Directors of the Company shall have withdrawn or modified its approval of the
Offer, the Merger and this Agreement in accordance with Section 4.1(b).

        1.3 Board of Directors. (a) Promptly upon the purchase by the Purchaser
of the Securities pursuant to the Offer and from time to time thereafter, the
Purchaser shall be entitled to designate up to the minimum number of directors
necessary in order for the result (expressed as a fraction) derived by dividing
the number of directors so designated by the total number of directors to be at
least equal to the result (expressed as a fraction) derived by dividing the
Shares then held by the Purchaser by the total number of Shares then
outstanding; provided, however, that until the Effective Time


                                       3
<PAGE>   7
(as defined in Section 2.5 hereof) the Board of Directors will have at least two
Independent Directors (as defined in Section 1.3(c) hereof). Upon request by the
Purchaser, the Company shall use its best efforts promptly, at the Company's
election, either to increase the size of the Board or to secure the resignation
of such number of directors as is necessary to enable the Purchaser's designees
to be elected to the Board, and to cause the Purchaser's designees to be so
elected.

        (b) The Company's obligations with respect to the election of the
Purchaser's designees to the Board of Directors of the Company shall be subject
to Section 14(f) of the Securities Exchange Act of 1934, as amended (the
"Exchange Act"), and Rule 14f-1 promulgated thereunder. The Company shall
promptly take all actions required pursuant to Section 14(f) and Rule 14f-1 in
order to fulfill its obligations under this Section 1.3 and shall include in the
Schedule 14D-9 such information with respect to the Company and its officers and
directors as is required under Section 14(f) and Rule 14f-1. The Parent and the
Purchaser will supply to the Company in writing and shall be solely responsible
for any information with respect to any of them and their nominees, officers,
directors and affiliates required by Section 14(f) and Rule 14f-1.

        (c) Following the election or appointment of the Purchaser's designees
pursuant to this Section 1.3 and prior to the Effective Time, any amendment to
this Agreement or of the Certificate of Incorporation or By-Laws of the Company,
any termination of this Agreement by the Company, any extension by the Company
of the time for the performance of any of the obligations or other acts of the
Parent or the Purchaser and any waiver of any of the Company's rights under this
Agreement will require the concurrence of a majority of the directors of the
Company then in office who are (i) not designated by the Purchaser nor otherwise
affiliated with the Parent or the Purchaser, (ii) are not employees or the
Chairman of the Company or any of its subsidiaries and (iii) are not affiliated
with Anasco GmbH (the "Independent Directors").


                                  2. THE MERGER

        2.1 Merger. Upon the terms and subject to the conditions of this
Agreement, and in accordance with the applicable provisions of the Delaware
General Corporation Law ("DGCL"), as promptly as practicable following the
consummation of the Offer, the Purchaser shall be merged with and into the
Company. The Company shall be the surviving corporation in the Merger (sometimes
referred to as the "Surviving Corporation") and shall continue its existence
under the laws of the State of Delaware.


                                       4
<PAGE>   8
The separate existence of the Purchaser shall cease.  The name of the Surviving
Corporation shall be "BioWhittaker, Inc."

        2.2 Effect of Merger. The Certificate of Incorporation and the Bylaws of
the Company in effect upon consummation of the Merger shall be the Certificate
of Incorporation and Bylaws of the Surviving Corporation. The directors of the
Purchaser immediately prior to the Effective Time (as defined in Section 2.5)
shall be the directors of the Surviving Corporation, and the officers set forth
on Schedule 2.2 hereto shall be the officers of the Surviving Corporation, in
each case until their respective successors are duly elected and qualified. The
Merger shall have the effects set forth in Section 259 of the DGCL.

        2.3 Conversion of Shares. Merger Consideration. At the Effective Time,
by virtue of the Merger and without any action on the part of any holder
thereof: (a) each Share, together with the associated right, if any, to purchase
Series A Shares or other securities of the Company pursuant to the Stockholder
Protection Rights Agreement dated January 20, 1995 between the Company and Bank
of Boston, as Rights Agent (the "Rights Agreement"), issued and outstanding
immediately prior to the Effective Time (other than Shares to be canceled
pursuant to clause (b) below and any Dissenting Shares (as defined in Section
2.6)) shall be converted into the right to receive in cash an amount per Share
equal to the Merger Consideration (as defined below), subject to any required
withholding of taxes and without interest; (b) each Share (together with all
associated Series A Shares) owned by Parent, the Purchaser or any other direct
or indirect subsidiary of Parent, or held in the treasury of the Company,
immediately prior to the Effective Time, shall be canceled and extinguished, and
no payment will be made with respect to those Shares; and (c) all shares of
common stock of the Purchaser, par value $.01 per share, then issued and
outstanding shall be converted into an equal number of shares of common stock of
the Surviving Corporation. "Merger Consideration" means (I) $138,948,952, or
such greater price divided by (II) the total number of Shares outstanding on a
fully diluted basis as of immediately prior to the Effective Time, assuming the
exercise of all outstanding Options (as defined below) and including all Shares
acquired by Parent or the Purchaser in the Offer.

        2.4 Stock Options. Immediately prior to the Effective Time, each then
outstanding option to purchase Shares, whether or not then exercisable,
including any options granted under the 1994 Stock Option Plan for Non-Employee
Directors (collectively, the "Options"), shall be canceled by the Company in
exchange for a right to receive a payment in cash in accordance with Section
2.7(b) (the "Option Consideration") equal to the product of (i) the number of
Shares previously subject to the Option and (ii) the excess, if any, of the
Merger Consideration over the exercise price for each Share 


                                       5
<PAGE>   9
under such Option. As of the Effective Time, each holder of an Option will be
entitled to receive only an amount equal to the Option Consideration. All
amounts payable under this Section 2.4 shall be subject to any required
withholding of taxes and shall be paid without interest. Effective as of the
Effective Time and subject to payment of the Option Consideration, the Company
shall cause each stock option or other equity based plan maintained with respect
to any Shares (or rights in respect thereof) (other than the BioWhittaker, Inc.
Savings and Stock Investment Plan (the "BSSIP") and the BioWhittaker, Inc.
Supplemental Executive Retirement Plan (the "SERP")) to be terminated.

        2.5 Consummation of the Merger. Upon the terms and subject to the con-
ditions of this Agreement, the Company shall execute in the manner required by
the DGCL, and deliver to the Secretary of State of the State of Delaware, a duly
executed certificate of merger as required by the DGCL, and the parties shall
take all such other and further actions as may be required by law to make the
Merger effective. Prior to the filing referred to in this Section 2.5, a closing
will be held at the offices of Debevoise & Plimpton, 875 Third Avenue, New York,
New York, on the third business day following the satisfaction of the condition
set forth in Section 5.1(c) hereof (or, in the event the Purchaser shall acquire
at least 90% of the outstanding Shares in the Offer, on the tenth business day
following the completion of the Offer) (or such other time as the Purchaser and
the Company may agree, immediately after the conditions set forth in Article V
have been satisfied or waived) for the purpose of confirming all of the
foregoing. The time the Merger becomes effective in accordance with applicable
law is referred to as the "Effective Time".

        2.6 Dissenters' Rights. Notwithstanding any provision of this Agreement
to the contrary, any shares of capital stock of the Company outstanding
immediately prior to the Effective Time held by a holder who has demanded and
perfected the right, if any, for appraisal of those shares in accordance with
the provisions of Section 262 of the DGCL and as of the Effective Time has not
withdrawn or lost such right to such appraisal ("Dissenting Shares") shall not
be converted into or represent a right to receive the consideration set forth in
Section 2.3, but the holder shall only be entitled to such rights as are granted
by the DGCL. If a holder of shares of capital stock of the Company who demands
appraisal of those shares under the DGCL shall effectively withdraw or lose
(through failure to perfect or otherwise) the right to appraisal, then, as of
the Effective Time or the occurrence of such event, whichever last occurs, those
shares shall be converted into and represent only the right to receive the
consideration as provided in Section 2.3, without interest, upon the surrender
of the certificate or certificates representing those shares. The Company shall
give the Parent (i) prompt notice of any written demands for appraisal of any
shares of capital stock of the


                                       6
<PAGE>   10
Company, attempted withdrawals of such demands, and any other instruments served
pursuant to the DGCL received by the Company relating to stockholders' rights of
appraisal and (ii) the opportunity to direct all negotiations and proceedings
with respect to demands for appraisal under the DGCL. The Company shall not,
except with the prior written consent of Parent, voluntarily make any payment
with respect to any demands for appraisals of capital stock of the Company,
offer to settle or settle any such demands or approve any withdrawal of any such
demands.

        2.7 Payment for Shares and Options. (a) Shares. Prior to the Effective
Time, the Purchaser shall designate a commercial bank or trust company organized
under the laws of the United States or any state of the United States with
capital, surplus and undivided profits of at least $500,000,000 to act as Paying
Agent with respect to the Merger (the "Paying Agent"). Each holder (other than
Parent, the Purchaser or any subsidiary of Parent) of a certificate or
certificates (the "Certificates") which immediately prior to the Effective Time
represented outstanding Shares will be entitled to receive, upon surrender to
the Paying Agent of the Certificates for cancellation, cash in an amount equal
to the product of the number of Shares previously represented by the
Certificates multiplied by the Merger Consideration, subject to any required
withholding of taxes. At or prior to the Effective Time, the Purchaser shall
make available to the Paying Agent sufficient funds to make all payments
pursuant to the preceding sentence. No interest shall accrue or be paid on the
cash payable upon the surrender of the Certificates. If payment is to be made to
a person other than the person in whose name the Certificates surrendered are
registered, it shall be a condition of payment that the Certificates so
surrendered shall be properly endorsed or otherwise in proper form for transfer
and that the person requesting the payment shall pay any transfer or other taxes
required by reason of the payment to a person other than the registered holder
of the Certificates surrendered or establish to the satisfaction of the
Surviving Corporation that the tax has been paid or is not applicable. Following
the Effective Time, until surrendered to the Paying Agent in accordance with the
provisions of this Section 2.7(a), each Certificate shall represent for all
purposes only the right to receive upon surrender thereof the Merger
Consideration multiplied by the number of Shares evidenced by the Certificate,
without any interest, subject to any required withholding taxes. Any funds
delivered or made available to the Paying Agent pursuant to this Section 2.7(a)
and not exchanged for Certificates within six months after the Effective Time
will be returned by the Paying Agent to the Surviving Corporation, which
thereafter will act as Paying Agent, subject to the rights of holders of
unsurrendered Certificates under this Section 2.7(a), and any former
stockholders of the Company who have not previously exchanged their Certificates
will thereafter be entitled to look only to the Surviving Corporation for
payment of their claim for the consideration set forth in Section 2.3, without
any interest, but will have no greater


                                       7
<PAGE>   11
rights against the Surviving Corporation than may be accorded to general
creditors thereof under applicable law. Notwithstanding the foregoing, neither
the Paying Agent nor any party hereto shall be liable to a holder of Shares for
any cash or interest delivered to a public official pursuant to applicable
abandoned property, escheat or similar laws. If any Certificates shall not have
been surrendered prior to three years after the Effective Time (or immediately
prior to such earlier date on which any payment in respect hereof would
otherwise escheat to or become the property of any governmental unit or agency),
the payment in respect of such Certificates shall, to the extent permitted by
applicable laws, become the property of the Surviving Corporation, free and
clear of all claims of interest of any person previously entitled thereto. As
soon as practicable after the Effective Time, the Surviving Corporation will
cause the Paying Agent to mail to each record holder of Certificates a form of
letter of transmittal (which will specify that delivery will be effected, and
risk of loss and title to the Certificates will pass, only upon proper delivery
of the Certificates to the Paying Agent) and instructions for use in effecting
the surrender of the Certificates for payment.

        (b) Options. Each holder of an Option, whether or not then exercisable,
will be entitled to receive cash in an amount equal to the Option Consideration
in respect of such Options (determined in accordance with Section 2.4 hereof),
subject to any required withholding taxes and without interest. As soon as
practicable after the Effective Time, and in any event no more than fifteen (15)
calendar days following the Effective Time, the Surviving Corporation shall
instruct the Paying Agent to pay, and the Paying Agent shall so pay, all amounts
due as Option Consideration to holders of Options as required by this Agreement.

        2.8 Closing of the Company's Transfer Books. At the Effective Time, the
stock transfer books of the Company shall be closed and no transfer of Shares
converted into the right to receive the Merger Consideration pursuant to the
terms hereof, Dissenting Shares or Shares to be canceled pursuant to Section 2.3
hereof shall thereafter be made. If, after the Effective Time, Certificates for
such Shares are presented to the Surviving Corporation, they shall be canceled
and exchanged for cash or merely canceled, as the case may be, pursuant to and
in accordance with Sections 2.3, 2.6 and 2.7 hereof, subject to applicable law
in the case of Dissenting Shares.


                                       8
<PAGE>   12
                        3. REPRESENTATIONS AND WARRANTIES

        3.1 Representations and Warranties of Parent and the Purchaser. The
Parent and the Purchaser represent and warrant to the Company that:

        (a) Corporate Organization. Each of the Parent and the Purchaser is a
    corporation duly organized, validly existing and in good standing under the
    laws of the State of Delaware and has all requisite corporate power to carry
    on its business as it is now being conducted; provided, however, that since
    it was incorporated, the Purchaser has not engaged in any business other
    than organizational matters and matters relating to the Offer and this
    Agreement. Parent owns all of the issued and outstanding capital stock of
    the Purchaser and all such stock has been validly issued and is fully paid
    and nonassessable and is owned by the Parent free and clear of all pledges,
    claims, liens, charges, encumbrances and security interests of any kind or
    nature whatsoever (collectively, "Liens"). Each of Parent and the Purchaser
    is qualified to do business and is in good standing in each jurisdiction in
    which the properties owned, leased or operated by it or the nature of the
    business conducted by it makes such qualification necessary, except where
    the failure to be so qualified and in good standing would not reasonably be
    expected, individually or in the aggregate, to have a Material Adverse
    Effect on Parent. "Material Adverse Effect" means, with respect to any
    person or entity, a material adverse effect on the business, assets,
    liabilities, operations or condition (financial or otherwise) of such person
    or entity and its subsidiaries, taken as a whole. True, accurate and
    complete copies of the Parent's and the Purchaser's Certificates of
    Incorporation and Bylaws, in each case as in effect on the date hereof,
    including all amendments thereto, have heretofore been made available to the
    Company.

        (b) Authority. Each of Parent and the Purchaser has the requisite
    corporate power and authority to execute and deliver this Agreement and to
    carry out their respective obligations pursuant hereto. The execution and
    delivery of this Agreement and the consummation of the transactions
    contemplated hereby have been duly authorized by all necessary corporate or
    other action on the part of each of Parent and the Purchaser. This Agreement
    has been duly executed by Parent and the Purchaser and, assuming due
    authorization, execution and delivery by the Company, constitutes a valid
    and binding obligation of each of them, enforceable against each of them in
    accordance with its terms, except as may be limited by bankruptcy,
    insolvency, moratorium or other similar laws affecting or relating to
    enforcement of creditors' rights generally or by general principles of
    equity. No other corporate actions or proceedings on the part of Parent or
    the Purchaser are necessary to authorize this Agreement, the consummation,
    by either of them, of


                                       9
<PAGE>   13
    the transactions contemplated hereby or the discharge, by either of them, of
    their respective obligations pursuant hereto.

        (c) Consents; No Violation. None of the execution and delivery of this
    Agreement by Parent or the Purchaser, the consummation by each of them of
    the transactions contemplated by this Agreement or the discharge, by either
    of them, of its respective obligations hereunder will (i) conflict with, or
    result in any breach or violation of, any provision of the Parent's or the
    Purchaser's Certificate of Incorporation or By-laws; (ii) constitute, with
    or without notice, the passage of time or both, a breach, violation or
    default, create a lien, or give rise to any right of termination,
    modification, cancellation, prepayment, acceleration or loss of material
    benefit under any law, order, judgment, writ, injunction, decree, statute,
    rule or regulation, governmental permit or license (collectively "Laws"), or
    any mortgage, indenture, lease, license, agreement or other instrument of
    Parent, the Purchaser or any of their respective subsidiaries, or to which
    Parent, the Purchaser or any of their respective subsidiaries or any of
    their respective properties is subject, except for breaches, violations,
    defaults, liens, or rights of termination, modification, cancellation,
    prepayment or acceleration which would not reasonably be expected,
    individually or in the aggregate, to have a Material Adverse Effect on
    Parent or materially adversely affect the ability of Parent or the Purchaser
    to consummate the transactions contemplated hereby; or (iii) require any
    consent, approval or authorization of, notification to, or filing with, any
    court, govern mental agency or regulatory or administrative authority,
    foreign or domestic (each, a "Governmental Entity") or any third party, on
    the part of Parent or the Purchaser, other than (w) the filing of a
    certificate of merger with respect to the Merger in accordance with the
    DGCL, (x) any applicable filings under federal or state securities, "Blue
    Sky" or state anti-takeover laws, (y) filings required pursuant to the
    Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the "HSR
    Act"), and (z) consents, approvals, authorizations, notifications or
    filings the failure of which to be obtained or made would not reasonably be
    expected, individually or in the aggregate, to have a Material Adverse
    Effect on the Parent or materially adversely affect the ability of the
    Parent or the Purchaser to consummate the transactions contemplated hereby.

        (d) Offer Documents; Schedule 14D-9. None of the Offer Documents will,
    on the date filed with the Commission or on the date first published, sent
    or given to the Company's stockholders, contain any untrue statement of a
    material fact or omit to state any material fact required to be stated
    therein or necessary in order to make the statements therein, in light of
    the circumstances under which they were made, not misleading; provided,
    however, that the foregoing shall not apply to the


                                       10
<PAGE>   14
    extent that any such untrue statement of a material fact or omission to
    state a material fact was made by the Parent or the Purchaser in reliance
    upon and in conformity with written information furnished to the Parent or
    the Purchaser by the Company specifically for use in the Offer Documents.
    The Offer Documents will comply in all material respects, both as to form
    and otherwise, with the requirements of the Exchange Act and the rules and
    regulations thereunder. None of the information supplied or to be supplied
    in writing by the Parent or the Purchaser specifically for inclusion in the
    Schedule 14D-9 will, at the time the Schedule 14D-9 is filed with the
    Commission, contain any untrue statement of a material fact, or omit to
    state any material fact required to be stated therein or necessary in order
    to make the statements therein, in light of the circumstances under which
    they were made, not misleading.

        (e) Financing. Parent and the Purchaser, collectively, have sufficient
    funds available to pay the aggregate Merger Consideration and Option
    Consideration contemplated by this Agreement and to pay all of its fees and
    expenses related to the transactions contemplated hereby.

        (f) No Other Representations or Warranties. Except for the
    representations and warranties contained in this Section 3.1, none of
    Parent, the Purchaser or any other Person makes any other express or implied
    representation or warranty on behalf of Parent, the Purchaser or any of
    their respective affiliates.

        3.2 Representations and Warranties of the Company. The Company repre-
sents and warrants to Parent and the Purchaser that:

        (a) Corporate Organization. Each of the Company and each of its sub-
    sidiaries is a corporation duly organized, validly existing and, except as
    otherwise indicated on the Disclosure Schedule, is in good standing under
    the laws of the jurisdiction in which it is incorporated and has the
    requisite corporate power to own, lease and operate its properties and
    assets and to carry on its businesses as they are now being conducted. The
    Company has delivered to Parent copies of the Certificates of Incorporation
    and By-laws, as amended to this date, of the Company and each of its
    subsidiaries, which Certificates and By-laws are in full force and effect.

        (b) Capitalization. The authorized capital stock of the Company consists
    of 40,000,000 Shares, and 5,000,000 shares of Preferred Stock, par value
    $.01 per share, of which 150,000 shares have been designated Series A
    Participating Cumulative Preferred Stock. As of the date hereof (and
    assuming the return and


                                       11
<PAGE>   15
    cancellation of the 179,656 Shares previously held by the Trust, as
    described in the third recital to this Agreement), (i) 10,881,210 Shares are
    issued and outstanding, all of which are validly issued, fully paid and
    nonassessable and not subject to preemptive rights except as described on
    the Disclosure Schedule delivered by the Company to Parent on the date
    hereof (the "Disclosure Schedule"); (ii) 179,656 Shares are held in the
    treasury of the Company as treasury stock; (iii) there are outstanding
    Options to purchase an aggregate of 1,071,388 Shares; and (iv) there are no
    outstanding Series A Shares. Except as set forth on the Disclosure Schedule,
    there are no stock appreciation rights outstanding. The Disclosure Schedule
    sets forth a list, complete and correct as of the date hereof, of the
    holders of all Options and the number of Shares issuable upon the exercise
    of each such Option and the exercise prices thereof. There are no bonds,
    debentures, notes or other indebtedness of the Company having the right to
    vote (or convertible into, or exchangeable for, securities having the right
    to vote) on any matters on which stockholders of the Company may vote.
    Except as set forth in this Section 3.2(b) or on the Disclosure Schedule, no
    shares of capital stock or other voting securities are issued, reserved for
    issuance or outstanding, nor are there any outstanding subscriptions,
    options, warrants, rights, convertible securities or other agreements or
    commitments of any character relating to the issued or unissued capital
    stock or other securities of the Company or any of its subsidiaries
    obligating the Company or any of its subsidiaries to issue, deliver, sell or
    purchase, or cause to be issued, delivered, sold or purchased, any
    securities of the Company or any of its subsidiaries. Except as set forth
    on the Disclosure Schedule, there are no voting trusts or other agreements
    or understandings to which the Company or any of its subsidiaries is a party
    with respect to the voting of capital stock of the Company or any of its
    subsidiaries.

        (c) Subsidiaries. The Disclosure Schedule sets forth a list, true and
    complete as of the date hereof, of all of the subsidiaries of the Company.
    All of the out standing shares of capital stock of each subsidiary of the
    Company have been validly issued and are fully paid and nonassessable and
    are owned by the Company or by a subsidiary of the Company are free and
    clear of any Liens. Except for the capital stock of its subsidiaries or as
    set forth on the Disclosure Schedule, as of the date hereof, the Company
    does not own, directly or indirectly, any capital stock or other ownership
    interest in any corporation, limited liability company, partnership, joint
    venture or other entity.

        (d) Authority. The Company has the requisite corporate power and
    authority to execute and deliver this Agreement and to carry out its
    obligations pursuant hereto. The execution and delivery of this Agreement
    and the consummation of


                                       12
<PAGE>   16
    the transactions contemplated hereby have been duly authorized by all
    necessary corporate action on the part of the Company, subject only, to the
    extent required by law, to approval by the stockholders of the Company as
    provided in Section 4.7 or as set forth on the Disclosure Schedule. This
    Agreement has been duly executed and delivered by, and, assuming due
    authorization, execution and delivery by Parent and the Purchaser,
    constitutes a valid and binding obligation of the Company, enforceable
    against the Company in accordance with its terms, except as may be limited
    by bankruptcy, insolvency, moratorium or other similar laws affecting or
    relating to the enforcement of creditors' rights generally or by general
    principles of equity. Except as set forth on the Disclosure Schedule and for
    the approval by the stockholders of the Company as provided in Section 4.7,
    no other corporate actions or proceedings on the part of the Company or its
    stockholders are necessary to authorize this Agreement, the Offer, the
    Merger or the consummation of the transactions contemplated hereby or its
    discharge of its obligations pursuant hereto.

        (e) Consents; No Violation. None of the execution and delivery of this
    Agreement by the Company, the consummation of the transactions contemplated
    hereby or the discharge of its obligations hereunder will, except as set
    forth on the Disclosure Schedule (i) conflict with, or result in a breach or
    a violation of, any provision of the Certificate of Incorporation or By-laws
    of the Company or any of its subsidiaries; (ii) constitute, with or without
    notice, the passage of time or both, a breach, violation or default, create
    a Lien, or give rise to any right of termination, modification,
    cancellation, prepayment, acceleration or the loss of any material benefit
    under any Laws or any mortgage, indenture, lease, license, agreement or
    other instrument of the Company or any of its subsidiaries, or to which the
    Company or any of its subsidiaries or any of their respective properties is
    subject, except for breaches, violations, defaults, liens, or rights of
    termination, modification, cancellation, prepayment or acceleration which
    would not reasonably be expected, individually or in the aggregate, to have
    a Material Adverse Effect on the Company or materially adversely affect the
    ability of the Company to consummate the transactions contemplated hereby;
    or (iii) require any consent, approval or authorization of, notification to,
    or filing with, any Governmental Entity or from any other third parties, on
    the part of the Company or any of its subsidiaries other than (v) required
    consents identified on the Disclosure Schedule, (w) the filing of a
    certificate of merger with respect to the Merger in accordance with the
    DGCL, (x) filings required under the HSR Act, (y) any applicable filings
    under federal and state securities laws or state anti-takeover laws, and (z)
    consents, approvals, authorizations, notifications or filings the failure of
    which to be obtained or made would not reasonably be expected, individually
    or in the aggregate, to have a


                                       13
<PAGE>   17
    Material Adverse Effect on the Company or materially adversely effect the
    ability of the Company to consummate the transactions contemplated hereby.

        (f) SEC Reports; Company Assets and Liabilities. The Company has filed
    all forms, reports, statements and schedules with the Commission required to
    be filed pursuant to the Exchange Act, and the Commission Rules, since
    January 1, 1995 (the "SEC Reports"). As of their respective filing dates,
    the SEC Reports complied in all material respects with all applicable
    requirements of the Exchange Act and the Commission Rules applicable to such
    SEC Reports, and did not contain any untrue statement of a material fact or
    omit to state a material fact required to be stated therein or necessary in
    order to make the statements made therein, in light of the circumstances
    under which they were made, not misleading. The audited and unaudited
    consolidated financial statements of the Company included (or incorporated
    by reference) in the SEC Reports comply as to form in all material respects
    with applicable accounting requirements and the published rules and
    regulations of the Commission with respect thereto, have been prepared in
    accordance with generally accepted accounting principles applied on a
    consistent basis (except as stated in the financial statements, including
    the related notes, and except that the quarterly financial statements do not
    contain all of the footnote disclosures required by generally accepted
    accounting principles) and fairly present, in all material respects, the
    financial position of the Company and its consolidated subsidiaries as of
    the respective dates thereof and the results of their operations,
    stockholders' equity and cash flows for the periods then ended, subject, in
    the case of the unaudited financial statements, to normal year-end
    adjustments and any other adjustments described therein. Except for
    liabilities and obligations incurred in the ordinary course of business
    consistent with past practices since the date of the most recent
    consolidated balance sheet included in the SEC Reports, neither the Company
    nor any of its subsidiaries has incurred any material liabilities or
    obligations of any nature (whether accrued, absolute, contingent or
    otherwise) other than those reflected in the SEC Reports and on the
    Disclosure Schedule and those incurred in connection with the transactions
    contemplated hereby.

        (g) No Material Adverse Change. Except as and to the extent disclosed in
    the SEC Reports or as set forth in the Disclosure Schedule, since October
    31, 1996, there has not been (i) any material adverse change in the
    business, operations or condition (financial or other) of the Company and
    its subsidiaries taken as a whole, (ii) any declaration, setting aside or
    payment of any dividend or other distribution (whether in cash, stock or
    property) with respect to any of the Company's capital stock, (iii) any
    split, combination or reclassification of any of the Company's capital stock
    or any issuance or the authorization of the issuance of any securities


                                       14
<PAGE>   18
    in respect of or in substitution for shares of its capital stock, (iv) any
    granting by the Company (x) to any executive officer or other key employee
    of the Company of any increase in compensation, except for normal increases
    in the ordinary course of business consistent with past practice or as
    required under employment agreements in effect as of the date of the most
    recent SEC Reports or set forth in the Disclosure Schedule or (y) to any
    such executive officer of any increase in severance or termination pay,
    except as was required under any employment, severance or termination
    agreements in effect as of the date of the most recent SEC Reports or set
    forth in the Disclosure Schedule, (v) any damage, destruction or loss,
    whether or not covered by insurance, that could reasonably be expected to
    have a Material Adverse Effect or (vi) except as may have been required by a
    change in generally accepted accounting principles or as disclosed in the
    SEC Reports, any change in accounting methods, principles or practices by
    the Company or any of its subsidiaries materially affecting its assets,
    liabilities or business.

        (h) Offer Documents; Schedule 14D-9. None of the information supplied in
    writing by the Company specifically for inclusion in the Offer Documents
    will, at the respective times the Offer Documents or any amendments or
    supplements thereto are filed with the Commission, contain any untrue
    statement of a material fact or omit to state any material fact required to
    be stated therein or necessary in order to make the statements therein, in
    light of the circumstances under which they were made, not misleading. The
    Schedule 14D-9 on the date filed with the Commission will not contain any
    untrue statement of a material fact or omit to state any material fact
    required to be stated therein or necessary in order to make the statements
    therein, in light of the circumstances under which they were made, not
    misleading; provided, however, that the foregoing shall not apply to the
    extent that any such untrue statement of a material fact or omission to
    state a material fact was made by the Company in reliance upon and in
    conformity with written information furnished to the Company by the Parent
    or the Purchaser specifically for use in the Schedule 14D-9. The Schedule
    14D-9 will comply in all material respects, both as to form and otherwise,
    with the requirements of the Exchange Act and the rules and regulations
    thereunder.

        (i) Litigation. Except as disclosed in the SEC Reports or on the
    Disclosure Schedule, there is no suit, action or proceeding pending or, to
    the knowledge of the Company, threatened against or affecting the Company or
    any of its subsidiaries that individually or in the aggregate would
    reasonably be expected (i) to have a Material Adverse Effect on the Company,
    (ii) as of the date hereof, to impair the ability of the Company to perform
    its obligations under this Agreement in any material respect or (iii) as of
    the date hereof, to delay in any material respect or


                                       15
<PAGE>   19
    prevent the consummation of any of the transactions contemplated by this
    Agreement, nor is there any judgment, decree, injunction, rule or order of
    any Governmental Entity or arbitrator outstanding against the Company or
    any of its subsidiaries having, or which would reasonably be expected to
    have a Material Adverse Effect on the Company.

        (j) Fees. Except as set forth on the Disclosure Schedule, neither the
    Company nor any of its subsidiaries has paid or become obligated to pay any
    fee or commission to any broker, finder or intermediary or other similar
    Person in connection with the transactions contemplated hereby or in
    connection with any other offer to acquire the Company's shares or assets.

        (k) Certificate and By-laws. Neither the Certificate of Incorporation
    nor the By-laws of the Company contains any provision that would require a
    vote of the Company's stockholders in excess of a majority of the
    outstanding shares of Company Common Stock in order to approve the Merger in
    accordance with the terms of this Agreement.

        (l) State Takeover Statutes. The Board of Directors of the Company has
    approved the terms of this Agreement and the Stockholder Agreement and the
    consummation of the Merger and the other transactions contemplated by this
    Agreement and the Stockholder Agreement, and such approval is sufficient to
    render inapplicable to the Merger and the other transactions contemplated by
    this Agreement and the Stockholder Agreement the provisions of Section 203
    of the DGCL. To the Company's knowledge, no state takeover statute or
    similar statute or regulation applies or purports to apply to the Merger,
    this Agreement or any of the transactions contemplated by this Agreement,
    and except for the Rights Agreement and related Series A Shares, no
    provision of the Certificate of Incorporation, By-laws or other governing
    instruments of the Company or any of its subsidiaries would, directly or
    indirectly, restrict or impair the ability of Parent to vote, or otherwise
    to exercise the rights of a stockholder with respect to, shares of the
    capital stock of Company and its subsidiaries that may be acquired or
    controlled by Parent.

        (m) Employee Benefit Plans: Employee Agreements. The Disclosure Schedule
    sets forth a true and complete list of each employee benefit plan within the
    meaning set forth in Section 3(3) of the Employee Retirement Income Security
    Act of 1974, as amended ("ERISA") and each bonus, incentive, deferred
    compensation, severance, termination, retention, change of control, stock
    option or other equity-based performance or other compensation plan,
    program, arrangement,


                                       16
<PAGE>   20
    policy or understanding, whether written or unwritten, that is maintained by
    the Company or any other Person that, together with the Company, is treated
    as a single employer under Section 414 of the Internal Revenue Code of 1986,
    as amended (the "Code") (each a "Commonly Controlled Entity"), or to which
    the Company or any Commonly Controlled Entity contributes or is obligated or
    required to contribute or with regard to which the Company or any of its
    Commonly Controlled Entities has knowledge of any event, transaction or
    condition that would reasonably be expected to result in any material
    liability at the Effective Time (collectively, the "Plans"). Each employment
    agreement to which the Company or any of its subsidiaries is a party, and
    each employee benefit plan adopted by the Company or any of its
    subsidiaries, which in either case becomes effective or grants rights to any
    person upon a "change of control" of the Company is set forth in the
    Disclosure Schedule. True and complete copies of each such Plan and the most
    recent annual report on Form 5500 for each such Plan have been delivered to
    the Purchaser.

        Each Plan intended to be qualified under Section 401(a) of the Code and
    the trust forming a part thereof has received a favorable determination
    letter from the Internal Revenue Service (the "IRS") as to its qualification
    under the Code and to the effect that each such trust is exempt from
    taxation under Section 501(a) of the Code and the Company knows of no event
    that has occurred since the date of such determination that would reasonably
    be expected to adversely affect such qualification or tax-exempt status.

        Except as set forth in the Disclosure Schedule, no material liability
    has been or, to the knowledge of the Company, is expected to be incurred by
    the Company or any Commonly Controlled Entity (either directly or
    indirectly, including as a result of an indemnification obligation or any
    joint and several liability obligations) as the result of a violation of
    Title I of ERISA or an "accumulated funding deficiency" as defined in
    Section 412 of the Code or Section 302 of ERISA or under or pursuant to
    Title IV of ERISA or the penalty or excise tax provisions of Chapter 43 of
    Subtitle D of the Code relating to employee benefit plans, and the Company
    knows of no event, transaction or condition that has occurred or exists with
    respect to the Company's employee benefit plans that would reasonably be
    expected to result in any such material liability to the Purchaser, the
    Surviving Corporation or any Commonly Controlled Entity or any employee
    benefit plan of the Surviving Corporation or any Commonly Controlled Entity.

        Except as otherwise set forth in the Disclosure Schedules, no benefit
    that is payable, or which may become payable as a result of the transactions
    contemplated


                                       17
<PAGE>   21
    hereunder, to any employee pursuant to any Plan shall constitute an "excess
    parachute payment" (as defined in Section 280G(b)(1) of the Code) which is
    subject to the imposition of an excise tax under Section 4999 of the Code or
    which would not be deductible by reason of Section 280G of the Code.

        (n) Compliance with Applicable Laws. Except as disclosed in the SEC
    Reports, the Company and each of its subsidiaries has in effect all Federal,
    state and local governmental approvals, authorizations, certificates,
    filings, franchises, licenses, notices, permits and rights ("Permits")
    necessary for it to own, lease or operate its properties and assets and to
    carry on its business as now conducted, and there has occurred no default
    under any such Permit, except for the lack of Permits and for defaults under
    Permits which lack of, or default under, individually or in the aggregate
    would not have a Material Adverse Effect on the Company. Except as disclosed
    in the SEC Reports, the Company and its subsidiaries are in compliance with
    all applicable statutes, laws, ordinances, rules, orders and regulations of
    any Governmental Entity, except for possible noncompliance which,
    individually or in the aggregate, would not have a Material Adverse Effect
    on the Company.

        (o) Contracts; Debt Instruments. Except as set forth on the Disclosure
    Schedules, (i) neither the Company nor any of its subsidiaries is in
    violation of or in default under (nor to the knowledge of the Company does
    there exist any condition which upon the passage of time, the giving of
    notice or both would cause such a violation of or default under) any loan or
    credit agreement, note, bond, mortgage, indenture, lease, permit,
    concession, franchise, license or any other contract, agreement, arrangement
    or understanding to which it is a party or by which it or any of its
    properties or assets is bound, except for violations or defaults that,
    individually or in the aggregate, would not reasonably be expected to have a
    Material Adverse Effect on the Company.

        (ii) The Company has made available to Parent (x) true and correct
    copies of all loan or credit agreements, notes, bonds, mortgages, indentures
    and other agreements and instruments pursuant to which any indebtedness of
    the Company or any of its subsidiaries in an aggregate principal amount in
    excess of $500,000 is outstanding or may be incurred and (y) accurate
    information regarding the respective principal amounts currently outstanding
    thereunder. For purposes of this Agreement, "indebtedness" shall mean, with
    respect to any Person, without duplication, (A) all obligations of such
    Person for borrowed money, or with respect to deposits or advances of any
    kind to such Person, (B) all obligations of such Person evidenced by bonds,
    debentures, notes or similar instruments, (C) all obligations of


                                       18
<PAGE>   22
    such Person under conditional sale or other title retention agreements
    relating to property purchased by such Person, (D) all obligations of such
    Person issued or assumed as the deferred purchase price of property or
    services (excluding obligations of such Person to creditors for raw
    materials, inventory, services and supplies incurred in the ordinary course
    of such Person's business), (E) all capitalized lease obligations of such
    Person, (F) all obligations of others secured by any Lien on property or
    assets owned or acquired by such Person, whether or not the obligations
    secured thereby have been assumed, (G) all obligations of such Person under
    interest rate or currency hedging transactions (valued at the termination
    value thereof), (H) all letters of credit issued for the account of such
    Person and (I) all guarantees and arrangements having the economic effect of
    a guarantee of such Person of any indebtedness of any other person.

        (p) Taxes and Tax Returns. Except as set forth in the SEC Reports or on
    the Disclosure Schedule: (i) all material tax returns, declarations,
    reports, estimates, information returns and statements required to be filed
    with respect to Taxes (as defined herein) under Federal, state, local or
    foreign laws ("Returns") by or with respect to the Company or any subsidiary
    of the Company have been timely filed (taking into account any extensions of
    time for filing such Returns); (ii) at the time filed, such Returns were
    true, correct and complete in all material respects; (iii) the Company and
    each subsidiary of the Company has timely paid or made provision in
    accordance with generally accepted accounting principles (or there has been
    paid or provision has been made on its behalf) for all material Taxes for
    all periods or portions thereof through the date hereof; (iv) there are no
    material liens for Taxes upon the assets of the Company or any subsidiary of
    the Company which are not provided for in the most recent financial
    statements included in the SEC Reports, except liens for Taxes not yet due;
    (v) there are no material outstanding deficiencies for any Taxes proposed,
    asserted or assessed against the Company or any subsidiary of the Company
    which are not provided for in the most recent financial statements included
    in the SEC Reports; (vi) there are no material Federal, state, local or
    foreign audits or other administrative proceedings or judicial proceedings
    presently pending with regard to any Taxes or Returns required to be filed
    by or with respect to the Company or any of its subsidiaries; (vii) the
    Company has filed a consolidated Return for Federal income tax purposes on
    behalf of itself and all of its domestic subsidiaries as the common parent
    corporation of an "affiliated group" (within the meaning of Section 1504(a)
    of the Code) of which such subsidiaries are "includible corporations" in
    such affiliated group within the meaning of Section 1504(b) of the Code;
    (viii) the Internal Revenue Service has completed examinations of the
    Federal income tax returns filed by or with respect to the Company (or the
    statute of limitations for the assessment of Federal income taxes for such
    period


                                       19
<PAGE>   23
    has expired) for all periods through and including the Company's taxable
    year ended October 31, 1994; (ix) none of the Company or any of its
    subsidiaries has been a member of an "affiliated group" (as defined above),
    or any similar affiliated, combined or consolidated group for state, local
    or foreign tax purposes (other than a group the common parent of which is
    the Company), or has any liability for the Taxes of any person (other than
    the Company or its current subsidiaries) under Treasury Regulation Section
    1.1502-6 or any similar provision of state, local or foreign law or as a
    transferee, successor, by contract or otherwise; (x) the Company has not
    (A) breached any covenant or representation contained in the Tax Agreement
    between the Company and Whittaker Corporation, dated as of September 24,
    1991, or the amendment thereto dated October 23, 1991 (collectively, the
    "Tax Agreement") or (B) entered into any of the transactions described in
    Section 2(c)(ii)(y) of the Tax Agreement and (xi) except as set forth in the
    Disclosure Schedule, neither the Company nor any of its subsidiaries is a
    party to any material tax sharing, tax indemnity or other agreement or
    arrangement with respect to Taxes with any entity not included in the
    Company's most recent financial statements included in the SEC Reports. For
    purposes of this Agreement, "Taxes" means all income, gross income, gross
    receipts, premium, sales, use, transfer, franchise, profits, withholding,
    payroll, employment, excise, severance, property and windfall profits
    taxes, and all other taxes, assessments or similar charges of any kind
    whatsoever thereon or applicable thereto, together with any interest and any
    penalties, additions to tax or additional amounts, in each case imposed by
    any taxing authority (domestic or foreign) upon the Company or any
    subsidiary of the Company, including, without limitation, all amounts
    imposed as a result of being a member of any affiliated or combined group.

        (q) Labor Matters. Neither the Company nor any of its subsidiaries is
    the subject of any suit, action or proceeding which is pending or, to the
    knowledge of the Company, threatened, asserting that the Company or any of
    its subsidiaries has committed an unfair labor practice (within the meaning
    of the National Labor Relations Act or applicable state statutes) or seeking
    to compel the Company or any of its subsidiaries to bargain with any labor
    organization as to wages and conditions of employment, in any such case,
    that would reasonably expected to have a Material Adverse Effect on the
    Company. No strike or other labor dispute involving the Company or any of
    its subsidiaries is pending or, to the knowledge of the Company, threatened,
    and, to the knowledge of the Company, there is no activity involving any
    employees of the company or any of its subsidiaries seeking to certify a
    collective bargaining unit or engaging in any other organizational activity,
    except for any such dispute or activity which would not reasonably be
    expected to have a Material Adverse Effect on the Company.


                                       20
<PAGE>   24
        (r) Environmental Matters. (i) Except as set forth on the Disclosure
    Schedule or in the SEC Reports, the Company's and each of its subsidiaries'
    operation and use of its respective assets, including its owned and leased
    real property, are in compliance in all respects with all applicable Laws
    relating to the protection of human health or the environment
    ("Environmental Laws"), except to the extent that any such noncompliance
    would not have a Material Adverse Effect on the Company. The Company and
    each of its subsidiaries has obtained all environmental, health and safety
    permits necessary for the operation of its respective business as presently
    conducted, and all such permits are in full force and effect and the Company
    and each of its subsidiaries is in compliance in all respects with the terms
    and conditions of each such permit, except, in each case, to the extent that
    any failure to obtain a permit or any such noncompliance would not have a
    Material Adverse Effect on the Company. Except as set forth on the
    Disclosure Schedule, neither the Company nor any of its subsidiaries has
    received any notice of, and, to the knowledge of the Company there is not,
    any administrative or judicial investigation, proceeding or action with
    respect to any material violation, alleged or proven, of Environmental Laws
    by the Company or any its subsidiaries or otherwise involving their
    respective owned or leased real property.

        (ii) Except as set forth on the Disclosure Schedule, to the knowledge of
    the Company, neither the Company nor any of its subsidiaries has taken or
    failed to take any action that has resulted in or will result in any
    liability or obligation relating to (x) the environmental conditions on,
    under, or about the assets of the Company or any of its subsidiaries or any
    of their respective owned or leased real property, or any properties owned,
    leased, operated or used by the Company or any of its subsidiaries or any
    predecessor of the Company or any of its subsidiaries at the present time or
    in the past, including, without limitation, the air, soil and groundwater
    conditions at such properties or (y) the past or present use, management,
    handling, transport, treatment, generation, storage, disposal or release of
    any Hazardous Substances (as defined in Section 6.5), except in the case of
    clauses (x) and (y) above, to the extent such liability or obligation would
    not have a Material Adverse Effect.

        (s) Rights Agreement. The Board of Directors of the Company (at a
    meeting duly called and held at which a quorum was present) as part of its
    approval of this Agreement has resolved to amend (and the Company has caused
    such amendments to become effective prior to the execution of this Agreement
    and the Stockholder Agreement) the Rights Agreement so that (i) neither the
    Parent, the Purchaser nor any of their respective affiliates shall
    constitute an Acquiring Person for any purpose of the Rights Agreement and
    (ii) neither the execution or delivery of this


                                       21
<PAGE>   25
    Agreement or the Stockholders Agreement, nor the consummation of any or all
    of the transactions contemplated by this Agreement or the Stockholders
    Agreement, will trigger the exercisability of the Rights (as defined in the
    Rights Agreement) or the separation of the Rights from the shares to which
    they are attached, or cause the Distribution Date (as defined in the Rights
    Agreement) to occur.

        (t) Effectiveness of Waiver. The Company has waived the Company's rights
    under the Stock Purchase Agreement, dated as of September 24, 1991, between
    the Company and Anasco GmbH (the "Anasco Stock Purchase Agreement") so that
    Anasco GmbH's execution or delivery of the Stockholders Agreement and its
    consummation of the transactions contemplated by the Stockholders Agreement,
    will not violate or breach any provision in the Anasco Stock Purchase
    Agreement.

        (u) Opinion of the Company's Financial Advisor. The Board of Directors
    of the Company has received a written opinion from Alex. Brown & Sons
    Incorporated ("Alex Brown") to the effect that, as of the date of this
    Agreement, the consideration to be received in the Offer and the Merger by
    the holders of Shares (other than Parent and its affiliates) is fair from a
    financial point of view to such holders of Shares.

        (v) No Other Representations or Warranties. Except for the
    representations and warranties contained in this Section 3.2, neither the
    Company nor any other Person makes any other express or implied
    representation or warranty on behalf of the Company or any of its
    affiliates.


                                  4. COVENANTS

        4.1 Acquisition Transactions. (a) After the date hereof and prior to the
Effective Time or earlier termination of this Agreement, unless Parent shall
otherwise agree in writing, the Company shall not, shall not permit any of its
subsidiaries to, and shall not authorize or permit any officer, director or
employee or any investment banker, attorney, accountant or other advisor or
representative of the Company or any of its subsidiaries to, directly or
indirectly, except as otherwise expressly permitted in this Section 4.1(a) or in
Section 4.1(b), (i) initiate, solicit, negotiate, encourage, or provide
confidential information to facilitate any proposal or offer to acquire all or
any substantial part of the business and properties of the Company and its
subsidiaries, taken as a whole, or beneficial ownership (as determined pursuant
to Rule 13d-3 promulgated under the Exchange Act) of 20% or more of the capital
stock of the Company, whether by merger, purchase of assets, tender offer or
otherwise, whether


                                       22
<PAGE>   26
for cash, securities or any other consideration or combination thereof (such
transactions being referred to herein as "Acquisition Transactions"), (ii) enter
into any agreement with respect to any Acquisition Transaction or give any
approval of the type referred to in Section 4.1(b) with respect to any
Acquisition Transaction or (iii) participate in any discussions regarding, or
take any other action to facilitate any inquiries or the making of any proposal
that constitutes or may reasonably be expected to lead to any Acquisition
Transaction. Notwithstanding the immediately preceding sentence, the Company and
its subsidiaries may, prior to the Company Stockholder Approval, in response to
any unsolicited proposal for an Acquisition Transaction, furnish information
concerning its business, properties or assets to the corporation, partnership,
person or other entity or group (a "Potential Acquiror") making such proposal
for an Acquisition Transaction and participate in negotiations with the
Potential Acquiror if (x) the Company's Board of Directors, after consultation
with one or more of its independent financial advisors, is of the reasonable
belief that such Potential Acquiror has the financial wherewithal to consummate
such an Acquisition Transaction, (y) the Company's Board of Directors reasonably
determines, after receiving advice from the Company's financial advisor, that
such Potential Acquiror has submitted a proposal for an Acquisition Transaction
that involves consideration to the Company's stockholders and other terms that
taken as a whole are superior to the Merger, and (z) based upon advice of
counsel to such effect, the Company's Board of Directors determines in good
faith that it is necessary to so furnish information and negotiate in order to
comply with its fiduciary duty to stockholders of the Company. In the event the
Company shall determine to provide any information as described above or shall
receive any offer of the type referred to in this Section 4.1 or shall receive
or become aware of any other proposal to acquire a substantial part of the
business and properties of the Company and its subsidiaries, taken as a whole,
or to acquire a substantial amount of capital stock of the Company, it shall
promptly inform Parent orally as to the fact that information is to be provided
and shall furnish to Parent the identity of the recipient of such information
and/or the proponent of any such offer or proposal and a description of the
material terms thereof. The Company will keep Parent fully informed of the
status and material details of any proposed Acquisition Transaction or other
transaction (including any material amendments or material proposed amendments
of any such proposed Acquisition Transaction or other transaction).

        (b) Neither the Board of Directors of the Company nor any committee
thereof (x) shall withdraw or modify or propose to withdraw or modify, in any
manner adverse to Parent the approval of recommendation of such Board of
Directors or such committee of this Agreement, the Offer or the Merger or (y)
approve or recommend, or propose to approve or recommend, any proposal for an
Acquisition Transaction except, in each case, in connection with a Superior
Proposal (as defined in Section 6.5).


                                       23
<PAGE>   27
        4.2 Interim Operations. (a) During the period from the date of this
Agreement to the Effective Time, except as contemplated by this Agreement, as
expressly permitted by Section 4.1 or as otherwise approved in writing by the
Purchaser, the Company shall not and shall cause its subsidiaries not to:

           (i) (x) declare, set aside or pay any dividends on, or make any other
        distributions in respect of, any of its capital stock, other than
        dividends and distributions by a direct or indirect wholly owned
        subsidiary of the Company to its parent, (y) split, combine or
        reclassify any of its capital stock or issue or authorize the issuance
        of any other securities in respect of, in lieu of or in substitution for
        shares of its capital stock or (z) purchase, redeem or otherwise acquire
        any shares of capital stock of the Company or any of its subsidiaries or
        any other securities thereof or any rights, warrants or options to
        acquire any such shares or other securities;

           (ii) issue, deliver, sell, pledge or otherwise encumber any shares of
        its capital stock, any other voting securities or any securities
        convertible into, or any rights, warrants or options to acquire, any
        such shares, voting securities or convertible securities, except upon
        exercise of any Option;

           (iii) amend its certificate of incorporation, by-laws or other
        comparable organizational documents;

           (iv) except as set forth on the Disclosure Schedule, acquire or agree
        to acquire (x) by merging or consolidating with, or by purchasing a
        substantial portion of the assets of, or by any other manner, any
        business or any corporation, limited liability company, partnership,
        joint venture, association or other business organization or division
        thereof or (y) any assets that individually or in the aggregate are
        material to the Company and its subsidiaries taken as a whole;

           (v) except as set forth on the Disclosure Schedule, sell, lease,
        license, mortgage or otherwise encumber or subject to any Lien or
        otherwise dispose of any of its properties or assets, other than in the
        ordinary course of business consistent with past practice, that are
        material to the Company and its subsidiaries taken as a whole;

           (vi) incur any indebtedness, except for borrowings for working
        capital purposes not in excess of $500,000 at any one time outstanding
        incurred in the ordinary course of business consistent with past
        practice and except for inter- 


                                       24
<PAGE>   28
        company indebtedness between the Company and any of its wholly-owned
        subsidiaries or between such wholly-owned subsidiaries, or make any
        loans, advances or capital contributions to, or investments in, any
        other person, other than to the Company or any direct or indirect wholly
        owned subsidiary of the Company;

           (vii) except as set forth on the Disclosure Schedule, make or agree
        to make any new capital expenditure or capital expenditures which in the
        aggregate are in excess of $250,000;

           (viii) make any tax election that could reasonably be expected to
        have a Material Adverse Effect on the Company or settle or compromise
        any material income tax liability;

           (ix) except in the ordinary course of business or except as would not
        reasonably be expected to have a Material Adverse Effect on the Company
        or except as set forth on the Disclosure Schedule, modify, amend or
        terminate any material contract or agreement to which the Company or any
        subsidiary is a party or waive, release or assign any material rights or
        claims thereunder;

           (x) make any material change to its accounting methods, principles or
        practices, except as may be required by generally accepted accounting
        principles or as disclosed in the Disclosure Schedule;

           (xi) permit any amendment to the form of benefit payments elected on
        February 16, 1996 pursuant to the BioWhittaker, Inc. Supplemental
        Executive Retirement Plan Deferral Agreement by any participant; or

           (xii) authorize, or commit or agree to take, any of the foregoing
        actions.

        (b) Other Actions. Except as expressly permitted by Section 4.1, the
    Company shall not, and shall not permit any of its subsidiaries to, take any
    action that would, or that could reasonably be expected to, result in (i)
    any of the representations and warranties of the Company set forth in this
    Agreement that are qualified as to materiality becoming untrue, (ii) any of
    such representations and warranties that are not so qualified becoming
    untrue in any respect or (iii) any of the conditions to the Merger set forth
    in Article 5 not being satisfied.

        (c) Advice of Changes. The Company shall promptly advise Parent and
    Parent shall promptly advise the Company orally and in writing of (i) any
    repre- 


                                       25
<PAGE>   29
    sentation or warranty made by it (or, in the case of Parent, made by it or
    the Purchaser) contained in this Agreement that is qualified as to
    materiality becoming untrue or inaccurate in any respect or any such
    representation or warranty that is not so qualified becoming untrue or
    inaccurate in any respect or (ii) the failure by it (or, in the case of
    Parent, a failure by it or the Purchaser) to comply with or satisfy in any
    material respect any covenant, condition or agreement to be complied with or
    satisfied by it under this Agreement, provided, however, that no such
    notification shall affect the representations, warranties, covenants or
    agreements of the parties or the conditions to the obligations of the
    parties under this Agreement.

        4.3 Access and Information. Throughout the period prior to the Effective
Time, so long as this Agreement remains in effect, the Company shall afford to
the Purchaser and its representatives such access, during normal business hours,
to the Company's and its subsidiaries' books, records (including, without
limitation, tax returns and work papers of the Company's independent auditors),
plant and personnel, and to such other information, as Parent shall reasonably
request. Parent and the Purchaser will treat, and will cause their respective
accountants, counsel and other representatives to treat, as strictly
confidential all non-public documents and non-public information concerning the
Company furnished to Parent or the Purchaser in connection with the
transactions contemplated by this Agreement, subject to the requirements of law
and the provisions of this Agreement. If the transactions contemplated by this
Agreement are not consummated, such confidence shall be maintained except to the
extent such information can be shown to have been (i) in the public domain
through no fault of Parent or the Purchaser or (ii) later lawfully acquired by
Parent or the Purchaser from other sources without any breach of duty to the
Company by Parent, the Purchaser or, to the knowledge of Parent or the
Purchaser, any third party. If requested by the Company, Parent and the
Purchaser will return to the Company all copies of written information furnished
by the Company to Parent or the Purchaser or its agents, representatives or
advisors.

        4.4 Certain Filings, Consents and Arrangements. Parent, the Purchaser
and the Company shall use their reasonable best efforts to make promptly any
required submissions under the HSR Act with respect to the Merger and the
transactions contemplated by this Agreement. The Company shall use its
reasonable best efforts to obtain all consents, approvals, permits or
authorizations as are required to be obtained from other parties to loan
agreements or other contracts material to the Company's business in connection
with the consummation of the Merger.

        4.5 Reasonable Best Efforts. (a) Subject to the terms and conditions
provided in this Agreement, each of the parties agrees to use its reasonable
best efforts to take


                                       26
<PAGE>   30
promptly, or cause to be taken, all actions and to do promptly, or cause to be
done, all things necessary, proper or advisable to consummate and make effective
the transactions contemplated by this Agreement, including using its reasonable
best efforts (i) to obtain all necessary waivers, consents and approvals, and
(ii) to effect all necessary registrations and filings, subject, however, to
Company Stockholder Approval (as defined in Section 4.7 hereof). In case at any
time after the Effective Time any further action is necessary or desirable to
carry out the obligations of the parties under this Agreement, the proper
officers and/or directors of Parent, the Purchaser and the Company, as the case
may be, shall take the necessary action.

        (b) In connection with and without limiting the foregoing, the Company
and its Board of Directors shall (i) take all action necessary to ensure that no
state takeover statute or similar statute or regulation, in each case as the
same is in effect on the date hereof, is or becomes applicable to the Offer, the
Merger, this Agreement, the Stockholder Agreement or any of the other
transactions contemplated by this Agreement or the Stockholder Agreement and
(ii) if any such state takeover statute or similar statute or regulation becomes
applicable to the Offer, the Merger, this Agreement, the Stockholder Agreement
or any other transaction contemplated by this Agreement or the Stockholder
Agreement take all action necessary to ensure that the Merger and the other
transactions contemplated by this Agreement and the Stockholder Agreement may be
consummated as promptly as practicable on the terms contemplated by this
Agreement and the Stockholder Agreement and otherwise to minimize the effect of
such statute or regulation on the Merger and the other transactions contemplated
by this Agreement and the Stockholder Agreement.

        4.6 Public Statements. So long as this Agreement remains in effect,
Parent and the Purchaser, on the one hand, and the Company, on the other hand,
will consult with each other before issuing, and provide each other the
opportunity to review, comment upon and concur with, any press release or other
public statements with respect to the transactions contemplated by this
Agreement, including the Offer and the Merger, and shall not issue any such
press release or make any such public statement prior to such consultation,
except as may be required by applicable law, court process or by obligations
pursuant to any listing agreement with any national securities exchange.

        4.7 Stockholder Approval. (a) If required by applicable law in order to
consummate the Merger, as soon as practicable following the purchase of the
Shares pursuant to the Offer, the Company shall duly call, give notice of,
convene and hold a meeting of its stockholders (the "Company Stockholders
Meeting") for the purpose of adopting and approving this Agreement and the
transactions contemplated hereby (the


                                       27
<PAGE>   31
"Company Stockholder Approval"). Without limiting the generality of the
foregoing, the Company agrees that its obligations pursuant to the first
sentence of this Section 4.7(a) shall not be affected by the commencement,
public proposal, public disclosure or communication to the Company of any
proposed Acquisition Transaction. The Company will, through its Board of
Directors, recommend to its stockholders the approval and adoption of this
Agreement and the transactions contemplated hereby, except to the extent that
the Board of Directors of the Company shall have withdrawn or modified its
approval or recommendation of this Agreement or the Merger and terminated this
Agreement in accordance with Section 4.1(b). At such meeting, the Parent and the
Purchaser will each vote, or cause to be voted, all Shares acquired in the Offer
or otherwise beneficially owned by it or any of its subsidiaries on the record
date for such meeting, in favor of the approval and adoption of this Agreement
and the transactions contemplated hereby.

        (b) The Company shall, if required by law, prepare and file a proxy
statement (the "Proxy Statement") with the Commission in connection with
obtaining the Company Stockholder Approval. Parent and the Purchaser shall
cooperate with the Company in the preparation of the Proxy Statement including,
without limitation, promptly providing information requested by the Company or
required by the Commission to be included in the Proxy Statement and responding
promptly to any inquiries from the Company made in connection with comments on
the Proxy Statement received from the Commission. The Company will use its
reasonable best efforts to cause the Proxy Statement to be mailed to the
Company's stockholders as promptly as practicable after the Commission completes
its review of the Proxy Statement.

        (c) The Company agrees that none of the information included or
incorporated by reference in the Proxy Statement or otherwise supplied by the
Company to its stockholders, including any amendments to any of the foregoing,
will be false or misleading with respect to any material fact or will omit to
state any material fact required to be stated therein or necessary in order to
make the statements therein, in light of the circumstances under which they are
made, not misleading; provided, that the foregoing shall not apply to
information supplied by or on behalf of Parent or the Purchaser specifically for
inclusion or incorporation by reference in any such document. Parent agrees that
none of the information supplied by or on behalf of Parent or the Purchaser
specifically for inclusion or incorporation by reference in any such document
will be false or misleading with respect to any material fact or will omit to
state any material fact required to be stated therein or necessary in order to
make the statements in such information, in light of the circumstances under
which they are made, not misleading.


                                       28
<PAGE>   32
        (d) Notwithstanding the foregoing, in the event that the Purchaser shall
acquire at least 90 percent of the outstanding Shares, the parties hereto agree,
at the request of the Parent or the Purchaser, to take all necessary and
appropriate action to cause the Merger to become effective, as soon as
practicable after the expiration of the Offer, without a meeting of stockholders
of the Company, in accordance with Section 253 of the DGCL.

        4.8 Stockholder Litigation. The Company shall consult with the Parent
regarding the defense or settlement of any stockholder litigation against the
Company and its directors relating to the transactions contemplated by this
Agreement; it being understood that the Company shall be entitled to control and
conduct any such litigation.

        4.9 Indemnification, Exculpation and Insurance. Parent and the Purchaser
agree that all rights to indemnification and exculpation from liabilities for
acts or omissions occurring at or prior to the Effective Time now existing in
favor of the current or former directors or officers of the Company and its
subsidiaries as provided in their respective certificates of incorporation,
by-laws (or comparable organizational documents) and indemnification agreements
shall survive the Merger and shall continue in full force and effect in
accordance with their terms for a period of not less than six years from the
Effective Time. Parent will cause to be maintained for a period of not less than
six years from the Effective Time the Company's current directors' and officers'
insurance and indemnification policy to the extent that it provides coverage for
events occurring prior to the Effective Time ("D&O Insurance") for all persons
who are directors and officers of the Company on the date of this Agreement, so
long as the annual premium therefor would not be in excess of 200% of the last
annual premium paid prior to the date of this Agreement (the "Maximum Premium");
provided, however, that Parent may, in lieu of maintaining such existing D&O
Insurance as provided above, cause coverage to be provided under any policy
maintained for the benefit of Parent or any of its subsidiaries or any policy
specifically obtained for this purpose, so long as the terms thereof are no less
advantageous to the intended beneficiaries thereof than the existing D&O
Insurance. If the existing D&O Insurance expires, is terminated or canceled
during such six-year period, Parent will use all reasonable efforts to cause to
be obtained as much D&O Insurance as can be obtained for the remainder of such
period for an annualized premium not in excess of the Maximum Premium, on terms
and conditions no less advantageous to the covered persons than the existing D&O
Insurance. The Company represents to Parent that the Maximum Premium is
$340,000.


                                       29
<PAGE>   33
        4.10 Amendment of Rights Agreement. The Company covenants and agrees
that it will not take action pursuant to or amend the Rights Agreement or redeem
the Rights or terminate the Rights Agreement prior to the Effective Time, except
as expressly contemplated or permitted by Section 3.1(s) of this Agreement.

        4.11 Borrowings under the Loan Agreement. The Company shall consult with
the Parent prior to electing any new interest rate for any interest period under
the Loan Agreement with Nationsbank identified in the Disclosure Schedule and
shall otherwise manage its obligations thereunder to insure that neither the
Company, the Parent nor the Purchaser shall incur any breakage or similar
prepayment costs in the event the Company prepays its outstanding indebtedness
thereunder at the Effective Time.


                                  5. CONDITIONS

        5.1 Conditions to the Obligations of Parent, the Purchaser and the
Company. The obligations of Parent, the Purchaser and the Company to consummate
the Merger are subject to the satisfaction, at or before the Effective Time, of
each of the following conditions:

        (a) The Purchaser shall have purchased all Shares duly tendered and not
    withdrawn pursuant to the terms of the Offer and subject to the terms
    thereof; provided that the obligation of the Parent and the Purchaser to
    effect the Merger shall not be conditioned on the fulfillment of the
    condition set forth in this Section 5.1 (a) if the failure of the Purchaser
    to purchase the Shares pursuant to the Offer shall have constituted a breach
    of the Offer or of this Agreement.

        (b) The consummation of the Merger shall not be precluded by any order,
    decree or injunction of a court of competent jurisdiction (each party
    agreeing to use its best efforts to have any such order reversed or
    injunction lifted), and there shall not have been any action taken or any
    Law enacted, promulgated or deemed applicable to the Merger by any
    Governmental Entity that makes consummation of the Merger illegal.

        (c) If required by Certificate of Incorporation and By-Laws of the
    Company and the DGCL, this Agreement shall have been approved and adopted by
    the affirmative vote of the holders of the requisite number of shares of
    Common Stock in accordance with the Certificate of Incorporation and By-Laws
    of the Company and the DGCL.


                                       30
<PAGE>   34
        (d) Any applicable waiting period under the HSR Act shall have expired
    or been terminated.

        5.2 Conditions to the Obligations of Parent and the Purchaser. The
obligations of Parent and the Purchaser to consummate the Merger are subject to
the satisfaction, at or before the Effective Time, of the following conditions:

        (a) The Company shall have performed all of its material agreements and
    covenants contained in this Agreement required to be performed on or prior
    to the Effective Time and the representations and warranties of the Company
    contained in this Agreement shall be true and correct in all material
    respects on and as of (i) the date made and (ii) except in the case of
    representations and warranties expressly made solely with reference to a
    particular date, the Effective Time, and Parent and the Purchaser shall have
    received a certificate of an executive officer of the Company to such
    effect.

        (b) The Company shall not have received notice from the holder or
    holders of more than 10% of the outstanding Shares, determined on a fully
    diluted basis, that such holder or holders have exercised or intend to
    exercise its or their appraisal rights under Section 262 of the DGCL.

        (c) The 179,656 Shares previously held by the Trust shall have been
    returned to the Company and canceled, as described in the third recital to
    this Agreement.

        5.3 Conditions to the Obligations of the Company. The obligations of the
Company to consummate the Merger are subject to the satisfaction, at or before
the Effective Time, of the following conditions:

        (a) Parent and the Purchaser shall have performed all of their
    respective material covenants and agreements contained in this Agreement
    required to be performed on or prior to the Effective Time and the
    representations and warranties of the Parent and the Purchaser contained in
    this Agreement shall be true and correct in all material respects on and as
    of (i) the date made and (ii) except in the case of representations and
    warranties expressly made solely with reference to a particular date, the
    Effective Time, and the Company shall have received a certificate of an
    executive officer of Parent to such effect.


                                       31
<PAGE>   35
                                6. MISCELLANEOUS

        6.1 Termination. This Agreement may be terminated and the Merger contem-
plated herein may be abandoned at any time prior to the Effective Time, whether
prior to or after approval by the stockholders of the Company:

        (a) by the mutual written consent of Parent, the Purchaser and the
Company;

        (b) by either the Parent or the Company if, on or before October 31,
        1997 and without fault of such terminating party, Purchaser shall not
        have purchased in the Offer such number of the Shares which, together
        with the number of Option Shares (as such term is defined in the
        Stockholder Agreement) subject to the Stockholder Agreement, represent
        in excess of 50% of the Shares on a fully diluted basis, or the Merger
        shall not have been consummated on or before November 30, 1997, provided
        however, that the right to terminate this Agreement shall not be
        available (i) to any party whose failure to fulfill any obligation under
        this Agreement has been the cause of, or resulted in, the failure of the
        Offer or the Merger to have occurred on or before the aforesaid date;

        (c) by either the Parent or the Company if the Offer shall expire or
        terminate in accordance with its terms without any Shares having been
        purchased thereunder and, in the case of termination by the Parent, the
        Purchaser shall not have been required by the terms of the Offer or this
        Agreement to purchase any Shares pursuant to the Offer;

        (d) by the Company if the Purchaser shall not timely commence the Offer
        as provided in Section 1.1(a);

        (e) if a Company Stockholder Approval is required by law, by either the
        Purchaser or the Company if, upon a vote at a duly held Company Stock-
        holders Meeting or any adjournment thereof at which such Company Stock-
        holder Approval shall have been voted upon, such Company Stockholder
        Approval shall not have been obtained;

        (f) unilaterally by the Purchaser or the Company (i) if the other fails
        to perform any material covenant or agreement in any material respect in
        this Agreement, and does not cure the failure in all material respects
        within 30 business days after the terminating party delivers written
        notice of the alleged


                                       32
<PAGE>   36
        failure or (ii) if any condition to the obligations of that party is not
        satisfied (other than by reason of a breach by that party of its
        obligations hereunder), and it reasonably appears that the condition
        cannot be satisfied prior to November 30, 1997;

        (g) by either the Purchaser or the Company if either is prohibited by an
        order or injunction (other than an order or injunction on a temporary or
        preliminary basis) of a court of competent jurisdiction or other
        Governmental Entity from consummating the Offer or the Merger and all
        means of appeal and all appeals from such order or injunction have been
        finally exhausted;

        (h) by the Purchaser if the Board of Directors of the Company shall have
        withdrawn or modified, or resolved to withdraw or modify, in any manner
        which is adverse to Parent or the Purchaser, its recommendation or
        approval of the Merger or this Agreement; provided, however, that a
        termination pursuant to this Section shall not become effective if, as a
        result of the Company's receipt of a proposal for an Acquisition
        Transaction from a third party, the Company, in accordance with Section
        4.1(b), withdraws or modifies, or resolves to withdraw or modify, in any
        manner which is adverse to Parent or the Purchaser, its recommendation
        or approval of the Offer, the Merger or this Agreement and if within ten
        business days of taking and disclosing to its stockholders the
        aforementioned position the Company publicly reconfirms its
        recommendation of the transactions contemplated hereby; or

        (i) by the Company if (i) the Board of Directors of the Company shall
        have determined in good faith, based on the advice of outside counsel,
        that it is necessary, in order to comply with its fiduciary duties to
        the Company's stockholders under applicable law, to terminate this
        Agreement to enter into an agreement with respect to or to consummate a
        transaction constituting a Superior Proposal (as defined in Section
        6.5), (ii) the Company shall have given notice to the Purchaser advising
        the Purchaser that the Company has received a Superior Proposal from a
        third party, specifying the material terms and conditions (including the
        identity of the third party), and that the Company intends to terminate
        this Agreement in accordance with this Section 6.1(i), (iii) either (A)
        the Purchaser shall not have revised its proposal for an Acquisition
        Transaction within two business days from the time on which such notice
        is deemed to have been given to Parent, or (B) if the Purchaser within
        such period shall have revised its proposal for an Acquisition
        Transaction, the Board of Directors of the Company, after receiving
        advice from the Company's financial advisor, shall have determined in
        its good faith reasonable


                                       33
<PAGE>   37
        judgment that the third party's proposal for an Acquisition Transaction
        is superior to Parent's revised proposal for an Acquisition Transaction,
        and (iv) the Company, at the time of such termination, pays the Expenses
        and the Termination Fee in accordance with Section 6.12.

    In the event of a termination of this Agreement and an abandonment of the
    Merger, no party hereto (or any of its directors, officers, representatives
    or agents) shall have any further liability or further obligation to any
    other party to this Agreement, except with respect to the provisions of this
    Article 6 and the other provisions that survive the Merger pursuant to
    Section 6.2 and except that nothing herein will relieve any party from
    liability for any willful breach of its representations, warranties,
    covenants and agreements set forth in this Agreement.

        6.2 Non-Survival of Representations, Warranties and Agreements. The
representations, warranties and agreements in this Agreement shall terminate at
the Effective Time or the termination of this Agreement pursuant to Section 6.1,
as the case may be, except that, in the event the Effective Time occurs, the
agreements set forth in Section 4.9 and the last sentence of Section 4.5(a)
shall survive indefinitely and, in the event this Agreement is terminated prior
to the occurrence of the Effective Time, the agreements set forth in Sections
4.3 and 6.12 shall survive indefinitely.

        6.3 Amendment and Waiver. This Agreement may not be amended except by an
instrument in writing signed on behalf of each of the parties hereto and in
compliance with applicable law. At any time prior to the Effective Time, the
parties hereto may (a) extend the time for the performance of any of the
obligations or other acts of the other parties hereto, (b) waive any
inaccuracies in the representations and warranties contained herein or in any
document delivered pursuant thereto and (c) waive compliance with any of the
agreements or conditions contained herein; provided, however, that no such
waiver may materially adversely affect the rights of the stockholders of the
Company. Any agreement on the part of a party hereto to any such extension or
waiver shall be valid if set forth in an instrument in writing signed on behalf
of such party.

        6.4 Entire Agreement. This Agreement and the two separate but
substantially identical Stockholder Agreements, each dated as of the date,
hereof among Parent and certain stockholders of the Company and the
Confidentiality Agreement dated as of March 20, 1997, between the Company and
Parent contain the entire agreement among Parent, the Purchaser and the Company
with respect to the Merger and the other transactions contemplated hereby and
thereby, and such agreements supersede all prior agreements among the parties
with respect to these matters.


                                       34
<PAGE>   38
        6.5 Definitions. (a) As used herein, the term "Hazardous Substance"
means asbestos-containing material and any and all hazardous or toxic
substances, materials or wastes as defined or listed under the Resource
Conservation and Recovery Act, the Toxic Substances Control Act, the
Comprehensive Environmental Response, Compensation and Liability Act or any
comparable state statute or any regulation promulgated under any of
such federal or state statutes.

        (b) As used herein, the term "Person" means any individual, corporation,
partnership, limited liability company, joint venture, association, trust,
unincorporated organization or other entity.

        (c) As used herein, the term "Superior Proposal" means a bonafide
proposal to acquire, directly or indirectly, for consideration consisting of
cash and/or securities, more than 50% of the Shares then outstanding or all or
substantially all the assets of the Company, provided (i) such proposed
transaction satisfies the tests set forth in clauses (x), (y) and (z) of the
second sentence of Section 4.1(a) hereof and (ii) the Board of Directors
determines, in its good faith reasonable judgment, that such proposed
transaction is reasonably likely to be consummated without undue delay.

        6.6 Applicable Law. This Agreement shall be governed by and construed in
accordance with the laws of the State of Delaware without giving effect to the
conflicts of law principles thereof.

        6.7 Headings. The descriptive headings contained in this Agreement are
for convenience and reference only and shall not affect in any way the meaning
or interpretation of this Agreement.

        6.8 Notices. Each party shall promptly give written notice to the other
party upon becoming aware of the occurrence or, to its knowledge, impending or
threatened occurrence, of any event which would cause or constitute a breach of
any of its representations, warranties or covenants contained or referenced in
this Agreement and will use its best efforts to prevent or promptly remedy the
same. All notices or other communications under this Agreement shall be in
writing and shall be given (and shall be deemed to have been duly given upon
receipt) by delivery in person, by facsimile, telex or other standard form of
telecommunications, by courier service, or by registered or certified mail,
postage prepaid, return receipt requested, addressed as follows:

        If to the Company:

           8830 Biggs Ford Road


                                       35
<PAGE>   39
           Walkersville, Maryland  21793-0127
           Fax:  (301) 845-1006
           Attn:   F. Dudley Staples, Esq.

        With a copy to:

           Venable, Baetjer, Howard & Civiletti, LLP
           1201 New York Avenue, NW
           Suite 1000
           Washington, D.C.  20005
           Fax:  (202) 962-8300
           Attn:  Ariel Vannier, Esq.

        If to Parent or the Purchaser:

           Cambrex Corporation
           One Meadowlands Plaza
           East Rutherford, New Jersey 07073
           Fax:  (201) 804-9851
           Attn:  Peter Thauer, Esq.

        With a copy to:

           Debevoise & Plimpton
           875 Third Avenue
           New York, New York 10022
           Fax:  (212) 909-6836
           Attn:  Ralph Arditi, Esq.

or to such other address or facsimile number as any party may have furnished to
the other parties in writing in accordance with this Section 6.8.

        6.9 Counterparts. This Agreement may be executed in any number of
counterparts, each of which shall be deemed to be an original but all of which
together shall constitute but one agreement.

        6.10 Severability. Any term or provision of this Agreement which is
invalid or unenforceable in any jurisdiction shall, as to that jurisdiction, be
ineffective to the extent of such invalidity or unenforceability without
rendering invalid or unenforceable the remaining terms and provisions of this
Agreement or affecting the validity or


                                       36
<PAGE>   40
enforceability of any of the terms or provisions of this Agreement in any other
jurisdiction. If any provision of this Agreement is so broad as to be
unenforceable, the provision shall be interpreted to be only so broad as is
enforceable.

        6.11 Parties in Interest; Assignment. This Agreement is binding upon and
is solely for the benefit of the parties hereto and their respective successors,
legal representatives and assigns, except that Section 4.9 is intended to be for
the benefit of the parties referred to therein, and may be enforced by such
parties. The Purchaser shall have the right (a) to assign to Parent or any
direct or indirect wholly-owned subsidiary of Parent any and all rights and
obligations of the Purchaser under this Agreement, including, without
limitation, the right to substitute in its place such a subsidiary as one of the
constituent corporations in the Merger (such subsidiary assuming all of the
obligations of the Purchaser in connection with the Merger) and may require
subsidiaries of the Company to merge with subsidiaries of the Purchaser (or its
assignees) in connection with the Merger and (b) to restructure the transaction
to provide for the merger of the Company with and into the Purchaser or such
other entity as provided above; provided, however, that the Company shall not be
deemed to have breached any of its representations and warranties herein by
reason of the Purchaser exercising its rights hereunder, and by exercising such
rights Parent will be deemed to have waived the receipt of any additional
consents of third parties required by virtue thereof; and provided further that
no such assignment shall affect any obligation of Parent or Purchaser hereunder
and that it shall remain primarily liable as to its assigned obligations. If the
Purchaser exercises its right to so restructure the transaction, the Company
shall promptly enter into appropriate agreements to reflect such restructuring.

        6.12 Fees and Expenses. (a) Except as provided below in this Section
6.12, all fees and expenses incurred in connection with the Offer, the Merger,
this Agreement, the Stockholder Agreement and the transactions contemplated by
this Agreement and the Stockholder Agreement shall be paid by the party
incurring such fees or expenses, whether or not the Merger is consummated.

        (b) The Company shall pay, or cause to be paid, in same day funds to
Parent the sum of (x) Parent's Expenses (as defined below) and (y) $4,125,000
(the "Termination Fee") upon demand if the Company terminates this Agreement
pursuant to Section 6.1(i). In addition, the Company shall pay or cause to be
paid, in same day funds to Parent the sum of Parent's Expenses and the
Termination Fee if (i) the Purchaser terminates this Agreement pursuant to
Section 6.1(f) or 6.1(h) at any time after a proposal for an Acquisition
Transaction has been made (ii) the Company or the Purchaser terminates this
Agreement pursuant to Section 6.1(b), 6.1(c) or 6.1(e) at any time after a
proposal for an Acquisition Transaction has been made or (iii) the


                                       37
<PAGE>   41
Purchaser terminates this Agreement pursuant to Section 6.1(f)(ii) at any time
after a proposal for an Acquisition Transaction has been made and, within nine
months after any termination referred to in the immediately preceding clauses
(i), (ii) or (iii) of this sentence, the Person that made the proposal for an
Acquisition Transaction (or an affiliate thereof) completes a merger,
consolidation or other business combination with the Company or a subsidiary of
the Company, or the purchase from the Company or from a subsidiary of the
Company of 30% or more (in voting power) of the voting securities of the Company
or of 30% or more (in market value) of the assets of the Company and its
subsidiaries, on a consolidated basis; provided that the Company will not have
any obligations under this Section 6.12(b) if the Purchaser terminates this
Agreement pursuant to Section 6.1(f)(ii) as a result of the failure of a
condition to be satisfied unless the reason for the failure of such condition to
be satisfied is reasonably related to the making of such proposal for an
Acquisition Transaction by the Person that ultimately consummated a transaction
with the Company. "Expenses" shall mean reasonable and reasonably documented
out-of-pocket fees and expenses incurred or paid by or on behalf of Parent in
connection with the Merger or the consummation of any of the transactions
contemplated by this Agreement (including, without limitation, the fees and
expenses of one counsel representing the financial institutions providing
financing to the Purchaser and all fees and expenses of Parent's investment
banking firm), provided that all such Expenses for this purpose shall not exceed
$1.2 million in the aggregate.

        6.13 Specific Performance. The parties hereto agree that irreparable
damage would occur in the event that any of the provisions of this Agreement
were not performed in accordance with their specific terms or were otherwise
breached. It is accordingly agreed that the parties shall be entitled to an
injunction or injunctions to prevent breaches of this Agreement and to enforce
specifically the terms and provisions hereof in any court of the United States
or any state having jurisdiction, this being in addition to any other remedy to
which they are entitled at law or in equity.


                                       38
<PAGE>   42
        IN WITNESS WHEREOF, the parties have duly executed this Agreement as of
the date set forth above.

                              BIOWHITTAKER, INC.


                              By: /s/ NOEL BUTERBAUGH
                                  ------------------------------------
                                  Name:  Noel Buterbaugh
                                  Title: President and Chief Executive Officer



                              CAMBREX CORPORATION


                              By: /s/ PETER TRACEY
                                  ------------------------------------
                                  Name:  Peter Tracey
                                  Title: Executive Vice President



                              BW ACQUISITION CORPORATION


                              By: /s/ PETER E. THAUER
                                  ------------------------------------
                                  Name:  Peter E. Thauer
                                  Title: Vice President


                                       39
<PAGE>   43


                                     ANNEX A

           Certain Conditions of the Offer Notwithstanding any other provision
of the Offer, the Purchaser shall not be required to accept for payment, or,
subject to any applicable rules and regulations of the Commission, including
Rule 14e-1(c) under the Exchange Act (relating to the Purchaser's obligation to
pay for or return tendered shares after the termination or withdrawal of the
Offer), to pay for any Securities tendered pursuant to the Offer, and (subject
to the terms of the Agreement) may amend or terminate the Offer or postpone the
acceptance for payment, the purchase of, and/or (subject to any such applicable
rules and regulations of the Commission) payment for, Securities tendered, (i)
unless there are validly tendered and not properly withdrawn prior to the
expiration of the Offer that number of Shares which, together with the number of
Option Shares (as such term is defined in the Stockholder Agreement) subject to
the Stockholder Agreement, represents in excess of 50% of the Shares on a
fully-diluted basis, or (ii) if at any time on or after the date of the
Agreement and at or before the time of payment for any such Shares (whether or
not any Shares shall theretofore have been accepted for payment or paid pursuant
to the Offer) any of the following conditions exists:

           (a) there shall have been any action or proceeding brought by any
      governmental authority before any federal or state court, or any order or
      preliminary or permanent injunction entered in any action or proceeding
      before any federal or state court or governmental, administrative or
      regulatory authority or agency, located or having jurisdiction within the
      United States or any country or economic region in which either the
      Company or Parent, directly or indirectly, has material assets or
      operations, or any other action taken, proposed or threatened, or statute,
      rule, regulation, legislation, interpretation, judgment or order proposed,
      sought, enacted, entered, enforced, promulgated, amended, issued or deemed
      applicable to Purchaser, the Company or any subsidiary or affiliate of
      Purchaser or the Company or the Offer or the Merger, by any legislative
      body, court, government or governmental, administrative or regulatory
      authority or agency located or having jurisdiction within the United
      States or any country or economic region in which either the Company or
      Parent, directly or indirectly, has material assets or operations, which
      could reasonably be expected to have the effect of: (i) making illegal, or
      otherwise restraining or prohibiting or making materially more costly, the
      making of the Offer, the acceptance for payment of, payment for, or owner-
      ship, directly or indirectly, of some of or all the Shares by Parent or
      Purchaser, the consummation of any of the transactions contemplated by the
      Agreement or materially delaying the Merger; (ii) prohibiting or
      materially limiting the owner-


                                       A-1


<PAGE>   44


         ship or operation by the Company or any of its subsidiaries, or by
         Parent, Purchaser or any of Parent's subsidiaries of all or any
         material portion of the business or assets of the Company and its
         subsidiaries taken as a whole or Parent or any of its subsidiaries, or
         compelling Purchaser, Parent or any of Parent's subsidiaries to dispose
         of or hold separate all or any material portion of the business or
         assets of the Company and its subsidiaries taken as a whole or Parent
         or any of its subsidiaries, in each case as a result of the
         transactions contemplated by the Offer or the Agreement; (iii) imposing
         or confirming material limitations on the ability of Purchaser, Parent
         or any of Parent's subsidiaries effectively to acquire or hold or to
         exercise full rights of ownership of Shares including, without
         limitation, the right to vote any Shares acquired or owned by Parent or
         Purchaser or any of Parent's subsidiaries on all matters properly
         presented to the shareholders of the Company, including, without
         limitation, the adoption and approval of the Agreement and the Merger
         or the right to vote any shares of capital stock of any subsidiary
         directly or indirectly owned by the Company; (iv) requiring divestiture
         by Parent or Purchaser, directly or indirectly, of any Shares; or (v)
         which could reasonably be expected to materially adversely affect the
         business, financial condition or results of operations of the Company
         and its subsidiaries taken as a whole or the value of the Shares or of
         the Offer to Purchaser or Parent;

                  (b) there shall have occurred (i) any general suspension of
         trading in, or limitation on prices for, securities on any national
         securities exchange or in the over-the-counter market in the United
         States, (ii) a declaration of a banking moratorium or any suspension of
         payments in respect of banks in the United States, (iii) any limitation
         (whether or not mandatory) by any U.S. government or governmental,
         administrative or regulatory authority or agency, on, or any other
         event that materially adversely affects, the extension of credit by
         banks or other lending institutions, (iv) a commencement of a war or
         armed hostilities or other national or international calamity directly
         or indirectly involving the United States which would reasonably be
         expected to have a Material Adverse Effect or materially adversely
         affect (or materially delay) the consummation of the Offer or (v) in
         the case of any of the foregoing existing at the time of the execution
         of the Agreement, a material acceleration or worsening thereof which
         acceleration or worsening is reasonably expected to have a Material
         Adverse Effect on the Company or to materially adversely affect the
         consummation of the Offer;

                  (c) (i) it shall have been publicly disclosed that beneficial
         ownership (determined for the purposes of this paragraph as set forth
         in Rule 13d-3


                                       A-2


<PAGE>   45


         promulgated under the Exchange Act) of 20% or more of the outstanding
         Shares has been acquired by any corporation (including the Company or
         any of its subsidiaries or affiliates), partnership, person or other
         entity or group (as defined in Section 13(d)(3) of the Exchange Act),
         other than Parent or any of its affiliates, or (ii) (A) the Board of
         Directors of the Company or any committee thereof shall have withdrawn
         or modified in a manner adverse to Parent or Purchaser the approval or
         recommendation of the Offer, the Merger or the Agreement and, within
         ten business days of taking and disclosing to its stockholders the
         aforementioned position, shall not have publicly reconfirmed its
         recommendation of the Offer, the Merger or the Agreement, or approved
         or recommended any takeover proposal or any other acquisition of Shares
         other than the Offer and the Merger, (B) any such corporation,
         partnership, person or other entity or group shall have entered into a
         definitive agreement or an agreement in principle with the Company with
         respect to a tender offer or exchange offer for any Shares or a merger,
         consolidation or other business combination with or involving the
         Company or any of its subsidiaries or (C) the Board of Directors of the
         Company or any committee thereof shall have resolved to do any of the
         foregoing;

                  (d) any of the representations and warranties of the Company
         set forth in the Agreement that are qualified as to materiality shall
         not be true and correct or any such representations and warranties that
         are not so qualified shall not be true and correct in any material
         respect, in each case as if such representations and warranties were
         made at the time of such determination, except with respect to
         representations and warranties made as of an earlier time;

                  (e) the Company shall have failed to perform any material
         obligation or to comply with any material agreement or material
         covenant of the Company to be performed or complied with by it under
         the Agreement;

                  (f) the Agreement shall have been terminated in accordance
         with its terms or the Offer shall have been terminated with the consent
         of the Company; or

                  (g) any waiting periods under the HSR Act applicable to the
         purchase of Shares pursuant to the Offer shall not have expired or been
         terminated or any material approval, permit, authorization, consent or
         waiting period of any domestic, foreign or supranational governmental,
         administrative or regulatory agency (federal, state, local, provincial
         or otherwise) located or having jurisdiction within the United States
         or any country or economic region in which either the


                                       A-3


<PAGE>   46


         Company or Parent, directly or indirectly, has material assets or
         operations, shall not have been obtained and such failure to obtain
         could reasonably be expected to have a Material Adverse Effect on the
         Company or the value of the Shares or the Offer to the Purchaser;

which, in the good faith sole judgment of Purchaser makes it inadvisable to
proceed with the Offer or with such acceptance for payment of or payment for
Shares or to proceed with the Merger.

         The foregoing conditions are for the sole benefit of Purchaser and may
be asserted by Purchaser regardless of the circumstances giving rise to any such
condition or may be waived by Purchaser in whole or in part at any time and from
time to time in its sole discretion (subject to the terms of the Agreement). The
failure by Purchaser at any time to exercise any of the foregoing rights shall
not be deemed a waiver of any such right, the waiver of any such right with
respect to particular facts and other circumstances shall not be deemed a waiver
with respect to any other facts and circumstances, and each such right shall be
deemed an ongoing right that may be asserted at any time and from time to time.


                                       A-4
<PAGE>   47
                                                                       Exhibit A







              List of Stockholders Party to Stockholders Agreement


Management Stockholders Agreement

       Anasco GmbH

Stockholders Agreement

       Noel Buterbaugh
       Thomas Winkler
       Philip Rohrer
       Leif Olsen
       Dudley Staples
       Joseph Alibrandi


<PAGE>   48


                                                                    Schedule 2.2







                        Officers of Surviving Corporation


Joseph F. Alibrandi                   Chairman of the Board

Noel L. Buterbaugh                    President and Chief Executive Officer

Thomas R. Winkler                     Executive Vice President and Chief
                                      Operating Officer

Philip L. Rohrer, Jr.                 Vice President and Chief Financial
                                      Officer

Leif E. Olson                         Vice President, Regulatory Affairs

Peter E. Thauer                       Vice President and Assistant Secretary

Douglas McMillan                      Vice President and Assistant Treasurer

F. Dudley Staples                     Secretary and General Counsel


<PAGE>   49


                   DISCLOSURE SCHEDULE (AS OF AUGUST 22, 1997)


3.2      REPRESENTATIONS AND WARRANTIES OF BIOWHITTAKER

         (b)      CAPITALIZATION.

                  -        Preemptive Rights - Pursuant to Section 8.01(c) of
                           the Stock Purchase Agreement, dated September 24,
                           1991, between BioWhittaker, Inc. and Anasco GmbH (the
                           "Anasco Stock Purchase Agreement"), BioWhittaker is
                           obligated to pay Anasco a Compensation Amount (as
                           defined in the Anasco Stock Purchase Agreement) upon
                           the exercise of Substitute Options (as defined in the
                           Anasco Stock Purchase Agreement). The compensation is
                           to be paid in either cash or Voting Securities (as
                           defined in the Anasco Stock Purchase Agreement) at
                           the election of BioWhittaker. Under the terms of the
                           Anasco Stock Purchase Agreement, such right will
                           terminate upon the sale of Anasco's shares of
                           BioWhittaker Common Stock upon consummation of the
                           Tender Offer, such that Anasco's beneficial ownership
                           is less than 5%.

                  -        Options to acquire 1,071,388 shares of stock
                           outstanding (see attached list).

                  -        For voting trusts or other voting agreements - see
                           Article VIII of the Anasco Stock Purchase Agreement.

                  -        For stock appreciation rights, BioWhittaker U.K.
                           Limited stock is subject to the rights of Alan Baines
                           under the Equity Compensation Plan Agreement with
                           Alan Baines dated as of December, 1991.

         (c)      SUBSIDIARIES.

                  -        BioWhittaker Technologies, Inc., a Delaware
                           Corporation

                  -        Clonetics Corporation, a Delaware Corporation

                  -        BioWhittaker USVI, Inc., a U.S. Virgin Islands
                           Corporation

                  -        BioWhittaker U.K. Limited, a United Kingdom
                           Corporation

                  -        BioWhittaker Holdings, Inc., a Delaware Corporation

                  -        With respect to BioWhittaker U.K. Limited, the stock
                           is subject to the rights of Alan Baines under the
                           Equity Compensation Plan Agreement with Alan Baines
                           dated as of December, 1991 and the provisions of the
                           Stock Purchase Agreement dated April 30, 1995,
                           between BioWhittaker, Inc and Boehringer Ingelheim
                           International GmbH, as amended by Amendment No. 1
                           dated July 26, 1995 (the "1995 Stock Purchase
                           Agreement").

                  -        With respect to the last sentence of Section 3.2(c),
                           BioWhittaker has the right to re-acquire an interest
                           in the Boehringer Ingelheim BioProducts Partnership
                           pursuant to the terms and conditions set forth in the
                           1995 Stock Purchase Agreement.


                                       1


<PAGE>   50


(d)      AUTHORITY.

         The following corporate actions could be required:

                  -        Board action required to call a meeting of
                           stockholders to approve the Merger.

                  -        Board action to comply with Section 1.3 of the
                           Agreement.


(e)      CONSENTS: NO VIOLATION (ASSUMES BIOWHITTAKER IS THE SURVIVING
         CORPORATION).

         (ii)       The following agreements are exceptions to (ii) 
                  - Loan agreement with NationsBank.
                  - The following Agreements would be affected by a Change of
                    Control as described below:

                  -        Stock Purchase Agreement as of 9/24/91 between
                           BioWhittaker, Inc. and Anasco GmbH (the "1991 SPA")

                  -        1995 Stock Purchase Agreement.

                  -        Joint Venture and Partnership Agreement, dated as of
                                           , 1991 (date left blank on our copy),
                           by and between Boehringer Ingelheim BioProducts, Inc.
                           and BioWhittaker International, Inc.

                  -        Technology License Agreement, dated as of October 31,
                           1991, by and between BioWhittaker, Inc and
                           BioWhittaker International, Inc. and Assignment and
                           Assumption of Technology License Agreement dated
                           October 31, 1991 between BioWhittaker International,
                           Inc. and Boehringer Ingelheim BioWhittaker.

                  -        Distributor Agreement, dated as of November 1, 1995,
                           by and between BioWhittaker, Inc. and Boehringer
                           Ingelheim BioProducts, Partnership.

                  -        Distributor Agreement by and between Boehringer
                           Ingelheim BioWhittaker and BioWhittaker UK, Limited.

                           1. If the Company undergoes a "Change of Control" as
                  contemplated by the Merger Agreement, Boehringer Ingelheim
                  would have a right to terminate the Company's option to
                  reacquire its interest in the BI Joint Venture Affiliate (see
                  8.3(a)(iii) of Stock Purchase Agreement between BioWhittaker,
                  Inc. and Boehringer International GmbH dated 4/28/95 ("the
                  1995 SPA")).

                           Under the express terms of the relevant agreements,
                  such a termination would also result in the following;

                           The covenants of Section 9.1 of the 1995 SPA would
                  cease to be in effect (see Section 9.1 of the 1995 SPA).

                           The covenants of Section 9.2(b) of the SPA would
                  become effective. In addition, and depending on whether the
                  Exercise Period is deemed to have "expired" upon receipt of a
                  notice of termination associated with a Change of Control date
                  (see the definitions of "Exercise Period" and "Option
                  Termination Date in Section 8.3(a) of the 1995 SPA), the
                  covenants of Section (9.2(a), (c) and (d) may also become
                  effective.

                           Pursuant to Section 9.4, of the 1995 SPA, Boehringer
                  Ingelheim would have a right of first refusal to purchase
                  BioWhittaker UK, Limited.

                           To the extent that there are inconsistencies in the
                  drafting of, or among the provisions of, the provisions of the
                  agreements referred to above, the Company expresses no opinion
                  in this Disclosure Schedule as to the correct interpretation
                  of such provisions.


                                        2


<PAGE>   51


                           2. If Anasco and its affiliates ceased to own 5% or
                  more of the Total Voting Power (as defined in the Stock
                  Purchase Agreement as of 9/24/91 between BioWhittaker, Inc.
                  and Anasco GmbH (the "1991 SPA")), the rights and obligations
                  of the parties under Article VIII of the 1991 SPA would
                  terminate (subject to a right of revival) if Anasco
                  subsequently re-acquired 5% or more of the Total Voting
                  Power). The rights and obligations at issue include Anasco's
                  rights to Board representation, registration rights and
                  compensation upon exercise of any Substitute Stock Options and
                  the Company's rights of first refusal with regard to Company
                  stock, to require Anasco to vote for Board nominees and to be
                  counted towards a quorum at a stockholder meeting and to
                  restrict certain other actions of Anasco relating to voting
                  rights and acquisitions of the Company.

                  -        Supplemental Executive Retirement Plan.

                  -        Written Consent of Directors (oral consent having
                           been obtained) required to cash out options issued to
                           Directors under the 1994 Stock Option Plan for
                           Non-Employee Directors.

                  -        Federal contracts are subject to the Federal
                           Assignment of Claims Act of 1940, as amended (31
                           U.S.C. 3727, 41 U.S.C. 15) and related rules,
                           regulations and contract clauses (see for example
                           Federal Acquisition Regulations Subpart 42.12) and
                           administrative and court decisions thereon; state
                           procurement laws may have similar provisions. While
                           there are strong arguments that this transaction as
                           structured is not an assignment or transfer under the
                           federal law, there is some authority to the contrary
                           and it is conceivable that a government contracting
                           officer could determine that consents were required.

                  (f)      SEC REPORTS, ETC.

                           See litigation schedule (Section 3.2(i) of the
                           Disclosure Schedule).

                  (g)      NO MATERIAL ADVERSE CHANGE.

                           MATERIAL ADVERSE CHANGES SINCE 10/31/96.

                           (i)      See litigation schedule (Section 3.2(i) of
                                    the Disclosure Schedule) and First Amendment
                                    dated January 23, 1997 to Asset Purchase and
                                    Supply Agreements with Carter-Wallace, Inc.

                           (ii)     See stock options granted in February, 1997
                                    as shown on the list of outstanding options
                                    referred to in Section 3.2(b) of this
                                    Disclosure Schedule; compensation
                                    information in most recent proxy disclosure
                                    does not include December, 1996 salary and
                                    bonus adjustments which have been separately
                                    disclosed to Purchaser.

                           (iv)     Employment Agreement pending with Alan
                                    Baines (copy furnished to Purchaser's
                                    representatives).


                           -        BioWhittaker executed a Change of Control
                                    Employment Agreement with each of the
                                    following persons on or about March 11,
                                    1997:


                                        3


<PAGE>   52


                                     Philip L. Rohrer, Jr.
                                     Thomas R. Winkler
                                     F. Dudley Staples, Jr.
                                     Leif Olsen

                  (vi) BioWhittaker will implement FASB 123 in 1997 as
                       disclosed in the most recent SEC Form 10-K. Also, the
                       IRS notified BioWhittaker that it will consent to a
                       change in tax accounting methods for inventory. A
                       copy of the Consent Agreement dated July 16, 1997 has
                       been provided.

         (i)      LITIGATION.

                  -    George Erie
                       v.
                       BioWhittaker, Inc., Noel Buterbaugh and Thomas R. Winkler
                       United States District Court
                       District of Massachusetts
                       Civil Action No. 97-11414 REK

                       George Erie was formerly employed by BioWhittaker as
                       a salesman. On May 22, 1997, Mr. Erie's employment
                       was terminated by BioWhittaker. Mr. Erie has filed
                       suit claiming damages for (a) breach of contract (an
                       alleged lifetime employment contract), (b) promissory
                       estoppel (based on a representation that the Company
                       would employ Mr. Erie until he chose to retire) and
                       (c) negligent or intentional misrepresentation
                       (inducing Mr. Erie to leave his prior employment).


                       Mr. Erie seeks damages in an undetermined amount, but
                       indicates that the compensation that he would have
                       earned from continued employment would have been not
                       less than $1,585,000. Mr. Erie also seeks interest and
                       costs, including reasonable attorney's fees.

                       At this time, the Company has not been required to
                       file a response to the original complaint. The
                       Company will contend that, in addition to other
                       defenses, Mr. Erie was employed at will.

                       Pennsylvania Regional Tissue & Transplant Bank t/d/b/a
                       Pennsylvania Regional Tissue Bank
                       v.
                       James S. Bardsley, Jr. et al
                       and
                       BioWhittaker, Inc.
                       United States District Court
                       Middle District of Pennsylvania
                       Scranton Division
                       Civil Action No. 3:CV-96-0608

                       Mr. Bardsley was, at one time, an employee of PRTB
                       and/or its subsidiaries. Mr. Bardsley left PRTB's
                       employ and set up Anatomic Gift Foundation and the
                       Human Cell Culture Center, Inc. (HCCC) in 1994 or
                       before. PRTB claims that the defendants (a) usurped a
                       corporate opportunity (b) converted and
                       misappropriated trade secrets


                                        4


<PAGE>   53


         (c) conspired to harm PRTB and other defendants, (d) breached
         agreements with PRTB and its subsidiaries, (e) breached their fiduciary
         duty to PRTB and its subsidiaries and (f) tortiously interfered with
         contractual relationships with organ procurement organizations,
         researchers and others.

         In the complaint, the plaintiff seeks unspecified damages in excess of
         $50,000 and punitive damages together with interest and costs and
         injunctions to prevent further violations of plaintiff's rights. In
         1996, BioWhittaker entered into a contract with HCCC (a copy of which
         has been furnished to Parent) to distribute certain products for HCCC.
         In July of 1997, the plaintiff filed a motion to join BioWhittaker as a
         party to the litigation. Defendants have responded opposing the motion
         to join BioWhittaker. At this time, BioWhittaker is not a party to the
         suit and will have a chance to file motions objecting to its joinder,
         if plaintiff's motion to join BioWhittaker is approved by the court.

- -        BioWhittaker, Inc.
         v.
         Pharmacia-Upjohn K.K, et al
         Tokyo District Court
         Case No. Tokyo District Court Hei-9(1997)-WAS-5792
         Case No. Tokyo District Court Hei-9(1997)-YO-22042

         BioWhittaker previously sued Pharmacia AB (now merged with Upjohn as
         Pharmacia & Upjohn, Inc.) and certain of its affiliates (collectively
         with Pharmacia referred to as Pharmacia) and one of its distributors in
         the United States for breach of its U.S. Patent on methods for testing
         for certain allergies. After a partial summary judgment in favor of
         BioWhittaker, Pharmacia agreed to a settlement in which it agreed to
         pay $3.5 million in damages for past infringement, $500,000 as a
         royalty for 1995 and royalties at a rate of 3% per annum for all sales
         in the United States, Canada and Australia until BioWhittaker's patents
         in those countries expired, with a minimum royalty of $300,000 per year
         on sales from the United States for years 1996-1999.

         At the time of the US settlement, there was a patent pending on the
         same technology in Japan. Pharmacia chose to oppose the issuance of
         that patent, but the Patent was issued over Pharmacia's opposition. Now
         that the patent has issued in Japan, after unsuccessful attempts to get
         Pharmacia to negotiate concerning use of the patented technology in
         Japan, the Company has filed a lawsuit against Pharmaria seeking
         damages and an injunction against future use of the patent. The amount
         of the controversy is approximately 7.5 billion yen, including
         approximately 5 billion yen of damages and compensation and
         approximately 2.5 billion yen representing the value of the injunctions
         against Pharmacia and one of its Japanese distributors.

- -        Promocell cases in Germany and France (trademark litigation by
         Clonetics that commenced prior to Clonetics acquisition) CellSystems
         Biotechnologie Vertriebs GmbH and Clonetics Corporation


                                        5


<PAGE>   54


         v.
         Dr. Detlef Hinz and Dirk Huttner
         Upper District Court Karlsruhe, Federal Republic of Germany
         Case No. 16:507
                 and
- -        Clonetics Corporation
         v.
         Docteur Detlef Hinz
         Docteur Dirk Huttner
         PromoCell
         la 2 ieme Chambre du Tribunal de Grande Instance de Rennes, France
         Case No. 3282/95

         These cases began prior to BioWhittaker's acquisition of Clonetics
         Corporation. Originally Messrs. Hinz and Huttner, trading as PromoCell
         filed suit in Germany against a Clonetics distributor and Clonetics
         Corporation seeking damages for trademark infringement. It was
         subsequently determined that Messrs. Hinz and Huttner had trademarked
         marks which were already in use by Clonetics and copied Clonetics
         promotional materials. Clonetics countersued for unfair trade practices
         and other causes of action seeking a cancellation of PromoCell's
         trademarks that copied the Clonetics trademarks, damages and other
         remedies. In the original trial court, Clonetics was awarded damages,
         the cancellation of the infringing marks and other remedies. On appeal,
         the intermediate court confirmed in part and reversed in part,
         indicating that Clonetics was entitled to cancellation of the marks
         registered by PromoCell, but was not entitled to damages. The matter is
         presently on appeal to the highest court in Germany and is awaiting the
         original trial in France where Clonetics had filed trademarks prior to
         PromoCell's use of similar marks.

- -        Dispute with Microbix concerning supply of HNK calls.

         Microbix BioSystems, Inc. v. BioWhittaker, Inc. and BioWhittaker
         Holdings, Inc., United States District Court for the District of
         Maryland, Case number MJ9-972525.

         Microbix Biosystems filed suit against BioWhittaker and BioWhittaker
         Holdings alleging anti trust violations, including violations of
         sections 1 and 2 of the Sherman Act, misrepresentation, promissory
         estoppel and breach of a requirements contract. Plaintiff seeks treble
         damages with regard to the anti-trust claims, injunctive relief
         prohibiting defendants from refusing to sell HNK cells to Microbix for
         five years and damages in excess of $75,000 on each of 2 counts, with
         exemplary punitive damages in the amount of $10 million, an order of
         specific performance, a declaration of rights and costs and expenses
         and attorneys fees for each cause of action.

- -        Claim of possible patent infringement of U.S. Patent No. 5,262,359.
         Notice of claim received from the Centers For Disease Control in letter
         dated August 8, 1997.

         On or about August 12, BioWhittaker received a letter dated August 8,


                                        6


<PAGE>   55


                  1997 from Marjorie Hunter, Technology Licensing Specialist
                  with the Centers for Disease Control and Prevention,
                  indicating that BioWhittaker was marketing H292 Human Lung
                  Mucocpidermoid Carcinoma Cells and alleging that the cells
                  were subject to a patent issued on November 16, 1993 relating
                  to methods for propagating human paramyxoviruses in the H292
                  cell line. She further indicated that the patent had been
                  exclusively licensed to Intracel Corporation. BioWhittaker is
                  in the process of investigating this claim. However, total
                  sales of the product alleged to infringe the patent have not
                  exceeded $20,000 in total for the period of four years since
                  the patent was issued.

         (j)      FEES.

                - Engagement letter between Alex. Brown & Sons Incorporated and
                  BioWhittaker, Inc. dated January 2, 1997.

         (m)      EMPLOYEE BENEFIT PLANS: EMPLOYEE AGREEMENTS.

                - Employment Agreements

                  Dr. Judith Blasser     Offer and relocation letter
                  Hoda Elgendy           Offer letter includes specific term and
                                         relocation benefit already paid
                  Marjorie Root          Relocation letter
                  Mary Tsao              Offer and relocation letter

                  On or before January 17, 1996, BioWhittaker executed
                  employment agreements with the following persons who were then
                  employees of CLONETICS CORPORATION, who are currently employed
                  by BioWhittaker:

                  Michael Campbell
                  Jeffrey Janus
                  Soverin Karmiol
                  Jess Stengel
                  Sandra Weise-Valone

                  BioWhittaker and or its British subsidiary executed employment
                  agreements with the following BIOWHITTAKER, U.K. employees:

                  Deborah Ann Wilson     Customer Support               08/01/91
                  Debbie Hobbs           Customer Service Executive     05/01/97
                  David Charles Guy      Product Specialist             06/15/92
                  Lindsay Aspinwall      Sales Representative           04/14/97
                  Philip Strun           Sales Representative           09/02/96
                  Jean Ibbotson          Office Administrator           05/01/95
                  Claire Truluck         Financial Assistant            01/27/97
                  Joanne Thorndike       Sales Representative           01/01/94
                  Kevin Jenkyn Jones     Sales Representative           01/30/95
                  Alan Baines            General Manager                Pending


                  In addition to the specific employment agreements listed
                  above, there


                                        7


<PAGE>   56


                  are employment offer letters that were given to some
                  employees, which do not commit BioWhittaker to any specific
                  term of employment or termination benefits. At or prior to
                  commencing employment, employees are also asked to sign
                  employment applications which indicate employment is at will
                  and Confidentiality and Ownership of Inventions Agreements
                  designed to protect BioWhittaker's trade secrets and
                  inventions.

                  TERMINATION AGREEMENTS

                  George Erie termination agreement proposed, but not accepted
                  as of August 21, 1997.

                  SEVERANCE AGREEMENTS

                  Severance Plan for employees terminated as a result of the
                  sale of the diagnostic product lines to Carter-Wallace.

                  COMMISSION AGREEMENT PLANS.

                  There are a total of 12 Sales Representatives, 2 Industrial
                  Account Managers, 2 Regional Managers and 8 Technical Sales
                  Representatives (Clonetics) with Commission Agreement Plans,
                  as well as National Sales Managers Dennis Barger and Sandra
                  Weise-Valone (Clonetics), and International Sales Manager
                  (Clonetics) Michael Campbell.

                  THE FOLLOWING MANAGERS FROM CLONETICS also have Employment
                  Contracts as noted above which include Commission Plans:

                                     Jeffrey Janus
                                     Jess Stengel
                                     Soverin Karmiol

                  SALARY PLANS

                  DISCRETIONARY BONUS PLAN

                           Levels of employees eligible:
                                    Director
                                    Manager
                                    Supervisor
                                    Various Scientific and Professional

                  1991 LONG-TERM INCENTIVE STOCK OPTION PLAN covers Executives
                  and Senior / Middle Management but terms of options granted to
                  executives and to others and at different times differ
                  slightly. See list of option holders included under Section
                  3.2(b) of this Disclosure Schedule. ALSO SEE 1994 STOCK OPTION
                  PLAN FOR NON-EMPLOYEE DIRECTORS.

                  SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN (SERP) for the
                  following


                                       8


<PAGE>   57


                employees:

                                  Noel Buterbaugh
                                  Thomas Winkler
                                  Philip Rohrer

                BENEFIT PLANS:

                SECTION 125 CAFETERIA PLAN

                Medical                             Blue Cross and Blue Shield
                                                    of Maryland
                                                    Prudential (Calif. Clonetics
                                                    Plan)
                Dental                              Blue Cross and Blue Shield
                                                    of Maryland
                Vision                              Vision Services Plan
                Prescription Card and Mail-in       Express Scripts
                Group Term Life Ins.                Medical Life
                Group Universal Life, AD&D          Prudential
                Short Term Disability               Prudential (Non-exempt)
                Long Term Disability (Core & Supp)  Prudential (All employees)
                Travel Accident Ins.                Reliance Standard
                Health Care Reimb. Acct.            Crawford, Slevin & Hicks
                Dependent Carr Reimb. Acct.         Crawford, Slevin & Hicks

                RETIREMENT PLANS.

         Employees Pension Plan (Target Plan).
         Savings and Stock Investment Plan (401(k)).

         OTHER BENEFIT PLANS:

         Vacation and vacation accruals
         Sick leave plan
         Holidays and Floating Holidays
         Educational Assistance


- -        Change of control employment agreements (See Section 3.2(g)).

- -        Consulting agreements with Diane Wyatt and Dr. Nick Harris (which
         include rights to potential commissions).

- -        Equity Compensation Plan Agreement with Alan Baines dated as of
         December, 1991.

(o)     CONTRACTS: DEBT INSTRUMENTS.

         (i)    See litigation schedule (Section 3.2(b) of this Disclosure
                Schedule) - In the Erie litigation, there is a claim of breach
                of a contract for employment and Microbix has alleged that it
                had an unwritten contract for supply of material which has
                been breached.


                                        9


<PAGE>   58


         (p)      TAXES AND TAX RETURNS.

         -        Audited through BioWhittaker's taxable year ended October 31,
                  1994.

         -        Tax Agreement dated as of September 24, 1991 between
                  BioWhittaker and Whittaker Corporation with amendment dated
                  October 23, 1991 and indemnification provision related to
                  such agreement in Section 10.02 of the Anasco Stock Purchase
                  Agreement.


         (r)      ENVIRONMENTAL MATTERS.

                  BioWhittaker has been identified as a de minimis participant
                  in the Spectron/Galaxy Superfund site. We have been advised
                  that a settlement is about to be proposed for the de minimis
                  participants.

4.2      COVENANTS

         (a)      INTERIM OPERATIONS. (EXCEPTIONS)

                  (vii) See attached list of capital expenditures.

                  (ix)  Resolution of Microbix dispute could require changes to
                  the Exclusive Supply Agreement with Abbott and resolution of
                  the Pennsylvania Regional Tissue Bank case could require
                  changes to the HCCC agreement.

                  (x)   FASB 123 becomes effective in 1997 as disclosed in
                  BioWhittaker's most recent SEC Form 10-K. Also, the IRS
                  notified BioWhittaker that it will consent to a change in tax
                  accounting methods for inventory. A copy of the Consent
                  Agreement dated July 16, 1997 has been provided.


                                       10
<PAGE>   59
                                 BIOWHITTAKER, INC.
                              OPEN C.A.R. STATUS REPORT
                            PERIOD 9 ENDING JULY 27, 1997

<TABLE>
<CAPTION>
DEPT    DEPT            CAR             AMOUNT          AMOUNT SPENT    BALANCE             CAR
NO.     NAME           NUMBER          APPROVED            TO DATE       OPEN           DESCRIPTION
- -----------------------------------------------------------------------------------------------------------------------------------
<S>     <C>            <C>             <C>             <C>             <C>             <C>
0610     MEDIA          171-9627-000    66,400.00       48,390.06       36,009.96       INTRASEPT FILLING MACHINE INSTALLATION
0610     MEDIA          171-9707-000    10,200.00        6,800.00        3,400.00       500L CONTAINER CONSTRUCTION
0610     MEDIA          171-9716-000    18,000.00            0.00       16,000.00       ERGO ELECTRIC LIFT & EXTENSION PALLET JACK
0610     MEDIA          171-9724-000    13,000.00        3,860.10        9,139.90       1100L TANK AGITATOR
0610     MEDIA          171-9728-000    32,100.00        3,914.01       28,185.99       FLOOR SCALE-SHUT OFF VALVES DRUM FILLS
0610     MEDIA          172-9814-000     6,790.00            0.00        5,790.00       LINE CLEARANCE
0610     MEDIA          172-9750-000     1,600.00        1,560.00           50.00       AUTOCLAVE CART PARKING STAND


0620     CELLS          171-9723-000    13,500.00        4,464.00        9,036.00       REPLACEMENT SYRINGES COZZOLI TUBING MACH
0620     CELLS          171-9748-000     8,500.00        3,241.94        5,258.06       GOWNING ROOM CELL SPECIAL LABS
0620     CELLS          171-9756-000     2,781.68            0.00        2,781.68       BWI CELLS SPECIALS LABS


0723     PILOT OPS      171-9729-000    27,800.00            0.00       27,800.00       BAG LEAK TESTING SYSTEM


0733     R&D            172-9746-000     9,589.75          183.49        9,396.26       SERUM FREE CHO MEDIA DEVELOPMENT


0614     B/C CUST SVC   172-9753-000     1,800.00            0.00        1,800.00       "ON HOLD" MESSAGE PROVIDER


0615     STER SVCS      171-9633-000    69,500.00       70,297.80         (797.90)      GLASSWARE WASHER
0615     STER SVCS      172-9729-000     2,200.00            0.00        2,200.00       ADDITIONAL BOTTLE CRUSHER
0615     STER SVCS      172-9754-000     8,500.00            0.00        8,500.00       CARTS & ACCESSORIES


0640     HUMAN RESC     171-9726-000    10,785.00        5,392.00        5,393.00      OFFICE FURNITURE HR


0671     OCCUP-EAST     171-9714-000    30,000.00        8,741.48       21,258.52      NEW ROOF BLDG 1
0671     OCCUP-EAST     171-9725-000    13,500.00            0.00       13,500.00      BLDG 1 BOILER FEED WATER SYSTEM


0672     OCCUP-WEST     171-9624-000    12,000.00       16,667.98       (4,067.98)     DESIGN SVCS FOR BWI CAFETERIA/EXEC OFFCS
                                                                                         (ON HOLD)
0672     OCCUP-WEST     171-9642-000   400,700.00      296,066.14      104,633.86      BLDG 100C ADDITION (SHIPPING)
0672     OCCUP-WEST     171-9704-000   256,000.00      279,412.08      (23,412.08)     CLONETIC MFG 602-803 BLDG 100B
                                                                                         (AMENDMENT PENDING)
0672     OCCUP-WEST     171-9706-000    50,000.00       48,025.14        1,974.86      ROOFTOP UNIT A/C4 REPLACEMENT
0672     OCCUP-WEST     171-9713-000    90,000.00       87,700.76        2,299.22      SECOND CHILLER REPLACEMENT
0672     OCCUP-WEST     171-9717-000   450,000.00       36,767.00      414,213.00      WFI STILL & ADDITION
</TABLE>












              
<PAGE>   60
                                 BIOWHITTAKER, INC.
                              OPEN C.A.R. STATUS REPORT
                            PERIOD 9 ENDING JULY 27, 1997

<TABLE>
<CAPTION>
DEPT    DEPT                CAR            AMOUNT      AMOUNT SPENT    BALANCE                   CAR
 NO.    NAME               NUMBER         APPROVED        TO DATE        OPEN                 DESCRIPTION
- ---------------------------------------------------------------------------------------------------------------------------
<S>     <C>     <C>     <C>             <C>             <C>           <C>              <C>
0872    OCCUP-WEST      172-9721-000        3,500.00       3,500.00         0.00       UTILITY RELOCATION DESIGN
0872    OCCUP-WEST      172-9723-000        9,180.00      10,251.17    (1,017.17)      100B CORE RENOVATION (AMENDMENT PENDING)
0872    OCCUP-WEST      172-9751-000        1,700.00         952.30       747.70       100/100B CONNECTING CORRIDOR A/C
0872    OCCUP-WEST      172-9752-000        2,200.00           0.00     2,200.00       BLDG 100A STOREFRONT DOORS

0901    SALES           171-9712-000       45,250.00       8,858.27    38,391.73       REFRIGERATION EQUIPMENT TO SUPPORT SOS

0912    OFFICE AUTO     171-9700-000       77,000.00      36,996.69    41,000.31       BLANKET CAR FOR FY97 PC PURCHASES

1030    VIROLOGY        172-9742-000        5,000.00       4,864.49       135.51       FLOW ROTOR-RETURN PRODUCTION 
1030    VIROLOGY        172-9755-000        5,500.00           0.00     5,500.00       SUPERSPEED ROTOR FOR FETLIN PRODUCTION

1348    LAL WALK        171-9637-000       11,300.00           0.00    11,300.00       90 WELL LAL DISPOSABLE MOLD
1348    LAL WALK        171-9727-000       39,000.00           0.00    39,000.00       SCREW CAP UPDATE FOR FD 6000 FAXALL
1348    LAL WALK        171-9731-000        7,330.00       7,368.58       (38.58)      13MM PART FOR WEST CAPPER

1349    LAL-CHINCO      171-9711-000       30,000.00      18,295.79    11,704.21       CHINCOTEAGUE PROCESSING ROOM HVAC
                                        ========================================
                               TOTAL    1,661,006.43   1,010,589.38   850,417.05
</TABLE> 
<PAGE>   61
                             CLONETICS-BIOWHITTAKER, INC.
                              OPEN C.A.R. STATUS REPORT
                             PERIOD ENDING JULY 27, 1997

<TABLE>
<CAPTION>

DEPT    DEPT                 CAR            AMOUNT           AMOUNT SPENT    BALANCE                CAR
 NO.    NAME                NUMBER          APPROVED           TO DATE        OPEN               DESCRIPTION
- ---------------------------------------------------------------------------------------------------------------------------
<S>     <C>                <C>              <C>              <C>             <C>            <C>
0516    Media              172-9706-000       8,200.00            0.00         8,200.00     Bag Packaging System

0620    Cells              171-9701-000     160,500.00       34,216,42       126,281.58     Mig Equipment for Clonetics 802/603 Core

0620    Cells              171-9704-000      29,000.00            0.00        29,000.00     Speical Lab-Clonetics

0628    Hepatocyte         171-9703-000      19,900.00        3,390.00        16,510.00     Hepatocyte Lab Equipment

0633    Ship Clonetics     171-9702-000      14,200.00       14,691.17         (481.17)     1840 Dewar (to be Capitalized Pd 10)

0912    Off Auto           171-9709-000       4,000.00            0.00         4,000.00     Clonetics Web Page

0912    Off Auto           171-9710-000       5,200.00            0.00         5,200.00     Network Remote Access
                                            ==========       =========       ==========
        TOTAL                               241,000.00       52,299.59       168,700.41
</TABLE>
<PAGE>   62
                              Bio Whittaker, Inc.
                           Individual Grantee Summary
                               Subsequent Options



             
                Option   Option              Number of shares
                                            --------------------
Graphics         Data    Price   Granted   Exercised   Cancelled   Available
- --------         ----    -----   -------   ---------   ---------   ---------
Butterbaugh/   
Steel.........  11/14/91  35,674   9,062                              9,062

                11/14/91  66,000  64,993                             84,993

HB, Stanley...  11/14/91  35,074   1,380                              1,350

Warbler Thomas. 11/14/91  55,010  71,873                             31,873

(Name above 
level)                           
- ------------
Total All Grantees                127,272                           127,280
<PAGE>   63
                              BIOWHITTAKER, INC.
                          INDIVIDUAL GRANTEE SUMMARY
                              SUBSEQUENT OPTIONS


                                                    NUMBER OF SHARES
                        GRANT     OPTION   ------------------------------------ 
    GRANTEE              DATE      PRICE   GRANTED  EXTENDED CANCELED AVAILABLE
    -------             -------   -------  -------  -------- -------- ---------
(Name below this line)

Andarre Wile ......... 04/20/97   $0.3750   25,000                      5,000
                       03/17/97    0.7990   20,000                      2,000

Albrand, Joseph ...... 01/13/97    0.1230    1,000                      5,000

Andrews, Rick ........ 02/17/97    0.7500    1,000                      2,000

Burgus, Dennis ....... 02/17/97    0.7500    2,000                      2,000

Barahby, Ron ......... 02/17/97    0.3750    6,000                      5,000
                       02/17/97    0.7500    2,400                      2,000

Blumenthal, Bob ...... 02/19/97    0.7600    1,000                      1,000

Brown, Garry ......... 02/17/97    0.7500    1,000                      1,000

Buterbaugh, Noey ..... 12/04/91    0.6000  100,000                    100,000
                       03/18/93    0.7600  100,000                    100,000
                       12/18/98    0.7500  100,000                    100,000
                       02/17/97    0.7500    9,000                      9,000

Campbell, Michael .... 02/17/97    0.7500    1,000                      1,000

Chara, Patrick ....... 02/17/97    0.7500    1,000                      1,000
                                                                      
Cooper Harold ........ 02/20/93    0.7500    5,000    1,847    3,333        0


Dirharren, John ...... 02/17/97    0.7500      100                        300

Burrell, Don ......... 02/17/97    0.7500      300                        300

Feminc, Linda ........ 08/07/93    0.7500    2,302                      2,500
                       02/17/97    0.1500      300                        800

Forrald, Bruce ....... 12/03/97    0.7500   19,000                     14,000
                       03/18/93    0.7500   19,000                     14,000
                       02/17/97    0.7500    1,000                     19,000

Goodman, Glen ........ 08/14/97    0.3740    2,500                     25,000
                       02/17/97    0.7900      300                        300

Haines, Pal .......... 02/17/97    0.7500      200                        200

HO, Stanley, L. ...... 12/19/97    0.6006   20,000                      20,000
                       02/17/97    0.7500   10,000                      19,000
                       02/17/97    0.7500    1,000                       1,000

Hocheder, Paul ....... 02/17/97    0.7500    5,006                         300

Jan, Silettery ....... 02/17/97    0.7500    4,000                       4,000

Karim, Sov ........... 02/17/97    0.7560    4,000                       1,000


<PAGE>   64
                              BIOWHITTAKER, INC.
                          INDIVIDUAL GRANTEE SUMMARY
                              SUBSEQUENT OPTIONS
      
                                                    NUMBER OF SHARES
                     GRANT     OPTION    -------------------------------------
  GRANTEE             DATE     PRICE     GRANTED EXERCISED CANCELLED AVAILABLE
  -------            -----     ------    ------- --------- --------- ---------

Lenon, Stanley...... 01/01/94   8.0350     1,400                       1,000
                     01/02/95   0.5000     1,000                       1,000
                     01/02/96   7.8250     1,000                       1,000
                     01/02/97   8.1250     5,000                       5,000

Lovernek, Bruce..... 02/17/97   6.7500       900                         900

Luperebeck, Pal..... 02/17/97   6.7500       300                         300

Misk, Lloyd......... 02/17/97   6.7500     2,000                       2,000

McCormick, William.. 02/20/93   6.3750     1,000                       5,000
                     02/17/95   6.7500     2,000                       2,000

McGulin, Cindy...... 02/17/97   6.7500       300                         300

Medan, Vaughn....... 01/17/95   7.7500     1,500                       5,000
                     02/17/97   6.7500     2,000                       2,000

McDonald, Rick...... 02/17/97   6.7500       300                         300

Olson, Leif......... 01/02/91   6.6400    10,000                      10,000
                     02/10/92   6.7500    20,000                      20,000
                     02/17/97   6.7500     3,000                       3,000

Punter, Joe......... 02/17/97   6.7500       200                         200

Patchisk, Richard... 02/17/97   6.7500     1,000                       1,000

Pescela, Sherry..... 02/20/95   5.1750     2,500                       2,500
                     02/17/97   6.7500       300                         300

Plater, Robert...... 02/17/95   7.7500     5,000                       5,000
                     02/17/97   6.7500     1,000                       1,000

Regiotta, Herb...... 02/17/97   6.7500     1,000                       1,000

Robertson, Marcus... 02/20/95   5.1750     2,500                       2,500
                     02/17/97   6.7500       300                         300

Rnww, Philip........ 12/02/91   6.1000    50,000                      50,000
                     02/10/97   6.7500    75,000                      75,000
                     12/10/97   0.6000    50,000                      50,000
                     02/17/97   6.7500     4,000                       4,000

Rouseau, James...... 08/20/95   5.2750     5,000                       5,000

Routshcn, Charles... 02/17/97   6.7500       500                         500

Schfrafer, Jess..... 02/17/97   6.7500       300                         300

Sever, John......... 01/02/94   6.6250     1,000                       1,000
                     01/20/95   6.5000     1,000                       1,000
                     01/02/96   7.6250     1,000                       1,000
                     01/02/97   6.1250     5,000                       5,000

Sheber, Ralph....... 04/20/95   7.1750     5,000                       5,000
                     02/17/97   6.7500     2,000                       2,000

<PAGE>   65
                              BIOWHITTAKER, INC.
                          INDIVIDUAL GRANTEE SUMMARY
                              SUBSEQUENT OPTIONS


                                                    NUMBER OF SHARES
                        GRANT     OPTION   ------------------------------------ 
    GRANTEE              DATE      PRICE   GRANTED  EXTENDED CANCELED AVAILABLE
    -------             -------   -------  -------  -------- -------- ---------
(Name below this line)

Shobes, Dotte ........ 02/08/97   $0.7500      300                        300

Staples, Dudley ...... 12/11/95    0.7500    3,000                      3,000

Stengel, Jesse ....... 02/17/97    0.7500    1,000                      1,000

Frank, Joy ........... 02/17/97    0.3750    5,600                      3,000
                       02/17/97    0.7560    2,000                      2,000

Valore, Sandy ........ 02/17/97    0.7500    1,000                      1,000

Vanderhagen, Brigota . 04/20/93    0.3750    5,000                      5,000

Vehneskey, Chamber ... 04/20/93    0.3750    2,500                      2,500
                       02/17/97    0.7500    1,000                      1,000

Wilder, Thomas ....... 12/02/91    0.8000   50,000                     50,000
                       03/16/93    0.7600   75,000                     71,000
                       12/10/93    0.9000  100,000                    100,000
                       02/17/97    0.7500    9,000                      9,000

(New above this line)
- -----------------------------------------------------------------------------
                                           640,100    1,111    1,333  640,000



<PAGE>   1
                                                                  Execution Copy
                                                                  EXHIBIT 11(c)2





                             STOCKHOLDERS AGREEMENT

                  STOCKHOLDERS AGREEMENT dated as of August 22, 1997 among
Cambrex Corporation, a Delaware corporation ("Parent"), BW Acquisition
Corporation, a Delaware corporation ("Purchaser") and ANASCO GmbH, a German
limited liability company ("Stockholder").


                  WHEREAS, concurrently herewith Parent, the Purchaser, and
BioWhittaker, Inc., a Delaware corporation (the "Company"), are entering into an
Agreement and Plan of Merger of even date herewith (as such agreement may be
amended from time to time, the "Merger Agreement"; capitalized terms used but
not otherwise defined herein shall have the respective meanings ascribed to them
in the Merger Agreement) pursuant to which the Purchaser will be merged with and
into the Company (the "Merger"); and

                  WHEREAS, in furtherance thereof, the Parent proposes that the
Purchaser make an offer (the "Offer") to purchase for cash all of the issued and
outstanding shares of common stock of the Company, and all associated rights to
purchase preferred stock, at a price of $11.625 per share net to the seller;

                  WHEREAS, Parent has required, as a condition to its entering
into the Merger Agreement and commencing the Offer, that Stockholder enter into,
and Stockholder has agreed to enter into, this Agreement.

                  NOW, THEREFORE, to satisfy this condition and in consideration
of Parent's entering into the Merger Agreement and causing the Offer to be
commenced, respectively, and in consideration of the premises and the
representations, warranties and covenants contained herein, the parties agree as
follows:

 
<PAGE>   2
                  1. Representations and Warranties of Stockholder. Stockholder
hereby represents and warrants to Parent as follows:

                  (a) Ownership of Shares. (i) Stockholder is the record holder
         and beneficial owner of the number of shares of the common stock of the
         Company, par value $.01 per share (the "Company Common Stock"), set
         forth opposite Stockholder's name on Schedule A hereto (the "Existing
         Shares", and together with any shares of Company Common Stock acquired
         by Stockholder after the date hereof and prior to the termination
         hereof, whether upon exercise of options or warrants, conversion of
         convertible securities, purchase, exchange or otherwise, the "Shares").

                  (ii) On the date hereof, the Existing Shares set forth
         opposite Stockholder's name on Schedule A constitute all of the shares
         of Company Common Stock owned by Stockholder.

                  (iii) Stockholder has (A) sole power of disposition; (B) sole
         voting power; and (C) sole power to demand dissenter's or appraisal
         rights, in each case with respect to all of Stockholder's Existing
         Shares and with no restrictions on such rights, subject to applicable
         federal securities laws and the terms of this Agreement.

                  (b) Power; Binding Agreement. Stockholder has all requisite
         legal capacity, power and authority to enter into and perform all of
         Stockholder's obligations under this Agreement. The execution, delivery
         and performance of this Agreement by Stockholder will not violate any
         other agreement to which Stockholder is a party or by which Stockholder
         is bound including, without limitation, any voting agreement,
         stockholders agreement, voting trust or other agreement. This Agreement
         has been duly and validly authorized, executed and delivered by
         Stockholder and constitutes a valid and binding agreement of
         Stockholder, enforceable

                                       2
<PAGE>   3



         against Stockholder in accordance with its terms, except as such
         enforceability may be limited by bankruptcy, insolvency, moratorium or
         other similar laws affecting or relating to the enforcement of
         creditors' rights generally or by general principles of equity. There
         is no beneficiary of or holder of a voting trust certificate whose
         consent is required for the execution and delivery of this Agreement or
         the consummation of the transactions contemplated hereby.

                  (c) No Conflicts. Except for filing under the
         Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the
         "HSR Act"), if applicable, (i) no filing with, and no permit,
         authorization, consent or approval of, any state or federal public body
         or authority is necessary for the execution of this Agreement by
         Stockholder and the consummation by Stockholder of the transactions
         contemplated hereby and (ii) neither the execution and delivery of this
         Agreement by Stockholder nor the consummation by Stockholder of the
         transactions contemplated hereby nor compliance by Stockholder with any
         of the provisions hereof shall (A) conflict with or result in any
         breach of the applicable organization documents applicable to
         Stockholder, (B) result in a material violation or breach of, or
         constitute (with or without notice or lapse of time or both) a default
         (or give rise to any third party right of termination, cancellation,
         modification, prepayment or acceleration) under any of the terms,
         conditions or provisions of any material note, bond, mortgage,
         indenture, license, contract, commitment, arrangement, understanding,
         agreement or other instrument or obligation of any kind to which
         Stockholder is a party or by which such Stockholder or any of such
         Stockholder's properties or assets may be bound or (C) violate any
         order, writ, injunction, decree, judgment, statute, rule, regulation or
         governmental permit or license (collectively, "Laws") applicable to
         Stockholder or any of such Stockholder's properties or assets.






                                       3
<PAGE>   4
                  (d) Stockholder's Shares and the certificates representing
         Shares are now and at all times during the term hereof will be held by
         Stockholder, or by a nominee or custodian for the benefit of
         Stockholder, free and clear of all liens, claims, security interests,
         proxies, voting trusts or agreements, understandings, arrangements or
         any other encumbrances whatsoever, except for any such encumbrances or
         proxies arising hereunder.

                   (e) No broker, investment banker, financial adviser or other
         Person is entitled to any broker's, finder's, financial adviser's or
         other similar fee or commission payable by Parent or Purchaser in
         connection with the transactions contemplated hereby based upon
         arrangements made by or on behalf of Stockholder.

                  (f) Stockholder understands and acknowledges that Parent is
         entering into the Merger Agreement in reliance upon Stockholder's
         execution and delivery of this Agreement.

                  2. Agreement to Tender. Stockholder hereby irrevocably agrees
to duly tender all of the Shares of Stockholder pursuant to the terms of the
Offer and not to withdraw such Shares prior to the expiration of the Offer.

                  3. Agreement to Vote; Proxy.

                  (a) Voting. Stockholder hereby agrees that, during the time
this Agreement is in effect, at any meeting of the stockholders of the Company,
however called, or in connection with any written consent of the stockholders of
the Company, Stockholder shall vote (or cause to be voted) the Shares of
Stockholder (i) in favor of the Merger, the execution and delivery by the
Company of the Merger Agreement and the approval of the terms thereof and each
of the other actions contemplated by the Merger Agreement and this Agreement and
any actions required in furtherance hereof and thereof; (ii) against any action
or agreement that would result in a breach of any covenant, representa-

                                       4
<PAGE>   5
tion or warranty or any other obligation or agreement of the Company under the
Merger Agreement, the Offer or this Agreement; and (iii) except as specifically
requested in writing by Parent in advance, against the following actions (other
than the Merger and the transactions contemplated by the Merger Agreement): (A)
any extraordinary corporate transaction, such as a merger, consolidation or
other business combination involving the Company or its subsidiaries; (B) a
sale, lease or transfer of a material amount of assets of the Company or its
subsidiaries or a reorganization, recapitalization, dissolution, liquidation or
winding up of the Company or any of its subsidiaries; (C) any change in the
majority of the board of directors of the Company; (D) any material change in
the present capitalization of the Company or any amendment of the Company's
Certificate of Incorporation; (E) any other material change in the Company's
corporate structure or business; and (F) any other action which is intended or
could reasonably be expected to impede, interfere with, delay, postpone,
discourage or materially adversely affect the Merger, the transactions
contemplated by the Merger Agreement or this Agreement or the contemplated
economic benefits of any of the foregoing. Stockholder shall not enter into any
agreement or understanding with any Person prior to the Termination Date (as
defined in Section 9 hereof) to vote in any manner inconsistent with clause
(i), (ii) or (iii) of the preceding sentence.

                  (b) PROXY. STOCKHOLDER HEREBY GRANTS TO, AND APPOINTS
PURCHASER, PETER THAUER AND PETER TRACEY IN THEIR RESPECTIVE CAPACITIES AS
OFFICERS OF PURCHASER, AND ANY INDIVIDUAL WHO SHALL HEREAFTER SUCCEED TO ANY
SUCH OFFICE OF PURCHASER, AND ANY OTHER DESIGNEE OF PURCHASER, EACH OF THEM
INDIVIDUALLY, SUCH STOCKHOLDER'S IRREVOCABLE (UNTIL THE TERMINATION DATE) PROXY
AND ATTORNEY-IN-FACT (WITH FULL POWER OF SUBSTITUTION) TO VOTE THE SHARES AS
INDICATED IN SECTION 3(a) ABOVE. STOCKHOLDER INTENDS THIS PROXY TO BE
IRREVOCABLE (UNTIL THE TERMINATION DATE) AND COUPLED WITH AN INTEREST AND WILL
TAKE SUCH FURTHER ACTION AND EXECUTE SUCH OTHER INSTRUMENTS AS MAY BE NECESSARY
TO EFFECTUATE THE

                                       5
<PAGE>   6
INTENT OF THIS PROXY AND HEREBY REVOKES ANY PROXY PREVIOUSLY GRANTED BY
STOCKHOLDER WITH RESPECT TO STOCKHOLDER'S SHARES.

                  4. Certain Covenants of Stockholder. Except in accordance with
the terms of this Agreement, Stockholder hereby covenants and agrees as follows:

                  (a) No Solicitation. Stockholder shall not, directly or
indirectly (including through advisors, agents or other intermediaries),
initiate, solicit, negotiate, encourage or provide confidential information to
facilitate any proposal or offer by any Person that constitutes or could
reasonably be expected to lead to an Acquisition Transaction; provided, however,
that no provision of this Agreement shall prohibit or in any way restrict the
right of Stockholder and its affiliates to initiate, solicit, negotiate,
encourage or provide confidential information to any party in connection with a
possible sale or other disposition by Stockholder or such affiliate of its
interest in Boehringer Ingelheim BioProducts, a Delaware general partnership. If
Stockholder receives any such inquiry or proposal, then Stockholder shall
promptly inform Parent of the material terms and conditions, if any, of such
inquiry or proposal and the identity of the Person making it. Stockholder will
immediately cease and cause to be terminated any existing activities,
discussions or negotiations with any parties conducted heretofore with respect
to any of the foregoing. Nothing in this Section 4(a) shall restrict or limit
the ability of Stockholder's designee on the Board of Directors of the Company
to take or perform in such capacity any of the actions or do any of the things
that the Company is permitted to take or perform under Section 4.1(a) and 4.1(b)
of the Merger Agreement.

                  (b) Restriction on Transfer, Proxies and Non-Interference;
Restriction on Withdrawal. Stockholder shall not, directly or indirectly: (i)
except pursuant to the terms of the Merger Agreement, the Offer and this
Agreement, offer for sale, sell, transfer, tender, pledge, encumber, assign or
otherwise dispose of (collectively, "Disposition"), enforce or permit the
execution of the provisions of




                                       6
<PAGE>   7
any agreement with the Company whereby the Company may be obligated to
repurchase, or enter into any other contract, option or other arrangement or
understanding with respect to, or otherwise consent to the Disposition of any or
all of Stockholder's Shares or any interest therein; (ii) except as contemplated
hereby, grant any proxies or powers of attorney, deposit any Shares into a
voting trust or enter into a voting agreement with respect to any Shares; or
(iii) take any action that would make any representation or warranty of
Stockholder contained herein untrue or incorrect or have the effect of
preventing or disabling Stockholder from performing Stockholder's obligations
under this Agreement.

                  (c) Waiver of Appraisal and Dissenter's Rights. Stockholder
hereby waives any rights of appraisal or rights to dissent from the Merger that
Stockholder may have.

                  5. Option. (a) Stockholder hereby grants to Purchaser an
irrevocable option (the "Option") to purchase Stockholder's Shares, on the terms
and subject to the conditions set forth herein.

         (b) The Option may be exercised by Purchaser, as a whole and not in
part, at any time and from time to time from and after any time when the Merger
Agreement has been terminated in accordance with its terms and prior to the
Termination Date, subject to the conditions set forth in Section 5(f).

                  (c) If Purchaser wishes to exercise the Option, Purchaser
shall send a written notice (the "Option Notice") to Stockholder of its
intention to exercise the Option, specifying the place, and, if then known, the
time and the date (the "Closing Date") of the closing (the "Closing") of the
purchase. The Closing Date shall occur on the third business day after the date
on which such notice is delivered.

                  (d) At the Closing, Stockholder shall deliver to Purchaser (or
its designee) all of Stockholder's Shares




                                       7
<PAGE>   8
required to be delivered pursuant to the Option Notice by delivery of a
certificate or certificates evidencing such Shares, duly endorsed to Purchaser
or accompanied by stock powers duly executed in favor of Purchaser, with all
necessary stock transfer stamps affixed.

                  (e) At the Closing, Purchaser shall pay, and Parent shall
cause Purchaser to pay, to Stockholder, by wire transfer in immediately
available funds to an account specified by Stockholder in writing no more than
two days prior to the Closing, an amount equal to the product of the Merger
Consideration and the number of shares purchased pursuant to the exercise of the
Option.

                  (f)  The Closing shall be subject to the satisfaction of each
of the following conditions:

                  (i) no court, arbitrator or governmental body, agency or
         official shall have issued any order, decree or ruling and there shall
         not be any statute, rule or regulation, restraining, enjoining or
         prohibiting the consummation of the purchase and sale of the Shares
         pursuant to the exercise of the Option;

                  (ii) any waiting period applicable to the consummation of the
         purchase and sale of the Shares pursuant to the exercise of the Option
         under the HSR Act shall have expired or been terminated; and

                  (iii) all actions by or in respect of, and any filing with,
         any governmental body, agency, official, or authority required to
         permit the consummation of the purchase and sale of the Shares pursuant
         to the exercise of the Option shall have been obtained or made and
         shall be in full force and effect.

                  6. Further Assurances. From time to time, at any party's
request and without further consideration, each other party shall execute and
deliver such additional documents and take all such further action as may be
necessary or desirable to consummate and make effective, in the most


                                       8
<PAGE>   9

expeditious manner practicable, the transactions contem plated by this
Agreement.

                  7. Obligations Attach to Shares. Stockholder agrees that this
Agreement and the obligations hereunder shall attach to such Stockholder's
Shares and shall be binding upon any Person to which legal or beneficial
ownership of such Shares shall pass, whether by operation of law or otherwise.

                  8. Stop Transfer. Stockholder agrees with, and covenants to,
Parent that Stockholder shall not request that the Company register the transfer
(book-entry or otherwise) of any certificate or uncertificated interest
representing any of Stockholder's Shares, unless such transfer is made in
compliance with the Offer or this Agreement. Stockholder agrees, with respect to
any Shares in certificated form, that Stockholder will submit to the Company,
within ten business days after the date hereof, the certificates representing
such Shares in order for the Company to inscribe upon such certificates the
following legend: "The shares of Common Stock, par value $.0l per share, of
BioWhittaker, Inc. (the "Company") represented by this certificate are subject
to a Stockholders Agreement dated as of August 22, 1997, and may not be sold or
otherwise transferred, except in accordance therewith. Copies of such Agreement
may be obtained at the principal executive offices of the Company." Stockholder
agrees that within ten business days after the date hereof, Stockholder will no
longer hold any Shares, whether certificated or uncertificated, in "street name"
or in the name of any nominee.

                  9. Termination. This Agreement shall terminate upon the
earlier of (a) twelve months from the date hereof or (b) the Effective Time;
provided, however, that if the Company is not in breach of its obligations under
the Merger Agreement and Stockholder is not in breach of its obligations under
this Agreement, this Agreement shall terminate upon termination of the Merger
Agreement (a) pursuant to Section 6.1(a), 6.1(d), 6.1(f)(i) and 6.1(g) thereof,
(b) pursuant to Section 6.1(b), 6.1(c) and 6.1(e) thereof (in


                                       9
<PAGE>   10
each case if no proposal for an Acquisition Transaction has been made), or (c)
by the Company pursuant to Section 6.1(f)(ii) thereof (unless a proposal for an
Acquisition Transaction has been made). The date of termination of this
Agreement is referred to herein as the "Termination Date".

                  10.      Miscellaneous.

                  (a) Entire Agreement; Assignment. This Agreement (i)
constitutes the entire agreement among the parties with respect to the subject
matter hereof and supersedes all other prior agreements and understandings, both
written and oral, among the parties with respect to the subject matter hereof
and (ii) shall not be assigned by operation of law or otherwise without the
prior written consent of (A) in the case of an assignment by Stockholder, Parent
and (B) in the case of an assignment by Parent or Purchaser, Stockholder,
provided that Parent may in its sole discretion assign its rights and
obligations hereunder to any of its direct or indirect wholly-owned
subsidiaries.

                  (b) Amendments. This Agreement may not be modified, amended,
altered or supplemented, except upon the execution and delivery of a written
agreement executed the parties hereto.

                  (c) Notices. All notices and other communications under this
Agreement shall be in writing and shall be given (and shall be deemed to have
been duly given upon receipt) by delivery in person, facsimile, telex or other
standard form of telecommunications, by courier service, or by registered or
certified mail, postage prepaid, return receipt requested, addressed

                  If to Parent or Purchaser, to:

                        Cambrex Corporation
                        One Meadowlands Plaza
                        East Rutherford, New Jersey 07073
                        Facsimile No.: (201) 804-9851
                        Attention: Peter Thauer, Esq.


                                       10
<PAGE>   11



                  With a copy to:

                         Debevoise & Plimpton
                         875 Third Avenue
                         New York New York 10022
                         Facsimile No.: (212) 909-6836
                         Attention: Ralph Arditi, Esq.

                  If to Stockholder, to:

                         ANASCO GmbH
                         D-55216 Ingelheim am Rhein
                         Federal Republic of Germany
                         Facsimile No.:  011-44-6132-77-4080

                  With copies to:

                         Boehringer Ingelheim GmbH
                         Bereich Recht Marken Versicherung Immobilien
                         D-55216 Ingelheim am Rhein
                         Federal Republic of Germany
                         Facsimile No.:  011-44-6132-77-3256

                  and:

                         Rogers & Wells
                         200 Park Avenue
                         New York, New York 10166
                         Facsimile No.: (212) 878-8375
                         Attention: Richard T. McDermott, Esq.

or to such other address or facsimile number as the Person to whom notice is
given shall have previously furnished to the others in writing in the manner set
forth above.

                  (d) Governing Law. This Agreement shall be governed by and
construed in accordance with the laws of the State of Delaware without giving
effect to the conflicts of laws principles thereof.


                                       11
<PAGE>   12
                  (e) Enforcement. The parties agree that irreparable damage
would occur in the event that any of the provisions of this Agreement were not
performed in accordance with their specific terms or were otherwise breached.
It is accordingly agreed that the parties shall be entitled to an injunction or
injunctions to prevent breaches of this Agreement and to enforce specifically
the terms and provisions of this Agreement.

                  (f) Counterparts. This Agreement may be executed in one or
more counterparts, each of which shall be deemed to be an original, but all of
which when taken together shall constitute one and the same Agreement.

                  (g) Descriptive Headings. The descriptive headings used herein
are inserted for convenience of reference only and are not intended to be part
of or to affect the meaning or interpretation of this Agreement.

                  (h) Severability. Whenever possible, each provision or
portion of any provision of this Agreement will be interpreted in such manner as
to be effective and valid under applicable law but if any provision or portion
of any provision of this Agreement is held to be invalid, illegal or
unenforceable in any respect under any applicable law or rule in any
jurisdiction, such invalidity, illegality or unenforceability will not affect
any other provision or portion of any provision in such jurisdiction, and this
Agreement will be reformed, construed and enforced in such jurisdiction as if
such invalid, illegal or unenforceable provision or portion of any provision had
never been contained herein.

                  (i) Definitions; Construction. For purposes of this Agreement:

                  (i) "beneficially own" or "beneficial ownership" with respect
         to any securities shall mean having "beneficial ownership" of such
         securities (as determined pursuant to Rule 13d-3 under the Exchange
         Act), including pursuant to any agreement, arrangement or


                                       12
<PAGE>   13
         understanding, whether or not in writing. Without duplicative counting
         of the same securities by the same holder, securities beneficially
         owned by a Person shall include securities beneficially owned by all
         other Persons with whom such Person would constitute a "group" as
         described in Section 13(d)(3) of the Exchange Act.

                  (iv) "Person" shall mean an individual, corporation,
         partnership, limited liability company, joint venture, association,
         trust, unincorporated organization or other entity.

                  (v) In the event of a stock dividend or distribution, or any
         change in the Company Common Stock by reason of any stock dividend,
         split-up, recapitalization, combination, exchange of shares or the
         like, the term "Shares" shall be deemed to refer to and include the
         Shares as well as all such stock dividends and distributions and any
         shares into which or for which any or all of the Shares may be changed
         or exchanged.

                  (j) Stock Purchase Agreement. Stockholder acknowledges that
its rights under Section 8.01(c) of the Stock Purchase Agreement, dated
September 24, 1991, between the Company and Stockholder, to receive any
Compensation Amount (as defined in such agreement) will terminate and be of no
further force or effect from and after its sale of its Shares to the Purchaser
in the Offer, as contemplated in this Agreement.


                                       13
<PAGE>   14


                  IN WITNESS WHEREOF, Parent, Purchaser and Stockholder have
caused this Agreement to be duly executed as of the day and year first above
written.

                                            CAMBREX CORPORATION


                                            BY:  /s/ Peter Tracey
                                                 ____________________
                                                 Name: Peter Tracey
                                                 Title: Executive Vice President


                                            BW ACQUISITION CORPORATION


                                            BY:  /s/ Peter E. Thauer 
                                                 ____________________
                                                 Name: Peter E. Thauer
                                                 Title: Vice President


                                            ANASCO GmbH


                                            BY:  /s/ Gerhard Huber
                                                 ____________________
                                                 Name: Dr. Gerhard Huber
                                                 Title: Authorized Signatory


                                            BY:  /s/ Jurgen Romhild
                                                 ____________________
                                                 Name: Jurgen Romhild
                                                 Title: Authorized Signatory





<PAGE>   15
                                                                      SCHEDULE A






Name                                                    Number of Shares

ANASCO GmbH                                             2,097,043
D-55216 Ingelheim am Rhein
Federal Republic of Germany
Facsimile No.:  011-44-6132-77-4080







<PAGE>   1
                                                                  Execution Copy
                                                                  EXHIBIT 11(c)3





                        MANAGEMENT STOCKHOLDERS AGREEMENT

                  MANAGEMENT STOCKHOLDERS AGREEMENT dated as of August 22, 1997
among Cambrex Corporation, a Delaware corporation ("Parent"), BW Acquisition
Corporation, a Delaware corporation ("Purchaser") and the parties listed on
Schedule A attached hereto (each a "Stockholder" and, collectively, the
"Stockholders").


                  WHEREAS, concurrently herewith Parent, the Purchaser, and
BioWhittaker, Inc., a Delaware corporation (the "Company"), are entering into an
Agreement and Plan of Merger of even date herewith (as such agreement may be
amended from time to time, the "Merger Agreement"; capitalized terms used but
not otherwise defined herein shall have the respective meanings ascribed to them
in the Merger Agreement) pursuant to which the Purchaser will be merged with and
into the Company (the "Merger"); and

                  WHEREAS, in furtherance thereof, the Parent proposes that the
Purchaser make an offer (the "Offer") to purchase for cash all of the issued and
outstanding shares of common stock of the Company, and all associated rights to
purchase preferred stock, at a price of $11.625 per share net to the seller;

                  WHEREAS, Parent has required, as a condition to its entering
into the Merger Agreement and commencing the Offer, that each Stockholder enter
into, and each such Stockholder has agreed to enter into, this Agreement.

                  NOW, THEREFORE, to satisfy this condition and in consideration
of Parent's entering into the Merger Agreement and causing the Offer to be
commenced, respectively, and in consideration of the premises and the
representations, warranties and covenants contained herein, the parties agree as
follows:







<PAGE>   2
                  1. Representations and Warranties of Each Stockholder. Each
Stockholder hereby severally as to itself represents and warrants to Parent as
follows:

                  (a) Ownership of Shares and Stock Options. (i) Such
         Stockholder (together, in the case of Mr. Buterbaugh, with Mr.
         Buterbaugh's wife) is the record holder and beneficial owner of the
         number of shares of the common stock of the Company, par value $.01 per
         share (the "Company Common Stock"), set forth opposite such
         Stockholder's name on Schedule A hereto (the "Existing Shares", and
         together with any shares of Company Common Stock acquired by such
         Stockholder after the date hereof and prior to the termination hereof,
         whether upon exercise of options or warrants, conversion of convertible
         securities, purchase, exchange or otherwise, the "Shares").

                  (ii) On the date hereof, the Existing Shares set forth
         opposite such Stockholder's name on Schedule A constitute all of the
         shares of Company Common Stock owned by such Stockholder.

                  (iii) Such Stockholder has (A) sole power of disposition; (B)
         sole voting power; and (C) sole power to demand dissenter's or
         appraisal rights, in each case with respect to all of such
         Stockholder's Existing Shares and with no restrictions on such rights,
         subject to applicable federal securities laws and the terms of this
         Agreement.

                  (iv) Each Stockholder owns validly issued and outstanding
         options (the "Stock Options") to acquire the number of shares of
         Company Common Stock set forth opposite such Stockholder's name on
         Schedule A hereto (all such shares underlying such Stockholder's Stock
         Options being referred to herein collectively as the "Option Shares").
         All such Stock Options are fully vested and freely exercisable by such
         Stockholder to






                                       2
<PAGE>   3



         acquire any and all such Option Shares at any time at his option.

                  (b) Power; Binding Agreement. Such Stockholder has all
         requisite legal capacity, power and authority to enter into and perform
         all of such Stockholder's obligations under this Agreement. The
         execution, delivery and performance of this Agreement by such
         Stockholder will not violate any other agreement to which such
         Stockholder is a party or by which such Stockholder is bound including,
         without limitation, any voting agreement, stockholders agreement,
         voting trust or other agreement. This Agreement has been duly and
         validly authorized, executed and delivered by such Stockholder and
         constitutes a valid and binding agreement of such Stockholder,
         enforceable against such Stockholder in accordance with its terms,
         except as such enforceability may be limited by bankruptcy, insolvency,
         moratorium or other similar laws affecting or relating to the
         enforcement of creditors' rights generally or by general principles of
         equity. There is no beneficiary of or holder of a voting trust
         certificate whose consent is required for the execution and delivery of
         this Agreement or the consummation of the transactions contemplated
         hereby. If such Stockholder is married and such Stockholder's Shares
         constitute community property or otherwise require spousal or other
         approval for this Agreement to be legal, valid and binding, this
         Agreement has been duly authorized, executed and delivered by, and
         constitutes a valid and binding agreement of, such Stockholder's
         spouse, enforceable against such person in accordance with its terms,
         except as such enforceability may be limited by bankruptcy, insolvency,
         moratorium or other similar laws affecting or relating to the
         enforcement of creditors' rights generally or by general principles of
         equity.

                  (c) No Conflicts. Except for filing under the
         Hart-Scott-Rodino Antitrust Improvements Act of 1976,









                                       3
<PAGE>   4
         as amended (the "HSR Act"), if applicable, (i) no filing with, and no
         permit, authorization, consent or approval of, any state or federal
         public body or authority is necessary for the execution of this
         Agreement by such Stockholder and the consummation by such Stockholder
         of the transactions contemplated hereby and (ii) neither the execution
         and delivery of this Agreement by such Stockholder nor the consummation
         by such Stockholder of the transactions contemplated hereby nor
         compliance by such Stockholder with any of the provisions hereof shall
         (A) conflict with or result in any breach of the applicable
         organization documents applicable to such Stockholder, (B) result in a
         material violation or breach of, or constitute (with or without notice
         or lapse of time or both) a default (or give rise to any third party
         right of termination, cancellation, modification, prepayment or
         acceleration) under any of the terms, conditions or provisions of any
         material note, bond, mortgage, indenture, license, contract,
         commitment, arrangement, understanding, agreement or other instrument
         or obligation of any kind to which such Stockholder is a party or by
         which such Stockholder or any of such Stockholder's properties or
         assets may be bound or (C) violate any order, writ, injunction, decree,
         judgment, statute, rule, regulation or governmental permit or license
         (collectively, "Laws") applicable to such Stockholder or any of such
         Stockholder's properties or assets.

                  (d) Such Stockholder's Shares and the certificates
         representing such Shares are now and at all times during the term
         hereof will be held by such Stockholder, or by a nominee or custodian
         for the benefit of such Stockholder, free and clear of all liens,
         claims, security interests, proxies, voting trusts or agreements,
         understandings, arrangements or any other encumbrances whatsoever,
         except for any such encumbrances or proxies arising hereunder.










                                       4
<PAGE>   5
                   (e) No broker, investment banker, financial adviser or other
         Person is entitled to any broker's, finder's, financial adviser's or
         other similar fee or commission in connection with the transactions
         contemplated hereby based upon arrangements made by or on behalf of
         such Stockholder.

                  (f) Such Stockholder understands and acknowledges that Parent
         is entering into the Merger Agreement in reliance upon such
         Stockholder's execution and delivery of this Agreement.

                  2. Agreement to Tender. Shares. Each Stockholder hereby
irrevocably agrees to duly tender all of the Shares of such Stockholder pursuant
to the terms of the Offer and not to withdraw such Shares prior to the
expiration of the Offer.

                  3. Agreement to Vote; Proxy.

                  (a) Voting. Each Stockholder hereby severally as to itself
agrees that, during the time this Agreement is in effect, at any meeting of the
stockholders of the Company, however called, or in connection with any written
consent of the stockholders of the Company, such Stockholder shall vote (or
cause to be voted) the Shares of such Stockholder (i) in favor of the Merger,
the execution and delivery by the Company of the Merger Agreement and the
approval of the terms thereof and each of the other actions contemplated by the
Merger Agreement and this Agreement and any actions required in furtherance
hereof and thereof; (ii) against any action or agreement that would result in a
breach of any covenant, representation or warranty or any other obligation or
agreement of the Company under the Merger Agreement, the Offer or this
Agreement; and (iii) except as specifically requested in writing by Parent in
advance, against the following actions (other than the Merger and the
transactions contemplated by the Merger Agreement): (A) any extraordinary
corporate transaction, such as a merger, consolidation or other business
combination involving the









                                       5
<PAGE>   6
Company or its subsidiaries; (B) a sale, lease or transfer of a material amount
of assets of the Company or its subsidiaries or a reorganization,
recapitalization, dissolution, liquidation or winding up of the Company or any
of its subsidiaries; (C) any change in the majority of the board of directors of
the Company; (D) any material change in the present capitalization of the
Company or any amendment of the Company's Certificate of Incorporation; (E) any
other material change in the Company's corporate structure or business; and (F)
any other action which is intended or could reasonably be expected to impede,
interfere with, delay, postpone, discourage or materially adversely affect the
Merger, the transactions contemplated by the Merger Agreement or this Agreement
or the contemplated economic benefits of any of the foregoing. Such Stockholder
shall not enter into any agreement or understanding with any Person prior to the
Termination Date (as defined in Section 9 hereof) to vote in any manner
inconsistent with clause (i), (ii) or (iii) of the preceding sentence.

                  (b) PROXY. EACH STOCKHOLDER HEREBY GRANTS TO, AND APPOINTS
PURCHASER, PETER THAUER AND PETER TRACEY IN THEIR RESPECTIVE CAPACITIES AS
OFFICERS OF PURCHASER, AND ANY INDIVIDUAL WHO SHALL HEREAFTER SUCCEED TO ANY
SUCH OFFICE OF PURCHASER, AND ANY OTHER DESIGNEE OF PURCHASER, EACH OF THEM
INDIVIDUALLY, SUCH STOCKHOLDER'S IRREVOCABLE (UNTIL THE TERMINATION DATE) PROXY
AND ATTORNEY-IN-FACT (WITH FULL POWER OF SUBSTITUTION) TO VOTE THE SHARES AS
INDICATED IN SECTION 3(a) ABOVE. EACH STOCKHOLDER INTENDS THIS PROXY TO BE
IRREVOCABLE (UNTIL THE TERMINATION DATE) AND COUPLED WITH AN INTEREST AND WILL
TAKE SUCH FURTHER ACTION AND EXECUTE SUCH OTHER INSTRUMENTS AS MAY BE NECESSARY
TO EFFECTUATE THE INTENT OF THIS PROXY AND HEREBY REVOKES ANY PROXY PREVIOUSLY
GRANTED BY SUCH STOCKHOLDER WITH RESPECT TO SUCH STOCKHOLDER'S SHARES.

                  4. Certain Covenants of Stockholders. Except in accordance
with the terms of this Agreement, each Stockholder hereby severally as to
itself covenants and agrees as follows:









                                       6
<PAGE>   7
                  (a) No Solicitation. Subject to the last sentence of this
Section 4(a), no Stockholder shall, directly or indirectly (including through
advisors, agents or other intermediaries), initiate, solicit, negotiate,
encourage or provide confidential information to facilitate any proposal or
offer by any person that constitutes or could reasonably be expected to lead to
an Acquisition Transaction. If any Stockholder receives any such inquiry or
proposal, then such Stockholder shall promptly inform Parent of the material
terms and conditions, if any, of such inquiry or proposal and the identity of
the Person making it. Subject to the last sentence of this Section 4(a), each
Stockholder will immediately cease and cause to be terminated any existing
activities, discussions or negotiations with any parties conducted heretofore
with respect to any of the foregoing. Nothing in this Section 4(a) shall
restrict or limit the ability of any Stockholder who is an officer or director
of the Company to take or perform in such capacity any of the actions or do any
of the things that the Company is permitted to take or perform under Section
4.1(a) and 4.1(b) of the Merger Agreement.

                  (b) Restriction on Transfer, Proxies and Non-Interference;
Restriction on Withdrawal. No Stockholder shall, directly or indirectly: (i)
except pursuant to the terms of the Merger Agreement, the Offer and this
Agreement, offer for sale, sell, transfer, tender, pledge, encumber, assign or
otherwise dispose of (collectively, "Disposition"), enforce or permit the
execution of the provisions of any agreement with the Company whereby the
Company may be obligated to repurchase, or enter into any other contract, option
or other arrangement or understanding with respect to, or otherwise consent to
the Disposition of any or all of such Stockholder's Shares, Stock Options or
Option Shares or any interest therein; (ii) except as contemplated hereby, grant
any proxies or powers of attorney, deposit any Shares, Stock Options or Option
Shares into a voting trust or enter into a voting agreement with respect to any
Shares, Stock Options or Option Shares; or (iii) take any action that would make
any representation or warranty of such









                                       7
<PAGE>   8
Stockholder contained herein untrue or incorrect or have the effect of
preventing or disabling such Stockholder from performing such Stockholder's
obligations under this Agreement.

                  (c) Waiver of Appraisal and Dissenter's Rights. Each
Stockholder hereby waives any rights of appraisal or rights to dissent from the
Merger that such Stockholder may have.

                  5. Option. (a) Each Stockholder, severally as to itself and
not jointly, hereby grants to Purchaser an irrevocable option (the "Option") to
purchase (i) such Stockholder's Shares and (ii) all Option Shares underlying all
of such Stockholder's Stock Options, in each case on the terms and subject to
the conditions set forth herein.

                  (b) The Option may be exercised by Purchaser, as a whole with
respect to all Shares and not in part, at any time and from time to time from
and after any time when the Merger Agreement is terminated in accordance with
its terms and prior to the Termination Date, subject to the conditions set forth
in Section 5(f). In addition, the Option may be exercised by Purchaser, as a
whole with respect to all Option Shares and not in part, at any time and from
time to time following the earlier to occur of (i) Purchaser's purchase of any
Shares pursuant to the Offer and (ii) any time when the Merger Agreement is
terminated in accordance with its terms and prior to the Termination Date, in
each case subject to the conditions set forth in Section 5(f).

                  (c) If Purchaser wishes to exercise the Option, Purchaser
shall send a written notice (the "Option Notice") to each Stockholder of its
intention to exercise the Option, specifying the place, and, if then known, the
time and the date (the "Closing Date") of the closing (the "Closing") of the
purchase. The Closing Date shall occur on the third business day after the date
on which such notice is delivered.










                                       8
<PAGE>   9





                  (d) At the Closing, each Stockholder shall deliver to
Purchaser (or its designee) all of such Stockholder's Shares and Option Shares,
as the case may be, required to be delivered pursuant to the Option Notice by
delivery of the Shares and the Option Shares, as the case may be, duly endorsed
to Purchaser or accompanied by stock powers duly executed in favor of Purchaser,
with all necessary stock transfer stamps affixed; it being understood and agreed
that to the extent any Stockholder is required to exercise his Stock Options in
order to deliver the Option Shares to Purchaser, such Stockholder will exercise
such Stock Options in accordance with their terms.

                  (e) At the Closing, Purchaser shall pay, and Parent shall
cause Purchaser to pay, to each Stockholder, by wire transfer in immediately
available funds to an account specified by such Stockholder in writing no more
than two days prior to the Closing, an amount equal to the product of the Merger
Consideration and the number of Shares and Option Shares purchased from such
Stockholder pursuant to the exercise of the Option.

                  (f) The Closing shall be subject to the satisfaction of each
of the following conditions:

                  (i) no court, arbitrator or governmental body, agency or
         official shall have issued any order, decree or ruling and there shall
         not be any statute, rule or regulation, restraining, enjoining or
         prohibiting the consummation of the purchase and sale of the Shares or
         the Option Shares, as the case may be, pursuant to the exercise of the
         Option;

                  (ii) any waiting period applicable to the consummation of the
         purchase and sale of the Shares or the Option Shares, as the case may
         be, pursuant to the exercise of the Option under the HSR Act shall have
         expired or been terminated; and










                                       9
<PAGE>   10





                  (iii) all actions by or in respect of, and any filing with,
         any governmental body, agency, official, or authority required to
         permit the consummation of the purchase and sale of the Shares pursuant
         to the exercise of the Option shall have been obtained or made and
         shall be in full force and effect.

                  6. Further Assurances. From time to time, at any party's
request and without further consideration, each other party shall execute and
deliver such additional documents and take all such further action as may be
necessary or desirable to consummate and make effective, in the most expeditious
manner practicable, the transactions contemplated by this Agreement.

                  7. Obligations Attach to Shares. Each Stockholder agrees that
this Agreement and the obligations hereunder shall attach to such Stockholder's
Shares and shall be binding upon any Person to which legal or beneficial
ownership of such Shares shall pass, whether by operation of law or otherwise;
it being understood and agreed that notwithstanding anything in this
Stockholders Agreement to the contrary, none of the provisions of this Agreement
(including, without limitation, any of the representations and warranties made
by such Stockholder) shall apply to any shares of Company Common Stock which are
beneficially owned by such Stockholder by virtue of such Stockholder's
participation in the BioWhittaker, Inc. Savings and Stock Investment Plan or by
virtue of such Stockholder's status as a trustee of such Plan.

                  8. Stop Transfer. Each Stockholder agrees with, and covenants
to, Parent that such Stockholder shall not request that the Company register the
transfer (book-entry or otherwise) of any certificate or uncertificated interest
representing any of such Stockholder's Shares, unless such transfer is made in
compliance with the Offer or this Agreement. Each Stockholder agrees, with
respect to any Shares in certificated form, that such Stockholder will submit to
the Company, within ten business days after the date hereof,









                                       10
<PAGE>   11





the certificates representing such Shares in order for the Company will inscribe
upon such certificates the following legend: "The shares of Common Stock, par
value $.0l per share, of BioWhittaker, Inc. (the "Company") represented by this
certificate are subject to a Stockholders Agreement dated as of August 22, 1997,
and may not be sold or otherwise transferred, except in accordance therewith.
Copies of such Agreement may be obtained at the principal executive offices of
the Company." Each Stockholder agrees that within ten business days after the
date hereof, such Stockholder will no longer hold any Shares, whether
certificated or uncertificated, in "street name" or in the name of any nominee.

                  9. Termination. This Agreement shall terminate upon the
earlier of (a) twelve months from the date hereof or (b) the Effective Time;
provided, however, that if the Company is not in breach of its obligations under
the Merger Agreement and none of the Stockholders are in breach of their
obligations under this Agreement, this Agreement shall terminate upon
termination of the Merger Agreement (a) pursuant to Section 6.1(a), 6.1(d),
6.1(f)(i) and 6.1(g) thereof, (b) pursuant to Section 6.1(b), 6.1(c) and 6.1(e)
thereof (in each case if no proposal for an Acquisition Transaction has been
made), or (c) by the Company pursuant to Section 6.1(f) thereof (unless a
proposal for an Acquisition Transaction has been made). The date of termination
of this Agreement is referred to herein as the "Termination Date".

                  10.      Miscellaneous.

                  (a) Entire Agreement; Assignment. This Agreement (i)
constitutes the entire agreement among the parties with respect to the subject
matter hereof and supersedes all other prior agreements and understandings, both
written and oral, among the parties with respect to the subject matter hereof
and (ii) shall not be assigned by operation of law or otherwise without the
prior written consent of (A) in the case of an assignment by a Stockholder,
Parent and (B) in









                                       11
<PAGE>   12
the case of an assignment by Parent or Purchaser, each Stockholder, provided
that Parent may in its sole discretion assign its rights and obligations
hereunder to any of its direct or indirect wholly-owned subsidiaries.

                  (b) Amendments. This Agreement may not be modified, amended,
altered or supplemented, except upon the execution and delivery of a written
agreement executed the parties hereto; provided, however, that Schedule A may be
supplemented by Parent without the agreement of any other party, by adding the
name and other relevant information concerning any stockholder of the Company
who agrees to be bound by the terms of this Agreement, and thereafter such added
stockholder shall be treated as a "Stockholder" for all purposes of this
Agreement.

                  (c) Notices. All notices and other communications under this
Agreement shall be in writing and shall be given (and shall be deemed to have
been duly given upon receipt) by delivery in person, facsimile, telex or other
standard form of telecommunications, by courier service, or by registered or
certified mail, postage prepaid, return receipt requested, addressed

                  If to Parent or Purchaser, to:

                           Cambrex Corporation
                           One Meadowlands Plaza
                           East Rutherford, New Jersey  07073
                           Facsimile No.: (201) 804-9851
                           Attention:  Peter Thauer, Esq.

                  With a copy to:

                           Debevoise & Plimpton
                           875 Third Avenue
                           New York New York  10022
                           Facsimile No.: (212) 909-6836
                           Attention:  Ralph Arditi, Esq.










                                       12
<PAGE>   13
                  If to a Stockholder, to such Stockholder's address
                  or facsimile number set forth in Schedule A
                  hereto,

or to such other address or facsimile number as the Person to whom notice is
given shall have previously furnished to the others in writing in the manner set
forth above.

                  (d) Governing Law. This Agreement shall be governed by and
construed in accordance with the laws of the State of Delaware without giving
effect to the conflicts of laws principles thereof.

                  (e) Enforcement. The parties agree that irreparable damage
would occur in the event that any of the provisions of this Agreement were not
performed in accordance with their specific terms or were otherwise breached.
It is accordingly agreed that the parties shall be entitled to an injunction or
injunctions to prevent breaches of this Agreement and to enforce specifically
the terms and provisions of this Agreement.

                  (f) Counterparts. This Agreement may be executed in one or
more counterparts, each of which shall be deemed to be an original, but all of
which when taken together shall constitute one and the same Agreement.

                  (g) Descriptive Headings. The descriptive headings used herein
are inserted for convenience of reference only and are not intended to be part
of or to affect the meaning or interpretation of this Agreement.

                  (h) Severability. Whenever possible, each provision or
portion of any provision of this Agreement will be interpreted in such manner as
to be effective and valid under applicable law but if any provision or portion
of any provision of this Agreement is held to be invalid, illegal or
unenforceable in any respect under any applicable law or rule in any
jurisdiction, such invalidity, illegality or unenforceability will not affect
any other provision or









                                       13
<PAGE>   14
portion of any provision in such jurisdiction, and this Agreement will be
reformed, construed and enforced in such jurisdiction as if such invalid,
illegal or unenforceable provision or portion of any provision had never been
contained herein.

                  (i) Definitions; Construction. For purposes of this Agreement:

                  (i) "beneficially own" or "beneficial ownership" with respect
         to any securities shall mean having "beneficial ownership" of such
         securities (as determined pursuant to Rule 13d-3 under the Exchange
         Act), including pursuant to any agreement, arrangement or
         understanding, whether or not in writing. Without duplicative counting
         of the same securities by the same holder, securities beneficially
         owned by a Person shall include securities beneficially owned by all
         other Persons with whom such Person would constitute a "group" as
         described in Section 13(d)(3) of the Exchange Act.

                  (iv) "Person" shall mean an individual, corporation,
         partnership, limited liability company, joint venture, association,
         trust, unincorporated organization or other entity.

                  (v) In the event of a stock dividend or distribution, or any
         change in the Company Common Stock by reason of any stock dividend,
         split-up, recapitalization, combination, exchange of shares or the
         like, the term "Shares" shall be deemed to refer to and include the
         Shares as well as all such stock dividends and distributions and any
         shares into which or for which any or all of the Shares may be changed
         or exchanged.









                                       14
<PAGE>   15





                  IN WITNESS WHEREOF, Parent, Purchaser and each Stockholder
have caused this Agreement to be duly executed as of the day and year first
above written.

                                            CAMBREX CORPORATION


                                            BY:  /s/ Peter Tracey
                                                 ____________________
                                                 Name: Peter Tracey
                                                 Title: Executive Vice President



                                            BW ACQUISITION CORPORATION


                                            BY:  /s/ Peter E. Thauer
                                                 ____________________
                                                 Name: Peter E. Thauer
                                                 Title: Vice President

                                            /s/ Noel Buterbaugh
                                            -------------------------
                                            Noel Buterbaugh

                                            /s/ Mrs. Noel Buterbaugh
                                            -------------------------
                                            Mrs. Noel Buterbaugh

                                            /s/ Thomas Winkler
                                            -------------------------
                                            Thomas Winkler

                                            /s/ Philip Rohrer
                                            -------------------------
                                            Philip Rohrer

                                            /s/ Leif Olsen
                                            -------------------------
                                            Leif Olsen










<PAGE>   16
                                            /s/ Dudley Staples
                                            -------------------------
                                            Dudley Staples

                                            /s/ Joseph Alibrandi
                                            -------------------------
                                            Joseph Alibrandi










                                     
<PAGE>   17
                                                                      Schedule A












<TABLE>
<CAPTION>
                 Officer/Director                        Shares Owned                 Stock Options Owned
                 ----------------                        ------------                 -------------------
                                                                             Substitute                  Subsequent Stock
                                                          Stock Owned          Stock                      Options/Director
                                                           Directly            Options                        Options
<S>                                                   <C>                 <C>                             <C>    
Noel Buterbaugh                                              5,020(1)            94,055                          309,000
President & CEO
BioWhittaker, Inc.
8830 Biggs Ford Road
Walkersville, MD  21793-0127
Phone:     301-898-7025, ext. 2308
Fax:       301-845-6099

Thomas R. Winkler                                              500               31,873                          231,000
Executive Vice President
and Chief Operating Officer
BioWhittaker, Inc.
8830 Biggs Ford Road
Walkersville, MD  21793-0127
Phone:     301-898-7025, ext. 2310
Fax:       301-845-6099

Philip L. Rohrer                                             1,900                -----                          179,000
Vice President
and Chief Financial Officer
BioWhittaker, Inc.
8830 Biggs Ford Road
Walkersville, MD  21793-0127
Phone:     301-898-7025, ext. 2369
Fax:       301-845-1006

Leif Olsen                                                       0                -----                           33,000
Vice President Regulatory Affairs
BioWhittaker, Inc.
8830 Biggs Ford Road
Walkersville, MD  21793-0127
Phone:     301-898-7025, ext. 2313
Fax:       301-845-6452
</TABLE>











<PAGE>   18
<TABLE>
<CAPTION>
                 Officer/Director                       Shares Owned                 Stock Options Owned
                 ----------------                       ------------                 -------------------
                                                                              Substitute                    Subsequent Stock
                                                         Stock Owned             Stock                      Options/Director
                                                          Directly              Options                          Options
<S>                                                   <C>                 <C>                             <C>    
F. Dudley Staples, Jr.                                           0                -----                           28,000
Secretary and General Counsel
BioWhittaker, Inc.
8830 Biggs Ford Road
Walkersville, MD  21793-0127
Phone:     301-898-7025, ext. 2362
Fax:       301-845-1006

Joseph F. Alibrandi                                        701,052                -----                            5,000
Chairman, BioWhittaker, Inc.
Whittaker Corporation
1955 N. Surveyor Avenue
Simi Valley, CA  93063
Phone:     805-584-4140
Fax:       805-526-1082
</TABLE>


(1)     720 shares are jointly owned by Mr. Buterbaugh's wife.











                                       2

<PAGE>   1
August 18, 1997                                REVISED



      [Name]
BioWhittaker, Inc.
8830 Biggs Ford Road
Walkersville, MD  21793


As discussed with you on July 22, 1997 it is our intention to provide the
following primary terms and conditions of employment after completion of the
acquisition by Cambrex of BioWhittaker. We acknowledge that you have entered
into a Change of Control Employment Agreement with BioWhittaker, Inc. and that
the terms and conditions described below apply to the extent they are not
covered by the Change of Control agreement and upon the expiration of the
agreement.

1. You will be employed by BioWhittaker as [title] having responsibility for
_____________________________, reporting directly to ______________of
BioWhittaker, Inc.

2. Your annual salary will be at a rate of $___________. All salary changes
above $100,000/year are subject to approval of the Compensation Committee of the
Cambrex Corporation Board of Directors. Salary levels are generally reviewed
annually. You will also be eligible to participate in the Cambrex Earnings
Improvement Program at a _______ of salary target level. This plan is currently
based on improvement in net income and ROI of both Cambrex and BioWhittaker and
can pay annual bonuses from 0% up to a maximum of 100% of salary subject to
approval by the Compensation Committee. It is agreed that for 1998 you will
receive a guaranteed minimum EIP bonus equal to your current bonus target award
under the BioWhittaker 1997 Management Incentive Compensation Plan.

3. You will be granted, subject to approval by the Cambrex Board of Directors,
an option to purchase ___________ shares of Cambrex Corporation subject to the
terms and conditions of Cambrex's 1996 Performance Stock Option Plan. The
purchase price per share will be set based on the closing price of Cambrex
common stock on the date of the merger with Cambrex. It is anticipated that
these shares will vest at $65, $70 and $75 per the conditions set out in the
option agreement.

4. You will continue to be entitled to participate and receive benefits under
the existing welfare benefits plans (including, medical, prescription, dental,
disability, life insurance
<PAGE>   2
Page 2
    [Name]
August 18, 1997


etc.) or similar plans under Cambrex which in the aggregate will provide a
similar quality of benefits.

5. Based on Plan provisions, you will be entitled to any accrued benefits under
the BioWhittaker defined contribution plans (retirement plans), [SERP] and
Savings Plan. Cambrex intends to recognize any liability for your benefits that
have accrued under the [BioWhittaker, Inc. Supplemental Executive Retirement
Plan], whether or not funded, that have accrued as of the date of the merger.
Cambrex will review with you the desirability of implementing after the merger
of the two companies Cambrex's defined benefit, Savings and SERP plans for
BioWhittaker employees.

6. You will continue to receive your current automobile allowance and other
reasonable fringe benefits provided by the company.

7. Any termination of your employment by Cambrex (not including death,
disability, or retirement), other than for Cause, shall result in a severance
payment equal to your monthly base salary for up to twelve months, from your
date of separation or until you secure other employment, whichever occurs
sooner. For the purposes of this provision, the term "Cause" shall mean:

         (i) the willful and continued failure of the Executive to perform
substantially the Executive's duties with the Company or one of its affiliates
(other than any such failure resulting from incapacity due to physical or mental
illness), after a written demand for substantial performance is delivered to the
Executive by the Chief Executive Officer or his designee of Cambrex Corporation,
which specifically identifies the manner in which the Chief Executive Officer
believes that the Executive has not substantially performed the Executive's
duties, or

         (ii) the willful engaging by the Executive in illegal conduct or gross
misconduct which is demonstrably injurious to the Company,

         (iii) commission of an intentional act of fraud, embezzlement or theft
by the Executive in connection with the Executive's duties or in the course of
the Executive's employment,

         (iv) causing intentional, wrongful damage to property of the Company,

         (v) intentionally and wrongfully disclosing secret processes or other
material confidential information of the Company or its customers, or
<PAGE>   3
Page 3
     [Name]
August 18, 1997


         (vi) participating without the Company's consent in the management of
any business enterprise which engages in substantial and direct competition with
the Company.

8. You agree that you are expected to play a prominent role in the development
of the BioWhittaker, Inc. business and will obtain confidential information and
trade secrets about the business. Therefore, it is a condition to Cambrex's
obligations under the Agreement and Plan of Merger Among Cambrex Corporation, BW
Acquisition Corporation and BioWhittaker, Inc. that you are bound by the
provisions of this Section 8.

You agree that during your employment with BioWhittaker, Inc. and during the two
year period following your termination for any reason (the "Restriction
Period"), you will not become associated with any entity, whether as a
principal, partner, employee, consultant or shareholder (other than as a holder
of not in excess of 1% of the outstanding voting shares of any publicly traded
company), that is actively engaged in any geographic area in any business which
is in competition with the business of BioWhittaker, Inc.

If you seek employment with a company which has several divisions, only certain
of which are competitive with BioWhittaker, Inc. and you seek employment with a
division which would not be deemed competitive with BioWhittaker, Inc., then you
may accept such employment, provided that the new employer is informed of the
restriction on your duties.

Whether any entity competes with BioWhittaker, Inc. shall be determined in good
faith by the Compensation Committee of the Board of Directors of Cambrex. Such
determination shall be made within 10 business days after receipt by an officer
of Cambrex of a written request for such a determination.

You agree that during the Restriction Period, you will not directly or
indirectly induce any employee of BioWhittaker, Inc. or any of its affiliates to
terminate employment with such entity, and will not directly or indirectly,
either individually or as owner, agent, employee, consultant or otherwise,
employ or offer employment to any person who is or was employed by BioWhittaker,
Inc. or an affiliate thereof, unless such person shall have ceased to be
employed by such entity for a period of at least 6 months.

You agree that during the Restriction Period, you will not, directly or
indirectly, solicit for yourself or for your benefit, any person, entity or
corporation which was a customer, client or distributor of BioWhittaker, Inc. at
any time during the Restriction Period, other than any such solicitation as part
of your responsibilities during your employment with
<PAGE>   4
Page 4
     [Name]
August 18, 1997


BioWhittaker, Inc. or any such solicitation that does not compete with any of
the sales or product lines of BioWhittaker, Inc.

The provisions of this paragraph 8 shall survive the termination of your
employment.

It is our intent that the compensation and benefits package provided to you be
similar in aggregate to your current arrangements. If you would like to discuss
this further, please contact me directly.

This agreement supersedes and replaces the agreement between Cambrex and
yourself dated July 29, 1997.

_________, we look forward to working with you to continue BioWhittaker's
profitable growth.

Sincerely,

/s/ Steven M. Klosk                             Agreed and Accepted:

Steven M. Klosk                                 /s/                     8/19/97
                                                -------------------------------
Executive Vice President - Administration       [Name of Executive]      Date

<PAGE>   1
CAMBREX CORPORATION
One Meadowlands Plaza
East Rutherford, NJ 07073
Tel: (201) 804-3000  Fax: (201) 804-9852
         August 18, 1997




                                     REVISED


Mr. Noel L. Buterbaugh
BioWhittaker, Inc.
8830 Biggs Ford Road
Walkersville, MD  21793


Dear Noel:

As discussed with you on July 22, 1997 it is our intention to provide the
following primary terms and conditions of employment after completion of the
acquisition by Cambrex of BioWhittaker:

1. You will be employed by BioWhittaker as President & CEO having full
responsibility for the business operations and reporting directly to the
President & CEO of Cambrex Corporation. As discussed, it is your intention and
our desire for you to continue in this role for the next one-two years and to
consider a possible consulting arrangement after your retirement from full-time
employment. It is your intention and our understanding that you may be retiring
prior to the contemplated two years, if the projected SERP Retirement Benefit is
less than the benefit that would have been received as of the date of the
acquisition.

2. Your annual salary will be at a rate of $270,005. All salary changes above
$100,000/year are subject to approval of the Compensation Committee of the
Cambrex Corporation Board of Directors. Salary levels are generally reviewed
annually. You will also be eligible to participate in the Cambrex Earnings
Improvement Program (EIP) at 40% of salary target level. This plan is currently
based on improvement in net income and ROI of both Cambrex and BioWhittaker and
can pay annual bonuses from 0% up to a maximum of 100% of salary subject to
approval by the Compensation Committee. It is agreed that for 1998 you will
receive a guaranteed minimum EIP bonus equal to your current bonus target award
under the BioWhittaker 1997 Management Incentive Compensation Plan.
<PAGE>   2
Page 2
Mr. Noel L. Buterbaugh
August 18, 1997


3. You will be granted, subject to approval by the Cambrex Board of Directors,
an option to purchase 25,000 shares of Cambrex Corporation subject to the terms
and conditions of Cambrex's 1996 Performance Stock Option Plan. The purchase
price per share will be set based on the closing price of Cambrex common stock
on the date of the merger with Cambrex. It is anticipated that these shares will
vest at $65, $70 and $75 per the conditions set out in the option agreement, or
the option will vest 100% two years after the date of grant subject to your
continued employment with BioWhittaker/Cambrex (or sooner if necessary, to
coincide with your retirement plans).

4. You will continue to be entitled to participate and receive benefits under
the existing welfare benefits plans (including, medical, prescription, dental,
disability, life insurance etc.) or similar plans under Cambrex, which in the
aggregate will provide a similar quality of benefits.

5. Based on Plan provisions, you will be entitled to any accrued benefits under
the BioWhittaker defined contribution plans (retirement plans), SERP and Savings
Plan. Cambrex intends to recognize any liability for your benefits that have
accrued under the BioWhittaker, Inc. Supplemental Executive Retirement Plan,
whether or not funded, that have accrued as of the date of the merger.

Cambrex will review with you the desirability of implementing after the merger
of the two companies Cambrex's defined benefit, Savings and SERP plans for
BioWhittaker employees.

6. You will continue to receive your current automobile allowance and other
reasonable fringe benefits provided by the company.

7. Any termination of your employment by Cambrex (not including death,
disability, or retirement), other than for Cause shall result in a severance
payment equal to your monthly base salary for up to twelve months, from your
date of separation or until you secure other employment, whichever occurs
sooner. For the purposes of this provision, the term "Cause" shall mean:
<PAGE>   3
Page 3
Mr. Noel L. Buterbaugh
August 18, 1997


         (i) the willful and continued failure of the Executive to perform
substantially the Executive's duties with the Company or one of its affiliates
(other than any such failure resulting from incapacity due to physical or mental
illness), after a written demand for substantial performance is delivered to the
Executive by the Chief Executive Officer or his designee of Cambrex Corporation,
which specifically identifies the manner in which the Chief Executive Officer
believes that the Executive has not substantially performed the Executive's
duties, or

         (ii) the willful engaging by the Executive in illegal conduct or gross
misconduct which is demonstrably injurious to the Company,

         (iii) commission of an intentional act of fraud, embezzlement or theft
by the Executive in connection with the Executive's duties or in the course of
the Executive's employment,

         (iv) causing intentional, wrongful damage to property of the Company,

         (v) intentionally and wrongfully disclosing secret processes or other
material confidential information of the Company or its customers, or

         (vi) participating without the Company's consent in the management of
any business enterprise which engages in substantial and direct competition with
the Company.

8. You agree that you are expected to play a prominent role in the development
of the BioWhittaker, Inc. business and will obtain confidential information and
trade secrets about the business. Therefore, it is a condition to Cambrex's
obligations under the Agreement and Plan of Merger Among Cambrex Corporation, BW
Acquisition Corporation and BioWhittaker, Inc. that you are bound by the
provisions of this Section 8.
<PAGE>   4
Page 4
Mr. Noel L. Buterbaugh
August 18, 1997


You agree that during your employment with BioWhittaker, Inc. and during the two
year period following your termination for any reason (the "Restriction
Period"), you will not become associated with any entity, whether as a
principal, partner, employee, consultant or shareholder (other than as a holder
of not in excess of 1% of the outstanding voting shares of any publicly traded
company), that is actively engaged in any geographic area in any business which
is in competition with the business of BioWhittaker, Inc.

If you seek employment with a company which has several divisions, only certain
of which are competitive with BioWhittaker, Inc. and you seek employment with a
division which would not be deemed competitive with BioWhittaker, Inc., then you
may accept such employment, provided that the new employer is informed of the
restriction on your duties.

Whether any entity competes with BioWhittaker, Inc. shall be determined in good
faith by the Compensation Committee of the Board of Directors of Cambrex. Such
determination shall be made within 10 business days after receipt of notice by
an officer of Cambrex for such a determination.

You agree that during the Restriction Period, you will not directly or
indirectly induce any employee of BioWhittaker, Inc. or any of its affiliates to
terminate employment with such entity, and will not directly or indirectly,
either individually or as owner, agent, employee, consultant or otherwise,
employ or offer employment to any person who is or was employed by BioWhittaker,
Inc. or an affiliate thereof, unless such person shall have ceased to be
employed by such entity for a period of at least 6 months.

You agree that during the Restriction Period, you will not, directly or
indirectly, solicit for yourself or for your benefit, any person, entity or
corporation which was a customer, client or distributor of BioWhittaker, Inc. at
any time during the Restriction Period, other than any such solicitation as part
of your responsibilities during your employment with BioWhittaker, Inc. or any
such solicitation that does not compete with any of the sales or product lines
of BioWhittaker, Inc.
<PAGE>   5
Page 5
Mr. Noel L. Buterbaugh
August 18, 1997


The provisions of this paragraph 8 shall survive the termination of your
employment.

It is our intent that the compensation and benefits package provided to you be
similar in aggregate to your current arrangements. If you would like to discuss
this further, please contact me directly.

This agreement supersedes and replaces the agreement between Cambrex and
yourself dated July 29, 1997.

Noel, we look forward to working with you to continue BioWhittaker's profitable
growth.

Sincerely,

                                                 Agreed and Accepted:

Steven M. Klosk                                  /s/                    8-19-97
Executive Vice President - Administration        ------------------------------
                                                 Noel L. Buterbaugh      Date

<PAGE>   1
 
                                                                       Exhibit 6
 
                              ASSUMPTION AGREEMENT
 
     WHEREAS, certain change of control employment agreements dated March 11,
1997 were entered into by and between BioWhittaker, Inc. ("BioWhittaker") and
Messrs. Thomas Winkler, Philip L. Rohrer, Jr., Leif Olsen and F. Dudley Staples,
Jr., each of whom is an executive office of BioWhittaker (the "Agreements"); and
 
     WHEREAS, BioWhittaker has entered into an Agreement and Plan of Merger,
dated August 22, 1997, with Cambrex Corporation ("Cambrex") and BW Acquisition
Corporation, a wholly owned subsidiary of Cambrex ("BW Acquisition") (the "Plan
of Merger"), pursuant to which BW Acquisition will be merged into BioWhittaker
following the completion of a tender offer as described in the Plan of Merger
(the "Tender Offer"), and BioWhittaker shall be the surviving company as a
wholly owned subsidiary of Cambrex (the "Surviving Company").
 
     NOW THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, the parties agree as follows:
 
          1.  Cambrex hereby agrees to cause the Surviving Company, pursuant to
     Section 11(c) of the Agreements, to, and the Surviving Company shall,
     assume expressly the obligations of BioWhittaker under the Agreements and
     perform such obligations in the same manner and to the same extent as
     BioWhittaker would be required to perform them if no such succession had
     taken place effective as of immediately following the effective date of the
     merger as defined in the Plan of Merger.
 
          2.  This Assumption Agreement may be executed in two or more
     counterparts each of which shall be deemed to constitute an original, but
     such counterparts together shall be deemed to be one and the same
     instrument and to become effective when one or more counterparts have been
     signed by each of the parties hereto. It shall not be necessary in making
     proof of this Agreement or any counterpart hereof to produce or account for
     the other counterpart.
<PAGE>   2
 
     IN WITNESS HEREOF, the parties hereto, intending to be legally bound, have
caused this Assumption of Obligations Under Change in Control Employment
Agreements to be executed by their duly authorized representatives as of August
22, 1997.
 
                                        BIOWHITTAKER, INC.
 
                                                     By:
 
                                                 Print Name:
 
                                                   Title:
 
                                                    Date:
 
                                        CAMBREX CORPORATION
 
                                                     By:
 
                                                 Print Name:
 
                                                   Title:
 
                                                    Date:
 
                                        BW ACQUISITION CORPORATION
 
                                                     By:
 
                                                 Print Name:
 
                                                   Title:
 
                                                    Date:


© 2022 IncJournal is not affiliated with or endorsed by the U.S. Securities and Exchange Commission