CARDINAL HEALTH INC
424B3, 1997-02-19
DRUGS, PROPRIETARIES & DRUGGISTS' SUNDRIES
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<PAGE>   1
                                             As Filed Pursuant to Rule 424(b)(3)
                                             Registration No. 333-21631


 
                            [Owen Healthcare Logo]             February 17, 1997
 
Dear Fellow Shareholder:
 
     You are cordially invited to attend a Special Meeting of Shareholders of
Owen Healthcare, Inc. ("Owen") to be held at 9800 Centre Parkway, Suite 1100,
Houston, Texas, on Tuesday, March 18, 1997, at 10:00 a.m., local time.
 
     At the Special Meeting you will be asked to vote on a proposal to approve
an Agreement and Plan of Merger, dated as of November 27, 1996 (the "Merger
Agreement"), providing for the merger (the "Merger") of a wholly owned
subsidiary of Cardinal Health, Inc. ("Cardinal") with and into Owen. Upon
consummation of the Merger, Owen will become a wholly owned subsidiary of
Cardinal, and Owen shareholders will be entitled to receive for each share of
Owen common stock a fraction of a common share of Cardinal equal to $27.25
divided by the average share price of the Cardinal common shares prior to the
Special Meeting calculated as described in the accompanying Proxy
Statement/Prospectus (the "Exchange Ratio"), provided that, except in certain
limited circumstances specified in the Merger Agreement, the Exchange Ratio will
be no more than 0.4974 and no less than 0.4500.
 
     DETAILED INFORMATION REGARDING THE MERGER, THE MERGER AGREEMENT, CARDINAL
AND OWEN IS SET FORTH IN THE ACCOMPANYING PROXY STATEMENT/PROSPECTUS AND THE
ANNEXES THERETO, WHICH YOU ARE URGED TO READ CAREFULLY IN THEIR ENTIRETY.
 
     FOR THE REASONS SET FORTH IN THE PROXY STATEMENT/PROSPECTUS, YOUR BOARD OF
DIRECTORS HAS DETERMINED THAT THE TERMS OF THE MERGER AGREEMENT AND THE
TRANSACTIONS CONTEMPLATED THEREBY ARE FAIR TO, AND IN THE BEST INTERESTS OF,
OWEN AND ITS SHAREHOLDERS AND RECOMMENDS THAT OWEN SHAREHOLDERS VOTE FOR THE
APPROVAL OF THE MERGER AGREEMENT.
 
     In connection with its approval of the transaction with Cardinal, the Board
of Directors of Owen has received written opinions dated November 27, 1996, from
each of its financial advisors, Smith Barney Inc. ("Smith Barney") and Rauscher
Pierce Refsnes, Inc. ("RPR"), to the effect that, as of such date and based upon
and subject to certain matters stated in such opinions, the Exchange Ratio was
fair, from a financial point of view, to the Owen shareholders. Copies of the
written opinions of Smith Barney and RPR dated November 27, 1996, each of which
sets forth a description of the assumptions made, matters considered and
limitations on the review undertaken, are attached to the accompanying Proxy
Statement/Prospectus as Annexes B and C, respectively, and should be read
carefully in their entirety.
 
     Approval of the Merger Agreement and the Merger requires the affirmative
vote of the holders of two-thirds of the outstanding shares of Owen common
stock. Each of the directors of Owen, who as of February 10, 1997 beneficially
owned in the aggregate approximately 22% of the outstanding Owen common stock,
has agreed to vote or direct the vote of all Owen common stock over which they
or their affiliates have voting power or control in favor of the Merger
Agreement and the Merger.
 
     In view of the importance of the action to be taken at this important
Special Meeting of Owen shareholders, we urge you to review carefully the
accompanying Proxy Statement/Prospectus. Whether or not you expect to attend the
Special Meeting, please complete, sign and date the enclosed proxy card and
return it as promptly as possible to ensure that your shares are voted at the
Special Meeting. Failure to vote will have the same effect as a vote against
approval of the Merger Agreement.
 
     If you have any questions about the Merger, please call Morrow & Co., which
is assisting with the solicitation of the proxies, at (800) 607-0088.
 
                                       Sincerely,
 
                                       /s/ Dian G. Owen
                                       DIAN G. OWEN
                                       Chairperson of the Board
<PAGE>   2
 
                             OWEN HEALTHCARE, INC.
 
                              9800 Centre Parkway
                                   Suite 1100
                           Houston, Texas 77036-8279
                            ------------------------
 
                   NOTICE OF SPECIAL MEETING OF SHAREHOLDERS
 
                           TO BE HELD MARCH 18, 1997
                            ------------------------
 
To the Shareholders of
Owen Healthcare, Inc.:
 
     NOTICE IS HEREBY GIVEN that a Special Meeting of Shareholders of Owen
Healthcare, Inc., a Texas corporation ("Owen"), will be held on Tuesday, March
18, 1997, at 10:00 a.m., local time, at 9800 Centre Parkway, Suite 1100,
Houston, Texas, for the following purposes:
 
          1. To consider and vote on a proposal (the "Merger Proposal") to
     approve the Agreement and Plan of Merger, dated as of November 27, 1996
     (the "Merger Agreement"), by and among Owen, Cardinal Health, Inc., an Ohio
     corporation ("Cardinal"), and Owl Merger Corp., a Texas corporation and a
     wholly owned subsidiary of Cardinal ("Subcorp"), pursuant to which, among
     other things, (i) Subcorp will be merged with and into Owen (the "Merger")
     with the result that Owen will become a wholly owned subsidiary of
     Cardinal, and (ii) each outstanding share (other than shares held in the
     treasury of Owen, if any, which will be cancelled) of Owen common stock, no
     par value ("Owen Common Stock"), will be converted into a fraction of a
     Cardinal common share, without par value, as determined pursuant to the
     share exchange formula set forth in the Merger Agreement. A copy of the
     Merger Agreement is attached as Annex A to the accompanying Proxy
     Statement/Prospectus.
 
          2. To transact such other business as may properly come before the
     meeting or any adjournment or postponement thereof.
 
     The Board of Directors has fixed the close of business on February 10,
1997, as the record date for the determination of the holders of Owen Common
Stock entitled to notice of, and to vote at, the Special Meeting and any
adjournments or postponements thereof. A list of the shareholders entitled to
vote at the Special Meeting will be kept on file for a period of 10 days prior
to the Special Meeting at the principal offices of Owen, and will be available
for inspection by any shareholder during normal business hours for such period
and at the Special Meeting. Owen shareholders will not be entitled to
dissenters' or appraisal rights under Texas law or any other statute in
connection with the Merger.
 
     Information regarding the Merger and related matters is contained in the
accompanying Proxy Statement/Prospectus and the Annexes thereto, which are
incorporated by reference herein and form a part of this Notice.
 
     YOUR VOTE IS IMPORTANT. THE MERGER PROPOSAL REQUIRES THE AFFIRMATIVE VOTE
OF THE HOLDERS OF TWO-THIRDS OF THE OUTSTANDING SHARES OF OWEN COMMON STOCK
ENTITLED TO VOTE AT THE SPECIAL MEETING. WHETHER OR NOT YOU PLAN TO ATTEND THE
SPECIAL MEETING, PLEASE COMPLETE, SIGN AND DATE THE ENCLOSED PROXY CARD (OR
VOTING INSTRUCTION CARD WITH RESPECT TO ANY INTEREST IN OWEN'S EMPLOYEE STOCK
OWNERSHIP PLAN) AND RETURN IT PROMPTLY IN THE ENCLOSED ENVELOPE. IF YOU DO
ATTEND THE SPECIAL MEETING AND WISH TO VOTE IN PERSON, YOU MAY WITHDRAW YOUR
PROXY AND VOTE IN PERSON. FAILURE TO VOTE, HOWEVER, WILL HAVE THE SAME EFFECT AS
A VOTE AGAINST THE MERGER.
 
     FOR THE REASONS SET FORTH IN THE PROXY STATEMENT/PROSPECTUS, YOUR BOARD OF
DIRECTORS HAS DETERMINED THAT THE TERMS OF THE MERGER AGREEMENT AND THE
TRANSACTIONS CONTEMPLATED THEREBY ARE FAIR TO, AND IN THE BEST INTERESTS OF,
OWEN AND ITS SHAREHOLDERS AND RECOMMENDS THAT YOU VOTE FOR THE APPROVAL OF THE
MERGER AGREEMENT.
 
                                         By Order of the Board of Directors
 
                                         /s/ Stephen A. Drury
                                         STEPHEN A. DRURY
                                         Executive Vice President and Corporate
                                         Secretary
 
Houston, Texas
February 17, 1997
 
            PLEASE DO NOT SEND ANY SHARE CERTIFICATES AT THIS TIME.
<PAGE>   3


 
[Cardinal Health Logo]                                    [Owen Healthcare Logo]
                             OWEN HEALTHCARE, INC.
 
                                PROXY STATEMENT
                            ------------------------
 
                             CARDINAL HEALTH, INC.
                                   PROSPECTUS
                            ------------------------
 
     This Proxy Statement/Prospectus is being furnished to holders of shares of
common stock, without par value ("Owen Common Stock"), of Owen Healthcare, Inc.,
a Texas corporation ("Owen"), in connection with the solicitation of proxies by
the Board of Directors of Owen for use at the Special Meeting of Owen
Shareholders to be held on Tuesday, March 18, 1997, at 9800 Centre Parkway,
Suite 1100, Houston, Texas, commencing at 10:00 a.m., local time, and at any
adjournment or postponement thereof (the "Special Meeting").
 
     At the Special Meeting, holders of Owen Common Stock ("Owen Shareholders")
as of the close of business on the Record Date (as hereinafter defined) will be
asked to consider and vote on a proposal to approve the Agreement and Plan of
Merger, dated as of November 27, 1996 (the "Merger Agreement"), providing for
the merger (the "Merger") of Owl Merger Corp. ("Subcorp"), a Texas corporation
and a wholly owned subsidiary of Cardinal Health, Inc., an Ohio corporation
("Cardinal"), with and into Owen. The Merger will be consummated on the terms
and subject to the conditions set forth in the Merger Agreement, as a result of
which (i) Owen will become a wholly owned subsidiary of Cardinal and (ii) Owen
Shareholders will be entitled to receive a fraction of a Cardinal Common Share,
without par value ("Cardinal Common Share"), for each outstanding share of Owen
Common Stock held by them (with cash in lieu of fractional shares) calculated by
dividing $27.25 by the average share price of the Cardinal Common Shares prior
to the Special Meeting calculated as described herein (the "Exchange Ratio"),
provided that, except in certain limited circumstances specified in the Merger
Agreement, the Exchange Ratio will be no more than 0.4974 and no less than
0.4500. For example, if the average share price of the Cardinal Common Shares is
$61.75 (the last sale price of Cardinal Common Shares on February 12, 1997), the
Exchange Ratio will be 0.4500. Under the Merger Agreement, the definitive
Exchange Ratio will be determinable after the close of trading on the sixth
trading day prior to the Special Meeting, at which time Owen Shareholders may
call Morrow & Co. at (800) 607-0088, to obtain the definitive Exchange Ratio.
See "The Merger Agreement -- Merger Consideration."
 
     This Proxy Statement/Prospectus also constitutes the Prospectus of Cardinal
with respect to the Cardinal Common Shares to be issued by Cardinal in the
Merger described herein in exchange for the outstanding shares of Owen Common
Stock. Cardinal Common Shares are quoted on the New York Stock Exchange (the
"NYSE") under the symbol "CAH." On February 12, 1997, the last sale price of
Cardinal Common Shares on the NYSE Composite Tape was $61.75. Owen Common Stock
is quoted on the NYSE under the symbol "OWN." On February 12, 1997, the last
sale price of Owen Common Stock on the NYSE Composite Tape was $27.50. Owen
Shareholders should obtain current quotes for the Cardinal Common Shares and
Owen Common Stock.
THE SECURITIES TO BE ISSUED PURSUANT TO THIS PROXY STATEMENT/PROSPECTUS HAVE NOT
 BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND EXCHANGE COMMISSION OR ANY
 STATE SECURITIES COMMISSION NOR HAS THE SECURITIES AND EXCHANGE COMMISSION OR
  ANY STATE SECURITIES COMMISSION PASSED UPON THE ACCURACY OR ADEQUACY OF THIS
  PROXY STATEMENT/PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL
                                    OFFENSE.
 
     All information contained or incorporated by reference in this Proxy
Statement/Prospectus with respect to Cardinal has been supplied by Cardinal. All
information contained or incorporated by reference in this Proxy
Statement/Prospectus with respect to Owen has been supplied by Owen.
 
     This Proxy Statement/Prospectus, the Letter to Owen Shareholders, the
Notice of the Special Meeting and the form of proxy for use at the Special
Meeting are first being mailed to Owen Shareholders on or about February 18,
1997.
                            ------------------------
 
       The date of this Proxy Statement/Prospectus is February 12, 1997.
<PAGE>   4
 
     NO PERSON IS AUTHORIZED TO GIVE ANY INFORMATION OR TO MAKE ANY
REPRESENTATION NOT CONTAINED HEREIN OR IN THE DOCUMENTS INCORPORATED BY
REFERENCE HEREIN AND, IF GIVEN OR MADE, SUCH INFORMATION OR REPRESENTATION MUST
NOT BE RELIED UPON AS HAVING BEEN AUTHORIZED. THIS PROXY STATEMENT/PROSPECTUS
DOES NOT CONSTITUTE AN OFFER TO SELL OR A SOLICITATION OF AN OFFER TO BUY
SECURITIES, OR THE SOLICITATION OF A PROXY, IN ANY JURISDICTION IN WHICH OR TO
ANY PERSON TO WHOM IT IS UNLAWFUL TO MAKE SUCH OFFER OR SOLICITATION IN SUCH
JURISDICTION. NEITHER THE DELIVERY OF THIS PROXY STATEMENT/PROSPECTUS NOR ANY
DISTRIBUTION OF CARDINAL COMMON SHARES MADE HEREUNDER SHALL, UNDER ANY
CIRCUMSTANCES, CREATE ANY IMPLICATION THAT THERE HAS BEEN NO CHANGE IN THE
AFFAIRS OF CARDINAL OR OWEN SINCE THE DATE HEREOF OR THAT THE INFORMATION
CONTAINED OR INCORPORATED BY REFERENCE HEREIN IS CORRECT AS OF ANY TIME AFTER
THE DATE HEREOF.
 
                           FORWARD-LOOKING STATEMENTS
 
     This Proxy Statement/Prospectus includes and incorporates by reference
forward-looking statements based on current plans and expectations of Owen,
Cardinal and Subcorp, relating to, among other matters, analyses, including
opinions from independent financial advisors to Owen's Board of Directors as to
the fairness from a financial point of view of the Exchange Ratio to Owen
Shareholders, based upon forecasts of future results, and estimates of amounts
that are not yet determinable. Such forward-looking statements are contained in
the sections entitled "Summary," "The Merger," "Certain Federal Income Tax
Consequences," "The Companies" and other sections of this Proxy
Statement/Prospectus. Such statements involve risks and uncertainties which may
cause actual future activities and results of operations to be materially
different from that suggested in this Proxy Statement/Prospectus, including,
among others, fluctuations in Owen's and Cardinal's quarterly operating results,
Owen's and Cardinal's dependence on their current managements, potential
conflicts of interests of certain persons, competition in the pharmacy
management industry, as well as other factors described elsewhere in this Proxy
Statement/Prospectus.
 
                             AVAILABLE INFORMATION
 
     Each of Cardinal and Owen is subject to the informational requirements of
the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and in
accordance therewith files reports, proxy statements, and other information with
the Securities and Exchange Commission (the "Commission"). Such reports, proxy
statements, and other information filed by either Cardinal or Owen with the
Commission can be inspected and copied at the public reference facilities
maintained by the Commission at its principal office at 450 Fifth Street, N.W.,
Room 1024, Washington, D.C. 20549, and at the following Regional Offices of the
Commission: New York Regional Office, 7 World Trade Center, 13th Floor, New
York, New York 10048, and Chicago Regional Office, Citicorp Center, 500 West
Madison, Suite 1400, Chicago, Illinois 60661. Copies of such material can also
be obtained from the Public Reference Section of the Commission at 450 Fifth
Street, N.W., Washington, D.C. 20549 at prescribed rates, or, with respect to
certain of such material, through the Commission's World Wide Web site
(http://www.sec.gov). The Cardinal Common Shares and the Owen Common Stock are
listed on the NYSE, and such reports, proxy statements and other information
concerning Cardinal or Owen should also be available for inspection and copying
at the offices of the NYSE, 20 Broad Street, New York, New York 10005.
 
     Cardinal has filed with the Commission a Registration Statement on Form S-4
under the Securities Act of 1933, as amended (the "Securities Act"), with
respect to the Cardinal Common Shares to be issued in the Merger (the
"Registration Statement"). This Proxy Statement/Prospectus does not contain all
of the information set forth in the Registration Statement, certain parts of
which are omitted in accordance with the rules and regulations of the
Commission. Reference is hereby made to the Registration Statement and related
exhibits for further information with respect to Cardinal and the securities
offered hereby. Statements contained herein concerning the provisions of any
document are necessarily summaries of such documents and not complete and, in
each instance, reference is made to the copy of such document attached hereto or
filed as an exhibit to the Registration Statement or otherwise filed with the
Commission. Each such statement is qualified in its entirety by such reference.
 
     OWEN SHAREHOLDERS WHO HAVE ANY QUESTIONS ABOUT CALCULATING THE EXCHANGE
RATIO OR ABOUT EXECUTING, CHANGING OR REVOKING A PROXY SHOULD CONTACT MORROW &
CO., INC. AT (800) 607-0088.
 
                                        i
<PAGE>   5
 
                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE
 
     The following documents filed by Cardinal with the Commission pursuant to
the Exchange Act (Commission File No. 0-12591) are hereby incorporated by
reference in this Proxy Statement/Prospectus:
 
          1. The description of Cardinal Common Shares contained in Cardinal's
     Registration Statement on Form 8-A dated August 19, 1994, and any amendment
     or report filed for the purpose of updating such description;
 
          2. Cardinal's Annual Report on Form 10-K for the fiscal year ended
     June 30, 1996, filed with the Commission on August 26, 1996 (the "1996
     Cardinal Form 10-K");
 
          3. The information contained in Cardinal's Proxy Statement dated
     September 27, 1996 for its Annual Meeting of Shareholders held on October
     29, 1996 that has been incorporated by reference in the 1996 Cardinal Form
     10-K and was filed with the Commission on Schedule 14A on October 5, 1996;
     and
 
          4. Cardinal's Quarterly Reports on Form 10-Q for the quarters ended
     September 30, 1996 and December 31, 1996.
 
     The following documents filed by Owen with the Commission pursuant to the
Exchange Act (Commission File No. 0-26416) are hereby incorporated by reference
in this Proxy Statement/Prospectus:
 
          1. The description of Owen Common Stock contained in Owen's
     Registration Statement on Form 8-A filed with the Commission on May 21,
     1996, and any amendment or report filed for the purpose of updating such
     description;
 
          2. Owen's Annual Report on Form 10-K for the fiscal year ended
     November 30, 1996, filed with the Commission on February 11, 1997 (the
     "1995 Owen Form 10-K"); and
 
          3. The information contained in Owen's Proxy Statement dated March 8,
     1996 for its Annual Meeting of Shareholders held on April 9, 1996 that has
     been incorporated by reference in the 1995 Owen Form 10-K and was filed
     with the Commission on Schedule 14A on March 13, 1996.
 
     All reports and other documents filed with the Commission by Cardinal or
Owen pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after
the date of this Proxy Statement/Prospectus and prior to the Special Meeting
shall be deemed to be incorporated by reference herein and to be a part hereof
from the respective dates of filing of such reports and other documents. Any
statement contained herein or in a document incorporated or deemed to be
incorporated by reference herein shall be deemed to be modified or superseded
for all purposes to the extent that a statement contained herein or in any other
subsequently filed document that is also incorporated or deemed to be
incorporated by reference herein modifies or supersedes such statement. Any such
statement so modified or superseded shall not be deemed, except as so modified
or superseded, to constitute a part of this Proxy Statement/Prospectus.
 
     THIS PROXY STATEMENT/PROSPECTUS INCORPORATES DOCUMENTS BY REFERENCE WITH
RESPECT TO CARDINAL AND OWEN THAT ARE NOT PRESENTED HEREIN OR DELIVERED
HEREWITH. COPIES OF THESE DOCUMENTS (NOT INCLUDING EXHIBITS TO SUCH DOCUMENTS
UNLESS SUCH EXHIBITS ARE SPECIFICALLY INCORPORATED BY REFERENCE IN SUCH
DOCUMENTS OR HEREIN) ARE AVAILABLE WITHOUT CHARGE TO ANY PERSON TO WHOM THIS
PROXY STATEMENT/PROSPECTUS IS DELIVERED UPON WRITTEN OR ORAL REQUEST TO THE
FOLLOWING:
 
<TABLE>
<CAPTION>
              CARDINAL DOCUMENTS                             OWEN DOCUMENTS
    ---------------------------------------      ---------------------------------------
    <S>                                          <C>
    Cardinal Health, Inc.                        Owen Healthcare, Inc.
    5555 Glendon Court                           9800 Centre Parkway, Suite 1100
    Dublin, Ohio 43016                           Houston, Texas 77036-8279
    Attention: David Bearman                     Attention: Stephen A. Drury
               Executive Vice President          Executive Vice President
               and Chief Financial Officer       and Corporate Secretary
</TABLE>
 
     IN ORDER TO ENSURE TIMELY DELIVERY, ANY REQUEST FOR DOCUMENTS SHOULD BE
MADE BY MARCH 11, 1997.
 
                                       ii
<PAGE>   6
 
                               TABLE OF CONTENTS
<TABLE>
<CAPTION>
                                        PAGE
                                        -----
<S>                                     <C>
FORWARD-LOOKING STATEMENTS............      i
AVAILABLE INFORMATION.................      i
INCORPORATION OF CERTAIN DOCUMENTS BY
  REFERENCE...........................     ii
SUMMARY...............................      1
  The Companies.......................      1
  The Special Meeting.................      2
  The Merger..........................      2
  Certain Federal Income Tax
     Consequences.....................      9
  Comparison of Shareholder Rights....      9
  Recent Developments.................      9
  Summary Historical and Unaudited Pro
     Forma Financial Information......     10
COMPARATIVE PER SHARE DATA............     15
MARKET PRICE AND DIVIDEND DATA........     17
THE SPECIAL MEETING...................     18
  General.............................     18
  Matters to Be Considered at the
     Special Meeting..................     18
  Record Date; Vote Required; Voting
     at the Meeting...................     18
  Voting of Proxies...................     18
  Solicitation of Proxies.............     19
  Recommendation of the Owen Board of
     Directors........................     19
  Appraisal Rights....................     20
THE MERGER............................     20
  Background of the Merger............     20
  Reasons for the Merger;
     Recommendations of the Boards of
     Directors........................     22
  Opinions of Owen's Financial
     Advisors.........................     23
  Interests of Certain Persons in the
     Merger...........................     28
  Accounting Treatment................     29
  Regulatory Approvals................     30
  Federal Securities Law
     Consequences.....................     30
  Stock Option Agreement..............     31
  Support/Voting Agreements...........     33
THE MERGER AGREEMENT..................     34
  The Merger..........................     34
  Merger Consideration................     34
  Exchange Procedures.................     35
  Representations, Warranties and
     Covenants........................     35
  No Negotiations or Solicitations....     38
  Conditions..........................     40
 
<CAPTION>
                                        PAGE
                                        -----
<S>                                     <C>
  Owen Stock Options..................     41
  Employee Benefits...................     41
  Termination; Effect of
     Termination......................     41
  Amendment and Waiver................     42
  Expenses............................     42
CERTAIN FEDERAL INCOME TAX
  CONSEQUENCES........................     43
THE COMPANIES.........................     44
  Business of Cardinal................     44
  Subcorp.............................     45
  Business of Owen....................     45
COMPARISON OF SHAREHOLDER RIGHTS......     45
  Amendment of Charter Documents......     45
  Amendment and Repeal of Bylaws and
     Regulations......................     46
  Removal of Directors................     46
  Vacancies on the Board..............     46
  Right to Call Special Meeting of
     Shareholders.....................     47
  Shareholder Action Without a
     Meeting..........................     47
  Class Voting........................     47
  Cumulative Voting...................     47
  Provisions Affecting Control Share
     Acquisitions and Business
     Combinations.....................     47
  Shareholder Notice Procedures.......     48
  Mergers, Acquisitions and Certain
     Other Transactions...............     49
  Consideration of Constituencies.....     49
  Rights of Dissenting Shareholders...     49
  Director Liability and
     Indemnification..................     50
DESCRIPTION OF CARDINAL CAPITAL
  STOCK...............................     51
LEGAL MATTERS.........................     52
EXPERTS...............................     52
OTHER MATTERS.........................     53
SHAREHOLDER PROPOSALS.................     53
 
ANNEXES:
A -- Agreement and Plan of Merger,
     dated as of November 27, 1996,
     among Cardinal Health, Inc., Owl
     Merger Corp. and Owen Healthcare,
     Inc.
B -- Opinion of Smith Barney Inc.
     dated November 27, 1996
C -- Opinion of Rauscher Pierce
     Refsnes, Inc. dated November 27,
     1996
</TABLE>
 
                                       iii
<PAGE>   7
 
                                    SUMMARY
 
     The following is a summary of certain information contained elsewhere in
this Proxy Statement/Prospectus and the Annexes hereto (the "Proxy
Statement/Prospectus"). This summary is not intended to be complete and is
qualified in its entirety by the more detailed information and financial
statements appearing elsewhere or incorporated by reference in this Proxy
Statement/Prospectus. Owen Shareholders are urged to read and consider carefully
all of the information contained or incorporated by reference in this Proxy
Statement/Prospectus, including the Annexes.
 
                                 THE COMPANIES
 
CARDINAL AND SUBCORP
 
     Cardinal is a leading health care service provider which offers an array of
value-added pharmaceutical distribution services to a broad base of customers.
It is one of the nation's largest wholesale distributors of pharmaceutical and
related health care products to independent and chain drug stores, hospitals,
alternate care centers and the pharmacy departments of supermarkets and mass
merchandisers located throughout the continental United States. Through its
Pyxis Corporation subsidiary ("Pyxis"), Cardinal develops and manufactures
unique point-of-use systems which automate the distribution, management and
control of medications and supplies in hospitals and alternate care facilities.
Cardinal is also the largest franchisor of independent retail pharmacies in the
United States through its Medicine Shoppe International, Inc. subsidiary
("MSI"). In addition, through its Allied Pharmacy Service subsidiary ("Allied"),
Cardinal provides pharmacy management services to hospitals. PCI Services, Inc.,
one of Cardinal's subsidiaries, is also a leading international provider of
integrated packaging services to pharmaceutical manufacturers.
 
     On December 16, 1996, Cardinal paid to the holders of record of Cardinal
Common Shares at the close of business on December 2, 1996 three Cardinal Common
Shares for every two Cardinal Common Shares then outstanding (the "Stock
Split"). Unless otherwise provided herein, the information in this Proxy
Statement/Prospectus reflects the Stock Split.
 
     Subcorp is a newly formed, wholly owned subsidiary of Cardinal formed for
the purpose of effecting the Merger.
 
     The principal executive offices of Cardinal and Subcorp are located at 5555
Glendon Court, Dublin, Ohio 43016, and its telephone number is (614) 717-5000.
See "The Companies -- Business of Cardinal."
 
OWEN
 
     Owen is the nation's leading provider of fully integrated pharmacy
management and information services to hospitals, with more than 320 hospital
pharmacies under management in 43 states as of November 30, 1996. Owen typically
manages all aspects of its hospital clients' pharmacy operations, including
staffing, purchasing, inventory control, medication dispensing, capturing
patient charges, administration, quality control and information technology.
Through its subsidiary, Meditrol Automation Systems, Inc., Owen also
manufactures, sells and services its Meditrol(R) system, which is comprised of
one or more computer-controlled, automated dispensing cabinets capable of being
linked to the hospital's central information system. A Meditrol(R) unit located
in patient care units, under pharmacy control, allows authorized nursing
personnel rapid access to medications, enhances the accuracy of dispensing and
patient charging, reduces drug waste and diversion, and eliminates many
time-consuming drug distribution and record-keeping functions. In addition to
its pharmacy management operations and Meditrol(R) automated medication
management, Owen manages 26 healthcare materials outsourcing agreements, offers
a proprietary materials numbering and classification system and a healthcare
supply price database on a subscription basis. Hospital pharmacy management
accounted for approximately 88% of Owen's revenues in fiscal 1996. The principal
executive offices of Owen are located at 9800 Centre Parkway, Suite 1100,
Houston, Texas 77036-8279, and its telephone number is (713) 777-8173. See "The
Companies -- Business of Owen."
 
                                        1
<PAGE>   8
 
                              THE SPECIAL MEETING
 
     Date, Time and Place of the Special Meeting.  The Special Meeting will be
held at 9800 Centre Parkway, Suite 1100, Houston, Texas, on Tuesday, March 18,
1997, at 10:00 a.m., local time, to consider and vote upon (i) a proposal to
approve the Merger Agreement (the "Merger Proposal"); and (ii) such other
matters as may properly come before the Special Meeting.
 
     Record Date.  Only Owen Shareholders of record at the close of business on
February 10, 1997 (the "Record Date"), will be entitled to notice of and to vote
at the Special Meeting. On the Record Date, there were 17,147,084 shares of Owen
Common Stock outstanding held by approximately 2,600 holders of record. See "The
Special Meeting -- Record Date; Vote Required; Voting at the Meeting."
 
     Required Vote.  Approval of the Merger Proposal requires the affirmative
vote of the holders of two-thirds of the shares of Owen Common Stock outstanding
and entitled to vote thereon. As of the Record Date, the directors and executive
officers of Owen and certain of their affiliates may be deemed to be beneficial
owners of approximately 22% of the outstanding Owen Common Stock. Each of the
directors of Owen, who as of the Record Date beneficially owned in the aggregate
approximately 22% of the outstanding Owen Common Stock, has agreed to vote or
direct the vote of all Owen Common Stock over which such person or such person's
affiliates have voting power or control in favor of the Merger Proposal. See
"The Special Meeting -- Record Date; Vote Required; Voting at the Meeting."
 
     Revocability of Proxies.  Any proxy given pursuant to this solicitation may
be revoked by (i) filing with the Secretary of Owen, before the taking of the
vote at the Special Meeting, a written notice of revocation bearing a later date
than the date of the proxy or any later-dated proxy relating to the same shares,
or (ii) attending the Special Meeting and voting in person. Owen Shareholders
who require assistance in changing or revoking a proxy should contact Owen's
proxy solicitor, Morrow & Co. at (800) 607-0088.
 
     Recommendation of the Board of Directors.  The Board of Directors of Owen
has determined that the terms of the Merger Agreement and the transactions
contemplated thereby are fair to, and in the best interests of, Owen and the
Owen Shareholders. Accordingly, the Owen Board of Directors recommends that Owen
Shareholders vote FOR the approval of the Merger Agreement.
 
     Appraisal Rights.  Owen Shareholders will not be entitled to any appraisal
or dissenters' rights in connection with the Merger. See "Comparison of
Shareholder Rights -- Rights of Dissenting Shareholders."
 
                                   THE MERGER
 
GENERAL; EXCHANGE RATIO; ADJUSTMENT ELECTION
 
     Pursuant to the Merger Agreement (a copy of which is attached hereto as
Annex A), each share of Owen Common Stock issued and outstanding immediately
prior to the Effective Time, other than shares held in the treasury of Owen, if
any, which will be cancelled, will be converted into and represent a fraction of
a Cardinal Common Share equal to the Exchange Ratio.
 
     The Exchange Ratio (rounded to the nearest ten-thousandth of a share and as
adjusted pursuant to the terms of the Merger Agreement to reflect the Stock
Split) is equal to (i) the quotient obtained by dividing (a) $27.25 by (b) the
average of the closing prices per share of the Cardinal Common Shares as
reported on the NYSE Composite Tape on each of the last ten trading days ending
on the sixth trading day prior to the Special Meeting (the "Average Share
Price"); provided, however, that (x) if the Average Share Price is less than
$54.7833, then the Exchange Ratio will be equal to 0.4974, or (y) if the Average
Share Price is greater than $60.5500, then the Exchange Ratio will be equal to
0.4500; or (ii) if Cardinal has made an Adjustment Election (as defined below),
then the Exchange Ratio will be the product of (a) 0.4974 and (b) the quotient
obtained by dividing $46.1333 by the Average Share Price. Pursuant to the Merger
Agreement, Owen has the right to terminate the Merger Agreement if the Average
Share Price is less than $46.1333 if Cardinal has not
 
                                        2
<PAGE>   9
 
given written notice to Owen in the manner provided in the Merger Agreement that
the Exchange Ratio shall be calculated pursuant to clause (ii) above (an
"Adjustment Election"). Therefore, if the Average Share Price is less than
$46.1333, then, prior to Owen exercising its right to terminate the Merger
Agreement, Cardinal would have the right to make an Adjustment Election, which,
if made, would increase the Exchange Ratio above 0.4974 and would mean that Owen
could not terminate the Merger Agreement because the Average Share Price is less
than $46.1333. If, however, the Average Share Price is less than $46.1333 and
Cardinal opts not to make an Adjustment Election, thereby leaving the Exchange
Ratio at 0.4974, then Owen would have the right to terminate the Merger
Agreement. The Board of Directors of Cardinal and Owen, respectively, have not
determined what actions they would take or what factors they would consider if
circumstances changed such that the Average Share Price was less than $46.1333.
If the Average Share Price falls below $46.1333 and an Adjustment Election has
not been made by Cardinal, the Owen Board would need to consider, in exercising
their fiduciary duties to Owen Shareholders, if the Merger Agreement is not
terminated whether to resolicit the votes of Owen Shareholders with respect to
approval of the Merger Agreement to provide Owen Shareholders with an
opportunity to reconsider their vote and/or investment decision. Consummation of
the Merger and the conversion of Owen Common Stock into Cardinal Common Shares
as described above are subject to the satisfaction or waiver of certain
conditions (see "The Merger Agreement -- Conditions") and the right of one or
both of Owen and Cardinal to terminate the Merger Agreement under certain
circumstances as described under the caption "The Merger
Agreement -- Termination; Effect of Termination."
 
     The following table sets forth the Exchange Ratio and the "value" of the
consideration to be received by Owen Shareholders for each share of Owen Common
Stock, assuming various Average Share Prices between $54.7833 and $60.5500:
 
<TABLE>
<CAPTION>
                                                 "VALUE" PER SHARE
                                                        OF
AVERAGE SHARE PRICE*       EXCHANGE RATIO       OWEN COMMON STOCK**
- --------------------       --------------       -------------------
<S>                        <C>                  <C>
      $54.7833                 0.4974                 $ 27.25
       55.0000                 0.4955                   27.25
       56.0000                 0.4866                   27.25
       57.0000                 0.4781                   27.25
       58.0000                 0.4698                   27.25
       59.0000                 0.4619                   27.25
       60.0000                 0.4542                   27.25
       60.5500                 0.4500                   27.25
</TABLE>
 
- ---------------
 
*  The Average Share Price is defined as the average of the closing prices per
   share of the Cardinal Common Shares as reported on the NYSE Composite Tape on
   each of the last ten trading days ending on the sixth trading day prior to
   the Special Meeting.
** Calculated by multiplying the Average Share Price by the Exchange Ratio. The
   actual value of the Cardinal Common Shares on the closing date of the Merger,
   which will be based upon the market value on a particular date of the
   Cardinal Common Shares received, may be higher or lower than the value
   indicated above, which is based on the average market value of the Cardinal
   Common Shares over a period of several days prior to the Special Meeting. The
   last sale price of the Cardinal Common Shares of the NYSE Composite Tape was
   $61.75 on February 12, 1997. Owen Shareholders should obtain current quotes
   for the Cardinal Common Shares.
 
     For example, if the average share price of the Cardinal Common Shares is
$61.75 (the last sale price of Cardinal Common Shares on February 12, 1997), the
Exchange Ratio will be 0.4500. If the Average Share Price is greater than
$60.5500, the Exchange Ratio would remain at 0.4500, which effectively would
increase the "value" of the consideration to be received by Owen Shareholders
per share of Owen Common Stock as the Average Share Price increases. If the
Average Share Price is less than $54.7833, the Exchange Ratio would remain at
0.4974, which effectively would decrease the "value" of the consideration to be
received by Owen Shareholders per share of Owen Common Stock as the Average
Share Price decreases. If the Average Share Price is less than $46.1333, Owen
may terminate the Merger Agreement unless Cardinal makes an Adjustment Election.
If Cardinal makes an Adjustment Election under such circumstances, the Exchange
 
                                        3
<PAGE>   10
 
Ratio would be increased to equal (i) 0.4974 multiplied by (ii) the quotient
obtained by dividing $46.1333 by the Average Share Price. Based on the recent
closing prices of Cardinal Common Shares on the NYSE Composite Tape, and on the
fact that the Average Share Price, if calculated as of the Record Date,
currently is significantly higher than $46.1333, neither Cardinal nor Owen has
reason to believe that the Adjustment Election will be triggered, although there
can be no assurance.
 
     As described above, the definitive Exchange Ratio will be determinable
after the close of trading on the sixth trading day prior to the Special
Meeting, at which time Owen Shareholders may call Morrow & Co. at (800)
607-0088, to obtain the definitive Exchange Ratio.
 
EFFECTIVE TIME OF THE MERGER; CLOSING DATE
 
     The Merger will become effective (the "Effective Time") when articles of
merger are filed with the Texas Secretary of State or at such later time as is
specified in the articles of merger. This filing will be made on a date (the
"Closing Date") specified by Cardinal and Owen, which date will be as soon as
practicable, but in any event within three business days, following the date
upon which all conditions set forth in the Merger Agreement have been satisfied
or waived, as the case may be, or such other time as Cardinal and Owen may
mutually agree. It is currently contemplated that the Closing Date will occur on
the date of the Special Meeting, subject to satisfaction or waiver of each of
the conditions to consummation of the Merger. See "The Merger
Agreement -- Conditions."
 
CONDITIONS TO CONSUMMATION OF THE MERGER
 
     Consummation of the Merger is subject to, among other things, (i) approval
by Owen Shareholders of the Merger Proposal; (ii) no temporary restraining
order, preliminary or permanent injunction or other order or decree which
prevents the consummation of the Merger having been issued and remaining in
effect, and no statute, rule or regulation having been enacted by any
governmental authority which prevents the consummation of the Merger; (iii)
expiration or termination of all waiting periods under the Hart-Scott-Rodino
Antitrust Improvements Act of 1976, as amended (the "HSR Act"); (iv) the
Commission having declared the Registration Statement effective, and at the
Effective Time, no stop order or similar restraining order having been
threatened by the Commission or entered by the Commission or any state
securities administrator prohibiting the Merger; (v) receipt by each of Owen and
Cardinal of legal opinions to the effect that the Merger will qualify as a
tax-free reorganization for federal income tax purposes; (vi) receipt by
Cardinal of a letter, in form and substance reasonably satisfactory to Cardinal,
from Deloitte & Touche LLP with respect to qualification of the Merger as a
pooling-of-interests for accounting and financial reporting purposes; and (vii)
no action having been instituted by any governmental authority which seeks to
prevent consummation of the Merger or seeking material damages in connection
with the transactions contemplated by the Merger Agreement which, in each case,
continues to be outstanding.
 
     In addition, consummation of the Merger by either party to the Merger
Agreement is conditioned upon the representations and warranties of the other
party being true and correct on and as of the Closing Date (except for those
made as of a specified time), except for such inaccuracies which have not had
and could not reasonably be expected to have in the reasonably foreseeable
future a material adverse effect on the representing or warranting party, and
performance in all material respects of each obligation and agreement and
compliance in all material respects with each covenant to be performed and
complied with by the other party thereto. See "The Merger -- Accounting
Treatment," "The Merger -- Interests of Certain Persons in the Merger," "The
Merger -- Regulatory Approvals," "The Merger Agreement -- Representations,
Warranties and Covenants" and "The Merger Agreement -- Conditions."
 
NO SOLICITATION
 
     Pursuant to the Merger Agreement, Owen has agreed not to, and to cause its
affiliates and representatives not to, solicit proposals from or provide
information to or engage in discussions with third parties with respect to
specified business combinations or similar transactions, subject to certain
exceptions that would permit
 
                                        4
<PAGE>   11
 
discussions with third parties regarding such transactions if necessary to
comply with the fiduciary duties of the Board of Directors of Owen. See "The
Merger Agreement -- No Negotiations or Solicitations."
 
TERMINATION OF THE MERGER AGREEMENT
 
     Under specified circumstances, the Merger Agreement may be terminated prior
to the Effective Time, before or after approval of the Merger Agreement by the
Owen Shareholders. See "The Merger Agreement -- Termination; Effect of
Termination."
 
TERMINATION FEES
 
     If the Merger Agreement is terminated for specified reasons involving a
competing business transaction relating to Owen, Owen would be required to pay
Cardinal a termination fee and expenses aggregating up to $14.8 million. See
"The Merger Agreement -- Termination; Effect of Termination."
 
OWEN OPTIONS
 
     At the Effective Time, each unexpired and unexercised option under stock
option plans of Owen in effect on the date of the Merger Agreement which has
been granted to current or former directors, officers or employees of Owen by
Owen (each, an "Owen Option") will be automatically converted into an option (a
"Cardinal Exchange Option") to purchase that number of Cardinal Common Shares
equal to the number of shares of Owen Common Stock issuable immediately prior to
the Effective Time upon exercise of the Owen Option (without regard to actual
restrictions on exercisability) multiplied by the Exchange Ratio, with an
exercise price per share equal to the exercise price per share which existed
under the corresponding Owen Option divided by the Exchange Ratio, and with
other terms and conditions that are the same as the terms and conditions of such
Owen Option immediately before the Effective Time; provided that with respect to
any Owen Option that is an "incentive stock option" within the meaning of
Section 422 of the Internal Revenue Code of 1986, as amended (the "Code"), the
foregoing conversion will be carried out in a manner satisfying the requirements
of Section 424(a) of the Code. As of the Record Date, 1,503,879 shares of Owen
Common Stock were issuable upon the exercise of outstanding Owen Options, which
options, assuming an Exchange Ratio of 0.4500 (assuming an Average Share Price
equal to the closing price of Cardinal Common Shares on February 12, 1997 of
$61.75), will be converted to become approximately 676,745 Cardinal Exchange
Options at the Effective Time. The average exercise price per share of all Owen
Options outstanding as of the Record Date is $6.2431 per share. Following the
Merger and assuming an Exchange Ratio of 0.4500, the average exercise price per
share of Cardinal Exchange Options will be approximately $13.8736 per share.
Each of the executive officers and directors of Owen currently holds Owen
Options which will become Cardinal Exchange Options. Pursuant to the terms of
the stock option agreements under which the Owen Options were issued to
nonemployee directors of Owen, the unvested portion of each such Owen Option
will vest upon consummation of the Merger.
 
EMPLOYEE BENEFITS
 
     Cardinal has agreed that, for a period of one year from and after the
Effective Time, it will cause Owen, as the surviving corporation in the Merger
(the "Surviving Corporation") to provide for the employees of the Surviving
Corporation benefits that are no less favorable, in the aggregate, than those
provided to employees of Owen immediately prior to the date of the Merger
Agreement. In the event Cardinal satisfies such obligations by adding employees
of Owen to Cardinal's medical plan (the "Cardinal Medical Plan"), then
eligibility of such employees for medical benefits under the Cardinal Medical
Plan will not be subject to standard exclusions for pre-existing conditions.
 
ACCOUNTING TREATMENT
 
     The Merger is intended to qualify as a pooling-of-interests for accounting
and financial reporting purposes. Consummation of the Merger is conditioned on,
among other matters, Cardinal's receipt of a letter, in form and substance
reasonably satisfactory to Cardinal, from Deloitte & Touche LLP to the effect
that the Merger will qualify as a pooling-of-interests. See "The
Merger -- Accounting Treatment."
 
                                        5
<PAGE>   12
 
REASONS FOR THE MERGER; RECOMMENDATIONS OF THE BOARDS OF DIRECTORS
 
     Owen.  The Owen Board of Directors, in the course of reaching its decision
to approve the Merger Agreement and the transactions contemplated thereby,
considered a number of factors, including among others: (i) the Owen Board's
view that larger diversified companies will be better able to compete
effectively in the rapidly changing and increasingly competitive health care
industry, (ii) the opportunity the Merger will afford to accelerate the growth
in sales of existing and new products and services through the companies'
combined operations, (iii) the terms and conditions of the proposed Merger,
including the premium to be paid and the tax-free nature of the transaction to
the Owen Shareholders, (iv) information regarding historical market prices and
other information with respect to the common stock of each of Owen and Cardinal,
(v) the prospects for positive long-term performance of Cardinal Common Shares,
(vi) the financial presentation of Owen's financial advisors, Smith Barney Inc.
("Smith Barney") and Rauscher Pierce Refsnes, Inc. ("RPR" and, together with
Smith Barney, the "Financial Advisors"), and the opinions dated November 27,
1996 of Smith Barney and RPR to the Owen Board of Directors to the effect that,
as of such date and based upon and subject to certain matters stated in such
opinions, the Exchange Ratio was fair, from a financial point of view, to the
Owen Shareholders (see "The Merger -- Opinions of Owen's Financial Advisors"),
(vii) the opportunity for shareholders of Owen to maintain a continuing equity
interest in the combined company, (viii) the increase in market capitalization
and liquidity for Owen Shareholders afforded by the combination of Owen and
Cardinal, (ix) the compatibility of the business and operating strategies of
Owen and Cardinal, and (x) the Owen Board's assessment of Owen's strategic
alternatives to the Merger, including remaining an independent company,
conducting acquisitions, and merging or consolidating with a party or parties
other than Cardinal. For additional information, see "The Merger -- Reasons for
the Merger; Recommendations of the Boards of Directors -- Owen."
 
     THE BOARD OF DIRECTORS OF OWEN HAS DETERMINED THAT THE TERMS OF THE MERGER
AGREEMENT AND THE TRANSACTIONS CONTEMPLATED THEREBY ARE FAIR TO, AND IN THE BEST
INTERESTS OF, OWEN AND THE OWEN SHAREHOLDERS. ACCORDINGLY, THE OWEN BOARD OF
DIRECTORS RECOMMENDS THAT OWEN SHAREHOLDERS VOTE FOR THE APPROVAL OF THE MERGER
AGREEMENT.
 
     Cardinal.  In the course of reaching its decision to approve the Merger
Agreement and the transactions contemplated thereby, the Board of Directors of
Cardinal consulted with Cardinal's legal and financial advisors as well as with
Cardinal's management, and considered a number of factors, including among
others (i) Owen's leadership role in reducing overall pharmacy costs and
delivering superior clinical results as more hospitals explore pharmacy
outsourcing in response to the health care industry's focus on cost containment;
(ii) the transaction's impact on Cardinal's continued development as a
value-added provider of logistical, information, packaging, marketing and other
health care services that distinguish Cardinal from its distribution
competitors; (iii) potential synergies associated with combining Cardinal's
Allied pharmacy management operation with Owen, allowing Owen to leverage its
fixed investments over a larger customer base and provide hospital customers
with better, more cost-effective services; (iv) the high quality of Owen's
management team and service organization; (v) the financial return anticipated
by Cardinal management after the Merger due to several factors, including the
higher return on committed capital and return on sales Owen has historically
earned relative to Cardinal; (vi) the ability to achieve the benefits of scale
and efficiencies with respect to investments in new technology, systems and
services; (vii) Owen's clinical information database regarding product efficacy
and treatment cost, which complement Cardinal's existing sources of data and
provide the platform for creation of potential new information businesses;
(viii) Owen's Meditrol(R) automated dispensing technology, which represents a
potential product extension opportunity to Cardinal's Pyxis units for those
hospitals with a focus on pharmacist control; and (ix) the fact that it is a
condition to the consummation of the Merger that the Merger be treated as a
pooling-of-interests for financial reporting and accounting purposes, therefore,
adding no goodwill relating to this transaction to Cardinal's balance sheet. For
additional information, see "The Merger -- Reasons for the Merger;
Recommendations of the Boards of Directors -- Cardinal."
 
                                        6
<PAGE>   13
 
OPINIONS OF OWEN'S FINANCIAL ADVISORS
 
     Smith Barney and RPR have acted as financial advisors to Owen in connection
with the proposed Merger and have delivered to the Board of Directors of Owen
separate written opinions dated November 27, 1996 to the effect that, as of the
dates of such opinions and based upon and subject to certain matters stated
therein, the Exchange Ratio was fair, from a financial point of view, to the
Owen Shareholders. Copies of the written opinions of Smith Barney and RPR dated
November 27, 1996, which set forth the assumptions made, matters considered and
limitations on the review undertaken, are attached as Annexes B and C,
respectively, to this Proxy Statement/Prospectus and should be read carefully in
their entirety. The opinions of the Financial Advisors are directed to the Board
of Directors of Owen and relate only to the fairness of the Exchange Ratio from
a financial point of view, do not address any other aspect of the Merger or
related transactions and do not constitute a recommendation to any shareholder
as to how such shareholder should vote at the Owen Special Meeting. See "The
Merger -- Opinions of Owen's Financial Advisors."
 
INTERESTS OF CERTAIN PERSONS IN THE MERGER
 
     In considering the recommendation of Owen's Board of Directors with respect
to the Merger Agreement, Owen Shareholders should be aware that certain officers
and directors of Owen (or their affiliates) have interests in the Merger that
are different from and in addition to the interests of Owen Shareholders
generally. These interests include, but are not limited to, the fact that (i)
each of the executive officers and directors of Owen currently hold Owen
Options, which will be converted into Cardinal Exchange Options in the Merger
based on the Exchange Ratio which applies to the Owen Common Stock and vesting
will be accelerated in the case of nonemployee directors; (ii) Owen and Cardinal
have agreed to enter into employment agreements with certain officers or
directors of Owen, including Dian G. Owen, Chairman, Carl E. Isgren, President
and CEO, Harlan C. Stai, Executive Vice President, and Stephen A. Drury,
Executive Vice President and Corporate Secretary, each at the Effective Time;
(iii) certain other officers of Owen may enter into employment agreements with
Owen and Cardinal in contemplation of the Merger; and (iv) Cardinal has agreed,
from and after the Effective Time, to cause Owen, as the surviving corporation
(the "Surviving Corporation"), to indemnify and hold harmless present and former
officers and directors of Owen in respect of acts or omissions occurring prior
to the Effective Time to the extent provided under the Articles of Incorporation
of Owen (the "Owen Articles") and the Bylaws of Owen (the "Owen Bylaws") in
effect on the date of the Merger Agreement, and has agreed to maintain in effect
after the Effective Time Owen's current policies of directors' and officers'
liability insurance through the remainder of its term, which ends in June 1997.
The Board of Directors of Owen was aware of these interests and took these
interests into account in approving the Merger Agreement and the transactions
contemplated thereby. See "The Merger -- Interests of Certain Persons in the
Merger" and "The Merger -- Support/Voting Agreements."
 
STOCK OPTION AGREEMENT
 
     Concurrently with the execution of the Merger Agreement, Cardinal and Owen
entered into a Stock Option Agreement (the "Stock Option Agreement"), pursuant
to which Owen granted to Cardinal an irrevocable option (the "Option") to
purchase up to 3,396,750 shares of Owen Common Stock (representing 19.9% of the
outstanding shares of Owen Common Stock as of the date of the Merger Agreement)
at an exercise price per share equal to the lower of (x) $27.25 or (y) the
Exchange Ratio multiplied by the average closing price of Cardinal Common Shares
as reported on the NYSE Composite Tape during the five trading days immediately
preceding the date of delivery to Owen of written notice of Cardinal's exercise
of the Option. The Option is exercisable only upon the occurrence of certain
events and provides Cardinal the right to require Owen to, or permits Owen at
its election to, under certain circumstances, purchase for cash the unexercised
portion of the Option and all shares of Owen Common Stock purchased pursuant to
the Option. The Option, which was required by Cardinal as a condition to
Cardinal's entering into the Merger Agreement, may deter proposals to acquire
Owen by other parties and increase the likelihood of consummation of the Merger.
See "The Merger -- Stock Option Agreement."
 
                                        7
<PAGE>   14
 
SUPPORT/VOTING AGREEMENTS
 
     Concurrently with the execution of the Merger Agreement, each of the
directors of Owen, who as of the Record Date beneficially owned in the aggregate
approximately 22% of the outstanding Owen Common Stock (each a "Supporting
Shareholder" and, together, the "Supporting Shareholders"), executed separate
Support/Voting Agreements with Cardinal pursuant to which each Supporting
Shareholder agreed, among other things, to vote or direct the vote of all shares
of Owen Common Stock beneficially owned by the Supporting Shareholder or its
affiliates, or over which the Supporting Shareholder or any of its affiliates
has voting power or control, directly or indirectly, to approve the Merger and
the Merger Agreement and the transactions contemplated thereby. Each Supporting
Shareholder also thereby agreed, among other things, not to and not to permit
any company, trust or other entity controlled by the Supporting Shareholder or
any of its affiliates to, (i) contract to sell, sell or otherwise transfer or
dispose of any shares of Owen Common Stock, other than pursuant to the Merger,
without Cardinal's prior written consent or (ii) solicit, initiate, encourage or
facilitate, or furnish or disclose nonpublic information in furtherance of, any
inquiries or the making of any proposal with respect to any recapitalization,
merger, consolidation or other business combination involving Owen, or
acquisition of any capital stock or any material portion of the assets (except
for acquisitions of assets in the ordinary course of business consistent with
past practice) of Owen, or any combination of the foregoing (a "Competing
Transaction"), or negotiate, explore or otherwise engage in discussions with any
person (other than Cardinal, Subcorp or their respective directors, officers,
employees, agents and representatives) with respect to any Competing Transaction
or enter into any agreement, arrangement, or understanding with respect to any
Competing Transaction or agree to or otherwise assist in the effectuation of any
Competing Transaction; provided, however, that nothing in any Support/Voting
Agreement prevents any Supporting Shareholder from taking any action or omitting
to take any action (I) as a member of the Board of Directors of Owen necessary
so as not to violate such Supporting Shareholder's fiduciary obligations as a
director of Owen or (II) as an officer of Owen at the direction or request of
the Board of Directors of Owen so long as such direction or request was not made
in violation of any of the terms of the Merger Agreement. Each Support/Voting
Agreement may be terminated at the option of any party thereto at any time after
the earlier of (i) the termination of the Merger Agreement and (ii) the
Effective Time. See "The Merger -- Support/Voting Agreements."
 
REGULATORY APPROVALS
 
     On December 11, 1996, Cardinal and Owen completed the required filings
under the HSR Act, with the Federal Trade Commission (the "FTC") and the
Antitrust Division of the Department of Justice (the "Antitrust Division") in
respect of the Merger, together with requests for early termination of the
waiting period under the HSR Act. Expiration or early termination of the
applicable waiting period under the HSR Act is a condition to the obligations of
Cardinal and Owen to consummate the Merger. On January 10, 1997, the parties
received second requests from the FTC for additional information and documents,
and the parties substantially complied with such requests on February 11, 1997.
See "The Merger -- Regulatory Approvals." Neither Cardinal nor Owen is aware of
any other governmental or regulatory non-action approval required for
consummation of the Merger, other than compliance with applicable securities
laws.
 
EXCHANGE PROCEDURES
 
     If the Merger Proposal is approved and the Merger is consummated, as soon
as practicable after the Effective Time, a letter of transmittal will be mailed
or delivered to each Owen Shareholder to be used in forwarding certificates
evidencing such holder's shares of Owen Common Stock for surrender and exchange
for certificates evidencing Cardinal Common Shares to which such holder has
become entitled and, if applicable, cash in lieu of fractional Cardinal Common
Shares. After receipt of such letter of transmittal, each holder of certificates
formerly representing shares of Owen Common Stock should surrender such
certificates to Boatmen's Trust Company, the exchange agent for the Merger,
pursuant to and in accordance with the instructions accompanying such letter of
transmittal, and each holder will receive in exchange therefor certificates
evidencing the whole number of Cardinal Common Shares to which he is entitled
and any cash which may be payable in lieu of fractional Cardinal Common Shares.
See "The Merger Agreement -- Merger
 
                                        8
<PAGE>   15
 
Consideration." Such letter of transmittal will be accompanied by instructions
specifying other details of the exchange. OWEN SHAREHOLDERS SHOULD NOT SEND IN
THEIR CERTIFICATES UNTIL THEY RECEIVE A LETTER OF TRANSMITTAL.
 
                    CERTAIN FEDERAL INCOME TAX CONSEQUENCES
 
     Owen expects to receive an opinion from Vinson & Elkins L.L.P. to the
effect that if the Merger is consummated in accordance with the terms of the
Merger Agreement, the Merger will qualify as a reorganization within the meaning
of Section 368(a) of the Code and no gain or loss will be recognized for federal
income tax purposes by Cardinal, Owen or the Owen Shareholders (except to the
extent such holders receive cash in lieu of fractional Cardinal Common Shares).
Such opinion is based upon and is subject to, among other things, customary
representations made to Vinson & Elkins L.L.P. See "Certain Federal Income Tax
Consequences."
 
                        COMPARISON OF SHAREHOLDER RIGHTS
 
     As a result of the Merger, shares of Owen Common Stock, the rights of which
are governed by Texas law and Owen's Articles of Incorporation and Bylaws, will
be converted into the right to receive Cardinal Common Shares, the rights of
which are governed by Ohio law and Cardinal's Articles of Incorporation and Code
of Regulations. There are differences between the rights of Owen Shareholders
and the rights of holders of Cardinal Common Shares. These differences result
from differences between Ohio and Texas law and differences between the
governing instruments of Owen and Cardinal. For a discussion of the various
differences between the rights of Owen Shareholders and Cardinal Shareholders,
see "Comparison of Shareholder Rights."
 
                              RECENT DEVELOPMENTS
 
     On January 27, 1997, Putnam Investments, Inc., One Post Office Square,
Boston, Massachusetts 02109, Marsh & McLennan Companies, Inc., 1166 Avenue of
the Americas, New York, New York 10036, Putnam Investment Management, Inc., One
Post Office Square, Boston, Massachusetts 02109, and The Putnam Advisory
Company, Inc., One Post Office Square, Boston, Massachusetts 02109, jointly
filed a report on Schedule 13G under the Exchange Act, reporting that Putnam
Investments, Inc. and Putnam Investment Management, Inc. together beneficially
owned 6,231,800 Cardinal Common Shares (or approximately 6.2% of the issued and
outstanding Cardinal Common Shares as of the date of such filing).
 
     On February 11, 1997, Massachusetts Financial Services Company, 500
Boylston Street, Boston, Massachusetts 02116, filed an amendment to its report
on Schedule 13G under the Exchange Act, reporting that it beneficially owned, as
of such date, 1,620,005 shares of Owen Common Stock (or approximately 9.4% of
the issued and outstanding shares of Owen Common Stock as of the Record Date).
 
                                        9
<PAGE>   16
 
                      SUMMARY HISTORICAL AND UNAUDITED PRO
                          FORMA FINANCIAL INFORMATION
 
CARDINAL SUMMARY HISTORICAL FINANCIAL INFORMATION
 
     The summary historical financial information of Cardinal set forth below
has been derived from and should be read in conjunction with the audited
financial statements and other financial information of Cardinal incorporated by
reference in this Proxy Statement/Prospectus. See "Incorporation of Certain
Documents by Reference."
 
<TABLE>
<CAPTION>
                                                    FISCAL YEAR ENDED(1)                        SIX MONTHS ENDED
                                 ----------------------------------------------------------     DECEMBER 31,(1)
                                 MARCH 31,   MARCH 31,    JUNE 30,    JUNE 30,    JUNE 30,   ----------------------
                                    1992      1993(2)     1994(2)       1995      1996(2)     1995(3)     1996(3)
                                 ----------  ----------  ----------  ----------  ----------  ----------  ----------
                                                       (IN THOUSANDS, EXCEPT PER SHARE DATA)
<S>                              <C>         <C>         <C>         <C>         <C>         <C>         <C>
EARNINGS STATEMENT DATA:
Net revenues.................... $3,739,700  $4,734,636  $5,963,280  $8,022,108  $8,862,425  $4,285,464  $5,116,996
Earnings available for Common
  Shares before cumulative
  effect of change in accounting
  principle.....................     38,560      65,086      79,825     137,534     111,864      58,458      78,251
Earnings per Common Share before
  cumulative effect of change in
  accounting principle (4):
    Primary..................... $     0.56  $     0.79  $     0.87  $     1.43  $     1.15  $     0.60  $     0.79
    Fully diluted...............       0.55        0.77        0.87        1.43        1.15        0.60        0.79
Cash dividends declared per
  Common Share (4).............. $     0.04  $     0.05  $     0.07  $     0.08  $     0.08  $     0.04  $     0.05
BALANCE SHEET DATA:
Total assets.................... $1,023,485  $1,265,861  $1,636,382  $2,160,961  $2,681,095  $2,386,568  $3,150,837
Long-term obligations, less
  current portion...............    306,066     276,748     210,196     209,214     265,144     211,633     297,909
Redeemable preferred stock......     19,560      20,400          --          --          --          --          --
Shareholders' equity............    281,651     395,762     567,345     799,559     930,710     864,149   1,097,589
</TABLE>
 
- ---------------
(1) Amounts reflect business combinations in fiscal 1992, 1994, 1995, 1996 and
    1997. The most significant of these business combinations have been
    accounted for as poolings-of-interests transactions and, accordingly, prior
    period amounts have been restated to retroactively reflect these
    combinations. For those business combinations which were accounted for as
    purchase transactions, the pro forma effect as if these transactions had
    occurred at the beginning of the respective periods would not have been
    significantly different.
 
(2) In fiscal 1996, Cardinal recorded charges of approximately $67.3 million
    ($47.8 million, net of tax) primarily in connection with the business
    combinations of Cardinal with MSI in November 1995 (the "MSI Merger") and
    Pyxis in May 1996 (the "Pyxis Merger"). In fiscal 1994, Cardinal recorded a
    charge to reflect estimated merger costs of approximately $35.9 million
    ($28.2 million, net of tax) in connection with the business combination of
    Cardinal with Whitmire Distribution Corporation ("Whitmire") in February
    1994 (the "Whitmire Merger"). During fiscal 1993, Cardinal received a
    termination fee of approximately $13.5 million, resulting from the
    termination by Durr-Fillauer Medical, Inc. of its agreement to merge with
    Cardinal. During fiscal 1993, Cardinal also recorded charges totaling
    approximately $13.7 million, primarily related to the closing of certain
    non-core operations and the restructuring of certain distribution
    operations. In addition, the modification of the terms of certain Whitmire
    stock options in fiscal 1993 resulted in a one-time stock option
    compensation charge of approximately $5.2 million. Collectively, these items
    are referred to as "unusual items." See Note 2 of "Notes to Consolidated
    Financial Statements" in the 1996 Cardinal Form 10-K, which is incorporated
    by reference in this Proxy Statement/Prospectus.
 
(3) During the six months ended December 31, 1995 and 1996, Cardinal recorded a
    charge of approximately $17.6 million ($12.5 million, net of tax) in
    connection with the MSI Merger and $17.4 million ($12.7
 
                                       10
<PAGE>   17
 
    million, net of tax) in connection with the business combination of Cardinal
    with PCI in October 1996 (the "PCI Merger"), respectively.
 
     The following supplemental information, presented for purposes of
     facilitating meaningful comparisons to ongoing operations and to other
     companies, summarizes the results of operations of Cardinal, adjusted to
     reflect the elimination of the effect of the unusual items discussed above
     and the redemption of Whitmire's preferred stock pursuant to the terms of
     the Whitmire Merger. Solely for purposes of the summary presented below,
     such redemption is assumed to have been funded from the liquidation of
     investments in tax-exempt marketable securities.
 
<TABLE>
<CAPTION>
                                                        FISCAL YEAR ENDED          SIX MONTHS ENDED
                                                 -------------------------------     DECEMBER 31,
                                                 MARCH 31,   JUNE 30,   JUNE 30,   -----------------
                                                   1993        1994       1996      1995      1996
                                                 ---------   --------   --------   -------   -------
                                                        (IN THOUSANDS, EXCEPT PER SHARE DATA)
    <S>                                          <C>         <C>        <C>        <C>       <C>
    Earnings available for Common Shares before
      cumulative effect of change in accounting
      principle, excluding unusual items.......   $70,280    $108,938   $159,697   $70,953   $90,906
    Earnings per Common Share before cumulative
      effect of change in accounting principle,
      excluding unusual items:
         Primary...............................   $  0.86    $   1.18   $   1.65   $  0.73   $  0.91
         Fully diluted.........................      0.83        1.18       1.64      0.73      0.91
</TABLE>
 
     Earnings as presented above are reconciled to the amounts in the preceding
table as follows:
 
<TABLE>
<CAPTION>
                                                        FISCAL YEAR ENDED          SIX MONTHS ENDED
                                                 -------------------------------     DECEMBER 31,
                                                 MARCH 31,   JUNE 30,   JUNE 30,   -----------------
                                                   1993        1994       1996      1995      1996
                                                 ---------   --------   --------   -------   -------
                                                                   (IN THOUSANDS)
    <S>                                          <C>         <C>        <C>        <C>       <C>
    Earnings available for Common Shares as
      reported, before cumulative effect of
      change in accounting principle...........   $65,086    $ 79,825   $111,864   $58,458   $78,251
    Supplemental adjustments:
      Unusual items, primarily merger costs....                28,180     47,833    12,495    12,655
      Preferred stock redemptions..............     2,876       1,205
      Interest adjustment on preferred stock...      (575)       (272)
      Termination fee..........................    (7,163)
      Restructuring charge.....................     7,265
      Stock option charge......................     2,791
                                                  -------    --------   --------   -------   -------
    Earnings as supplementally adjusted........   $70,280    $108,938   $159,697   $70,953   $90,906
                                                  =======    ========   ========   =======   =======
</TABLE>
 
(4) Earnings and cash dividends per share have been adjusted to give retroactive
    effect for stock splits, including the three-for-two split paid on December
    16, 1996.
 
                                       11
<PAGE>   18
 
OWEN SUMMARY HISTORICAL FINANCIAL INFORMATION
 
     The summary historical financial information of Owen set forth below has
been derived from and should be read in conjunction with the audited
consolidated financial statements and other financial information of Owen
incorporated by reference in this Proxy Statement/Prospectus. See "Incorporation
of Certain Documents by Reference."
 
<TABLE>
<CAPTION>
                                                         FISCAL YEAR ENDED NOVEMBER 30,
                                              ----------------------------------------------------
                                                1992       1993     1994(1)    1995(5)      1996
                                              --------   --------   --------   --------   --------
                                                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
<S>                                           <C>        <C>        <C>        <C>        <C>
EARNINGS STATEMENT DATA:
Revenues....................................  $256,605   $290,277   $320,409   $383,995   $449,331
Net income..................................     2,583      4,803      5,191      8,110     10,907
Earnings per share(2):
  Primary...................................  $   0.30   $   0.56   $   0.53   $   0.62   $   0.60
  Fully diluted(3)..........................      0.27       0.48       0.46       0.56       0.60
 
BALANCE SHEET DATA:
Total assets................................  $ 70,040   $ 76,867   $106,415   $147,730   $169,168
Long-term debt, less current portion........    17,012     22,759     31,255          2         --
ESOP Common Stock(4)........................    15,575     16,986     21,046         --         --
Shareholders' equity(4).....................     4,297      7,997     20,311    110,300    120,222
</TABLE>
 
- ---------------
(1) Amounts reflect the business combination with Meditrol, Inc. in April 1994,
    which was accounted for using the purchase method. See Note 9 of "Notes to
    Consolidated Financial Statements" in the 1996 Owen Form 10-K, which is
    incorporated by reference in this Proxy Statement/Prospectus.
 
(2) Earnings per share have been adjusted to give retroactive effect to a
    five-for-two stock split paid by Owen in June 1995.
 
(3) Includes the effect of Owen's convertible subordinated notes prior to their
    conversion into shares of Owen Common Stock in August 1995.
 
(4) Represents Owen's obligations to repurchase shares of Owen Common Stock
    owned by Owen's ESOP. Upon completion of the public offering in August 1995,
    this obligation terminated and such amount was reclassified as shareholders'
    equity. See Note 7 of "Notes to Consolidated Financial Statements" in the
    1996 Owen Form 10-K, which is incorporated by reference in this Proxy
    Statement/Prospectus.
 
(5) In August 1995, Owen completed a secondary offering of common stock which
    yielded $50.7 million in net proceeds to Owen for the 4,598,400 shares sold
    by Owen, with which Owen repaid its long-term debt and amounts outstanding
    under its revolving credit line. In addition, the holders of $10 million in
    convertible subordinated notes of Owen converted such notes into 2,380,952
    shares of Owen Common Stock. See Note 4 of "Notes to Consolidated Financial
    Statements" in the 1996 Owen Form 10-K, which is incorporated by reference
    in this Proxy Statement/Prospectus.
 
                                       12
<PAGE>   19
 
UNAUDITED PRO FORMA COMBINED SUMMARY FINANCIAL INFORMATION
 
     The unaudited pro forma combined summary financial information of Cardinal
and Owen set forth below gives effect to the Merger under the
pooling-of-interests accounting method, and assumes that the Merger had occurred
at the beginning of the periods presented. The pro forma data presents the
consolidated statement of earnings for Cardinal for the fiscal years ended June
30, 1994, June 30, 1995 and June 30, 1996, and the six months ended December 31,
1995 and December 31, 1996, combined with the statement of earnings of Owen for
the twelve months ended May 31, 1994, May 31, 1995 and May 31, 1996, and the six
months ended November 30, 1995 and November 30, 1996. The unaudited pro forma
balance sheet information presents the balance sheet of Cardinal at June 30,
1996 and December 31, 1996, combined with the balance sheet of Owen as of May
31, 1996 and November 30, 1996, respectively. Owen's fiscal year ends on
November 30. The pro forma information is presented for illustrative purposes
only and is not necessarily indicative of the operating results or financial
position that would have occurred if the Merger had been consummated at such
time, nor is it necessarily indicative of future operating results or financial
position.
 
<TABLE>
<CAPTION>
                                         FISCAL YEAR ENDED(1)                  SIX MONTHS ENDED(1)
                               ----------------------------------------           DECEMBER 31,
                                JUNE 30,       JUNE 30,       JUNE 30,      -------------------------
                                1994(2)          1995         1996(2)        1995(2)        1996(2)
                               ----------     ----------     ----------     ----------     ----------
                                               (IN THOUSANDS, EXCEPT PER SHARE DATA)
<S>                            <C>            <C>            <C>            <C>            <C>
EARNINGS STATEMENT DATA:
Net revenues.................  $6,267,348     $8,368,641     $9,273,818     $4,482,412     $5,351,882
Earnings available for Common
  Shares, excluding Owen
  merger expenses............      84,827        143,003        122,448         62,887         83,003
Earnings per Common Share,
  excluding Owen merger
  expenses(3)(4):
  Primary....................  $     0.88     $     1.41     $     1.17     $     0.60     $     0.77
  Fully diluted..............        0.88           1.40           1.16           0.60           0.77
Cash dividends declared per
  Common Share(5)............  $     0.07     $     0.08     $     0.08     $     0.04     $     0.05
 
BALANCE SHEET DATA:
Total assets.................                                $2,833,501                    $3,320,005
Long-term obligations, less
  current portion............                                   265,144                       297,909
Shareholders' equity(6)......                                 1,047,201                     1,217,811
</TABLE>
 
- ---------------
(1) Amounts reflect business combinations in fiscal 1994, 1995, 1996 and 1997.
 
(2) Amounts reflect the effect of unusual items recorded by Cardinal in the
    fiscal years ended June 30, 1994 and June 30, 1996 and the six months ended
    December 31, 1995 and December 31, 1996. The following pro forma
    supplemental information summarizes the pro forma results of Cardinal and
    Owen, adjusted to reflect the elimination of the effect of the unusual items
    discussed in Notes 2 and 3 of "Summary -- Summary Historical and Unaudited
    Pro Forma Financial Information -- Cardinal Summary Historical Financial
    Information."
 
                                       13
<PAGE>   20
 
<TABLE>
<CAPTION>
                                                      FISCAL YEAR ENDED          SIX MONTHS ENDED
                                                ------------------------------     DECEMBER 31,
                                                JUNE 30,   JUNE 30,   JUNE 30,   -----------------
                                                  1994       1995       1996      1995      1996
                                                --------   --------   --------   -------   -------
                                                      (IN THOUSANDS, EXCEPT PER SHARE DATA)
    <S>                                         <C>        <C>        <C>        <C>       <C>
    Pro forma earnings available for Common
      Shares, excluding Owen merger expenses
      and unusual items.......................  $113,940   $143,003   $170,281   $75,382   $95,658
    Pro forma earnings per Common Share,
      excluding Owen merger expenses and
      unusual items:
      Primary.................................  $   1.18   $   1.41   $   1.62   $  0.72   $  0.89
      Fully diluted...........................      1.17       1.40       1.62      0.72      0.88
</TABLE>
 
(3) Earnings per Common Share have been adjusted to give retroactive effect to
    all stock splits (a five-for-four stock split paid by Cardinal in June 1994,
    a five-for-two stock split paid by Owen in June 1995 and a three-for-two
    stock split paid by Cardinal in December 1996).
 
(4) Earnings per Common Share amounts assume the conversion of each share of
    Owen Common Stock into 0.4725 Cardinal Common Shares (assuming an Exchange
    Ratio based on an Average Share Price equal to the closing price of Cardinal
    Common Shares on November 26, 1996 of $57.67). See "The Merger
    Agreement -- Merger Consideration."
 
(5) Cash dividends declared per Common Share represent the historical dividends
    of Cardinal for all periods presented and exclude all dividends paid by
    entities with which Cardinal has merged. Owen paid no dividends during these
    periods. Cash dividends declared per Common Share have been adjusted to give
    retroactive effect to a five-for-four stock split paid by Cardinal in June
    1994 and a three-for-two stock split paid by Cardinal in December 1996.
 
(6) Amount does not reflect the pro forma effect of expenses related to the
    Merger. Upon consummation of the merger, the combined company will record a
    one-time charge to reflect transaction and other costs incurred as a result
    of the Merger. While an estimate of such costs is not currently available,
    Cardinal and Owen do not anticipate that these costs will have a significant
    effect on the combined company's financial condition.
 
                                       14
<PAGE>   21
 
                           COMPARATIVE PER SHARE DATA
 
     Set forth below are earnings, cash dividends declared and book value per
share data for Cardinal and Owen on both historical and pro forma combined bases
and on a per share equivalent pro forma basis for Owen. Pro forma combined
earnings per share are derived from the Unaudited Pro Forma Combined Financial
Information presented elsewhere in this Proxy Statement/Prospectus, which gives
effect to the Merger under the pooling-of-interests accounting method. Pro forma
combined cash dividends declared per share reflect Cardinal cash dividends per
share declared in the periods indicated and exclude all dividends paid by all
entities with which Cardinal has merged. Book value per share for the pro forma
combined presentation is based upon outstanding Cardinal Common Shares, adjusted
to include estimated Cardinal Common Shares to be issued in the Merger for
outstanding shares of Owen Common Stock at the Effective Time. The per share
equivalent pro forma combined data for shares of Owen Common Stock is based on
the assumed conversion of each share of Owen Common Stock into 0.4725 Cardinal
Common Shares (based on an Exchange Ratio calculated with an assumed Average
Share Price equal to the closing price of Cardinal Common Shares on November 26,
1996 of $57.67). See "The Merger Agreement -- Merger Consideration." The
information set forth below should be read in conjunction with the respective
audited and unaudited financial statements of Cardinal and Owen incorporated by
reference or contained in this Proxy Statement/ Prospectus and the "Unaudited
Pro Forma Combined Summary Financial Information" and the notes thereto
presented in the "Summary" hereto. See "Incorporation of Certain Documents by
Reference."
 
<TABLE>
<CAPTION>
                                                                          FISCAL YEAR ENDED
                                                                            NOVEMBER 30,
                                                                      -------------------------
                                                                      1994      1995      1996
                                                                      -----     -----     -----
<S>                                                                   <C>       <C>       <C>
OWEN -- HISTORICAL
Earnings per share:
  Primary...........................................................  $0.53     $0.62     $0.60
  Fully diluted.....................................................   0.46      0.56      0.60
Book value per share................................................                       7.04
</TABLE>
 
<TABLE>
<CAPTION>
                                                                                  SIX MONTHS ENDED
                                                   FISCAL YEAR ENDED JUNE 30,       DECEMBER 31,
                                                   --------------------------     ----------------
                                                   1994      1995       1996      1995       1996
                                                   -----     -----     ------     -----     ------
<S>                                                <C>       <C>       <C>        <C>       <C>
CARDINAL -- HISTORICAL(1)
Earnings per Common Share:
  Primary........................................  $0.87     $1.43      $1.15     $0.60      $0.79
  Fully diluted..................................   0.87      1.43       1.15      0.60       0.79
Cash dividends declared per Common Share.........   0.07      0.08       0.08      0.04       0.05
Book value per share.............................                        9.70                10.95
 
CARDINAL AND OWEN -- PRO FORMA COMBINED(1)(2):
Earnings per Common Share, excluding the Merger
  expenses(3):
  Primary........................................  $0.88     $1.41      $1.17     $0.60      $0.77
  Fully diluted..................................   0.88      1.40       1.16      0.60       0.77
Cash dividends declared per Common Share.........   0.07      0.08       0.08      0.04       0.05
Book value per share, excluding the
  Merger expenses(3).............................                       10.07                11.24
</TABLE>
 
                                       15
<PAGE>   22
 
<TABLE>
<CAPTION>
                                                                                  SIX MONTHS ENDED
                                                   FISCAL YEAR ENDED JUNE 30,       DECEMBER 31,
                                                   --------------------------     ----------------
                                                   1994      1995       1996      1995       1996
                                                   -----     -----     ------     -----     ------
<S>                                                <C>       <C>       <C>        <C>       <C>
EQUIVALENT PRO FORMA COMBINED PER OWEN
  SHARE(1)(2):
Earnings per Common Share, excluding the Merger
  expenses(3):
  Primary........................................  $0.42     $0.67      $0.55     $0.28      $0.36
  Fully diluted..................................   0.42      0.66       0.55      0.28       0.36
Cash dividends declared per Common Share.........   0.03      0.04       0.04      0.02       0.02
Book value per share, excluding the Merger
  expenses(3)....................................                        4.76                 5.31
</TABLE>
 
- ---------------
(1) Cardinal's historical earnings per Common Share, the pro forma combined
    earnings per Common Share, and the equivalent pro forma combined earnings
    per Common Share reflect the effect of unusual items recorded by Cardinal in
    the fiscal years ended June 30, 1994 and June 30, 1996 and the six months
    ended December 31, 1995 and December 31, 1996. See a discussion of these
    items in Notes 2 and 3 of "Summary -- Summary Historical and Unaudited Pro
    Forma Financial Information -- Cardinal Summary Historical Financial
    Information." Excluding the impact of the unusual items, the amounts would
    be as follows:
 
<TABLE>
<CAPTION>
                                                                                 SIX MONTHS
                                                  FISCAL YEAR ENDED JUNE            ENDED
                                                            30,                 DECEMBER 31,
                                                 -------------------------     ---------------
                                                 1994      1995      1996      1995      1996
                                                 -----     -----     -----     -----     -----
    <S>                                          <C>       <C>       <C>       <C>       <C>
    Cardinal -- historical earnings per Common
      Share, excluding unusual items:
      Primary..................................  $1.18     $1.43     $1.65     $0.73     $0.91
      Fully diluted............................   1.18      1.43      1.64      0.73      0.91
    Pro forma combined earnings per Common
      Share, excluding the Merger expenses and
      unusual items:
      Primary..................................  $1.18     $1.41     $1.62     $0.72     $0.89
      Fully diluted............................   1.17      1.40      1.62      0.72      0.88
    Equivalent pro forma combined earnings per
      Common Share, excluding the Merger
      expenses and unusual items:
      Primary..................................  $0.56     $0.67     $0.77     $0.34     $0.42
      Fully diluted............................   0.55      0.66      0.77      0.34      0.42
</TABLE>
 
(2) The pro forma combined and the equivalent pro forma combined information
    (excluding the book value information which is calculated based on the
    balance sheets of Cardinal as of June 30, 1996 and Owen as of May 31, 1996
    for fiscal year ended June 30, 1996, and Cardinal as of December 31, 1996
    and Owen as of November 30, 1996, for the six months ended December 31,
    1996) present the combination of Cardinal for the fiscal years ended June
    30, 1994, June 30, 1995 and June 30, 1996 and the six months ended December
    31, 1995 and December 31, 1996, combined with the statement of earnings of
    Owen for the twelve months ended May 31, 1994, May 31, 1995 and May 31, 1996
    and the six months ended November 30, 1995 and November 30, 1996,
    respectively.
 
(3) Upon consummation of the Merger, the combined company will record a one-time
    charge to reflect transaction and other costs incurred as a result of the
    Merger. While an estimate of such costs is not currently available, Cardinal
    and Owen do not anticipate that these costs will have a significant effect
    on the combined company's financial condition.
 
                                       16
<PAGE>   23
 
                         MARKET PRICE AND DIVIDEND DATA
 
     The following table reflects (i) the range of the reported high and low
closing prices of Cardinal Common Shares on the NYSE Composite Tape and the per
share dividends paid thereon and (ii) the range of the reported high and low
closing prices of Owen Common Stock on the NYSE Composite Tape since May 24,
1996 and the range of the reported high and low bid prices of Owen Common Stock
on the National Quotation Bureau, Inc. OTC Bulletin Board from May 12, 1994 to
August 4, 1995 and on the Nasdaq National Market from August 5, 1995 to May 24,
1996, in each case for the calendar quarters indicated. Owen has not paid
dividends on the Owen Common Stock for the periods indicated. The information in
the table has been adjusted to reflect retroactively all applicable stock
splits.
 
<TABLE>
<CAPTION>
                                                                CARDINAL                  OWEN
                                                              COMMON SHARES           COMMON STOCK
                                                       ---------------------------   ---------------
                   CALENDAR YEAR                        HIGH     LOW     DIVIDENDS    HIGH     LOW
- ---------------------------------------------------    ------   ------   ---------   ------   ------
<S>                                                    <C>      <C>      <C>         <C>      <C>
1994:
  First quarter....................................    $27.06   $22.20    $ 0.016    $   --   $   --
  Second quarter...................................     27.20    22.94      0.016      6.00     6.00
  Third quarter....................................     28.09    24.42       0.02      7.20     6.00
  Fourth quarter...................................     32.17    27.42       0.02      7.80     7.20
1995:
  First quarter....................................    $33.92   $29.50    $  0.02    $ 8.00   $ 7.20
  Second quarter...................................     31.67    28.17       0.02     14.50     7.40
  Third quarter....................................     37.67    29.17       0.02     17.63    13.63
  Fourth quarter...................................     38.59    34.09       0.02     27.63    15.50
1996:
  First quarter....................................    $42.83   $35.00    $  0.02    $26.00   $20.00
  Second quarter...................................     50.17    40.17       0.02     25.75    13.13
  Third quarter....................................     55.08    44.67       0.02     13.88    11.00
  Fourth quarter...................................     58.38    51.92       0.02     26.50    11.63
1997:
  First quarter (through February 12, 1997)........    $64.00   $57.50    $ 0.025    $28.13   $26.00
</TABLE>
 
     On November 26, 1996, the last full trading day prior to the public
announcement of the Merger Agreement, the last sale price of Cardinal Common
Shares was $57.67 per share and the last sale price of Owen Common Stock was
$16.75 per share, as reported on the NYSE Composite Tape. The implied value of
Owen Common Stock at November 27, 1996, on an equivalent per share basis, was
$27.25. On February 12, 1997, the most recent practicable date prior to the
printing of this Proxy Statement/Prospectus, the last sale prices of Cardinal
Common Shares and Owen Common Stock were $61.75 per share and $27.50 per share,
respectively, as reported on the NYSE Composite Tape. Owen Shareholders are
encouraged to obtain current market quotations for Cardinal Common Shares and
Owen Common Stock.
 
     Cardinal has applied for the listing of the Cardinal Common Shares to be
issued in the Merger on the NYSE.
 
     Cardinal anticipates that it will continue to pay quarterly cash dividends.
However, the timing and amount of any future dividends remain within the
discretion of the Cardinal Board of Directors and will depend on Cardinal's
future earnings, financial condition, capital requirements and other factors.
 
     Owen has not declared any dividends on the Owen Common Stock in the past
three years. Pursuant to the Merger Agreement, Owen has agreed that, during the
period from the date of the Merger Agreement to the Effective Time, Owen will
not make, declare or pay any dividend or distribution on the Owen Common Stock.
 
                                       17
<PAGE>   24
 
                              THE SPECIAL MEETING
 
GENERAL
 
     This Proxy Statement/Prospectus is being furnished to Owen Shareholders in
connection with the solicitation of proxies by the Board of Directors of Owen
for use at the Special Meeting to be held on Tuesday, March 18, 1997, at 9800
Centre Parkway, Suite 1100, Houston, Texas, commencing at 10:00 a.m., local
time, and at any adjournment or postponement thereof.
 
     This Proxy Statement/Prospectus, the Letter to Owen Shareholders, the
Notice of the Special Meeting and the form of proxy for use at the Special
Meeting are first being mailed to Owen Shareholders on or about February 18,
1997.
 
MATTERS TO BE CONSIDERED AT THE SPECIAL MEETING
 
     At the Special Meeting, Owen Shareholders will consider and vote on:
 
          1. The Merger Proposal to approve the Merger Agreement (a copy of
     which is included as Annex A to this Proxy Statement/Prospectus).
 
          2. Such other business as may properly come before the Special
     Meeting.
 
RECORD DATE; VOTE REQUIRED; VOTING AT THE MEETING
 
     The Board of Directors of Owen has fixed February 10, 1997, as the Record
Date for determination of Owen Shareholders entitled to notice of and to vote at
the Special Meeting. Accordingly, only holders of Owen Common Stock of record at
the close of business on February 10, 1997, will be entitled to notice of and to
vote at the Special Meeting. Each holder of record of Owen Common Stock on the
Record Date is entitled to cast one vote per share, exercisable in person or by
a properly executed proxy, at the Special Meeting. As of the Record Date, there
were 17,147,084 shares of Owen Common Stock outstanding and entitled to vote
which were held by approximately 2,600 holders of record.
 
     Pursuant to the Owen Articles, the Owen Bylaws and applicable law, the
affirmative vote of the holders of two-thirds of the shares of Owen Common Stock
outstanding and entitled to vote thereon is required to approve the Merger
Proposal. As of the Record Date, the directors and executive officers of Owen
and certain of their affiliates may be deemed to be beneficial owners of 22% of
the outstanding shares of Owen Common Stock. In addition, each of the directors
of Owen and certain of their affiliates, who as of the Record Date beneficially
owned in the aggregate approximately 22% of the outstanding Owen Common Stock,
has agreed to vote or direct the vote of all Owen Common Stock over which such
person or such person's affiliates have voting power or control in favor of the
Merger Proposal.
 
VOTING OF PROXIES
 
     All properly executed proxies received prior to or at the Special Meeting
and not revoked will be voted at such meeting in accordance with the
instructions indicated in such proxies. If no instructions are indicated, such
proxies will be voted FOR approval of the Merger Proposal.
 
     If any other matters are properly presented at the Special Meeting for
consideration, including, among other things, consideration of a motion to
adjourn such meeting to another time or place (including, without limitation,
for the purpose of soliciting additional proxies), the persons named in the
enclosed form of proxy, and acting thereunder, will have discretion to vote on
such matters in accordance with their best judgment (unless authorization to use
such discretion is withheld). Owen is not aware of any matters expected to be
presented at the meeting other than the Merger Proposal.
 
     Any proxy given pursuant to this solicitation may be revoked by the person
giving it at any time before it is voted. Proxies may be revoked by (i) filing
with the Secretary of Owen, before the taking of the vote at the Special
Meeting, a written notice of revocation bearing a later date than the date of
the proxy, (ii) duly
 
                                       18
<PAGE>   25
 
executing a later dated proxy relating to the same shares and delivering it to
the Secretary of Owen before the taking of the vote at the Special Meeting, or
(iii) attending the Special Meeting and voting in person. In order to vote in
person at the Special Meeting, Owen Shareholders must attend the meeting and
cast their votes in accordance with the voting procedures established for the
meeting. Attendance at the meeting will not in and of itself constitute a
revocation of a proxy. Any written notice of revocation or subsequent proxy must
be sent so as to be delivered at or before the taking of the vote at the meeting
to Owen Healthcare, Inc., 9800 Centre Parkway, Suite 1100, Houston, Texas 77036,
Attention: Stephen A. Drury, Executive Vice President and Corporate Secretary.
Owen Shareholders who require assistance in changing or revoking a proxy should
contact Owen's proxy solicitor, Morrow & Co. at (800) 607-0088.
 
     Pursuant to the Owen Articles and applicable law, broker non-votes and
abstaining votes will not be counted in favor of the Merger Proposal. Since the
Merger Proposal requires the affirmative vote of two-thirds of the outstanding
Owen Common Stock, abstentions and broker non-votes will have the same effect as
votes against such proposal.
 
     The trustee of the Owen Health, Inc. Employee Stock Ownership Plan (the
"ESOP") has the sole right to exercise any voting rights relating to the Owen
Common Stock held for participants in such plan. Participants of the ESOP,
however, have the right to direct the trustee as to the manner in which voting
rights, including the right to vote on the Merger Proposal, will be exercised
with respect to the number of whole shares of Owen Common Stock allocated to
their accounts and shown on the voting instruction cards which they will receive
from the administrator of the ESOP; fractional shares of Owen Common Stock held
by the ESOP will be aggregated into whole shares and voted by the trustee to the
extent possible to reflect the voting directions of the participants with
respect to the number of whole shares of Owen Common Stock in their account. In
the absence of such voting instructions by a participant of the ESOP, the shares
of Owen Common Stock allocated to such participant's account will be voted by
the trustee in the same proportion as the shares for which voting instruction
cards are returned by other participants in the ESOP. The trustee of the ESOP
will vote in accordance with participant instructions unless the trustee is
required, under the Employee Retirement Income Security Act of 1974, as amended,
to vote otherwise in accordance with certain fiduciary duties.
 
     No participant of the Owen Healthcare, Inc. 401(k) Savings Plan (as
amended, the "401(k) Plan") has the right to request, direct or demand that the
trustee or the administrative committee thereof exercise in his behalf rights or
privileges to vote shares of Owen Common Stock allocated to his account. The
trustee of the 401(k) Plan will vote the shares of Owen Common Stock held by
such plan in the manner directed by the administrative committee thereof.
 
SOLICITATION OF PROXIES
 
     The expenses of the solicitation of proxies for the Special Meeting will be
borne by Owen, except that expenses incurred in connection with filing, printing
and mailing the Registration Statement and this Proxy Statement/Prospectus will
be shared equally by Cardinal and Owen, subject to each party's obligation to
reimburse the other for its expenses under certain circumstances. See "The
Merger Agreement -- Termination; Effect of Termination." In addition to
solicitation by mail, proxies may be solicited by directors, officers and
employees of Owen in person or by telephone, telegram or other means of
communication. These persons will receive no additional compensation for
solicitation of proxies, but may be reimbursed for reasonable out-of-pocket
expenses in connection with such solicitation. Arrangements will also be made by
Owen with custodians, nominees and fiduciaries for forwarding of proxy
solicitation materials to beneficial owners of shares held of record by such
custodians, nominees and fiduciaries, and Owen will reimburse such custodians,
nominees and fiduciaries for reasonable expenses incurred in connection
therewith.
 
     Owen has retained Morrow & Co. to distribute proxy solicitation materials
to brokers, banks and other nominees and to assist in the solicitation of
proxies from Owen Shareholders. The fee for such firm's services is estimated
not to exceed $7,500 plus reimbursement for reasonable out-of-pocket costs and
expenses in connection therewith.
 
                                       19
<PAGE>   26
 
RECOMMENDATION OF THE OWEN BOARD OF DIRECTORS
 
     The Board of Directors of Owen has unanimously determined that the terms of
the Merger Agreement and the transactions contemplated thereby are fair to, and
in the best interests of, Owen and the Owen Shareholders. Accordingly, the Owen
Board of Directors recommends that Owen Shareholders vote FOR the approval of
the Merger Agreement.
 
APPRAISAL RIGHTS
 
     Owen Shareholders will not be entitled to any appraisal rights under Texas
law or any other statute in connection with the Merger. See "Comparison of
Shareholder Rights -- Rights of Dissenting Shareholders."
 
                                   THE MERGER
 
BACKGROUND OF THE MERGER
 
     The healthcare industry is undergoing a period of rapid consolidation. Owen
recognizes that a result of this consolidation is that its potential clients are
becoming larger and demanding the services of a larger organization. Owen's
competitors have aligned themselves with larger organizations that give them
better access to the new healthcare market, and Owen believes that its smaller
size increasingly puts it at a competitive disadvantage when competing for
business from large hospitals and integrated health networks. Accordingly, Owen
decided to seek out a strong partner to assist in meeting new market
opportunities. Between September 1996 and November 1996, Owen engaged in
discussions with several third parties, each of which contacted Owen expressing
interest in pursuing a strategic merger with Owen. In connection with these
expressions of interest and the ensuing discussions, in September 1996, Owen
engaged Smith Barney and RPR as its financial advisors.
 
     As part of its growth strategy, Cardinal continuously evaluates and
maintains a variety of contacts with potential candidates for business
combinations. On October 16, 1996, Cardinal's Chairman and CEO telephoned Owen's
President and CEO and raised the subject of Cardinal pursuing a possible
acquisition of Owen. On October 25, 1996, a second telephone conversation
between these individuals took place during which a possible transaction was
further discussed.
 
     At a regularly scheduled meeting of the Cardinal Board of Directors held on
October 29, 1996, the Cardinal Board was advised of the contacts with Owen and
the subject matter of the initial discussions. Also at a regularly scheduled
meeting of the Owen Board of Directors held on the same day, the Owen Board was
advised of the contacts with Cardinal and the status of the exploratory
discussions to date. At this meeting, the Owen Board authorized members of Owen
management to further investigate the interest expressed by Cardinal as well as
several other potential acquirors. After the Owen Board meeting, Owen's
President and CEO indicated to Cardinal's Chairman that he would be willing to
meet to further discuss a potential business combination between the two
companies.
 
     Throughout November 1996, Owen engaged in serious discussions concerning a
possible business combination with two potential acquirors, including Cardinal.
Each of Cardinal and the other party ultimately submitted a proposal to Owen.
 
     On November 4, 1996, representatives of Cardinal and Owen, including
Cardinal's Chairman and Owen's President and CEO, met in Houston to discuss a
potential business combination. After these conversations, a representative of
Owen indicated to a representative of Cardinal that Owen would not be interested
in pursuing any additional discussions unless Cardinal and Owen entered into a
mutually acceptable confidentiality agreement that would permit Owen and
Cardinal to exchange information about their respective businesses. During the
ensuing days, representatives of Owen and Cardinal negotiated the terms of a
confidentiality agreement, and, on November 12, 1996, Cardinal and Owen entered
into the confidentiality agreement.
 
     In mid-November 1996, representatives of Owen and Cardinal and their
respective advisors discussed the possibility of a business combination and
conducted substantial due diligence of each other's businesses and operations.
As a result of these discussions, on November 20, 1996, representatives of
Cardinal delivered to representatives of Owen a written proposal indicating that
Cardinal would be willing to consider a business combination with Owen in which
all outstanding shares of Owen Common Stock would be exchanged for
 
                                       20
<PAGE>   27
 
Cardinal Common Shares in a transaction structured to qualify as a tax-free
reorganization under the Code and accounted for under the pooling-of-interests
method in which Owen Shareholders would receive, for each share of Owen Common
Stock, a fraction of a Cardinal Common Share having a fixed value while the
price of Cardinal stock remains within a certain range, all of which would be
subject to final due diligence by Cardinal and to further negotiations.
 
     On November 22, 1996, the Owen Board met to receive a preliminary
presentation on Owen's due diligence review on Cardinal and to discuss the terms
of a possible transaction as indicated by representatives of Owen as well as to
receive a presentation on possible transactions with other parties. At the
meeting, the Owen Board considered the terms of a possible transaction with
Cardinal, including the terms of a stock option agreement with Owen and
support/voting agreements (the execution of each of which Cardinal had indicated
would be a condition to its entering into a definitive agreement to effect a
combination with Owen), as well as the terms of a proposed stock option
agreement between Cardinal and the Chairman of Owen, which had been discussed
between the representatives of Owen and Cardinal and the terms of a termination
fee in the range of 2%-5% of the transaction value. Based on its review at the
meeting, the Owen Board authorized its representatives to continue to pursue a
potential business combination with Cardinal and the other party.
 
     The Owen Board met again telephonically on November 23, 1996, at which
meeting counsel reviewed for the Owen Board the proposed terms of the merger
agreement and related documents that had been provided by Cardinal. The sense of
the meeting was that negotiations should be continued with both Cardinal and the
other potential acquiror, pending receipt and review of the terms of the other
party's proposed transaction documents. Proposed transaction documents were
received from the other party and reviewed by Owen and its counsel on November
24, 1996. The Owen Board met telephonically on November 25, 1996 to review the
status of the competing proposals. At that time, because the Owen Board
determined that the other party's proposal was not likely to provide superior
value to the Owen Shareholders than the Cardinal proposal, the Owen Board
determined to notify the other party that, based on the terms of the proposals
received thus far, Owen was inclined to proceed with a transaction with
Cardinal, subject to satisfactory negotiation of the definitive terms of an
agreement. Owen did not receive an increase in the other party's proposal in
response.
 
     From November 22 to November 26, senior members of Owen management,
together with Owen's representatives who had been authorized by the Owen Board
to negotiate with Cardinal, conferred with representatives of Cardinal and
Cardinal's senior management and negotiated the detailed terms, provisions and
conditions of the Merger Agreement, and of the Stock Option Agreement and the
Support/Voting Agreements. At the same time, representatives of Cardinal and
Owen completed their due diligence of each other's businesses. Late in these
discussions, the terms of the Exchange Ratio and the termination fee were
negotiated.
 
     A special meeting of the Cardinal Board was held after the close of
business on November 26, 1996 to consider the terms of the proposed transaction
with Owen. At this meeting, the Cardinal Board discussed in detail the terms of
the possible transaction with Owen, approved the transaction subject to
negotiation of definitive documentation and authorized Cardinal management to
continue due diligence and to negotiate definitive documentation, subject to
approval of the Exchange Ratio by the Executive Committee of the Cardinal Board.
After further negotiations between management and advisors of both companies,
the Executive Committee of the Cardinal Board acted by written consent to
approve the final Exchange Ratio.
 
     At a special meeting held on November 27, 1996, the Owen Board received
detailed reports of the status of the continuing negotiations with Cardinal and
the terms and provisions of the Merger Agreement, the Stock Option Agreement and
the Support/Voting Agreements as negotiated by Owen's representatives, including
the Exchange Ratio and the termination fee. After receiving presentations from
Owen's financial and legal advisors, the Owen Board received the oral opinions
of Smith Barney and RPR (which opinions were subsequently confirmed by delivery
of written opinions dated November 27, 1996) to the effect that, as of November
27, 1996 and based upon and subject to certain matters stated in such opinions,
the Exchange Ratio was fair, from a financial point of view, to the Owen
Shareholders. The Owen Board then determined that the terms of the Merger
Agreement and the transactions contemplated thereby were fair to, and in the
best interests of, Owen and its shareholders, and accordingly, the Owen Board
unanimously approved the
 
                                       21
<PAGE>   28
 
Merger Agreement, the Stock Option Agreement and the Support/Voting Agreements
and resolved to recommend that the Owen Shareholders vote for the approval and
adoption of the Merger Agreement at a special meeting of Owen Shareholders to be
held for that purpose. See "-- Reasons for the Merger; Recommendations of the
Boards of Directors -- Owen."
 
     Later that day, after the Owen Board special meeting, the Merger Agreement,
the Stock Option Agreement and the Support/Voting Agreements were executed, and
the parties issued a joint press release announcing the Merger.
 
REASONS FOR THE MERGER; RECOMMENDATIONS OF THE BOARDS OF DIRECTORS
 
     Owen. In the course of reaching its decision to approve the Merger
Agreement and the transactions contemplated thereby, the Board of Directors of
Owen consulted with Owen's legal and financial advisors as well as with Owen's
management, and considered a number of factors, including (i) the Owen Board's
view that larger diversified companies will be better able to compete
effectively in the rapidly changing and increasingly competitive health care
industry, (ii) the opportunity the Merger will afford to accelerate the growth
in sales of existing and new products and services through the companies'
combined operations, (iii) the terms and conditions of the proposed Merger,
including the premium to be paid (approximately 63% based on the closing price
of the Owen Common Stock on the day prior to announcement of the Merger) and the
tax-free nature of the transaction to the Owen Shareholders, (iv) information
regarding historical market prices and other information with respect to the
common stock of each of Owen and Cardinal, (v) the prospects for positive
long-term performance of Cardinal Common Shares, (vi) the financial presentation
of Owen's financial advisors, Smith Barney and RPR, and the opinions dated
November 27, 1996 of Smith Barney and RPR to the Owen Board of Directors to the
effect that, as of such date and based upon and subject to certain matters
stated in such opinions, the Exchange Ratio was fair, from a financial point of
view, to the Owen Shareholders (see "The Merger -- Opinions of Owen's Financial
Advisors), (vii) the opportunity for shareholders of Owen to maintain a
continuing equity interest in the combined company, (viii) the increase in
market capitalization and liquidity for Owen Shareholders afforded by the
combination of Owen and Cardinal, (ix) the compatibility of the business and
operating strategies of Owen and Cardinal, and (x) the Owen Board's assessment
of Owen's strategic alternatives to the Merger, including remaining an
independent company, conducting acquisitions, and merging or consolidating with
a party or parties other than Cardinal.
 
     The foregoing discussion of the factors considered by the Owen Board is not
intended to be exhaustive. In view of the wide variety of factors considered in
connection with its evaluation of the Merger, the Owen Board did not find it
practicable to, and did not, quantify or otherwise attempt to assign relative
weights to the specific factors considered in reaching its determinations.
 
     FOR THE REASONS DISCUSSED ABOVE, THE BOARD OF DIRECTORS OF OWEN HAS
DETERMINED THAT THE TERMS OF THE MERGER AGREEMENT AND THE TRANSACTIONS
CONTEMPLATED THEREBY ARE FAIR TO, AND IN THE BEST INTERESTS OF, OWEN AND ITS
SHAREHOLDERS. ACCORDINGLY, THE OWEN BOARD OF DIRECTORS RECOMMENDS THAT OWEN
SHAREHOLDERS VOTE FOR THE APPROVAL OF THE MERGER AGREEMENT.
 
     Cardinal. In the course of reaching its decision to approve the Merger
Agreement and the transactions contemplated thereby, the Board of Directors of
Cardinal consulted with Cardinal's legal and financial advisors as well as with
Cardinal's management, and considered a number of factors, including among
others (i) Owen's leadership role in reducing overall pharmacy costs and
delivering superior clinical results as more hospitals explore pharmacy
outsourcing in response to the health care industry's focus on cost containment;
(ii) the transaction's impact on Cardinal's continued development as a
value-added provider of logistical, information, packaging, marketing and other
health care services that distinguish Cardinal from its distribution
competitors; (iii) potential synergies associated with combining Cardinal's
Allied pharmacy management operation with Owen, allowing Owen to leverage its
fixed investments over a larger customer base and provide hospital customers
with better, more cost-effective services; (iv) the high quality of Owen's
management team and service organization; (v) the financial return anticipated
by Cardinal management after the Merger due to several factors, including the
higher return on committed capital and return on sales Owen has historically
 
                                       22
<PAGE>   29
 
earned relative to Cardinal; (vi) the ability to achieve the benefits of scale
and efficiencies with respect to investments in new technology, systems and
services; (vii) Owen's clinical information database regarding product efficacy
and treatment cost, which complement Cardinal's existing sources of data and
provide the platform for creation of potential new information businesses; and
(viii) Owen's Meditrol(R) automated dispensing technology, which represents a
potential product extension opportunity to Cardinal's Pyxis units for those
hospitals with a focus on pharmacist control.
 
     The Cardinal Board also considered the fact that it is a condition to the
consummation of the Merger that the Merger be treated as a pooling-of-interests
for financial reporting and accounting purposes, therefore, adding no goodwill
relating to this transaction to Cardinal's balance sheet.
 
     The foregoing discussion of the factors considered by the Cardinal Board is
not intended to be exhaustive. In view of the wide variety of factors considered
in connection with its evaluation of the Merger, the Cardinal Board did not find
it practicable to, and did not, quantify or otherwise attempt to assign relative
weights to the specific factors considered in reaching its determination.
 
OPINIONS OF OWEN'S FINANCIAL ADVISORS
 
     The Financial Advisors were retained by Owen to act as Owen's financial
advisors in connection with the proposed Merger. In connection with such
engagement, Owen requested that the Financial Advisors evaluate the fairness,
from a financial point of view, to the Owen Shareholders of the consideration to
be received by such shareholders in the Merger. On November 27, 1996, at a
meeting of the Board of Directors of Owen held to evaluate the proposed Merger,
the Financial Advisors each delivered oral opinions (subsequently confirmed by
delivery of written opinions dated November 27, 1996) to the Board of Directors
of Owen to the effect that, as of the date of such opinions and based upon and
subject to certain matters stated therein, the Exchange Ratio was fair, from a
financial point of view, to the Owen Shareholders.
 
     Smith Barney Opinion.  In arriving at its opinion, Smith Barney reviewed
the Merger Agreement and held discussions with certain senior officers,
directors and other representatives and advisors of Owen and certain senior
officers and other representatives of Cardinal concerning the businesses,
operations and prospects of Owen and Cardinal. Smith Barney examined certain
publicly available business and financial information relating to Owen and
Cardinal as well as certain financial forecasts and other information and data
for Owen and Cardinal which were provided to or otherwise discussed with Smith
Barney by the respective managements of Owen and Cardinal, including information
relating to certain strategic implications and operational benefits anticipated
to result from the Merger. Smith Barney reviewed the financial terms of the
Merger, as set forth in the Merger Agreement in relation to, among other things:
current and historical market prices and trading volumes of Owen Common Stock
and Cardinal Common Shares; the respective companies' historical and projected
earnings and other operating data; and the capitalization and financial
condition of Owen and Cardinal. Smith Barney also considered, to the extent
publicly available, the financial terms of certain other similar transactions
recently effected which Smith Barney considered relevant in evaluating the
Merger and analyzed certain financial, stock market and other publicly available
information relating to the businesses of other companies whose operations Smith
Barney considered relevant in evaluating those of Owen and Cardinal. Smith
Barney also evaluated the potential pro forma financial impact of the Merger on
Cardinal. In connection with its engagement, Smith Barney was requested to
approach, and held discussions with, third parties to solicit indications of
interest in a possible acquisition of Owen. In addition to the foregoing, Smith
Barney conducted such other analyses and examinations and considered such other
financial, economic and market criteria as Smith Barney deemed appropriate in
arriving at its opinion. Smith Barney noted that its opinion was necessarily
based upon information available, and financial, stock market and other
conditions and circumstances existing and disclosed, to Smith Barney as of the
date of its opinion.
 
     In rendering its opinion, Smith Barney assumed and relied, without
independent verification, upon the accuracy and completeness of all financial
and other information and data publicly available or furnished to or otherwise
reviewed by or discussed with Smith Barney. With respect to financial forecasts
and other information and data furnished to or otherwise reviewed by or
discussed with Smith Barney, the managements of Owen and Cardinal advised Smith
Barney that such forecasts and other information and data were prepared
 
                                       23
<PAGE>   30
 
on bases reflecting reasonable estimates and judgments as to the future
financial performance of Owen and Cardinal and the strategic implications and
operational benefits anticipated to result from the Merger. Smith Barney
assumed, with the consent of the Board of Directors of Owen, that the Merger
will be treated as a pooling-of-interests in accordance with generally accepted
accounting principles and as a tax-free reorganization for federal income tax
purposes. Smith Barney's opinion, as set forth therein, relates to the relative
values of Owen and Cardinal. Smith Barney did not express any opinion as to what
the value of the Cardinal Common Shares actually will be when issued to Owen
Shareholders pursuant to the Merger or the price at which the Cardinal Common
Shares will trade subsequent to the Merger. Smith Barney did not make and was
not provided with an independent evaluation or appraisal of the assets or
liabilities (contingent or otherwise) of Owen or Cardinal nor did Smith Barney
make any physical inspection of the properties or assets of Owen or Cardinal.
Although Smith Barney evaluated the Exchange Ratio from a financial point of
view, Smith Barney was not asked to and did not recommend the specific
consideration payable in the Merger, which was determined through negotiation
between Owen and Cardinal. No other limitations were imposed by Owen on Smith
Barney with respect to the investigations made or procedures followed by Smith
Barney in rendering its opinion.
 
     RPR Opinion.  In connection with its opinion, RPR reviewed publicly
available business and financial information relating to Owen and Cardinal. RPR
also, among other things, reviewed the Merger Agreement and discussed with
certain members of senior management of Owen and Cardinal the past and current
business operations, financial condition and future prospects of Owen and
Cardinal. RPR reviewed certain financial analyses and forecasts of Owen and
Cardinal which were provided to or otherwise discussed with RPR by the
respective managements of Owen and Cardinal. RPR reviewed the financial terms of
the Merger as set forth in the Merger Agreement in relation to, among other
things: current and historical market prices and trading volumes of Owen Common
Stock and Cardinal Common Shares; the respective companies' historical and
projected earnings and operating data; and the capitalization and financial
condition of Owen and Cardinal. RPR compared certain financial and stock market
information for Owen and Cardinal with similar information for certain other
companies the securities of which are publicly traded and reviewed the financial
terms of certain recent business combinations in the healthcare industry
specifically and in other industries generally whose operations RPR considered
relevant in evaluating those of Owen and Cardinal. RPR also evaluated the
potential pro forma financial impact of the Merger on Cardinal. In connection
with its engagement, RPR was requested to approach, and prior to the date of the
Merger Agreement held discussions with, certain third parties to solicit
indications of interest in a possible acquisition of Owen.
 
     In addition, RPR considered such other information and financial, economic
and market criteria which RPR deemed relevant, and conducted such other analyses
as RPR deemed appropriate under the circumstances. In connection with its
review, RPR relied upon and assumed the accuracy and completeness of the
financial and other information publicly available or furnished to RPR by Owen
and Cardinal or their representatives. RPR did not independently verify the
accuracy or completeness of such information. With respect to the financial
forecasts provided to or otherwise reviewed by or discussed with RPR, RPR
assumed that such forecasts were prepared on bases reflecting reasonable
estimates and judgments as to the future performance of Owen and Cardinal,
respectively. In addition, RPR did not make an independent evaluation or
appraisal of the assets of Owen and Cardinal, nor was RPR furnished with any
such appraisals. RPR assumed, with the consent of the Board of Directors of
Owen, that the Merger will be treated as a pooling-of-interests in accordance
with generally accepted accounting principles and as a tax-free reorganization
for federal income tax purposes. RPR did not express any opinion as to what the
value of the Cardinal Common Shares actually will be when issued to Owen
Shareholders pursuant to the Merger or the price at which the Cardinal Common
Shares will trade subsequent to the Merger. Although RPR evaluated the Exchange
Ratio from a financial point of view, RPR was not asked to and did not recommend
the specific consideration payable in the Merger, which was determined through
negotiation between Owen and Cardinal. No other limitations were imposed by Owen
on RPR with respect to the investigations made or procedures followed by RPR in
rendering its opinion.
 
     COPIES OF THE WRITTEN OPINIONS OF SMITH BARNEY AND RPR DATED NOVEMBER 27,
1996, WHICH SET FORTH THE ASSUMPTIONS MADE, MATTERS CONSIDERED AND LIMITATIONS
ON THE REVIEW UNDERTAKEN, ARE ATTACHED HERETO AS ANNEXES B AND C, RESPECTIVELY,
AND ARE INCORPORATED HEREIN BY REFERENCE. OWEN SHAREHOLDERS ARE URGED TO READ
THESE OPINIONS CAREFULLY IN THEIR ENTIRETY. THE OPINIONS OF THE FINANCIAL
ADVISORS ARE DIRECTED TO THE
 
                                       24
<PAGE>   31
 
BOARD OF DIRECTORS OF OWEN AND RELATE ONLY TO THE FAIRNESS OF THE EXCHANGE RATIO
FROM A FINANCIAL POINT OF VIEW, DO NOT ADDRESS ANY OTHER ASPECT OF THE MERGER OR
RELATED TRANSACTIONS AND DO NOT CONSTITUTE A RECOMMENDATION TO ANY SHAREHOLDER
AS TO HOW SUCH SHAREHOLDER SHOULD VOTE AT THE OWEN SPECIAL MEETING. THE SUMMARY
OF THE OPINIONS OF THE FINANCIAL ADVISORS SET FORTH IN THIS PROXY
STATEMENT/PROSPECTUS ARE QUALIFIED IN THEIR ENTIRETY BY REFERENCE TO THE FULL
TEXT OF SUCH OPINIONS.
 
     Financial Analyses of the Financial Advisors.  In preparing their
respective opinions, the Financial Advisors performed a variety of financial and
comparative analyses, including those described below. The summary of such
analyses does not purport to be a complete description of the analyses
underlying the Financial Advisors' opinions. The preparation of a fairness
opinion is a complex analytic process involving various determinations as to the
most appropriate and relevant methods of financial analyses and the application
of those methods to the particular circumstances and, therefore, such an opinion
is not readily susceptible to summary description. Accordingly, the Financial
Advisors believe that their analyses must be considered as a whole and that
selecting portions of their analyses and factors, without considering all
analyses and factors, could create a misleading or incomplete view of the
processes underlying such analyses and opinions. In their analyses, the
Financial Advisors made numerous assumptions with respect to Owen, Cardinal,
industry performance, general business, economic, market and financial
conditions and other matters, many of which are beyond the control of Owen and
Cardinal. The estimates contained in such analyses and the valuation ranges
resulting from any particular analysis are not necessarily indicative of actual
values or predictive of future results or values, which may be significantly
more or less favorable than those suggested by such analyses. In addition,
analyses relating to the value of businesses or securities do not purport to be
appraisals or to reflect the prices at which businesses or securities actually
may be sold. Accordingly, such analyses and estimates are inherently subject to
substantial uncertainty. The Financial Advisors' opinions and analyses were only
one of many factors considered by the Board of Directors of Owen in its
evaluation of the Merger and should not be viewed as determinative of the views
of Owen's Board of Directors or management with respect to the Exchange Ratio or
the proposed Merger.
 
     Selected Company Analysis.  Using publicly available information, the
Financial Advisors analyzed, among other things, the market values and trading
multiples of Owen, Cardinal and eight selected publicly traded companies in the
pharmaceutical services industry, consisting of: (i) four hospital
management/outsourcing companies: Value Health, Inc., Emcare Holdings, Inc.,
Horizon Medical Health Management, Inc., and Servicemaster Limited Partnership
(the "Hospital Management/Outsourcing Companies") and (ii) four institutional
pharmacy companies: Capstone Pharmacy Services, Inc., NCS Healthcare, Inc.,
Omnicare, Inc., and Vitalink Pharmacy Services, Inc. (the "Institutional
Pharmacy Companies" and, together with the Hospital Management/Outsourcing
Companies, the "Selected Companies"). With respect to the Selected Companies,
the Financial Advisors focused primarily on the Hospital Management/Outsourcing
Companies, the operations of which the Financial Advisors considered to be the
most comparable to Owen. The Financial Advisors compared market values as
multiples of, among other things, latest 12 months and estimated calendar 1996
and 1997 net income, and adjusted market values (equity market value, plus total
debt, minority interest and the book value of preferred stock, less cash and
cash equivalents) as multiples of, among other things, latest 12 months revenue,
earnings before interest, taxes, depreciation and amortization ("EBITDA") and
earnings before interest and taxes ("EBIT"). Net income projections of Owen,
Cardinal and the Selected Companies were based on estimates of selected
investment banking firms. All multiples were based on closing stock prices as of
November 22, 1996. Applying a range of multiples for the Hospital
Management/Outsourcing Companies of latest 12 months net income and estimated
calendar 1996 and 1997 net income of 15.5x to 17.5x, 12.8x to 18.2x and 11.5x to
15.0x, respectively, and latest 12 months revenue, EBITDA and EBIT of 0.4x to
1.3x, 6.0x to 11.6x and 7.4x to 14.7x, respectively, to corresponding financial
data for Owen resulted in an equity reference range for Owen of approximately
$9.08 to $16.07 per share, as compared to the equity value implied by the
Exchange Ratio of approximately $27.25 per share based on a closing stock price
of Cardinal Common Shares on November 22, 1996.
 
     The Financial Advisors also analyzed, among other things, the market values
and trading multiples of Cardinal and the following four selected publicly
traded companies in the drug distribution industry:
 
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<PAGE>   32
 
AmeriSource Health Corporation, Bergen Brunswig Corporation, Bindley Western
Corporation and McKesson Corporation (the "Drug Distribution Companies"). The
Financial Advisors compared market values as multiples of, among other things,
latest 12 months and estimated calendar 1996 and 1997 net income, and adjusted
market values as multiples of, among other things, latest 12 months net revenue,
EBITDA and EBIT. Net income projections for Cardinal and the Drug Distribution
Companies were based on estimates of selected investment banking firms. All
multiples were based on closing stock prices as of November 22, 1996. Mean and
median multiples of latest 12 months and estimated calendar 1996 and 1997 net
income and latest 12 months net revenues, EBITDA and EBIT for the Drug
Distribution Companies were as follows: (i) latest 12 months net income: 30.0x
(mean) and 21.8x (median); (ii) estimated calendar 1996 and 1997 net income:
28.1x (mean) and 19.8x (median) and 24.3x (mean) and 17.1x (median),
respectively; (iii) latest 12 months net revenue: 0.3x (mean) and 0.2x (median);
(iv) latest 12 months EBITDA: 14.3x (mean) and 11.8x (median); and (v) latest 12
months EBIT: 16.5x (mean) and 12.7x (median). The multiples of latest 12 months
and estimated calendar 1996 and 1997 net income and latest 12 months net
revenue, EBITDA and EBIT for Cardinal were 36.6x, 31.6x, 25.4x, 0.7x, 18.7x and
20.8x, respectively.
 
     Selected Merger and Acquisition Transactions Analysis.  Using publicly
available information, the Financial Advisors reviewed the purchase price and
implied transaction multiples paid or proposed to be paid in the following three
selected transactions in the pharmaceutical services industry (acquiror/target):
Vitalink Pharmacy Services, Inc./TeamCare Pharmacy, Inc. (the "Vitalink/TeamCare
Transaction"), Capstone Pharmacy Services, Inc./Symphony Pharmacy Services, Inc.
(the "Capstone/Symphony Transaction"), and Cardinal/Pyxis Corporation (the
"Cardinal/Pyxis Transaction" and, together with the Vitalink/TeamCare
Transaction and the Capstone/Symphony Transaction, the "Selected Transactions").
With respect to the Selected Transactions, the Financial Advisors focused
primarily on the Cardinal/Pyxis Transaction, which the Financial Advisors
considered to be the most comparable to the Merger. Applying a range of adjusted
multiples for the Cardinal/Pyxis Transaction of latest 12 months net income,
estimated calendar 1996 net income and latest 12 months EBITDA and EBIT of 24.7x
to 30.1x, 19.5x to 23.9x, 14.1x to 17.3x and 15.0x to 18.4x, respectively, to
corresponding financial data for Owen resulted in an equity reference range for
Owen of approximately $16.19 to $19.09 per share, as compared to the equity
value implied by the Exchange Ratio of approximately $27.25 per share based on a
closing stock price of Cardinal Common Shares on November 22, 1996.
 
     No company, transaction or business used in the "Selected Company Analysis"
or "Selected Merger and Acquisition Transactions Analysis" as a comparison is
identical to Owen, Cardinal or the Merger. Accordingly, an analysis of the
results of the foregoing is not entirely mathematical; rather, it involves
complex considerations and judgments concerning differences in financial and
operating characteristics and other factors that could affect the acquisition,
public trading or other values of the Selected Companies, the Selected
Transactions or the business segment, company or transaction to which they are
being compared.
 
     Discounted Cash Flow Analysis.  The Financial Advisors performed a
discounted cash flow analysis of the projected free cash flow of Owen for the
fiscal years 1997 through 2000, based on internal estimates of the management of
Owen. The stand-alone discounted cash flow analysis of Owen was determined by
(i) adding (x) the present value of projected free cash flows over the four-year
period from 1997 to 2000 and (y) the present value of Owen's estimated terminal
value in year 2000 and (ii) subtracting the current net debt of Owen. The range
of estimated terminal values for Owen at the end of the four-year period was
calculated by applying terminal multiples ranging from 13.0x to 17.0x to Owen's
projected 2001 unlevered net income, representing Owen's estimated value beyond
the year 2000. The cash flows and terminal values of Owen were discounted to
present value using discount rates ranging from 12.0% to 16.0%, with particular
focus on a discount rate of 14.0%. Based on such terminal value multiples and a
discount rate of 14.0%, this analysis resulted in an equity reference range for
Owen of approximately $24.54 to $31.57 per share.
 
     Contribution Analysis.  The Financial Advisors analyzed the respective
contributions of Owen and Cardinal to the estimated revenue, EBITDA, EBIT and
net income of the combined company for fiscal years 1997 and 1998 based, in the
case of Owen, on internal estimates of the management of Owen and, in the case
of Cardinal, on estimates of selected investment banking firms. This analysis
indicated that (i) in fiscal year 1997, Owen would contribute approximately 4.9%
of revenue, 7.7% of EBITDA, 5.5% of EBIT and 5.9% of net income, and Cardinal
would contribute approximately 95.1% of revenue, 91.7% of EBITDA, 93.8% of
 
                                       26
<PAGE>   33
 
EBIT and 93.4% of net income of the combined company, and (ii) in fiscal year
1998, Owen would contribute approximately 5.3% of revenue, 9.0% of EBITDA, 6.9%
of EBIT and 7.1% of net income, and Cardinal would contribute approximately
94.7% of revenue, 90.0% of EBITDA, 92.0% of EBIT and 91.9% of net income, of the
combined company. The contribution analysis assumed certain cost savings and
other potential synergies that were not allocated to either Owen or Cardinal and
represented approximately 0.6%, 0.7% and 0.7% of EBITDA, EBIT and net income,
respectively, of the combined company in fiscal 1997 and approximately 1.0%,
1.1% and 1.1% of EBITDA, EBIT and net income, respectively, of the combined
company in fiscal 1998. Immediately following consummation of the Merger,
shareholders of Owen and Cardinal would own approximately 7.8% and 92.2%,
respectively, of the combined company.
 
     Pro Forma Merger Analysis.  The Financial Advisors analyzed certain pro
forma effects resulting from the Merger, including, among other things, the
impact of the Merger on Cardinal's projected EPS for fiscal years 1997 through
2000 based, in the case of Owen, on internal estimates of the management of Owen
and, in the case of Cardinal, on estimates of selected investment banking firms
for fiscal years 1997 and 1998 and extrapolated for subsequent fiscal years
based on analysts' growth rate estimates for Cardinal. The results of the pro
forma merger analysis suggested that the Merger could be neutral to Cardinal's
EPS in fiscal years 1997 through 1999 and accretive thereafter, assuming certain
cost savings and other potential synergies anticipated by the management of Owen
to result from the Merger were achieved. The actual results achieved by the
combined company may vary from projected results and the variations may be
material.
 
     Exchange Ratio Analysis.  The Financial Advisors compared the Exchange
Ratio with the historical ratio of the daily closing prices of Owen Common Stock
and Cardinal Common Shares during the six-month and 12-month periods preceding
November 22, 1996. The exchange ratios of the daily closing prices of one share
of Owen Common Stock to one Cardinal Common Share during the six-month and
12-month periods preceding November 22, 1996 were 0.1822 and 0.2801,
respectively, as compared to the Exchange Ratio of 0.3169 based on the closing
stock price of Cardinal Common Shares on November 22, 1996.
 
     Other Factors and Comparative Analyses.  In rendering their opinions, the
Financial Advisors considered certain other factors and conducted certain other
comparative analyses, including, among other things, a review of (i) preliminary
indications of interest received from third parties other than Cardinal; (ii)
the history of trading prices and value for Owen Common Stock and Cardinal
Common Shares and the relationship between movements of such Common Stock,
movements of the common stock of the Selected Companies and movements in the S&P
500 Index; (iii) selected published analysts' reports on Owen and Cardinal,
including analysts' estimates as to the earnings growth potential of Owen and
Cardinal and historical earnings performance of the respective companies
relative to earnings estimates of selected investment banking firms; (iv) the
premiums paid in selected transactions having a transaction value of $250
million to $1.0 billion; and (v) the pro forma ownership of the combined
company.
 
     Pursuant to the terms of the Financial Advisors' engagement, Owen has
agreed to pay the Financial Advisors for their services in connection with the
Merger an aggregate financial advisory fee equal to 1% of the total
consideration (including liabilities assumed) payable in connection with the
Merger. Owen has also agreed to reimburse the Financial Advisors for reasonable
travel and other out-of-pocket expenses incurred by the Financial Advisors in
performing their services, including the reasonable fees and expenses of their
legal counsel, and to indemnify the Financial Advisors and related persons
against certain liabilities, including liabilities under the federal securities
laws, arising out of the Financial Advisors' engagement.
 
     In the ordinary course of business, the Financial Advisors and their
respective affiliates may actively trade or hold the securities of Owen and
Cardinal for their own account or for the account of customers and, accordingly,
may at any time hold a long or short position in such securities. Smith Barney
has in the past provided investment banking and financial advisory services to
Owen and Cardinal unrelated to the proposed Merger, and RPR has in the past
provided investment banking and financial advisory services to Owen unrelated to
the proposed Merger, for which services Smith Barney and RPR have received
compensation. In addition, Smith Barney and its affiliates (including Travelers
Group Inc. and its affiliates) may maintain relationships with Owen and
Cardinal.
 
                                       27
<PAGE>   34
 
     The Financial Advisors are nationally recognized investment banking firms
and were selected by Owen based on their experience, expertise and familiarity
with Owen and its business. The Financial Advisors regularly engage in the
valuation of businesses and their securities in connection with mergers and
acquisitions, negotiated underwritings, competitive bids, secondary
distributions of listed and unlisted securities, private placements and
valuations for estate, corporate and other purposes.
 
INTERESTS OF CERTAIN PERSONS IN THE MERGER
 
     In considering the recommendation of the Owen Board with respect to the
Merger Agreement, Owen Shareholders should be aware that certain officers and
directors of Owen (or their affiliates) have interests in the Merger that are
different from and in addition to the interests of Owen Shareholders generally.
The Board of Directors of Owen was aware of these interests and took these
interests into account in approving the Merger Agreement and the transactions
contemplated thereby.
 
     Owen Options.  Prior to the Effective Time, Cardinal and Owen will take all
such actions as may be necessary to cause each unexpired and unexercised Owen
Option under stock option plans of Owen in effect on the date of the Merger
Agreement which has been granted to current or former directors, officers or
employees of Owen by Owen to be automatically converted at the Effective Time
into a Cardinal Exchange Option to purchase that number of Cardinal Common
Shares equal to the number of shares of Owen Common Stock issuable immediately
prior to the Effective Time upon exercise of the Owen Option (without regard to
actual restrictions on exercisability) multiplied by the Exchange Ratio, with an
exercise price per share equal to the exercise price per share which existed
under the corresponding Owen Option divided by the Exchange Ratio, and with
other terms and conditions that are the same as the terms and conditions of such
Owen Option immediately before the Effective Time; provided that with respect to
any Owen Option that is an "incentive stock option" within the meaning of
Section 422 of the Code, the foregoing conversion will be carried out in a
manner satisfying the requirements of Section 424(a) of the Code. As of the
Record Date, 1,503,879 shares of Owen Common Stock were issuable upon the
exercise of outstanding Owen Options, which options, assuming an Exchange Ratio
of 0.4500 (assuming an Average Share Price equal to the last sale price of
Cardinal Common Shares on February 11, 1997 of $61.50), will be converted to
become approximately 676,745 Cardinal Exchange Options at the Effective Time.
The average exercise price per share of all Owen Options outstanding as of the
Record Date is $6.2431 per share. Following the Merger and assuming an Exchange
Ratio of 0.4500, the average exercise price per share of Cardinal Exchange
Options will be approximately $13.8736 per share. Assuming the exercise of all
Cardinal Exchange Options immediately after the Effective Time and assuming an
Exchange Ratio of 0.4500, the holders thereof would hold approximately 0.7% of
all Cardinal Common Shares issued and outstanding immediately after the
Effective Time (without including any Cardinal Common Shares otherwise held by
such holders). Each of the executive officers and directors of Owen currently
hold Owen Options which will become Cardinal Exchange Options. Pursuant to the
terms of the stock option agreements under which the Owen Options were issued to
nonemployee directors of Owen, the unvested portion of each such Owen Option
will automatically vest upon consummation of the Merger.
 
     Cardinal has agreed under the Merger Agreement to file with the Commission,
within ten business days after the Closing Date, a registration statement on
Form S-8 or other appropriate form under the Securities Act to register the
Cardinal Common Shares issuable upon exercise of the Cardinal Exchange Options
and to use its reasonable efforts to cause such registration statement to remain
effective until the exercise or expiration of such options.
 
     Employment Agreements.  In connection with the Merger, Carl E. Isgren,
Harlan C. Stai and Stephen A. Drury of Owen have agreed to enter into employment
agreements with Owen and Cardinal at the Effective Time. In addition, it is
expected that Dian G. Owen will enter into an employment agreement with Owen and
Cardinal at the Effective Time (the "Owen Employment Agreement"). Such
agreements (the "New Employment Agreements") provide for base salary, incentive
compensation, and other benefits.
 
     The Owen Employment Agreement will be for a term of three years. Under this
agreement, Ms. Owen will receive a base salary of $225,000, payable over three
years, plus health benefits. In addition, during the
 
                                       28
<PAGE>   35
 
first year of the Owen Employment Agreement, Owen will provide her with
continued use of the office she currently occupies.
 
     Mr. Isgren's New Employment Agreement will be for a term ending on August
31, 2000. The agreement provides that Mr. Isgren will receive health benefits
and a base salary of $28,750 per month until August 31, 1997, which base salary
will be $16,667 per month from August 31, 1997 until the end of the term of the
agreement.
 
     The New Employment Agreements with Messrs. Stai and Drury will be for a
term of 18 months beginning at the Effective Time. These agreements provide for
annual salaries of $225,700 for Mr. Stai and $220,000 for Mr. Drury. Each of
these agreements also provides that the employee in question will continue to be
entitled to his annual bonus under Owen's annual bonus program in effect from
time to time during the term of the respective agreements.
 
     Under each of the New Employment Agreements, if the employee's employment
is terminated by Owen without "cause" (as defined in the New Employment
Agreement) or by the executive for "good reason" (as defined in the New
Employment Agreement), Owen will be obligated to continue to pay the employee's
base salary and to provide the employee with health benefits for the remaining
term of the New Employment Agreement; but any earnings or health benefits the
employee obtains from other employment will reduce Owen's obligations to provide
the employee with continued base salary or health benefits, as applicable.
 
     Under each of the New Employment Agreements, the employee is subject to a
confidentiality covenant, a covenant not to solicit employees of Owen, Cardinal
and their affiliates, and a covenant not to compete with Owen, Cardinal and
their affiliates. The noncompetition covenant will remain in effect until one
year after the end of the employment period in the case of Messrs. Stai and
Drury, and until two years after the end of the employment period in the case of
Ms. Owen and Mr. Isgren.
 
     Indemnification; Insurance.  In the Merger Agreement, Cardinal has agreed
that, from and after the Effective Time, it will cause the Surviving Corporation
(including, to the extent required, providing sufficient funding) to indemnify
and hold harmless the present and former officers and directors of Owen in
respect of acts or omissions occurring prior to the Effective Time to the extent
provided under the Owen Articles and Owen Bylaws in effect on the date of the
Merger Agreement. Cardinal has also agreed to maintain in effect after the
Effective Time the policies of directors' and officers' liability insurance in
effect on the date of the Merger Agreement through the remainder of its term,
which ends in June 1997.
 
ACCOUNTING TREATMENT
 
     The Merger is intended to qualify as a pooling-of-interests for accounting
and financial reporting purposes. Consummation of the Merger is conditioned on
Cardinal's receipt of a letter, in form and substance reasonably satisfactory to
Cardinal, from Deloitte & Touche LLP, independent auditors of Cardinal,
confirming at the Effective Time its letter dated the date of this Proxy
Statement/Prospectus to the effect that the Merger will qualify as a
pooling-of-interests for accounting and financial reporting purposes.
 
     Under the pooling-of-interests method of accounting, the recorded assets
and liabilities of Cardinal and Owen will be carried forward to the combined
company at their historical recorded amounts, income of the combined company
will include income of Owen and Cardinal for the entire fiscal year in which the
combination occurs, and the reported income of the separate companies for
previous periods will be combined and restated as income of the combined
company. Cardinal has agreed in the Merger Agreement to use its best efforts to
prepare and publicly release as soon as practicable (but in any event within
fifteen days) following the end of the first full calendar month completed after
the Effective Time, a report in the form of a quarterly earnings report,
registration statement filed with the Commission, a report filed with the
Commission on Form 10-K, 10-Q or 8-K or any other public filing, statement or
announcement which includes the combined financial results (including combined
sales and net income) of Cardinal and Owen for a period of at least 30 days of
combined operations of Cardinal and Owen following the Effective Time. See "The
Merger Agreement -- Conditions" and "Summary -- Summary Historical and Unaudited
Pro Forma Combined Financial Information."
 
                                       29
<PAGE>   36
 
     Owen and Cardinal have each agreed in the Merger Agreement to obtain
written undertakings ("Affiliate Letters") at least 30 days prior to the Special
Meeting from each person who may be at the Effective Time or was on the date of
the Merger Agreement an "affiliate" of such party for purposes of Rule 145 under
the Securities Act to the effect that, among other things, such person will not
sell, transfer or otherwise dispose of, or direct or cause the sale, transfer or
other disposition of, any shares of Owen Common Stock or Cardinal Common Shares
or Owen Options beneficially owned thereby during the 30 days prior to the
Effective Time and will not sell, transfer or otherwise dispose of, or direct or
cause the sale, transfer or other disposition of, any Cardinal Common Shares or
Cardinal Exchange Options (or Cardinal Common Shares issuable upon exercise
thereof) beneficially owned thereby as a result of the Merger or otherwise until
after such time as Cardinal shall have publicly released a report in the form of
a quarterly earnings report, registration statement filed with the Commission,
report filed with the Commission or any other public filing, statement or
announcement which includes the combined financial results of Cardinal and Owen
for a period of at least 30 days of combined operations of Cardinal and Owen
following the Effective Time. See "The Merger Agreement -- Representations,
Warranties and Covenants."
 
REGULATORY APPROVALS
 
     Under the HSR Act and the rules that have been promulgated thereunder by
the FTC, the Merger may not be consummated unless certain filings have been
submitted to the Antitrust Division and the FTC and certain waiting period
requirements have been satisfied. Cardinal and Owen completed the required
filings to the FTC and the Antitrust Division on December 11, 1996. On January
10, 1997, the parties received second requests from the FTC for additional
information and documents, and the parties substantially complied with such
requests on February 11, 1997.
 
     The Antitrust Division and the FTC frequently scrutinize the legality under
the antitrust laws of transactions such as the Merger. At any time before or
after the consummation of the Merger, 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 consummation of the Merger
or seeking the divestiture of substantial assets of Owen or Cardinal. Owen and
Cardinal believe that the consummation of the Merger will not violate the
antitrust laws. There can be no assurance, however, that a challenge to the
Merger on antitrust grounds will not be made, or, if such a challenge is made,
what the result will be.
 
     Other than as described in this Proxy Statement/Prospectus, consummation of
the Merger does not require the approval of any Federal or state agency.
 
FEDERAL SECURITIES LAW CONSEQUENCES
 
     All Cardinal Common Shares issued in connection with the Merger will be
freely transferable, except that any Cardinal Common Shares received by persons
who are deemed to be "affiliates" (as such term is defined under the Securities
Act) of Cardinal or Owen prior to the Merger may be sold by them only in
transactions permitted by the resale provisions of Rule 145 under the Securities
Act with respect to affiliates of Cardinal or Owen, or Rule 144 under the
Securities Act with respect to persons who are or become affiliates of Cardinal,
or as otherwise permitted under the Securities Act. Persons who may be deemed to
be affiliates of Cardinal or Owen generally include individuals or entities that
control, are controlled by or are under common control with, such person and
generally include the executive officers and directors of such person as well as
principal shareholders of such person.
 
     Affiliates may not sell their Cardinal Common Shares acquired in connection
with the Merger, except pursuant to an effective registration under the
Securities Act covering such shares or in compliance with Rule 145 under the
Securities Act (or Rule 144 under the Securities Act in the case of persons who
become affiliates of Cardinal) or another applicable exemption from the
registration requirements of the Securities Act. In general, Rule 145 under the
Securities Act provides that for two years following the Effective Time an
affiliate (together with certain related persons) would be entitled to sell
Cardinal Common Shares acquired in connection with the Merger only through
unsolicited "broker transactions" or in transactions directly with a
 
                                       30
<PAGE>   37
 
"market maker," as such terms are defined in Rule 144. Additionally, the number
of shares to be sold by an affiliate (together with certain related persons and
certain persons acting in concert) within any three-month period for purposes of
Rule 145 under the Securities Act may not exceed the greater of 1% of the
outstanding Cardinal Common Shares or the average weekly trading volume of such
shares during the four calendar weeks preceding such sale. With the exception of
Dian Owen, no affiliate of Owen is expected to receive Cardinal Common Shares in
the Merger which exceed 1% of the outstanding Cardinal Common Shares. Rule 145
under the Securities Act will remain available to affiliates if Cardinal remains
current with its informational filings with the Commission under the Exchange
Act. Two years after the Effective Time, an affiliate will be able to sell such
Cardinal Common Shares without being subject to such manner of sale or volume
limitations provided that Cardinal is current with its Exchange Act
informational filings and such affiliate is not then an affiliate of Cardinal.
Three years after the Effective Time, an affiliate will be able to sell such
Cardinal Common Shares without any restrictions so long as such affiliate had
not been an affiliate of Cardinal for at least three months prior to the date of
such sale. See "-- Accounting Treatment."
 
     Pursuant to the Affiliate Letters, Cardinal has agreed that, for so long as
any affiliate party to an Affiliate Letter holds any Cardinal Common Shares as
to which such affiliate is subject to the limitations of Rule 145, Cardinal will
use its reasonable efforts to file all reports required to be filed by it
pursuant to the Exchange Act and the rules and regulations thereunder so as to
satisfy the requirements of paragraph (c) of Rule 144 under the Securities Act
that there be available current public information with respect to Cardinal, and
to that extent to make available to such affiliate the exemption afforded by
Rule 145 with respect to the sale, transfer or other disposition of the Cardinal
Common Shares. See "-- Accounting Treatment."
 
STOCK OPTION AGREEMENT
 
     In connection with the execution of the Merger Agreement, Cardinal and Owen
entered into the Stock Option Agreement pursuant to which Owen granted to
Cardinal an irrevocable Option to purchase up to 3,396,750 shares of Owen Common
Stock (representing, without giving effect to the exercise of the Option, 19.9%
of the outstanding shares of Owen Common Stock as of the date of the Merger
Agreement) at an exercise price per share equal to the lower of (x) $27.25 or
(y) the Exchange Ratio multiplied by the average of the closing prices of
Cardinal Common Shares as reported on the NYSE Composite Tape during the five
consecutive trading days ending on (and including) the trading day immediately
prior to the date of exercise. Cardinal may exercise the Option, in whole or in
part, at any time or from time to time following the occurrence of certain
"Purchase Events" which are described below. No Purchase Event has occurred as
of the date of this Proxy Statement/Prospectus.
 
     The Option terminates upon the earliest to occur of (i) the Effective Time,
(ii) 5:00 p.m. Houston time, on the date which is one year following the
occurrence of a Purchase Event, and (iii) the termination of the Merger
Agreement in accordance with its terms. Notwithstanding the foregoing, if the
Option cannot be exercised before its date of termination as a result of any
injunction, order or similar restraint issued by a court of competent
jurisdiction, the Option will expire on the 30th business day after such
injunction, order or restraint shall have been dissolved or when such
injunction, order or restraint shall have become permanent and no longer subject
to appeal, as the case may be.
 
     Under the Stock Option Agreement, a "Purchase Event" is defined as the
occurrence of any of the following: (i) any person (other than Cardinal or any
of its subsidiaries) shall have commenced (as such term is defined in Rule 14d-2
under the Exchange Act), or shall have filed a registration statement under the
Securities Act with respect to, a tender offer or exchange offer to purchase any
shares of Owen Common Stock such that, upon consummation of such offer, such
person would own or control 10% or more of the then outstanding Owen Common
Stock; (ii) Owen or any of its subsidiaries shall or shall have entered into,
authorized, recommended, proposed or publicly announced an intention to enter
into, authorize, recommend, or propose, an agreement, arrangement or
understanding with any person (other than Cardinal or any of its subsidiaries)
to, or any person (other than Cardinal or any of its subsidiaries) shall have
publicly announced an intention to, (A) effect any Competing Transaction, (B)
purchase, lease or otherwise acquire 10% or more of the assets of Owen or any of
its subsidiaries or (C) purchase or otherwise acquire (including by way of
merger, consolidation, tender or exchange offer or similar transaction)
beneficial ownership (as defined in
 
                                       31
<PAGE>   38
 
Rule 13d-3 under the Exchange Act) of securities representing 10% or more of the
voting power of Owen or any of its subsidiaries; (iii) any person (other than
Cardinal or any subsidiary of Cardinal, and other than Dian G. Owen) shall have
acquired beneficial ownership or the right to acquire beneficial ownership of
10% or more of the voting power of Owen; (iv) the Board of Directors of Owen
shall have withdrawn, modified or changed in a manner adverse to Cardinal, or
refused to reaffirm within two business days of any written request from
Cardinal, its recommendation of the Merger Agreement or the Merger; (v) if Dian
G. Owen shall have breached any of her obligations under her Support/Voting
Agreement with Cardinal; (vi) if at the Special Meeting (including any
adjournment or postponement thereof) the requisite vote of the Owen Shareholders
to approve the Merger Proposal shall not have been obtained; or (vii) the Merger
Agreement shall have been terminated by either Cardinal or Owen pursuant to
Section 7.1 thereof (other than a termination pursuant to Sections 7.1(a),
7.1(b), 7.1(c) (other than a termination by Cardinal pursuant to Section 7.1(c)
of the Merger Agreement if Owen's or Owen's affiliate's failure to perform any
material covenant or obligation under the Merger Agreement has been the cause of
or resulted in the failure of the Merger to occur on or before May 31, 1997), or
7.1(g)).
 
     At the request of Cardinal, at any time commencing upon the occurrence of a
Purchase Event and ending 13 months immediately thereafter (the "Cardinal
Repurchase Period"), Owen (or any successor entity thereof) is required to
repurchase the Option from Cardinal together with all (but not less than all)
shares of Owen Common Stock purchased by Cardinal pursuant thereto with respect
to which Cardinal then has beneficial ownership, at a price (when calculated on
a per share basis, the "Per Share Repurchase Price") equal to the sum of: (i)
the difference between (A) the "Market/Tender Offer Price" for shares of Owen
Common Stock (defined as the higher of (x) the highest price per share at which
a tender or exchange offer has been made for shares of Owen Common Stock or (y)
the highest closing price per share of Owen Common Stock as reported by the NYSE
Composite Tape for any day within that portion of the Cardinal Repurchase Period
which precedes the date Cardinal gives notice of the required repurchase) and
(B) the exercise price, as adjusted pursuant to the Stock Option Agreement,
multiplied by the number of shares of Owen Common Stock with respect to which
the Option has not been exercised, but only if such Market/Tender Offer Price is
greater than such exercise price; (ii) the exercise price paid by Cardinal for
any shares of Owen Common Stock acquired pursuant to the Option; (iii) the
difference between the Market/Tender Offer Price and the exercise price paid by
Cardinal for any shares of Owen Common Stock purchased pursuant to the exercise
of the Option, multiplied by the number of shares so purchased, but only if such
Market/Tender Offer Price is greater than such exercise price; and (iv)
Cardinal's out-of-pocket expenses incurred in connection with pursuing the
transactions contemplated by the Merger Agreement, including, without
limitation, legal, accounting and investment banking fees, less any amounts
previously paid by Owen to Cardinal solely in reimbursement for costs pursuant
to the Merger Agreement.
 
     Except to the extent that Cardinal shall have previously exercised its
rights described in the preceding paragraph, at the request of Owen during the
six-month period commencing 180 days following the first occurrence of a
Purchase Event, Owen may repurchase from Cardinal, and Cardinal is required to
sell to Owen, all (but not less than all) of the Owen Common Stock acquired by
Cardinal pursuant to the Option and with respect to which Cardinal has
beneficial ownership at the time of such repurchase at a price per share equal
to the greater of (i) 110% of the Market/Tender Offer Price per share
(calculated in the manner described above but utilizing the period beginning on
the occurrence of a Purchase Event and ending on the date Owen exercises its
repurchase right), (ii) the Per Share Repurchase Price or (iii) the sum of (A)
the aggregate Purchase Price of the shares so repurchased plus (B) interest on
the aggregate Purchase Price paid for the shares so repurchased from the date of
purchase by Cardinal to the date of repurchase at the highest rate of interest
announced by Bank One, Columbus, NA as its prime or base lending or reference
rate during such period, less any dividends received on the shares so
repurchased, plus (C) Cardinal's out-of-pocket expenses incurred in connection
with pursuing the transactions contemplated by the Merger Agreement, including,
without limitation, legal, accounting and investment banking fees, less any
amounts previously paid by Owen to Cardinal solely in reimbursement for costs
pursuant to the Merger Agreement, which sum shall be divided by the number of
shares of Owen Common Stock to be repurchased by Owen.
 
                                       32
<PAGE>   39
 
     Pursuant to the Stock Option Agreement, at any time after a Purchase Event,
Owen will be obligated, under certain circumstances, to file a registration
statement under the Securities Act if necessary in order to permit the sale or
other disposition of the shares of Owen Common Stock that have been acquired
upon exercise of the Option. Owen is not required to file more than one such
registration statement under the Stock Option Agreement.
 
     The foregoing is a summary of the material provisions of the Stock Option
Agreement, a copy of which is filed as an exhibit to the Registration Statement.
See "Available Information." This summary is qualified in its entirety by
reference to the Stock Option Agreement which is incorporated herein by this
reference.
 
SUPPORT/VOTING AGREEMENTS
 
     Concurrently with the execution of the Merger Agreement, Cardinal and each
Supporting Shareholder executed separate Support/Voting Agreements pursuant to
which each Supporting Shareholder agreed that, among other things, such
Supporting Shareholder (i) will not, will not permit any company, trust or other
entity controlled by such Supporting Shareholder to, and will not permit any of
its affiliates to, contract to sell, sell or otherwise transfer or dispose of
any of the shares of the capital stock of Owen of which such Supporting
Shareholder or its affiliates is the record or beneficial owner ("Supporting
Shareholder Shares") or any interest therein or securities convertible thereinto
or any voting rights with respect thereto, other than (x) pursuant to the Merger
or (y) with Cardinal's prior written consent (except, solely in the case of Ms.
Owen, with respect to up to 25,000 shares of Owen Common Stock that may be
transferred to charitable organizations qualified under Section 501(c)(3) of the
Code); (ii) will not, will not permit any such company, trust or other entity
to, and will not permit any of its affiliates to, directly or indirectly
(including through its officers, directors, employees, or other
representatives), solicit, initiate, encourage or facilitate, or furnish or
disclose non-public information in furtherance of, any inquiries or the making
of any proposal with respect to any Competing Transaction, or negotiate, explore
or otherwise engage in discussions with any person (other than Cardinal, Subcorp
or their respective directors, officers, employees, agents and representatives)
with respect to any Competing Transaction or enter into any agreement,
arrangement, or understanding with respect to any Competing Transaction or agree
to or otherwise assist in the effectuation of any Competing Transaction;
provided, however, that nothing in any Support/Voting Agreement prevents any
Supporting Shareholder from taking any action or omitting to take any action (x)
as a member of the Board of Directors of Owen necessary so as not to violate
such Supporting Shareholder's fiduciary obligations as a Director or (y) as an
officer of Owen at the direction or request of the Board of Directors of Owen so
long as such direction or request was not made in violation of any of the terms
of the Merger Agreement; and (iii) will vote all of such Supporting Shareholder
Shares beneficially owned by such Supporting Shareholder or its affiliates, or
over which such Supporting Shareholder or any of its affiliates has voting power
or control, directly or indirectly (including any Owen Common Stock acquired
after the date of the Support/Voting Agreement), at the record date for any
meeting of shareholders of Owen called to consider and vote to approve the
Merger and the Merger Agreement and/or the transactions contemplated thereby in
favor thereof and neither Supporting Shareholder nor any of its affiliates will
vote such Supporting Shareholder Shares in favor of any Competing Transaction.
Each Support/Voting Agreement may be terminated at the option of any party
thereto at any time after the earlier of (i) termination of the Merger Agreement
and (ii) the Effective Time.
 
     Each Supporting Shareholder and the number of shares of Owen Common Stock
beneficially owned by it or over which it had voting control as of the Record
Date are as follows: Dian G. Owen (2,513,605 shares); Stephen A. Drury (39,263
shares); J.D. Epstein (2,500 shares); Carl E. Isgren (393,852 shares); Donald M.
Jones (86,530 shares); Hugh M. Morrison (1,000 shares); Diane Peterson (0
shares); Robert M. Rutledge (35,016 shares); Harlan C. Stai (175,603 shares);
Robert L. Williams (445,073 shares). Such numbers include shares allocated to
the respective accounts of such individuals who are participants in the ESOP but
do not include shares in the ESOP for which such person may be deemed to have
voting control solely because he or she acts as a trustee for the ESOP (to which
none of the Support/Voting Agreement applies).
 
     The foregoing is a summary of the material provisions of the Support/Voting
Agreements, a form of which is filed as an exhibit to the Registration
Statement. See "Available Information." This summary is
 
                                       33
<PAGE>   40
 
qualified in its entirety by reference to the form of Support/Voting Agreement
which is incorporated herein by reference.
 
                              THE MERGER AGREEMENT
 
     The following is a summary of material provisions of the Merger Agreement,
a copy of which is included as Annex A to this Proxy Statement/Prospectus. This
summary is qualified in its entirety by reference to the Merger Agreement which
is incorporated herein by this reference.
 
THE MERGER
 
     The Merger Agreement provides that Subcorp will be merged with and into
Owen with the result that Owen as the Surviving Corporation becomes a wholly
owned subsidiary of Cardinal, subject to the requisite approval of Owen
Shareholders and the satisfaction or waiver of the other conditions to the
Merger. The Merger will become effective at the Effective Time upon the filing
of duly executed articles of merger with the Texas Secretary of State or at such
later time as shall be agreed upon by Cardinal and Owen and specified in the
articles of merger. This filing is to be made on the Closing Date specified by
Cardinal and Owen, which date will be as soon as possible, but in any event
within three business days, following the date upon which all conditions set
forth in the Merger Agreement have been satisfied or waived, as the case may be,
or such other time as the parties may mutually agree. It is currently
anticipated that the Effective Time will occur shortly after the later of the
date of the Special Meeting, assuming the Merger Agreement and the Merger are
approved at such meeting and all other conditions to the Merger have been
satisfied or waived.
 
MERGER CONSIDERATION
 
     Exchange Ratio.  Upon consummation of the Merger pursuant to the Merger
Agreement, each share of Owen Common Stock issued and outstanding immediately
prior to the Effective Time (other than shares held in the treasury of Owen, if
any, which will be cancelled) will be converted into and represent a fraction of
a Cardinal Common Share equal to the Exchange Ratio. The Exchange Ratio (rounded
to the nearest ten-thousandth of a share and as adjusted pursuant to the Merger
Agreement to reflect the Stock Split) is equal to (i) the quotient obtained by
dividing (a) $27.25 by (b) the Average Share Price; provided, however, that (x)
if the Average Share Price is less than $54.7833, then the Exchange Ratio will
be equal to 0.4974, or (y) if the Average Share Price is greater than $60.5500,
then the Exchange Ratio will be equal to 0.4500; or (ii) if Cardinal has made an
Adjustment Election, then the Exchange Ratio will be equal to the product of (a)
0.4974 and (b) the quotient obtained by dividing $46.1333 by the Average Share
Price. For additional information regarding an Adjustment Election, see
"Summary -- The Merger -- General; Exchange Ratio; Adjustment Election."
 
     The definitive Exchange Ratio will be determinable after the close of
trading on the sixth trading day prior to the Special Meeting, at which time
Owen Shareholders may call Morrow & Co. at (800) 607-0088, to obtain the
definitive Exchange Ratio.
 
     Fractional Shares.  No certificates for fractional Cardinal Common Shares
will be issued in the Merger, and to the extent that an outstanding share of
Owen Common Stock would otherwise have become a fractional Cardinal Common
Share, the holder thereof, upon presentation of such fractional interest
represented by an appropriate certificate of Owen Common Stock to the exchange
agent designated by Cardinal as described under "-- Exchange Procedures", will
be entitled to receive a cash payment therefor in an amount equal to the value
(determined with reference to the closing price of Cardinal Common Shares on the
NYSE Composite Tape on the last full trading day immediately prior to the
Effective Time) of such fractional interest.
 
     Conversion of Subcorp Common Stock.  Each share of common stock, $0.01 par
value per share, of Subcorp issued and outstanding immediately prior to the
Effective Time will be converted into one share of common stock, $0.01 par value
per share, of Owen as the Surviving Corporation. Such newly issued shares will
thereupon constitute all of the issued and outstanding capital stock of the
Surviving Corporation.
 
                                       34
<PAGE>   41
 
EXCHANGE PROCEDURES
 
     HOLDERS OF SHARES OF OWEN COMMON STOCK SHOULD NOT SEND IN THEIR OWEN STOCK
CERTIFICATES UNTIL THEY RECEIVE A LETTER OF TRANSMITTAL.
 
     As soon as practicable after the Effective Time, a letter of transmittal
will be mailed to each holder of record of a certificate or certificates (the
"Certificates") which immediately prior to the Effective Time represented
outstanding shares of Owen Common Stock whose shares were converted into the
right to receive Cardinal Common Shares. This letter of transmittal must be used
in forwarding Certificates for surrender in exchange for certificates evidencing
Cardinal Common Shares to which a holder of shares of Owen Common Stock prior to
the Effective Time has become entitled and, if applicable, cash in lieu of any
fractional Cardinal Common Share. Such letter of transmittal will be accompanied
by instructions specifying other details of the exchange. After receipt of such
letter of transmittal, each holder of Certificates should surrender such
Certificates to Boatmen's Trust Company, the exchange agent for the Merger,
pursuant to and in accordance with the instructions accompanying such letter of
transmittal, and each such holder will receive in exchange therefor a
certificate evidencing the whole number of Cardinal Common Shares to which he is
entitled and a check representing the amount of cash payable in lieu of any
fractional Cardinal Common Share, if any, and unpaid dividends and
distributions, if any, which such holder has the right to receive pursuant to
the Merger Agreement, after giving effect to any required withholding tax. No
interest will be paid or accrued on the cash in lieu of fractional shares, if
any, and unpaid dividends and distributions, if any, payable to holders of
Certificates. Certificates surrendered for exchange by any person constituting
an "affiliate" of Owen for purposes of Rule 145(c) under the Securities Act
shall not be exchanged until Cardinal has received an executed Affiliate Letter
from such person as prescribed under the Merger Agreement.
 
     After the Effective Time, each Certificate, until so surrendered and
exchanged, will be deemed, for all purposes, to represent only the right to
receive upon surrender a certificate representing Cardinal Common Shares and
cash in lieu of fractional shares, if any, and unpaid dividends and
distributions, if any, as provided above. The holder of such unexchanged
Certificates will not be entitled to receive any dividends or other
distributions declared or made by Cardinal having a record date on or after the
Effective Time until the Certificate is surrendered. Subject to applicable laws,
upon surrender of such unexchanged Certificates, such dividends and
distributions, if any, will be paid without interest and less the amount of any
withholding taxes which may be required thereon.
 
REPRESENTATIONS, WARRANTIES AND COVENANTS
 
     The Merger Agreement contains various representations, warranties and
covenants of Cardinal and Owen. The representations and warranties made by the
parties in the Merger Agreement will not survive the Effective Time, although it
is a condition of each party's obligations under the Merger Agreement that the
other parties' representations and warranties be true and correct except for
such inaccuracies which have not had and would not reasonably be expected to
have in the reasonably foreseeable future a material adverse effect on the
representing or warranting party.
 
     Pursuant to the Merger Agreement, each of Cardinal and Owen has agreed that
it will (i) use its reasonable efforts to take all action and to do all things
necessary, proper or advisable to consummate the Merger and the transactions
contemplated by the Merger Agreement (including, without limitation, satisfying
their respective conditions precedent to the Merger); (ii) (A) file any
Notification and Report Forms and related materials required to be filed with
the FTC and the Antitrust Division under the HSR Act with respect to the Merger
(which filings required to date have been made) and promptly make any further
filings pursuant thereto that may be necessary, proper or advisable, (B)
cooperate with respect to, and cause each of their respective subsidiaries to
cooperate with respect to, and agree to use all reasonable efforts to contest
and resist, any suit, claim, action, proceeding or investigation (an "Action"),
including legislative, administrative or judicial Action, and to have vacated,
lifted, reversed or overturned any decree, judgment, injunction or other order
(whether temporary, preliminary or permanent) (an "Order") of any governmental
authority that is in effect and that restricts, prevents or prohibits the
consummation of the Merger or any other transactions contemplated by the Merger
Agreement, including, without limitation, by pursuing all available avenues of
 
                                       35
<PAGE>   42
 
administrative and judicial appeal and all available legislative action; and (C)
upon the terms and subject to the conditions set forth in the Merger Agreement,
in connection with the HSR Act, take, or cause to be taken, all actions, and to
do, or cause to be done, and assist and cooperate with the other parties in
doing, all things necessary, proper or advisable to consummate and make
effective, in the most expeditious manner practicable, the Merger and the other
transactions contemplated by the Merger Agreement, including the obtaining of
all necessary actions or nonactions, waivers, consents and approvals from
governmental authorities and the making of all necessary registrations and
filings (including filings with governmental authorities, if any) and the taking
of all reasonable steps as may be necessary to obtain an approval or waiver
from, or to avoid an action or proceeding by, any governmental authority;
provided, however, that a party will not be obligated to take any action
pursuant to this clause (C) if the taking of such action or the obtaining of any
waiver, consent, approval or exemption is reasonably likely (x) to impact in a
materially adverse manner the economic or business benefits of the transactions
contemplated by the Merger Agreement so as to render inadvisable the
consummation of the Merger or (y) to result in an Order (1) prohibiting or
limiting the ownership or operation by Cardinal of any material portion of the
business or assets of Owen or compelling Cardinal to dispose of or hold separate
any of the business or assets of Cardinal or any material portion of the
business or assets of Owen as a result of the Merger or any of the other
transactions contemplated by the Merger Agreement, (2) imposing limitations on
the ability of Cardinal to acquire or hold, or exercise full rights of ownership
of, any shares of capital stock of Owen, including, without limitation, the
right to vote such capital stock on all matters properly presented to the Owen
Shareholders, or (3) prohibiting Cardinal from effectively controlling in any
material respect the business or operations of Owen; (iii) use its reasonable
efforts to obtain early termination of the applicable waiting period; (iv) use
its reasonable efforts to take any additional action that may be necessary,
proper or advisable in connection with any other notices to, filings with, and
authorizations, consents and approvals of any governmental authority that it may
be required to give, make or obtain; (v) permit representatives of the other
party to have appropriate access at all reasonable times to the other's
premises, properties, books, records, contracts, tax records, documents,
customers and suppliers; (vi) unless otherwise required by applicable laws or
requirements of the NYSE (and in that event only if time does not permit) at all
times prior to the earlier of the Effective Time or termination of the Merger
Agreement pursuant to its terms, to consult with the other before issuing any
press release with respect to the Merger and not to issue any such press release
prior to such consultation; and (vii) use its best efforts to cause the Merger
to qualify for pooling-of-interests accounting treatment for financial reporting
purposes and to constitute a tax free "reorganization" under Section 368(a) of
the Code and to permit Owen's legal counsel and Cardinal's legal counsel to
issue their respective opinions to that effect.
 
     Cardinal has agreed in the Merger Agreement (i) to prepare this Proxy
Statement/Prospectus for filing by Owen with the Commission on a confidential
basis as soon as is reasonably practicable, to prepare and file the Registration
Statement with the Commission as soon as is reasonably practicable following
clearance of this Proxy Statement/Prospectus by the Commission and use all
reasonable efforts to have the Registration Statement to be declared effective
by the Commission as promptly as practicable, to advise Owen in writing if, at
any time prior to the Effective Time, Cardinal shall have obtained knowledge of
any information pertaining to Cardinal contained in or omitted from the
Registration Statement that would require an amendment or supplement to the
Registration Statement or this Proxy Statement/Prospectus and to promptly take
such action as shall be required to amend or supplement the Registration
Statement, to maintain the effectiveness of the Registration Statement through
the Effective Time, to take such other reasonable actions (other than qualifying
to do business in any jurisdiction in which it is not so qualified) required to
be taken under any applicable state securities laws in connection with the
issuance of Cardinal Common Shares in the Merger; (ii) from and after the
Effective Time, to cause the Surviving Corporation (including, to the extent
required, providing sufficient funding) to indemnify and hold harmless the
present and former officers and directors of Owen in respect of acts or
omissions occurring prior to the Effective Time to the extent provided under the
Owen Articles and Owen Bylaws in effect on the date of the Merger Agreement;
(iii) from and after the Effective Time, to maintain the policies of directors'
and officers' liability insurance of Owen in effect on the date of the Merger
Agreement through the remainder of their terms which end in June 1997; (iv) for
a period of one year from and after the Effective Time, to cause the Surviving
Corporation to provide for the benefit of employees of the Surviving Corporation
benefits that are no less favorable, in the aggregate, than those
 
                                       36
<PAGE>   43
 
provided to employees of Owen immediately prior to the date of the Merger
Agreement; (v) to give prompt notice to Owen of (x) the occurrence or
non-occurrence of any event the occurrence or non-occurrence of which would
cause any Cardinal or Subcorp representation or warranty contained in the Merger
Agreement to be untrue or inaccurate at or prior to the Effective Time and (y)
any material failure of Cardinal to comply with or satisfy any covenant,
condition or agreement to be complied with or satisfied by it under the Merger
Agreement; (vi) use its best efforts to prepare and publicly release as soon as
practicable (but in any event within fifteen days) following the end of the
first full calendar month completed after the Effective Time, a report in the
form of a quarterly earnings report, registration statement filed with the
Commission, a report filed with the Commission on Form 10-K, 10-Q or 8-K or any
other public filing, statement or announcement which includes the combined
financial results (including combined sales and net income) of Cardinal and Owen
for a period of at least 30 days of combined operations of Cardinal and Owen
following the Effective Time; (vii) that, prior to the Effective Time, Subcorp
shall not conduct any business or make any investments other than as
specifically contemplated by the Merger Agreement and will not have any assets
(other than a de minimis amount of cash paid to Subcorp for the issuance of its
stock to Cardinal) or any material liabilities; (viii) to use its reasonable
efforts to cause the Cardinal Common Shares issuable pursuant to the Merger to
be approved for listing on the NYSE, subject to official notice of issuance,
prior to the Effective Time; and (ix) to cause each such person who may be at
the Effective Time or was on the date hereof an "affiliate" of Cardinal for
purposes of Rule 145 under the Securities Act, to execute and deliver to
Cardinal no less than 30 days prior to the date of the Special Meeting, the
written undertakings set forth in an exhibit to the Merger Agreement.
 
     Owen covenants in the Merger Agreement (i) to take all action in accordance
with the federal securities laws, the Texas Law (as defined under the caption
"Comparison of Shareholder Rights") and the Owen Articles and Owen Bylaws
necessary to convene the Special Meeting for the Owen Shareholders to consider
and vote upon approval of the Merger Proposal; (ii) (A) to promptly furnish
Cardinal with all information concerning Owen as may be required for inclusion
in the Registration Statement, (B) to cooperate with Cardinal in the preparation
of the Registration Statement in a timely fashion and use all reasonable efforts
to assist Cardinal in having the Registration Statement declared effective by
the Commission as promptly as practicable, (C) if at any time prior to the
Effective Time, any information pertaining to Owen contained in or omitted from
the Registration Statement makes such statements contained in the Registration
Statement false or misleading, to promptly so inform Cardinal and provide
Cardinal with the information necessary to make statements contained therein not
false and misleading, (D) to use all reasonable efforts to cooperate with
Cardinal in the preparation and filing of this Proxy Statement/Prospectus with
the Commission, and (E) to use all reasonable efforts to mail at the earliest
practicable date to Owen Shareholders this Proxy Statement/Prospectus, which
shall include all information required under applicable law to be furnished to
Owen Shareholders in connection with the Merger and the transactions
contemplated thereby and shall include the recommendation of the Owen Board in
favor of the Merger unless the Owen Board concludes in good faith on the basis
of the advice of its outside legal counsel that the failure to withdraw such
recommendation is reasonably likely to result in a breach of the fiduciary
obligations of the Owen Board under applicable law; (iii) during the period from
the date of the Merger Agreement to the Effective Time, to conduct its
operations in the ordinary course except as expressly contemplated by the Merger
Agreement and the transactions contemplated thereby and use its reasonable best
efforts to maintain and preserve its business organization and its material
rights and franchises and to retain the services of its officers and key
employees and maintain relationships with customers, suppliers, lessees,
licensees and other third parties, and to maintain all of its operating assets
in their current condition (normal wear and tear excepted), to the end that
their goodwill and ongoing business shall not be impaired in any material
respect; (iv) to use its best efforts consistent with past practice to preserve
its ownership rights to its intellectual property free and clear of any liens,
claims or encumbrances; (v) to cause each such person who may be at the
Effective Time or was on the date of the Merger Agreement an "affiliate" of Owen
for purposes of Rule 145 under the Securities Act, to execute and deliver to
Cardinal no less than 30 days prior to the date of the Special Meeting, the
written undertakings set forth in an exhibit to the Merger Agreement, and on or
prior to such date to provide, with the advice of the outside counsel, Cardinal
with a letter (reasonably satisfactory to counsel to Cardinal) specifying all of
the persons or entities who may be deemed to be "affiliates" of Owen as provided
above; (vi) to give prompt notice to Cardinal of (x) the occurrence or
non-occurrence of any event the occurrence or non-
 
                                       37
<PAGE>   44
 
occurrence of which would cause any Owen representation or warranty contained in
the Merger Agreement to be untrue or inaccurate at or prior to the Effective
Time and (y) any material failure of Owen to comply with or satisfy any
covenant, condition or agreement to be complied with or satisfied by it
thereunder; and (vii) to consult with Cardinal prior to making publicly
available its financial results for any period.
 
     Owen also covenants in the Merger Agreement that, during the period from
the date of the Merger Agreement to the Effective Time, Owen will not, except as
otherwise expressly contemplated by the Merger Agreement and the transactions
contemplated thereby or as set forth therein (including the schedules thereto),
without the prior written consent of Cardinal: (i) do or effect any of the
following actions with respect to its securities: (A) adjust, split, combine or
reclassify its capital stock, (B) make, declare or pay any dividend or
distribution on, or directly or indirectly redeem, purchase or otherwise
acquire, any shares of its capital stock or any securities or obligations
convertible into or exchangeable for any shares of its capital stock, (C) grant
any person any right or option to acquire any shares of its capital stock, (D)
issue, deliver or sell or agree to issue, deliver or sell any additional shares
of its capital stock or any securities or obligations convertible into or
exchangeable or exercisable for any shares of its capital stock or such
securities (except pursuant to the exercise of outstanding options to purchase
Owen Common Stock), or (E) enter into any agreement, understanding or
arrangement with respect to the sale or voting of its capital stock; (ii) sell,
transfer, lease, pledge, mortgage, encumber or otherwise dispose of any of its
property or assets other than in the ordinary course of business; (iii) make or
propose any changes in the Owen Articles or Owen Bylaws; (iv) merge or
consolidate with any other person or acquire a material amount of assets or
capital stock of any other person except to the extent permitted under the
Merger Agreement; (v) incur, create, assume or otherwise become liable for any
indebtedness for borrowed money or assume, guarantee, endorse or otherwise as an
accommodation become responsible or liable for the obligations of any other
individual, corporation or other entity, other than in the ordinary course of
business, consistent with past practice not in excess of $8 million in the
aggregate; (vi) create any subsidiaries; (vii) enter into or modify any
employment, severance, termination or similar agreements or arrangements with,
or grant any bonuses, salary increases, severance or termination pay to, any
officer, director, consultant or employee other than in the ordinary course of
business consistent with past practice, or otherwise increase the compensation
or benefits provided to any officer, director, consultant or employee except as
may be required by applicable law or in the ordinary course of business
consistent with past practice; (viii) enter into, adopt or amend any employee
benefit or similar plan except as may be required by applicable law; (ix) change
any method or principle of accounting in a manner that is inconsistent with past
practice except to the extent required by generally accepted accounting
principles; (x) settle any Actions, whether pending as of the date of the Merger
Agreement or thereafter made or brought involving, individually or in the
aggregate, an amount in excess of $500,000; (xi) write up, write down or write
off the book value of any assets, individually or in the aggregate, in excess of
$250,000 except for depreciation and amortization in accordance with generally
accepted accounting principles consistently applied; (xii) incur or commit to
any capital expenditures, obligations or liabilities in respect thereof which in
the aggregate exceed or would exceed $3 million; (xiii) pay (or agree to become
obligated to pay) any fees and expenses to attorneys, accountants and investment
bankers in connection with the Merger in excess of the amount set forth in the
Merger Agreement; (xiv) take any action to exempt or make not subject to the
provisions of Article 10 of the Owen Articles any person or entity (other than
Cardinal or its subsidiaries) or any action taken thereby, which person, entity
or action would have otherwise been subject to the restrictive provisions
thereof and not exempt therefrom; (xv) take any action that could likely result
in Owen's representations and warranties set forth in the Merger Agreement
becoming false or inaccurate in any material respect; (xvi) permit or cause any
subsidiary to do any of the foregoing or agree or commit to do any of the
foregoing; or (xvii) agree in writing or otherwise to take any of the foregoing
actions.
 
NO NEGOTIATIONS OR SOLICITATIONS
 
     Pursuant to the Merger Agreement, Owen agreed that, during the term of the
Merger Agreement, it will not, and will not authorize or permit any of its
subsidiaries or any of its or its subsidiaries' directors, officers, employees,
agents or representatives, directly or indirectly, to solicit, initiate,
encourage or facilitate, or furnish or disclose non-public information in
furtherance of, any inquiries or the making of any proposal with respect to any
Competing Transaction, or negotiate, explore or otherwise engage in discussions
with any person (other
 
                                       38
<PAGE>   45
 
than Cardinal, Subcorp or their respective directors, officers, employees,
agents and representatives) with respect to any Competing Transaction or enter
into any agreement, arrangement or understanding requiring it to abandon,
terminate or fail to consummate the Merger or any other transactions
contemplated by the Merger Agreement; provided that, at any time prior to the
approval of the Merger Proposal by the Owen Shareholders, Owen may furnish
information to, and negotiate or otherwise engage in discussions with, any party
who delivers a written proposal for a Competing Transaction which was not
solicited or encouraged after the date of the Merger Agreement if and so long as
the Owen Board determines in good faith by a majority vote, based upon
consultation and advice of its outside legal counsel, that failing to take such
action is reasonably likely to constitute a breach of the fiduciary duties of
the Owen Board under applicable law and such a proposal is, after consulting
with Smith Barney or RPR (or any other nationally recognized investment banking
firm), more favorable to Owen Shareholders from a financial point of view than
the transactions contemplated by the Merger Agreement (including any adjustment
to the terms and conditions of such transactions proposed by Cardinal in
response to such Competing Transaction). Further, pursuant to the Merger
Agreement, Owen agreed to immediately cease all existing activities, discussions
and negotiations with any parties conducted prior to the date of the Merger
Agreement with respect to any of the foregoing, and agreed in the event that
prior to the approval of the Merger Proposal by the Owen Shareholders the Owen
Board receives advice of outside legal counsel that failure to do so is
reasonably likely to result in breach of the fiduciary duties of the Owen Board
under applicable law, the Owen Board may (subject to this and the following
sentences) withdraw or modify its recommendation in favor of the Merger and/or
comply with Rule 14e-2 promulgated under the Exchange Act with respect to a
Competing Transaction, provided that it gives Cardinal two business days prior
written notice of its intention to do so (provided that the foregoing shall in
no way limit or otherwise affect Cardinal's right to terminate the Merger
Agreement pursuant to its terms). Any such withdrawal or modification of such
recommendation by the Owen Board shall not change the approval of the Owen Board
for purposes of causing either the provisions of Article 10 of the Owen Articles
or any state takeover statute or other state law to be inapplicable to the
transactions contemplated hereby, including the Merger, the Stock Option
Agreement or the Support/Voting Agreements or change the obligation of Owen to
present the Merger for approval at the Special Meeting. Owen has also agreed
under the Merger Agreement, from and after the execution of this Agreement, to
immediately advise Cardinal in writing of the receipt, directly or indirectly,
of any inquiries, discussions, negotiations, or proposals relating to a
Competing Transaction (including the specific terms thereof and the identity of
the other party or parties involved) and to promptly furnish to Cardinal a copy
of any such written proposal in addition to any information provided to or by
any third party relating thereto.
 
     Under the Merger Agreement, if prior to the approval of the Merger Proposal
by the Owen Shareholders, the Owen Board shall determine in good faith, after
consultation with its financial and legal advisors, that any written proposal
from a third party for a Competing Transaction received after the date of the
Merger Agreement that was not solicited or encouraged by Owen or any of its
subsidiaries or affiliates in violation of the Merger Agreement is more
favorable to the Owen Shareholders from a financial point of view than the
transactions contemplated by the Merger Agreement (including any adjustment to
the terms and conditions of such transaction proposed in writing by Cardinal in
response to such Competing Transaction) and is in the best interest of the Owen
Shareholders and Owen has received (x) advice of its outside legal counsel that
failure to enter into such a Competing Transaction is reasonably likely to
constitute a breach of the Owen Board's fiduciary duties under applicable law
and (y) a written opinion (a copy of which has been delivered to Cardinal) from
Smith Barney or RPR that the Competing Transaction is more favorable from a
financial point of view to the Owen Shareholders than the transactions
contemplated by the Merger Agreement (including any adjustment to the terms and
conditions of such transaction proposed in writing by Cardinal), Owen may
terminate the Merger Agreement (the "Fiduciary Termination Right") and enter
into a letter of intent, agreement-in-principle, acquisition agreement or other
similar agreement (each, an "Acquisition Agreement") with respect to such
Competing Transaction, provided that, prior to any such termination, (i) Owen
has provided Cardinal written notice that it intends to terminate the Merger
Agreement pursuant to this provision, identifying the Competing Transaction then
determined to be more favorable and the parties thereto and delivering a copy of
the Acquisition Agreement for such Competing Transaction in the form to be
entered into, and (ii) at least two full business days after Owen has provided
the notice referred to in clause
 
                                       39
<PAGE>   46
 
(i) above (provided that the opinions referred to in clauses (x) and (y) above
shall continue in effect without revision or modification), Owen delivers to
Cardinal (A) a written notice of termination of this Agreement pursuant to this
provision, (B) a check in the amount of Cardinal's costs (as defined in the
Merger Agreement) as the same may have been estimated by Cardinal in good faith
prior to the date of such delivery (subject to an adjustment payment between the
parties upon Cardinal's definitive determination of such costs), plus the amount
of the termination fee provided in the Merger Agreement and described below
under "-- Termination; Effect of Termination", (C) a written acknowledgment from
Owen that (x) the termination of the Merger Agreement and the entry into the
Acquisition Agreement for the Competing Transaction will be a "Purchase Event"
as defined in the Stock Option Agreement and (y) the Stock Option Agreement
shall be honored in accordance with its terms and (D) a written acknowledgment
from each other party to such Competing Transaction that it is aware of the
substance of Owen's acknowledgment under clause (C) above and waives any right
it may have to contest the matters thus acknowledged by Owen.
 
CONDITIONS
 
     The obligations of Cardinal and Owen to consummate the Merger are subject
to fulfillment of the following conditions, among others: (i) no temporary
restraining order, preliminary or permanent injunction or other order or decree
which prevents the consummation of the Merger shall have been issued and remain
in effect, and no statute, rule or regulation shall have been enacted by any
governmental authority which prevents the consummation of the Merger; (ii) all
waiting periods applicable to the consummation of the Merger under the HSR Act
shall have expired or been terminated; (iii) the Merger and the transactions
contemplated by the Merger Agreement shall have been approved by the Owen
Shareholders in the manner required by any applicable law; (iv) the Commission
shall have declared the Registration Statement effective, and at the Effective
Time, no stop order or similar restraining order prohibiting the Merger shall
have been threatened by the Commission or entered by the Commission or any state
securities administrator; (v) no Action shall be instituted by any governmental
authority which seeks to prevent consummation of the Merger or seeking material
damages in connection with the transactions contemplated by the Merger Agreement
which continues to be outstanding; and (vi) Cardinal shall have received a
letter, in form and substance reasonably satisfactory to Cardinal, from Deloitte
& Touche LLP dated the date of the Proxy Statement/Prospectus and confirmed in
writing at the Effective Time stating that the Merger will qualify as a
pooling-of-interests transaction under Opinion 16 of the Accounting Principles
Board.
 
     The obligations of Owen to consummate the Merger and the transactions
contemplated by the Merger Agreement are further subject to the receipt of
certain closing certificates and a legal opinion and fulfillment of the
following conditions: (i) the representations and warranties of each of Cardinal
and Subcorp shall be true and correct on and as of the Closing Date (except for
those made as of a specified date), except for such inaccuracies which have not
had and could not reasonably be expected to have in the reasonably foreseeable
future a material adverse effect on Cardinal; (ii) each of Cardinal and Subcorp
shall have performed in all material respects each obligation and agreement and
shall have complied in all material respects with each covenant to be performed
and complied with by it under the Merger Agreement at or prior to the Effective
Time; (iii) the Cardinal Common Shares to be issued in the Merger shall have
been authorized for listing on the NYSE, subject to official notice of issuance;
and (iv) Owen shall have received the opinion of Vinson & Elkins L.L.P., dated
on or prior to the effective date of the Registration Statement, to the effect
that (a) the Merger will constitute a reorganization under section 368(a) of the
Code, (b) Owen, Cardinal and Subcorp will each be a party to that
reorganization, and (c) no gain or loss will be recognized by the shareholders
of Owen upon the receipt of Cardinal Common Shares in exchange for shares of
Owen Common Stock pursuant to the Merger except with respect to cash received in
lieu of fractional share interests in Cardinal Common Shares.
 
     The obligations of Cardinal to consummate the Merger and the other
transactions contemplated by the Merger Agreement are further subject to the
receipt of certain closing certificates and a legal opinion and fulfillment of
the following conditions: (i) the representations and warranties of Owen shall
be true and correct on and as of the Closing Date (except for those made as of a
specified date), except for such inaccuracies which have not had and could not
reasonably be expected to have in the reasonably foreseeable future a
 
                                       40
<PAGE>   47
 
material adverse effect on Owen; (ii) Owen shall have performed in all material
respects each obligation and agreement and shall have complied in all material
respects with each covenant to be performed and complied with by it under the
Merger Agreement at or prior to the Effective Time; (iii) Cardinal shall have
received the opinion of Wachtell, Lipton, Rosen & Katz, dated on or prior to the
effective date of the Registration Statement, to the effect that (a) the Merger
will constitute a reorganization under section 368(a) of the Code, (b) Cardinal,
Subcorp and Owen will each be a party to that reorganization, and (c) no gain or
loss will be recognized by Cardinal, Subcorp or Owen by reason of the Merger;
and (iv) there shall not have been a breach of the Stock Option Agreement.
 
OWEN STOCK OPTIONS
 
     Cardinal and Owen covenant in the Merger Agreement to cause unexpired and
unexercised Owen Options granted to current or former directors, officers or key
employees of Owen by Owen to be automatically converted at the Effective Time
into Cardinal Exchange Options. See "The Merger -- Interests of Certain Persons
in the Merger -- Owen Options." Cardinal further covenants to use its reasonable
efforts to file with the Commission, within ten business days after the Closing
Date, a registration statement on Form S-8 or other appropriate form under the
Securities Act to register the Cardinal Common Shares issuable upon exercise of
the Cardinal Exchange Options and to use its reasonable efforts to cause such
registration statement to remain effective until the exercise or expiration of
such options.
 
EMPLOYEE BENEFITS
 
     Cardinal has agreed that, for a period of one year from and after the
Effective Time, it will cause the Surviving Corporation to provide for the
benefit of employees of the Surviving Corporation benefits that are no less
favorable, in the aggregate, than those provided to employees of Owen
immediately prior to the date of the Merger Agreement. In the event Cardinal
satisfies such obligations by adding employees of Owen to Cardinal's medical
plan (the "Cardinal Medical Plan"), then eligibility of such employees for
medical benefits under the Cardinal Medical Plan will not be subject to standard
exclusions for pre-existing conditions.
 
TERMINATION; EFFECT OF TERMINATION
 
     The Merger Agreement may be terminated at any time prior to the Effective
Time, whether before or after approval and adoption of the Merger Agreement by
Owen Shareholders (i) by mutual consent of Cardinal and Owen; (ii) by either
Cardinal or Owen if any permanent injunction or other order of a court or other
competent governmental authority preventing the consummation of the Merger
becomes final and non-appealable; (iii) by either Cardinal or Owen if the Merger
is not consummated before May 31, 1997, unless that deadline is extended by the
Boards of Directors of both Cardinal and Owen (provided that a party shall not
have a right to so terminate the Merger Agreement if such party's failure or
such party's affiliate's failure to perform any material covenant or obligation
under the Merger Agreement has been the cause of or resulted in the failure of
the Merger to occur on or before such date); (iv) by Cardinal if the Owen Board
of Directors of Owen shall withdraw, modify or change its recommendation in
favor of the Merger in a manner adverse to Cardinal, or if the Owen Board shall
have refused to affirm such recommendation within two business days of any
written request from Cardinal; (v) by Cardinal or Owen if at the Special Meeting
(including any adjournment or postponement thereof) the requisite vote of the
Owen Shareholders to approve the Merger Proposal shall not have been obtained;
(vi) by Owen, pursuant to the Fiduciary Termination Right; (vii) by Owen, no
earlier than the fifth trading day or later than the third full trading day
immediately preceding the date of the Special Meeting, if the Average Share
Price is less than $46.1333, provided that Owen will have no right to terminate
pursuant to this clause (vii) unless (x) Owen shall have given, during the three
trading day period referred to above, one full trading day's prior written
notice of its intention to terminate pursuant to this clause (vii) and (y)
Cardinal during such one full trading day notice period shall not have made an
Adjustment Election; or (viii) by Cardinal if Owen shall have breached any of
its obligations under the Stock Option Agreement or if Dian G. Owen shall have
breached any of her obligations under her Voting/Support Agreement with
Cardinal.
 
                                       41
<PAGE>   48
 
     The Merger Agreement provides that if the Merger Agreement is terminated
and it is judicially determined that termination was caused by an intentional
breach of the Merger Agreement, the breaching party shall indemnify and hold
harmless the other parties thereto for their respective out-of-pocket costs,
fees and expenses of their counsel, accountants, financial advisors and other
experts and advisors as well as fees and expenses incident to negotiation,
preparation and execution of the Merger Agreement and related documentation and
shareholders' meetings and consents ("Costs"). If the Merger Agreement is
terminated for any of the reasons set forth in the preceding paragraph (other
than a termination pursuant to clauses (i) (prior to the public announcement of
a Competing Transaction), (ii), (iii) (other than a termination by Cardinal
pursuant to clause (iii) if Owen's failure to perform any material covenant or
obligation under the Merger Agreement has been the cause of or resulted in the
failure of the Merger to occur on or before May 31, 1997), (v), (vii) of the
preceding paragraph) or the Merger Agreement is terminated pursuant to clause
(v) of the preceding paragraph and within 12 months after the date of
termination Owen enters into an Acquisition Agreement for a Business Combination
(as defined below) or consummates a Business Combination Owen will, in the case
of a termination by Cardinal, within three business days following any such
termination or, in the case of a termination by Owen, (except in each case, if
the termination is pursuant to clause (v) of the preceding paragraph, then,
prior to consummation of a Business Combination) or execution of the definitive
agreement with respect thereto) concurrently with such termination, pay to
Cardinal in cash by wire transfer in immediately available funds to an account
designated by Cardinal (i) in reimbursement for Cardinal's expenses an amount in
cash equal to the aggregate amount of Cardinal's Costs incurred in connection
with pursuing the transactions contemplated by the Merger Agreement, including,
without limitation, legal, accounting and investment banking fees, up to but not
in excess of an amount equal to $1.8 million in the aggregate and (ii) a
termination fee in an amount equal to $13 million. For the purposes of the
immediately preceding sentence, "Business Combination" means (i) a merger,
consolidation, share exchange, business combination or similar transaction
involving Owen as a result of which the Owen Shareholders prior to such
transaction in the aggregate cease to own at least a majority of the voting
securities of the entity surviving or resulting from such transaction (or the
ultimate parent entity thereof), (ii) a sale, lease, exchange, transfer or other
disposition of more than 50% of the assets of Owen and its subsidiaries, taken
as a whole, in a single transaction or a series of related transactions, or
(iii) the acquisition, by a person (other than Cardinal or any affiliate
thereof) or group (as such term is defined under Section 13(d) of the Exchange
Act and the rules and regulations thereunder) of beneficial ownership (as
defined in Rule 13d-3 under the Exchange Act) of more than 50% of the Owen
Common Stock whether by tender or exchange offer or otherwise.
 
AMENDMENT AND WAIVER
 
     The Merger Agreement may be amended in writing by the parties thereto, by
action taken or authorized by their respective Boards of Directors, at any time
before or after approval and adoption of the Merger Proposal by Owen
Shareholders, but after each such approval, no amendment shall be made which by
law requires further approval or authorization by Owen Shareholders without such
further approval or authorization.
 
     At any time prior to the Effective Time, Cardinal (with respect to Owen) or
Owen (with respect to Cardinal and Subcorp) by action taken or authorized by
their respective Boards of Directors may, to the extent legally allowed, (i)
extend the time for performance of any of the obligations or other acts of such
party, (ii) waive any inaccuracies in the representations and warranties
contained in the Merger Agreement or any document delivered pursuant thereto,
and (iii) waive compliance with any of the agreements or conditions contained
therein; provided that such waiver or extension is set forth in a written
instrument signed on behalf of such party.
 
EXPENSES
 
     Except as otherwise provided in the Merger Agreement and the Stock Option
Agreement (as described above), Cardinal and Owen will pay their own Costs and
expenses associated with the transactions contemplated by the Merger Agreement,
except that those expenses incurred in connection with filing,
 
                                       42
<PAGE>   49
 
printing and mailing the Registration Statement and this Proxy
Statement/Prospectus (including filing fees related thereto) will be shared
equally by Cardinal and Owen.
 
                    CERTAIN FEDERAL INCOME TAX CONSEQUENCES
 
     The following is a general summary of the material federal income tax
consequences of the Merger to the holders of Owen Common Stock and is based upon
current provisions of the Code, existing regulations thereunder, current
administrative rulings of the Internal Revenue Service (the "IRS") and court
decisions, all of which are subject to change. No attempt has been made to
comment on all federal income tax consequences of the Merger that may be
relevant to particular holders, including holders that are subject to special
tax rules such as dealers in securities, foreign persons, mutual funds,
insurance companies, tax-exempt entities and holders who do not hold their
shares as capital assets. HOLDERS OF OWEN COMMON STOCK ARE ADVISED AND EXPECTED
TO CONSULT THEIR OWN TAX ADVISORS REGARDING THE FEDERAL INCOME TAX CONSEQUENCES
OF THE MERGER IN LIGHT OF THEIR PERSONAL CIRCUMSTANCES AND THE CONSEQUENCES
UNDER STATE, LOCAL AND FOREIGN TAX LAWS.
 
     Owen has received from its counsel, Vinson & Elkins L.L.P., an opinion to
the effect that for federal income tax purposes the merger will constitute a
reorganization within the meaning of section 368(a) of the Code, that Cardinal,
Subcorp and Owen will each be a party to that reorganization, and that the Owen
Shareholders will not recognize any gain or loss upon the receipt of Cardinal
Common Shares in exchange for their Owen Common Stock except with respect to
cash received in lieu of a fractional interest in Cardinal Common Shares. The
Merger Agreement provides that Owen is not obligated to consummate the Merger
unless Owen shall have received such opinion. Such opinion is subject to certain
assumptions and based on certain representations of Cardinal, Subcorp and Owen.
Owen Shareholders should be aware that such opinion is not binding on the IRS
and no assurance can be given that the IRS will not adopt a contrary position or
that a contrary IRS position would not be sustained by a court.
 
     Assuming the Merger qualifies as a reorganization under section 368(a) of
the Code, the following federal income tax consequences will occur:
 
          (a) no gain or loss will be recognized by Cardinal, Subcorp or Owen by
     reason of the Merger;
 
          (b) no gain or loss will be recognized by a holder of Owen Common
     Stock upon the exchange of all of such holder's shares of Owen Common Stock
     solely for Cardinal Common Shares pursuant to the Merger;
 
          (c) the aggregate basis of the Cardinal Common Shares received by a
     holder of Owen Common Stock (including any fractional share interest deemed
     received) will be the same as the aggregate basis of the shares of Owen
     Common Stock surrendered in exchange therefor;
 
          (d) the holding period of the Cardinal Common Shares received by a
     holder of Owen Common Stock (including any fractional share interest deemed
     received) will include the holding period of the shares of Owen Common
     Stock surrendered in exchange therefor, provided that such shares of Owen
     Common Stock are held as capital assets at the Effective Time; and
 
          (e) a holder of Owen Common Stock who receives cash in lieu of a
     fractional interest in Cardinal Common Shares will recognize gain or loss
     equal to the difference, if any, between such shareholder's basis in the
     fractional share (as described in paragraph (c) above) and the amount of
     cash received. Such gain or loss will be eligible for long-term capital
     gain or loss treatment if the Owen Common stock is held by such
     shareholders as a capital asset at the Effective Time and the holding
     period for the fractional share (as described in paragraph (d) above) is
     more than one year.
 
     THE FOREGOING DISCUSSION OF MATERIAL FEDERAL INCOME TAX CONSEQUENCES IS FOR
GENERAL INFORMATION PURPOSES ONLY AND IS NOT TAX ADVICE. THE OPINION OF COUNSEL
IS NOT BINDING ON THE INTERNAL REVENUE SERVICE. BECAUSE OF THE COMPLEXITY OF THE
TAX LAWS, AND BECAUSE THE TAX CONSEQUENCES OF ANY PARTICULAR SHAREHOLDER MAY BE
AFFECTED BY MATTERS NOT DISCUSSED HEREIN, EACH OWEN SHAREHOLDER IS URGED TO
CONSULT HIS OWN TAX ADVISER WITH RESPECT TO HIS OWN PARTICULAR CIRCUMSTANCES AND
WITH RESPECT TO THE SPECIFIC TAX CONSEQUENCES OF
 
                                       43
<PAGE>   50
 
THE MERGER TO HIM, INCLUDING THE APPLICABILITY AND EFFECT OF STATE, LOCAL AND
FOREIGN TAX LAWS, ESTATE TAX LAWS AND PROPOSED CHANGES IN APPLICABLE TAX LAWS.
 
                                 THE COMPANIES
 
BUSINESS OF CARDINAL
 
     Cardinal is a leading health care service provider, offering an array of
value-added pharmaceutical distribution services to a broad base of customers,
and is a holding company operating through a number of separate operating
subsidiaries. It is one of the nation's largest wholesale distributors of
pharmaceutical and related health care products to independent and chain drug
stores, hospitals, alternate care centers and the pharmacy departments of
supermarkets and mass merchandisers located throughout the continental United
States. Through its Pyxis subsidiary, Cardinal develops and manufactures unique
point-of-use systems which automate the distribution, management and control of
medications and supplies in hospitals and alternate care facilities. Cardinal is
also the largest franchisor of independent retail pharmacies in the United
States through its Medicine Shoppe subsidiary. In addition, through its Allied
division, Cardinal provides pharmacy management services to hospitals. PCI
Services, Inc., one of Cardinal's subsidiaries, is also a leading international
provider of integrated packaging services to pharmaceutical manufacturers.
 
     As a full-service wholesale distributor, Cardinal complements its
distribution activities by offering a broad range of value-added support
services to assist Cardinal's customers and suppliers in maintaining and
improving their market positions and to strengthen Cardinal's role in the
channel of distribution. These support services include computerized order entry
and order confirmation systems, customized invoicing, generic sourcing programs,
product movement and management reports, consultation on store operation and
merchandising, and customer training. Cardinal's proprietary software systems
feature customized databases specially designed to help its customers order more
efficiently, contain costs, and monitor their purchases which are covered by
group contract purchasing arrangements.
 
     Cardinal operates several specialty health care businesses which offer
value-added services to Cardinal's customers and suppliers while providing
Cardinal with additional opportunities for growth and profitability. For
example, Cardinal operates a pharmaceutical repackaging program for both
independent and chain drugstore customers and serves as a distributor of
therapeutic plasma products and other specialty pharmaceuticals to hospitals,
clinics and other managed care facilities on a nationwide basis through the
utilization of telemarketing and direct mail programs. These specialty
distribution activities are part of Cardinal's overall strategy of developing
diversified products and services to enhance the profitability of its business
and that of its customers and suppliers.
 
     In February 1994, Cardinal combined with Whitmire, a Folsom,
California-based drug wholesaler. The majority of Whitmire's sales were
concentrated in the western and central United States, complementing Cardinal's
former concentration of sales in the eastern United States and positioning the
combined company to service both customers and suppliers on a national basis. As
a result of the Whitmire Merger, Cardinal now maintains a network of
pharmaceutical distribution centers enabling it to routinely serve the entire
population of the continental U.S. on a next-day basis.
 
     Cardinal has completed several additional business combinations since the
Whitmire Merger. On July 1, 1994, Cardinal acquired Humiston-Keeling, Inc., a
Calumet City, Illinois-based drug wholesaler serving customers located primarily
in the upper midwest region of the United States. On July 18, 1994, Cardinal
completed a merger with Behrens Inc., a Waco, Texas-based drug wholesaler
serving customers located primarily in Texas and adjoining states. On November
13, 1995, Cardinal completed a merger with MSI, a St. Louis, Missouri-based
franchisor of independent apothecary-style retail pharmacies in the United
States and abroad. On May 7, 1996, Cardinal completed a merger with Pyxis, a San
Diego, California-based designer, manufacturer, marketer and servicer of unique,
point-of-use systems which automate the distribution, management and control of
medications and supplies in hospitals and other healthcare facilities. Pyxis had
previously acquired Allied in August 1995. Finally, on October 11, 1996,
Cardinal completed a merger
 
                                       44
<PAGE>   51
 
with PCI, a Philadelphia, Pennsylvania-based provider of integrated packaging
services to pharmaceutical manufacturers.
 
     Additional information concerning Cardinal and its subsidiaries is included
in the Cardinal documents filed with the Commission, which are incorporated by
reference herein. See "Incorporation of Certain Documents by Reference."
 
SUBCORP
 
     Subcorp is a newly formed, wholly owned subsidiary of Cardinal formed for
the purpose of effecting the Merger.
 
BUSINESS OF OWEN
 
     Owen is the nation's leading provider of fully integrated pharmacy
management and information services to hospitals, with more than 320 hospital
pharmacies under management in 43 states as of November 30, 1996. Owen typically
manages all aspects of its hospital clients' pharmacy operations, including
staffing, purchasing, inventory control, medication dispensing, capturing
patient charges, administration, quality control and information technology.
Through its subsidiary, Meditrol Automation Systems, Inc., Owen also
manufactures, sells and services its Meditrol(R) system, which is comprised of
one or more computer-controlled, automated dispensing cabinets capable of being
linked to the hospital's central information system. A Meditrol(R) unit located
in patient care units, under pharmacy control, allows authorized nursing
personnel rapid access to medications, enhances the accuracy of dispensing and
patient charging, reduces drug waste and diversion and eliminates many
time-consuming drug distribution and record keeping functions. In addition to
its pharmacy management operations and Meditrol(R) automated medication
management, Owen manages 26 healthcare materials outsourcing agreements and
offers a proprietary materials numbering and classification system and a
healthcare supply price database on a subscription basis. Hospital pharmacy
management accounted for approximately 88% of Owen's revenues in fiscal 1996.
 
     Additional information concerning Owen and its subsidiaries is included in
the Owen documents filed with the Commission, which are incorporated by
reference herein. See "Incorporation of Certain Documents by Reference."
 
                        COMPARISON OF SHAREHOLDER RIGHTS
 
     As a result of the Merger, Owen Shareholders will receive Common Shares of
Cardinal, an Ohio corporation, in exchange for their shares of Common Stock in
Owen, a Texas corporation. The following is a summary of certain material
differences between the rights of holders of Owen Common Stock and the rights of
holders of Cardinal Common Shares. These differences arise in part from the
differences between the Texas Business Corporation Act (the "Texas Law") and the
Ohio Revised Code (the "Ohio Law"). Additional differences arise from the
governing instruments of the two companies (in the case of Owen, the Owen
Articles and the Owen Bylaws, and, in the case of Cardinal, the Cardinal
Articles and the Cardinal Regulations). Although it is impractical to compare
all of the aspects in which the Texas Law and the Ohio Law and the companies'
governing instruments differ with respect to shareholders' rights, the following
discussion summarizes certain significant differences between them.
 
AMENDMENT OF CHARTER DOCUMENTS
 
     The Texas Law requires the affirmative vote of two-thirds of the
outstanding shares of Owen Common Stock entitled to vote thereon in order to
amend the Owen Articles, unless any class or series of shares is entitled to
vote thereon as a class, in which event the Texas Law requires the affirmative
vote of the holders of at least two-thirds of the shares within each such class
or series of outstanding shares and of at least two-thirds of the total
outstanding shares entitled to vote thereon. The Owen Articles provide that
certain provisions described below under "-- Provisions Affecting Control Share
Acquisitions and Business Combinations" may only be amended upon approval by the
holders of 75% of the outstanding Owen Common Stock. To amend an
 
                                       45
<PAGE>   52
 
Ohio corporation's articles of incorporation, the Ohio Law requires the approval
of shareholders holding two-thirds of the voting power of the corporation or, in
cases in which class voting is required, of shareholders holding two-thirds of
the voting power of each class, unless otherwise specified in such corporation's
articles of incorporation. The Cardinal Articles specify that the holders of a
majority of the voting power of Cardinal or, when appropriate, any class of
shareholders, may amend the Cardinal Articles.
 
AMENDMENT AND REPEAL OF BYLAWS AND REGULATIONS
 
     Under the Texas Law, holders of a majority of the voting power of a
corporation and, unless reserved exclusively to the shareholders in whole or in
part in the articles of incorporation, the directors of the corporation have the
power to adopt, amend and repeal the bylaws of a corporation. The Owen Articles
grant the Directors of Owen such power. In addition, the Owen Bylaws require
that any adoption, amendment or repeal by the Owen Shareholders be approved by
at least two-thirds of the voting power of the outstanding shares entitled to
vote in the election of directors.
 
     The Ohio Law provides that only shareholders of a corporation have the
power to amend and repeal that corporation's code of regulations. The Cardinal
Regulations require that such amendments be approved by the affirmative vote of
the holders of a majority of the voting power entitled to vote on such matter,
except that the affirmative vote of the holders of not less than 75% of the
shares having voting power is required to amend, change, adopt any provision
inconsistent with, or repeal the provisions of the Cardinal Regulations dealing
with the number and classification of directors, the term of office of directors
or the removal of directors, or the provision relating to amendments to the
Cardinal Regulations.
 
REMOVAL OF DIRECTORS
 
     The Texas Law provides that directors may be removed from office in
accordance with the provisions of the bylaws or articles of incorporation of the
corporation. The Owen Bylaws provide that directors may be removed with or
without cause, by the holders of 75% of the outstanding shares entitled to vote
at a shareholders meeting called expressly for that purpose.
 
     The Ohio Law provides that, unless the governing documents of a corporation
provide otherwise, directors may be removed, with or without cause, by the
affirmative vote of the holders of a majority of the voting power of the
corporation with respect to the election of directors, except that, as a result
of the provision for cumulative voting described below, unless all the directors
or all the directors of a particular class are removed, no individual director
may be removed if the votes of a sufficient number of shares are cast against
his removal which, if cumulatively voted at an election of all the directors, or
all the directors of a particular class, as the case may be, would be sufficient
to elect at least one director. The Cardinal Regulations provide that such
removal requires the affirmative votes of holders of at least 75% of such voting
power. In addition, the Cardinal Regulations provide that any director may be
removed by the Board of Directors for certain causes specified in Section
1701.58(B) of the Ohio Law (if a director is found by order of court to be of
unsound mind, if he is adjudicated a bankrupt or if he fails to meet any
qualifications for office).
 
VACANCIES ON THE BOARD
 
     The Texas Law provides that any vacancy occurring in the board of directors
may be filled by the affirmative vote of a majority of the remaining directors,
though less than a quorum. In addition, the Owen Bylaws provide that such
vacancies shall be filled for the unexpired portion of the term by a majority of
the remaining directors.
 
     The Ohio Law provides that unless the governing documents of a corporation
provide otherwise, vacancies on the board of directors may be filled by a
majority of the remaining directors of a corporation. The Cardinal Regulations
provide that vacancies may be filled by the Board of Directors until Cardinal
Shareholders hold a meeting to fill such vacancy. In addition, Cardinal
Shareholders may elect a director to fill a vacancy (including any vacancy that
previously has been filled by the Board of Directors) at any meeting of Cardinal
Shareholders called for that purpose.
 
                                       46
<PAGE>   53
 
RIGHT TO CALL SPECIAL MEETING OF SHAREHOLDERS
 
     The Texas Law permits special meetings of shareholders to be called by (i)
the president, the board of directors or such other person or persons as the
articles of incorporation or bylaws may provide or (ii) by the holders of at
least 10% of all the shares entitled to vote at the proposed special meeting
(which percentage may be raised by the articles of incorporation but not to
exceed 50%). The Owen Bylaws provide that special meetings may be called by the
president or the majority of the Owen Board or by holders of at least 10% of the
outstanding shares entitled to vote at such meeting.
 
     Under the Ohio Law, the holders of at least 25% of the outstanding shares
of a corporation, unless the corporation's regulations specify another
percentage, which may in no case be greater than 50%, the directors by action at
a meeting or a majority of the directors acting without a meeting, the chairman
of the board, the president or, in case of the president's death or disability,
the vice president authorized to exercise the authority of the president have
the authority to call special meetings of shareholders. The Cardinal Regulations
expressly provide that special meetings of Cardinal Shareholders may be called
by the Chairman of the Board, the president, a majority of the directors acting
with or without a meeting or the holders of at least 25% of the outstanding
Cardinal Common Shares.
 
SHAREHOLDER ACTION WITHOUT A MEETING
 
     Under both the Texas Law and the Ohio Law, any action that may be taken by
shareholders at a meeting may be taken without a meeting with the unanimous
written consent of all shareholders entitled to vote at such meeting.
 
CLASS VOTING
 
     The Texas Law requires that the holders of the outstanding shares of a
class shall be entitled to vote as a class, and the holders of the outstanding
shares of a series shall be entitled to vote as a class, upon amendments to a
corporation's articles of incorporation that increase or decrease the aggregate
number of authorized shares or the par value of the shares of any such class or
series or that affect the rights and preferences of such class or series are
affected in certain respects. Under the Ohio Law, holders of a particular class
of shares are entitled to vote as a separate class if the rights of that class
are affected in certain respects by mergers, consolidations or amendments to the
articles of incorporation.
 
CUMULATIVE VOTING
 
     Under the Texas Law, shareholders have the right to cumulate their votes
for the election of directors unless such right is expressly prohibited in the
articles of incorporation. The Owen Articles expressly prohibits cumulative
voting. Under the Ohio Law, unless the articles of incorporation are amended to
eliminate cumulative voting for directors following their initial filing with
the Ohio Secretary of State, each shareholder has the right to vote cumulatively
in the election of directors if certain notice requirements are satisfied. The
Cardinal Articles have not been amended to eliminate the rights of Cardinal
Shareholders to vote cumulatively in the election of directors.
 
PROVISIONS AFFECTING CONTROL SHARE ACQUISITIONS AND BUSINESS COMBINATIONS
 
     The Owen Articles require the approval by the holders of 75% of the voting
power of the outstanding capital stock of Owen entitled to vote generally in the
election of directors (the "Owen Voting Stock") as a condition to mergers and
certain other Business Transactions (as defined below) involving Owen and an
Interested Shareholder (as defined below) unless the transaction is approved by
a majority of the members of the Owen Board who are Disinterested Directors (as
defined below). An "Interested Shareholder" is defined generally as anyone who
is the beneficial owner of more than 10% of the Owen Voting Stock and includes
any person who is an assignee of or has succeeded to any shares of Voting Stock
in a transaction not involving a public offering that were at any time within
the prior two-year period beneficially owned by an Interested Shareholder. The
term "beneficial owner" includes persons directly and indirectly owning or
having the right to acquire or vote the stock. A "Business Transaction"
generally includes the following transactions: (i) a
 
                                       47
<PAGE>   54
 
merger or consolidation of Owen or any subsidiary thereof with an Interested
Shareholder or with any corporation or entity which is, or after such merger or
consolidation would be, an affiliate of an Interested Shareholder; (ii) the sale
or other disposition by Owen or a subsidiary thereof of assets of $20 million or
more if an Interested Shareholder (or an affiliate thereof) is a party to the
transaction; (iii) the issuance of stock or other securities of Owen or a
subsidiary thereof to an Interested Shareholder (or an affiliate thereof) in
exchange for cash or property with a fair market value of $20 million or more;
(iv) the adoption of any plan or proposal for the liquidation or dissolution of
Owen proposed by or on behalf of any Interested Shareholder (or an affiliate
thereof); or (v) any reclassification of securities, recapitalization, merger
with a subsidiary or any other transaction which has the effect, directly or
indirectly, of increasing the proportionate share of any class of outstanding
stock (or securities convertible into stock) of Owen or a subsidiary owned by an
Interested Shareholder. A "Disinterested Director" is any member of the Owen
Board who (i) is not affiliated with an Interested Shareholder and (ii) was a
director prior to September 1, 1992, or was a newly-elected or appointed
director who was recommended by a majority of the Disinterested Directors then
on the Owen Board.
 
     The Owen Articles also provide that a vote of the holders of 75% or more of
the voting power of the Owen Voting Stock is required to amend, alter or repeal,
or adopt any provision inconsistent with, the above provisions.
 
     Chapter 1704 of the Ohio Law prohibits an interested shareholder from
engaging in a wide range of business combinations similar to those prohibited by
the Owen Articles. However, under Chapter 1704, an interested shareholder
includes a shareholder who directly or indirectly exercises or directs the
exercise of 10% or more of the voting power of the corporation. Chapter 1704
restrictions do not apply under certain circumstances including, but not limited
to, the following (i) if directors of the corporation have approved the
transactions or the interested shareholder's acquisition of shares of the
corporation prior to the date the interested shareholder became a shareholder of
the corporation, and (ii) if the corporation, by action of its shareholders
holding at least 66 2/3% of the voting power of the corporation, adopts an
amendment to its articles of incorporation specifying that Chapter 1704 shall
not be applicable to the corporation. No such amendment has been adopted by
Cardinal.
 
     Under Section 1701.831 of the Ohio Law, unless the articles of
incorporation or regulations of a corporation otherwise provide, any "control
share acquisition" of an "issuing public corporation" can only be made with the
prior approval of the corporation's shareholders. A "control share acquisition"
is defined as any acquisition of shares of a corporation that, when added to all
other shares of that corporation owned by the acquiring person, would enable
that person to exercise levels of voting power in any of the following ranges:
at least 20% but less than 33 1/3%; at least 33 1/3% but less than 50%; 50% or
more. The Cardinal Regulations expressly provide that the provisions of Section
1701.831 of the Ohio Law shall not apply. Neither the Texas Law nor the Owen
Articles or Owen Bylaws have similar control share acquisition provisions.
 
SHAREHOLDER NOTICE PROCEDURES
 
     The Owen Bylaws establish an advance notice procedure for the nomination,
other than by or at the direction of the Owen Board of Directors or a committee
thereof, of candidates for election as directors as well as for shareholder
proposals to be considered at meetings of shareholders (the "Shareholder Notice
Procedure"). Notice of shareholder proposals and director nominations must be
given timely in writing to the Secretary of Owen prior to the meeting at which
such matters are to be acted upon or directors are to be elected. Under the
Shareholder Notice Procedure, for notice of shareholder proposals or director
nominations to be timely, such notice must be received by the Secretary of Owen
at Owen's principal executive offices, with respect to shareholder proposals and
elections to be held at the annual meeting, not later than the close of business
on the 70th day prior to the anniversary of the immediately preceding annual
meeting (or, if the date of the annual meeting is advanced by more than 20 days,
not later than the close of business on the 10th day after the first public
announcement of the date of such meeting), and with respect to an election to be
held at a special meeting, not later than the close of business on the 10th day
following the first public announcement of the date of the special meeting.
Notwithstanding the foregoing, in the event that the number of directors to be
elected is increased and there is no public announcement naming all of the
nominees for director or specifying the size of the increased Owen Board made by
Owen at least 80 days prior to the anniversary of the preceding
 
                                       48
<PAGE>   55
 
year's annual meeting, a shareholder's notice will be timely, but only with
respect to nominees for any new positions created by such increase, if it is
received by Owen not later than the close of business on the 10th day after such
public announcement is first made by Owen.
 
     The Shareholder Notice Procedure may have the effect of precluding a
contest for the election of directors or the consideration of shareholder
proposals if the proper procedures are not followed, and of discouraging or
deterring a third party from conducting a solicitation of proxies to elect its
own slate of directors or to approve its own proposal, without regard to whether
consideration of such nominees or proposals might be harmful or beneficial to
Owen and its shareholders.
 
     The Cardinal Articles and the Cardinal Code do not contain similar
provisions.
 
MERGERS, ACQUISITIONS AND CERTAIN OTHER TRANSACTIONS
 
     Under the Texas Law, a Texas corporation must have a plan of merger or
exchange approved by the affirmative vote of at least two-thirds of the
outstanding shares entitled to vote thereon unless any class or series of shares
of any such corporation is entitled to vote as a class thereon, in which event
the vote required shall be the affirmative vote of the holders of at least
two-thirds of the outstanding shares within each class or series of shares
entitled to vote thereon as a class and at least two-thirds of the outstanding
shares otherwise entitled to vote thereon, unless the board of directors
conditions its submission to shareholders of a plan of merger or exchange by
requiring a greater vote or a vote by class or series. The Owen Articles does
not provide for a different percentage except with respect to Interested
Shareholders. See "-- Provisions Affecting Control Share Acquisitions and
Business Combinations."
 
     The Ohio Law generally requires approval of mergers, dissolutions,
dispositions of all or substantially all of a corporation's assets, and majority
share acquisitions and combinations involving issuance of shares representing
one-sixth or more of the voting power of the corporation immediately after the
consummation of the transaction (other than so-called parent-subsidiary
mergers), by two-thirds of the voting power of the corporation, unless the
articles of incorporation specify a different proportion (not less than a
majority). The Cardinal Articles provide that the vote of a majority of the
voting power of Cardinal is required to approve such actions.
 
CONSIDERATION OF CONSTITUENCIES
 
     Section 1701.59 of the Ohio Law permits a director, in determining what he
reasonably believes to be in the best interests of the corporation, to consider,
in addition to the interests of the corporation's shareholders, any of the
following (i) the interests of the corporation's employees, suppliers,
creditors, and customers, (ii) the economy of the state and nation, (iii)
community and societal considerations and (iv) the long-term as well as
short-term interests of the corporation and its shareholders, including the
possibility that these interests may be best served by the continued
independence of the corporation. The Texas Law contains no comparable provision.
 
RIGHTS OF DISSENTING SHAREHOLDERS
 
     Under the Texas Law, appraisal rights are available to dissenting
shareholders in connection with certain plans of merger, certain plans of
exchange, and any sale, lease, exchange or other disposition of all or
substantially all the property and assets of the corporation requiring special
authorization of the shareholders under the Texas Law. However, the Texas Law
does not provide for appraisal rights (i) if the shares of the corporation are
listed on a national securities exchange or held of record by not less than
2,000 holders on the record date fixed to determine the shareholders entitled to
vote on the plan of merger or the plan of exchange, and (ii) the shareholder is
not required by the terms of the plan of merger or the plan of exchange to
accept for his shares any consideration other than (a) shares of a corporation
that, immediately after the effective time of the merger or exchange, will be
part of a class or series of shares of which are (1) listed, or authorized for
listing upon official notice of issuance, on a national securities exchange, or
(2) held of record by not less than 2,000 holders, and (b) cash in lieu of
fractional shares otherwise entitled to be received. The Owen Articles do not
provide otherwise.
 
                                       49
<PAGE>   56
 
     Under the Ohio Law, dissenting shareholders are entitled to appraisal
rights in connection with the lease, sale, exchange, transfer, or other
disposition of all or substantially all of the assets of a corporation and in
connection with certain amendments to the corporation's articles of
incorporation. Shareholders of an Ohio corporation being merged into or
consolidated with another corporation are also entitled to appraisal rights. In
addition, shareholders of an acquiring corporation are entitled to appraisal
rights in any merger, combination or majority share acquisition in which such
shareholders are entitled to voting rights. The Ohio Law provides shareholders
of an acquiring corporation with voting rights if the acquisition (a "majority
share acquisition") involves the transfer of shares of the acquiring corporation
entitling the recipients thereof to exercise one-sixth or more of the voting
power of such acquiring corporation immediately after the consummation of the
transaction.
 
     Under the Texas Law, among other procedural requirements, a shareholder's
written demand for appraisal of shares must be filed with the corporation before
the meeting to take such action that would give rise to such appraisal rights.
Under the Ohio Law, a shareholder's written demand must be delivered to the
corporation not later than ten days after the taking of the vote on the matter
giving rise to appraisal rights.
 
DIRECTOR LIABILITY AND INDEMNIFICATION
 
     The Owen Bylaws provide that, subject to certain limitations, its officers
and directors will be indemnified by Owen against judgments, penalties, fines,
settlements and reasonable expenses actually incurred by such persons, to the
fullest extent permitted under the Texas Law. Generally, the Texas Law permits a
corporation to indemnify a person who was, is, or is threatened to be made a
named defendant or respondent in a proceeding because the person was or is a
director or officer of the corporation if it is determined that such person (i)
conducted himself in good faith, (ii) reasonably believed (a) in the case of
conduct in his official capacity as a director or officer of the corporation,
that his conduct was in the corporation's best interests, or (b) in other cases,
that his conduct was at least not opposed to the corporation's best interests,
and (iii) in the case of any criminal proceeding, had no reasonable cause to
believe that his conduct was unlawful. In addition, the Texas Law requires a
corporation to indemnify a director or officer for any action that such director
or officer is wholly successful in defending on the merits.
 
     In addition, the Owen Articles provide that a director of Owen will not be
liable to Owen for monetary damages for an act or omission in the director's
capacity as a director, except in the case of (i) a breach of the director's
duty of loyalty to the corporation or the shareholders, (ii) an act or omission
not in good faith that involves intentional misconduct or a knowing violation of
the law, (iii) a transaction from which a director received an improper benefit,
whether or not the benefit resulted from an action taken within the scope of the
director's office, (iv) an action or omission for which the liability of the
director is expressly provided by statute, or (v) an act related to an unlawful
stock repurchase or dividend. The Owen Articles further excuse a director from
liability to the fullest extent permitted by the Texas Law.
 
     There is under the Ohio Law no comparable provision limiting the liability
of officers, employees or agents of the corporation and the Cardinal Articles
contain no such provision. However, under the Ohio Law, a director is not liable
for monetary damages unless it is proved by clear and convincing evidence that
his action or failure to act was undertaken with deliberate intent to cause
injury to the corporation or with reckless disregard for the best interests of
the corporation.
 
     Under the Ohio Law, Ohio corporations are permitted to indemnify directors,
officers, employees, and agents within prescribed limits and must indemnify them
under certain circumstances. The Ohio Law does not authorize payment by a
corporation of judgments against a director, officer, employee, or agent after a
finding of negligence or misconduct in a derivative suit absent a court order.
Indemnification is required, however, to the extent such person succeeds on the
merits. In all other cases, if it is determined that a director, officer,
employee, or agent acted in good faith and in a manner he reasonably believed to
be in or not opposed to the best interests of the corporation, indemnification
is discretionary, except as otherwise provided by a corporation's articles of
incorporation, code of regulations, or by contract, except with respect to the
advancement of expenses of directors (as discussed in the next paragraph). The
statutory right to indemnifica-
 
                                       50
<PAGE>   57
 
tion is not exclusive in Ohio, and Ohio corporations may, among other things,
purchase insurance to indemnify those persons.
 
     The Ohio Law provides that a director (but not an officer, employee, or
agent) is entitled to mandatory advancement of expenses, including attorneys'
fees, incurred in defending any action, including derivative actions, brought
against the director, provided the director agrees to cooperate with the
corporation concerning the matter and to repay the amount advanced if it is
proved by clear and convincing evidence that his act or failure to act was done
with deliberate intent to cause injury to the corporation or with reckless
disregard for the corporation's best interests.
 
     The Cardinal Articles provide for indemnification by Cardinal to the
fullest extent expressly permitted by the Ohio Law of any person made or
threatened to be made a party to any action, suit, or proceeding by reason of
the fact that he is or was a director, officer, employee, or agent of Cardinal
or of any other corporation for which he was serving as a director, officer,
employee, or agent at the request of Cardinal. See also "The Merger -- Interests
of Certain Persons in the Merger."
 
     Cardinal has entered into indemnification contracts with each of its
directors and executive officers. These contracts generally: (i) confirm the
existing indemnity provided to them under the Cardinal Regulations and assure
that this indemnity will continue to be provided; (ii) provide that if Cardinal
does not maintain directors' and officers' liability insurance, Cardinal will,
in effect, become a self-insurer of the coverage; and (iii) provide that, in
addition, the directors and officers shall be indemnified to the fullest extent
permitted by law against all expenses (including legal fees), judgments, fines,
and settlement amounts paid or incurred by them in any action or proceeding,
including any action by or in the right of Cardinal, on account of their service
as a director, officer, employee or agent of Cardinal or at the request of
Cardinal as a director, officer, employee or agent of another corporation or
enterprise.
 
                     DESCRIPTION OF CARDINAL CAPITAL STOCK
 
     As of February 10, 1997, the authorized capital stock of Cardinal consisted
of: (i) 150,000,000 Cardinal Common Shares, of which 100,454,578 were issued and
outstanding, 229,567 were issued and held in treasury, and 4,186,213 were
reserved for issuance pursuant to options outstanding under stock incentive
plans (with approximately 2,092,199 additional Cardinal Common Shares available
for issuance under such plans), (ii) 5,000,000 Class B common shares, without
par value, none of which was outstanding or reserved for issuance, (iii) 500,000
Nonvoting Preferred Shares, without par value ("Preferred Shares"), none of
which has been issued or reserved for issuance.
 
     The holders of Cardinal Common Shares do not have preemptive rights and
have no rights to convert their shares into any other security. All Cardinal
Common Shares are entitled to participate equally, and ratably in dividends on
Cardinal Common Shares as may be declared by Cardinal's Board of Directors. In
the event of the liquidation of Cardinal, holders of Cardinal Common Shares are
entitled to share ratably in assets remaining after payment of all liabilities,
subject to prior distribution rights of any Preferred Shares then outstanding.
Holders of Cardinal Common Shares are entitled to one vote per share for the
election of directors and upon all matters on which shareholders are entitled to
vote. Cardinal Shareholders are afforded the right to vote their shares
cumulatively for the election of the nominees to fill the particular class of
directors to be elected at each annual meeting, subject to compliance with
certain procedural requirements.
 
     The Cardinal Articles provide that the Cardinal Board is authorized to
approve the issuance of the Preferred Shares from time to time in one or more
series without future authorization of its shareholders. The Board of Directors
is authorized to adopt amendments to the Cardinal Articles from time to time
fixing or changing the terms and designations of the Preferred Shares, including
(i) division of such shares into series and the designation and authorized
number of shares of each series, (ii) dividend rate, (iii) dates of payment of
dividends and the dates from which they are cumulative, (iv) liquidation price,
(v) redemption rights and price, (vi) sinking fund requirements, (vii)
conversion rights, and (viii) restrictions on the issuance of such shares.
Holders of Preferred Shares will have no voting rights, except as required by
law. Holders of Preferred
 
                                       51
<PAGE>   58
 
Shares will have no preemptive rights to subscribe to or for any additional
capital shares of Cardinal. Cardinal has no present plans to issue any Preferred
Shares.
 
     The Cardinal Regulations provide that the Board of Directors shall consist
of that number of directors as determined by action of the Board of Directors,
but in no case fewer than nine or more than fourteen members, divided into three
classes, and require that any proposal to either remove a director during his
term of office or to further amend the Cardinal Regulations relating to the
classification, number, or removal of directors be approved by the affirmative
vote of the holders of not less than 75% of the shares having voting power with
respect to such proposal. The Board of Directors may fill any vacancy with a
person who shall serve until the Cardinal Shareholders hold an election to fill
the vacancy. The purpose of these provisions is to prevent directors from being
removed from office prior to the expiration of their respective terms, thus
protecting the safeguards inherent in the classified board structure unless
dissatisfaction with the performance of one or more directors is widely shared
by Cardinal Shareholders. However, these provisions could also have the effect
of increasing from one year to two or three years (depending upon the number of
Cardinal Common Shares held) the amount of time required for an acquiror to
obtain control of Cardinal by electing a majority of the Board of Directors and
may also make the removal of incumbent management more difficult and discourage
or render more difficult certain mergers, tender offers, proxy contests, or
other potential takeover proposals. To the extent that these provisions have the
effect of giving management more bargaining power in negotiations with a
potential acquiror, they could result in management's using the bargaining power
not only to try to negotiate a favorable price for an acquisition, but also to
negotiate more favorable terms for management.
 
     Although Cardinal continually evaluates possible candidates for acquisition
and intends to seek additional acquisition opportunities in the health care
field, as of the date of this Proxy Statement/Prospectus no material acquisition
has been agreed upon or become the subject of a letter of intent or agreement in
principle.
 
                                 LEGAL MATTERS
 
     The validity of the Cardinal Common Shares to be issued in the Merger will
be passed upon for Cardinal by Wachtell, Lipton, Rosen & Katz, special counsel
to Cardinal.
 
     Vinson & Elkins L.L.P. has rendered the opinion referred to under the
caption "Certain Federal Income Tax Consequences." J.D. Epstein, a director of
Owen, is a partner in Vinson & Elkins L.L.P. As of the Record Date, Mr. Epstein
owned beneficially an aggregate of 2,500 shares of Owen Common Stock.
 
                                    EXPERTS
 
     The consolidated financial statements and the related financial statement
schedule of Cardinal and its consolidated subsidiaries as of June 30, 1996 and
1995, and for each of the three years in the period ended June 30, 1996, have
been incorporated in this Proxy Statement/Prospectus by reference from the 1996
Cardinal Form 10-K. Such consolidated financial statements and the related
financial statement schedule of Cardinal and its subsidiaries, except Pyxis,
have been audited by Deloitte & Touche LLP as stated in their report which is
incorporated herein by reference. The financial statements of Pyxis
(consolidated with those of Cardinal in the consolidated financial statements)
have been audited by Ernst & Young LLP, as stated in their report which is
incorporated herein by reference from the 1996 Cardinal Form 10-K.
 
     The consolidated financial statements of Owen and its consolidated
subsidiaries as of November 30, 1996 and 1995, and for each of the three years
in the period ended November 30, 1996, have been incorporated in this Proxy
Statement/Prospectus by reference from the 1996 Owen Form 10-K. Such
consolidated financial statements of Owen and its subsidiaries have been audited
by Price Waterhouse LLP as stated in their report which is incorporated herein
by reference.
 
     Such consolidated financial statements of Cardinal and its consolidated
subsidiaries and Owen and its consolidated subsidiaries are incorporated by
reference or contained herein in reliance upon the respective reports of such
firms given upon their authority as experts in accounting and auditing. All of
the foregoing firms are independent auditors.
 
                                       52
<PAGE>   59
 
                                 OTHER MATTERS
 
     Representatives of each of Deloitte & Touche LLP and Price Waterhouse LLP
are expected to be present at the Special Meeting with the opportunity to make
statements if they so desire. Such representatives are also expected to be
available to respond to appropriate questions.
 
                             SHAREHOLDER PROPOSALS
 
     Owen Shareholder proposals in respect of the 1997 Annual Meeting of Owen
Shareholders were required to have been submitted to Owen by January 28, 1997
for inclusion in the proxy statement and form of proxy relating to that meeting.
If the Merger is consummated, there will be no 1997 Annual Meeting of Owen
Shareholders.
 
                                       53
<PAGE>   60
 
                                                                         ANNEX A
 
                          AGREEMENT AND PLAN OF MERGER
 
                                     AMONG
 
                             CARDINAL HEALTH, INC.
 
                                 ("CARDINAL"),
 
                                OWL MERGER CORP.
                  A WHOLLY OWNED DIRECT SUBSIDIARY OF CARDINAL
                                  ("SUBCORP"),
 
                                      AND
 
                             OWEN HEALTHCARE, INC.
                                    ("OWEN")
 
                               November 27, 1996
<PAGE>   61
 
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                                                                            PAGE
                                                                                            ----
<S>  <C>    <C>  <C>                                                                        <C>
AGREEMENT AND PLAN OF MERGER..............................................................   A-1
PRELIMINARY STATEMENTS....................................................................   A-1
AGREEMENT.................................................................................   A-1
 
  ARTICLE I: THE MERGER...................................................................   A-1
      1.1   The Merger....................................................................   A-1
      1.2   Effective Time................................................................   A-1
      1.3   Effects of the Merger.........................................................   A-2
      1.4   Certificate of Incorporation and Bylaws.......................................   A-2
      1.5   Directors and Officers........................................................   A-2
      1.6   Additional Actions............................................................   A-2
 
  ARTICLE II: CONVERSION OF SECURITIES....................................................   A-2
      2.1   Conversion of Capital Stock...................................................   A-2
      2.2   Exchange Ratio; Fractional Shares.............................................   A-2
      2.3   Exchange of Certificates......................................................   A-3
            (a)  Exchange Agent...........................................................   A-3
            (b)  Exchange Procedures......................................................   A-3
            (c)  Distributions with Respect to Unexchanged Shares.........................   A-4
            (d)  No Further Ownership Rights in Owen Common Stock.........................   A-4
            (e)  Termination of Exchange Fund.............................................   A-4
            (f)  No Liability.............................................................   A-4
            (g)  Investment of Exchange Fund..............................................   A-5
      2.4   Treatment of Stock Options....................................................   A-5
 
  ARTICLE III: REPRESENTATIONS AND WARRANTIES OF CARDINAL AND SUBCORP.....................   A-5
      3.1   Organization and Standing.....................................................   A-5
      3.2   Corporate Power and Authority.................................................   A-5
      3.3   Capitalization of Cardinal and Subcorp........................................   A-6
      3.4   Conflicts; Consents and Approval..............................................   A-6
      3.5   Brokerage and Finder's Fees...................................................   A-7
      3.6   Accounting Matters; Reorganization............................................   A-7
      3.7   Cardinal SEC Documents........................................................   A-7
      3.8   Registration Statement........................................................   A-7
      3.9   No Material Adverse Change....................................................   A-8
 
  ARTICLE IV: REPRESENTATIONS AND WARRANTIES OF OWEN......................................   A-8
      4.1   Organization and Standing.....................................................   A-8
      4.2   Subsidiaries..................................................................   A-8
      4.3   Corporate Power and Authority.................................................   A-8
      4.4   Capitalization of Owen........................................................   A-9
      4.5   Conflicts; Consents and Approvals.............................................   A-9
      4.6   No Material Adverse Change....................................................   A-9
      4.7   Owen SEC Documents............................................................  A-10
      4.8   Taxes.........................................................................  A-10
      4.9   Compliance with Law...........................................................  A-11
      4.10  Intellectual Property.........................................................  A-11
      4.11  Title to and Condition of Properties..........................................  A-12
</TABLE>
 
                                       A-i
<PAGE>   62
 
<TABLE>
<CAPTION>
                                                                                            PAGE
                                                                                            ----
<S>  <C>    <C>  <C>                                                                        <C>
      4.12  Registration Statement; Proxy Statement.......................................  A-12
      4.13  Litigation....................................................................  A-13
      4.14  Brokerage and Finder's Fees; Expenses.........................................  A-13
      4.15  Accounting Matters; Reorganization............................................  A-13
      4.16  Employee Benefit Plans........................................................  A-13
      4.17  Contracts.....................................................................  A-15
      4.18  Labor Matters.................................................................  A-16
      4.19  Operation of Owen's Business; Relationships...................................  A-16
      4.20  Permits; Compliance...........................................................  A-16
      4.21  Product Warranties and Liabilities............................................  A-16
      4.22  Environmental Matters.........................................................  A-16
      4.23  Opinion of Financial Advisors.................................................  A-17
      4.24  Board Recommendation..........................................................  A-17
      4.25  State Takeover Laws...........................................................  A-17
      4.26  Lease Arrangements............................................................  A-17
 
    ARTICLE V: COVENANTS OF THE PARTIES...................................................  A-17
      5.1   Mutual Covenants..............................................................  A-18
            (a)  General..................................................................  A-18
            (b)  HSR Act..................................................................  A-18
            (c)  Other Governmental Matters...............................................  A-18
            (d)  Pooling-of-Interests.....................................................  A-18
            (e)  Tax-Free Treatment.......................................................  A-18
            (f)  Public Announcements.....................................................  A-19
      5.2   Covenants of Cardinal.........................................................  A-19
            (a)  Preparation of Registration Statement....................................  A-19
            (b)  Indemnification..........................................................  A-19
            (c)  Insurance................................................................  A-19
            (d)  Employee Benefits........................................................  A-19
            (e)  Notification of Certain Matters..........................................  A-19
            (f)  Pooling Press Release....................................................  A-19
            (g)  Merger Sub...............................................................  A-20
            (h)  NYSE Listing.............................................................  A-20
            (i)  Affiliates of Cardinal...................................................  A-20
            (j)  Access...................................................................  A-20
      5.3   Covenants of Owen.............................................................  A-20
            (a)  Owen Shareholders Meeting................................................  A-20
            (b)  Information for the Registration Statement and Preparation of Proxy
                 Statement................................................................  A-20
            (c)  Conduct of Owen's Operations.............................................  A-20
            (d)  Intellectual Property Matters............................................  A-22
            (e)  No Solicitation..........................................................  A-22
            (f)  Termination Right........................................................  A-22
            (g)  Affiliates of Owen.......................................................  A-23
            (h)  Access...................................................................  A-23
            (i)  Notification of Certain Matters..........................................  A-23
            (j)  Subsequent Financial Statements..........................................  A-23
</TABLE>
 
                                      A-ii
<PAGE>   63
 
<TABLE>
<CAPTION>
                                                                                            PAGE
                                                                                            ----
<S>  <C>    <C>  <C>                                                                        <C>
ARTICLE VI: CONDITIONS....................................................................  A-24
      6.1   Mutual Conditions.............................................................  A-24
      6.2   Conditions to Obligations of Owen.............................................  A-24
      6.3   Conditions to Obligations of Cardinal and Subcorp.............................  A-25
 
  ARTICLE VII: TERMINATION AND AMENDMENT..................................................  A-25
      7.1   Termination...................................................................  A-25
      7.2   Effect of Termination.........................................................  A-26
      7.3   Amendment.....................................................................  A-27
      7.4   Extension; Waiver.............................................................  A-27
 
  ARTICLE VIII: MISCELLANEOUS.............................................................  A-27
      8.1   Survival of Representations and Warranties....................................  A-27
      8.2   Notices.......................................................................  A-27
      8.3   Interpretation................................................................  A-28
      8.4   Counterparts..................................................................  A-28
      8.5   Entire Agreement..............................................................  A-28
      8.6   Third Party Beneficiaries.....................................................  A-28
      8.7   Governing Law.................................................................  A-28
      8.8   Consent to Jurisdiction; Venue................................................  A-29
      8.9   Specific Performance..........................................................  A-29
      8.10  Assignment....................................................................  A-29
      8.11  Expenses......................................................................  A-29
</TABLE>
 
Exhibit A-1 -- Form of Owen Affiliate Letter
Exhibit A-2 -- Form of Cardinal Affiliate Letter
Exhibit B -- Form of Opinion of Cardinal and Subcorp's Counsel
Exhibit C -- Form of Opinion of Owen's Counsel
 
                                      A-iii
<PAGE>   64
 
                          AGREEMENT AND PLAN OF MERGER
 
     This Agreement and Plan of Merger (this "Agreement") is made and entered
into as of the 27th day of November, 1996, by and among Cardinal Health, Inc.,
an Ohio corporation ("Cardinal"), Owl Merger Corp., a Texas corporation and a
wholly owned subsidiary of Cardinal ("Subcorp") and Owen Healthcare, Inc., a
Texas corporation ("Owen").
 
                             PRELIMINARY STATEMENTS
 
     A. Cardinal desires to acquire the pharmacy management services business,
the automated medication management business and other businesses operated by
Owen through the merger of Subcorp with and into Owen, with Owen as the
surviving corporation (the "Merger"), pursuant to which each share of Owen
Common Stock (as defined in Section 4.4) outstanding at the Effective Time (as
defined in Section 1.2) will be converted into the right to receive Cardinal
Common Shares (as defined in Section 3.3) as more fully provided herein.
 
     B. The Board of Directors of Owen has determined that the Merger is
consistent with and in furtherance of the long-term business strategy of Owen
and Owen desires to combine its pharmacy management services, automated
medication management and other businesses with the healthcare service
businesses operated by Cardinal and for the holders of shares of Owen Common
Stock ("Owen Shareholders") to have a continuing equity interest in the combined
Cardinal/Owen businesses.
 
     C. The parties intend that the Merger constitute a tax-free
"reorganization" within the meaning of Section 368(a)(1)(A) of the Internal
Revenue Code of 1986, as amended (the "Code"), by reason of Section 368(a)(2)(E)
thereof.
 
     D. The parties intend that the Merger be accounted for as a
pooling-of-interests for financial reporting purposes.
 
     E. The respective Boards of Directors of Cardinal, Subcorp and Owen have
determined the Merger in the manner contemplated herein to be desirable and in
the best interests of their respective shareholders and, by resolutions duly
adopted, have approved and adopted this Agreement.
 
                                   AGREEMENT
 
     Now, therefore, in consideration of these premises and the mutual and
dependent promises hereinafter set forth, the parties hereto agree as follows:
 
                                   ARTICLE I
 
                                   THE MERGER
 
     1.1 The Merger.  Upon the terms and subject to the conditions hereof, and
in accordance with the provisions of the Texas Business Corporation Act (the
"TBCA"), Subcorp shall be merged with and into Owen at the Effective Time. As a
result of the Merger, the separate corporate existence of Subcorp shall cease
and Owen shall continue its existence under the laws of the State of Texas.
Owen, in its capacity as the corporation surviving the Merger, is hereinafter
sometimes referred to as the "Surviving Corporation."
 
     1.2 Effective Time.  As promptly as possible on the Closing Date (as
defined below), the parties shall cause the Merger to be consummated by filing
with the Secretary of State of the State of Texas (the "Texas Secretary of
State") articles of merger (the "Articles of Merger") in such form as is
required by and executed in accordance with Article 5.04 of the TBCA. The Merger
shall become effective (the "Effective Time") when the Articles of Merger has
been filed with the Texas Secretary of State or at such later time as shall be
agreed upon by Cardinal and Owen and specified in the Articles of Merger. Prior
to the filing referred to in this Section 1.2, a closing (the "Closing") shall
be held at the offices of Cardinal, 5555 Glendon Court, Dublin, Ohio 43016, or
such other place as the parties may agree as soon as practicable (but in any
event within three
 
                                       A-1
<PAGE>   65
 
business days) following the date upon which all conditions set forth in Article
VI hereof have been satisfied or waived, or at such other date as Cardinal and
Owen may agree; provided, that the conditions set forth in Article VI have been
satisfied or waived at or prior to such date. The date on which the Closing
takes place is referred to herein as the "Closing Date." For all tax purposes,
the Closing shall be effective at the end of the day on the Closing Date.
 
     1.3 Effects of the Merger.  From and after the Effective Time, the Merger
shall have the effects set forth in Article 5.06A of the TBCA.
 
     1.4 Certificate of Incorporation and Bylaws.  The Articles of Merger shall
provide that at the Effective Time (i) the Certificate of Incorporation of the
Surviving Corporation as in effect immediately prior to the Effective Time shall
be amended as of the Effective Time so as to contain the provisions, and only
the provisions, contained immediately prior thereto in the Certificate of
Incorporation of Subcorp, except for Article I thereof which shall continue to
read "The name of the corporation is 'Owen Healthcare, Inc.'", and (ii) the
Bylaws of Subcorp in effect immediately prior to the Effective Time shall be the
Bylaws of the Surviving Corporation; in each case until amended in accordance
with applicable law.
 
     1.5 Directors and Officers.  From and after the Effective Time, the
officers of Owen shall be the officers of the Surviving Corporation and the
directors of Subcorp shall be the directors of the Surviving Corporation, in
each case until their respective successors are duly elected and qualified. On
or prior to the Closing Date, Owen shall deliver to Cardinal evidence
satisfactory to Cardinal of the resignations of the directors of Owen, such
resignations to be effective as of the Effective Time.
 
     1.6 Additional Actions.  If, at any time after the Effective Time, the
Surviving Corporation shall consider or be advised that any further deeds,
assignments or assurances in law or any other acts are necessary or desirable to
(a) vest, perfect or confirm, of record or otherwise, in the Surviving
Corporation its right, title or interest in, to or under any of the rights,
properties or assets of Owen, or (b) otherwise carry out the provisions of this
Agreement, Owen and its officers and directors shall be deemed to have granted
to the Surviving Corporation an irrevocable power of attorney to execute and
deliver all such deeds, assignments or assurances in law and to take all acts
necessary, proper or desirable to vest, perfect or confirm title to and
possession of such rights, properties or assets in the Surviving Corporation and
otherwise to carry out the provisions of this Agreement, and the officers and
directors of the Surviving Corporation are authorized in the name of Owen or
otherwise to take any and all such action.
 
                                   ARTICLE II
 
                            CONVERSION OF SECURITIES
 
     2.1 Conversion of Capital Stock.  At the Effective Time, by virtue of the
Merger and without any action on the part of Cardinal, Subcorp or Owen or their
respective shareholders:
 
          (a) Each share of common stock, $0.01 par value, of Subcorp issued and
     outstanding immediately prior to the Effective Time shall be converted into
     one share of common stock, $0.01 par value, of the Surviving Corporation.
     Such newly issued shares shall thereafter constitute all of the issued and
     outstanding capital stock of the Surviving Corporation.
 
          (b) Subject to the other provisions of this Article II, each share of
     Owen Common Stock issued and outstanding immediately prior to the Effective
     Time shall be converted into and represent a number of Cardinal Common
     Shares equal to the Exchange Ratio (as defined below).
 
          (c) Each share of capital stock of Owen held in the treasury of Owen
     shall be cancelled and retired and no payment shall be made in respect
     thereof.
 
     2.2 Exchange Ratio; Fractional Shares.  The "Exchange Ratio" (rounded to
the nearest ten-thousandth of a share) shall be equal to (a) the quotient
obtained by dividing (x) $27.25 by (y) the average of the closing prices per
share (or, if the Cardinal Common Shares should not trade on any trading day,
the average of the
 
                                       A-2
<PAGE>   66
 
bid and asked prices therefor on such day), of the Cardinal Common Shares as
reported on the New York Stock Exchange ("NYSE") Composite Tape ("NYSE Composite
Tape") on each of the last ten trading days ending on the sixth trading day
prior to the meeting of Owen Shareholders at which the vote to approve the
Merger occurs (the "Average Share Price"); provided, however, that (i) if the
Average Share Price is less than $82.175, then the Exchange Ratio shall be equal
to 0.3316, or (ii) if the Average Share Price is greater than $90.825, then the
Exchange Ratio shall be equal to 0.3000; or (b) if Cardinal has made an
Adjustment Election (as defined in Section 7.1), then the product of (x) 0.3316
and (y) the quotient obtained by dividing $69.20 by the Average Share Price. No
certificates for fractional Cardinal Common Shares shall be issued as a result
of the conversion provided for in Section 2.1(b). In lieu of any such fractional
shares, the holder of a certificate previously evidencing Owen Common Stock,
upon presentation of such fractional interest represented by an appropriate
certificate for Owen Common Stock to the Exchange Agent pursuant to Section 2.3,
shall be entitled to receive a cash payment therefor in an amount equal to the
value (determined with reference to the closing price of Cardinal Common Shares
as reported on the NYSE Composite Tape on the last full trading day immediately
prior to the Effective Time) of such fractional interest. Such payment with
respect to fractional shares is merely intended to provide a mechanical rounding
off of, and is not a separately bargained for, consideration. If more than one
certificate representing shares of Owen Common Stock shall be surrendered for
the account of the same holder, the number of Cardinal Common Shares for which
certificates have been surrendered shall be computed on the basis of the
aggregate number of shares represented by the certificates so surrendered. In
the event that prior to the Effective Time Cardinal shall declare a stock
dividend or other distribution payable in Cardinal Common Shares or securities
convertible into Cardinal Common Shares, or effect a stock split,
reclassification, combination or other change with respect to Cardinal Common
Shares (including, without limitation, the previously announced split of three
Cardinal Common Shares for every two Cardinal Common Shares currently
outstanding, payable December 16, 1996 to holders of record of Cardinal Common
Shares at the close of business on December 2, 1996), the Exchange Ratio set
forth in this Section 2.2 shall be adjusted to reflect such dividend,
distribution, stock split, reclassification, combination or other change.
 
     2.3 Exchange of Certificates.
 
     (a) Exchange Agent.  Promptly following the Effective Time, Cardinal shall
deposit with Boatmen's Trust Company or such other exchange agent as may be
designated by Cardinal and reasonably acceptable to Owen (the "Exchange Agent"),
for the benefit of Owen Shareholders, for exchange in accordance with this
Section 2.3, certificates representing Cardinal Common Shares issuable pursuant
to Section 2.1 in exchange for outstanding shares of Owen Common Stock and shall
from time-to-time deposit cash in an amount reasonably expected to be paid
pursuant to Section 2.2 (such Cardinal Common Shares and cash, together with any
dividends or distributions with respect thereto, being hereinafter referred to
as the "Exchange Fund").
 
     (b) Exchange Procedures.  As soon as practicable after the Effective Time,
the Exchange Agent shall mail to each holder of record of a certificate or
certificates (the "Certificates") which immediately prior to the Effective Time
represented outstanding shares of Owen Common Stock whose shares were converted
into the right to receive Cardinal Common Shares pursuant to Section 2.1(b) (i)
a letter of transmittal (which shall specify that delivery shall be effected,
and risk of loss and title to the Certificates shall pass, only upon delivery of
the Certificates to the Exchange Agent and shall be in such form and have such
other customary provisions as Cardinal may reasonably specify) and (ii)
instructions for effecting the surrender of the Certificates in exchange for
certificates representing Cardinal Common Shares. Upon surrender of a
Certificate for cancellation to the Exchange Agent, together with a duly
executed letter of transmittal, the holder of such Certificate shall be entitled
to receive in exchange therefor (x) a certificate or certificates representing
that whole number of Cardinal Common Shares which such holder has the right to
receive pursuant to Section 2.1 in such denominations and registered in such
names as such holder may request and (y) a check representing the amount of cash
in lieu of fractional shares, if any, and unpaid dividends and distributions, if
any, which such holder has the right to receive pursuant to the provisions of
this Article II, after giving effect to any required withholding tax. The shares
represented by the Certificate so surrendered shall forthwith be cancelled. No
interest will be paid or accrued on the cash in lieu of fractional shares, if
any, and unpaid
 
                                       A-3
<PAGE>   67
 
dividends and distributions, if any, payable to holders of shares of Owen Common
Stock. In the event of a transfer of ownership of shares of Owen Common Stock
which is not registered on the transfer records of Owen, a certificate
representing the proper number of Cardinal Common Shares, together with a check
for the cash to be paid in lieu of fractional shares, if any, and unpaid
dividends and distributions, if any, may be issued to such transferee if the
Certificate representing such shares of Owen Common Stock held by such
transferee is presented to the Exchange Agent, accompanied by all documents
required to evidence and effect such transfer and to evidence that any
applicable stock transfer taxes have been paid. Until surrendered as
contemplated by this Section 2.3, each Certificate shall be deemed at any time
after the Effective Time to represent only the right to receive upon surrender a
certificate representing Cardinal Common Shares and cash in lieu of fractional
shares, if any, and unpaid dividends and distributions, if any, as provided in
this Article II.
 
     (c) Distributions with Respect to Unexchanged Shares.  Notwithstanding any
other provisions of this Agreement, no dividends or other distributions declared
or made after the Effective Time with respect to Cardinal Common Shares having a
record date after the Effective Time shall be paid to the holder of any
unsurrendered Certificate, and no cash payment in lieu of fractional shares
shall be paid to any such holder, until the holder shall surrender such
Certificate as provided in this Section 2.3. Subject to the effect of Applicable
Laws (as defined in Section 4.9), following surrender of any such Certificate,
there shall be paid to the holder of the certificates representing whole
Cardinal Common Shares issued in exchange therefor, without interest, (i) at the
time of such surrender, the amount of dividends or other distributions with a
record date after the Effective Time theretofore payable with respect to such
whole Cardinal Common Shares and not paid, less the amount of any withholding
taxes which may be required thereon, and (ii) at the appropriate payment date
subsequent to surrender, the amount of dividends or other distributions with a
record date after the Effective Time but prior to surrender and a payment date
subsequent to surrender payable with respect to such whole Cardinal Common
Shares, less the amount of any withholding taxes which may be required thereon.
 
     (d) No Further Ownership Rights in Owen Common Stock.  All Cardinal Common
Shares issued upon surrender of Certificates in accordance with the terms hereof
(including any cash paid pursuant to this Article II) shall be deemed to have
been issued in full satisfaction of all rights pertaining to such shares of Owen
Common Stock represented thereby, and there shall be no further registration of
transfers on the stock transfer books of Owen of shares of Owen Common Stock
outstanding immediately prior to the Effective Time. If, after the Effective
Time, Certificates are presented to the Surviving Corporation for any reason,
they shall be cancelled and exchanged as provided in this Section 2.3.
Certificates surrendered for exchange by any person constituting an "affiliate"
of Owen for purposes of Rule 145(c) under the Securities Act of 1933, as amended
(the "Securities Act"), shall not be exchanged until Cardinal has received
written undertakings from such person in the form attached hereto as Exhibit
A-1.
 
     (e) Termination of Exchange Fund.  Any portion of the Exchange Fund which
remains undistributed to Owen Shareholders six months after the date of the
mailing required by Section 2.3(b) shall be delivered to Cardinal, upon demand
thereby, and holders of Certificates previously representing shares of Owen
Common Stock who have not theretofore complied with this Section 2.3 shall
thereafter look only to Cardinal for payment of any claim to Cardinal Common
Shares, cash in lieu of fractional shares thereof, or dividends or
distributions, if any, in respect thereof.
 
     (f) No Liability.  None of Cardinal, the Surviving Corporation or the
Exchange Agent shall be liable to any person in respect of any shares of Owen
Common Stock (or dividends or distributions with respect thereto) or cash from
the Exchange Fund delivered to a public official pursuant to any applicable
abandoned property, escheat or similar law. If any Certificates shall not have
been surrendered prior to seven years after the Effective Time of the Merger (or
immediately prior to such earlier date on which any cash, any cash in lieu of
fractional shares or any dividends or distributions with respect to whole shares
of Owen Common Stock in respect of such Certificate would otherwise escheat to
or become the property of any Governmental Authority (as defined in Section
3.4)), any such cash, dividends or distributions in respect of such Certificate
shall, to the extent permitted by Applicable Laws, become the property of
Cardinal, free and clear of all claims or interest of any person previously
entitled thereto.
 
                                       A-4
<PAGE>   68
 
     (g) Investment of Exchange Fund.  The Exchange Agent shall invest any cash
included in the Exchange Fund, as directed by Cardinal, on a daily basis. Any
interest and other income resulting from such investments shall be paid to
Cardinal upon termination of the Exchange Fund pursuant to Section 2.3(e).
 
     2.4 Treatment of Stock Options.
 
     (a) Prior to the Effective Time, Cardinal and Owen shall take all such
actions as may be necessary to cause each unexpired and unexercised option under
stock option plans of Owen in effect on the date hereof which has been granted
to current or former directors, officers or key employees of Owen by Owen (each,
an "Owen Option") to be automatically converted at the Effective Time into an
option (a "Cardinal Exchange Option") to purchase that number of Cardinal Common
Shares equal to the number of shares of Owen Common Stock issuable immediately
prior to the Effective Time upon exercise of the Owen Option (without regard to
actual restrictions on exercisability) multiplied by the Exchange Ratio, with an
exercise price equal to the exercise price which existed under the corresponding
Owen Option divided by the Exchange Ratio, and with other terms and conditions
that are the same as the terms and conditions of such Owen Option immediately
before the Effective Time; provided that with respect to any Owen Option that is
an "incentive stock option" within the meaning of Section 422 of the Code, the
foregoing conversion shall be carried out in a manner satisfying the
requirements of Section 424(a) of the Code. In connection with the issuance of
Cardinal Exchange Options, Cardinal shall (i) reserve for issuance the number of
Cardinal Common Shares that will become subject to Cardinal Exchange Options
pursuant to this Section 2.4 and (ii) from and after the Effective Time, upon
exercise of Cardinal Exchange Options, make available for issuance all Cardinal
Common Shares covered thereby, subject to the terms and conditions applicable
thereto.
 
     (b) Owen agrees to issue treasury shares of Owen, to the extent available,
upon the exercise of Owen Options prior to the Effective Time.
 
     (c) Cardinal agrees to use its reasonable efforts to file with the
Securities and Exchange Commission (the "Commission") within ten business days
after the Closing Date a registration statement on Form S-8 or other appropriate
form under the Securities Act to register Cardinal Common Shares issuable upon
exercise of the Cardinal Exchange Options and use its reasonable efforts to
cause such registration statement to remain effective until the exercise or
expiration of such options.
 
                                  ARTICLE III
 
             REPRESENTATIONS AND WARRANTIES OF CARDINAL AND SUBCORP
 
     In order to induce Owen to enter into this Agreement, Cardinal and Subcorp
hereby represent and warrant to Owen that the statements contained in this
Article III are true, correct and complete.
 
     3.1 Organization and Standing.  Each of Cardinal and Subcorp is a
corporation duly organized, validly existing and in good standing under the laws
of its state of incorporation with full corporate power and authority to own,
lease, use and operate its properties and to conduct its business as and where
now owned, leased, used, operated and conducted. Each of Cardinal and Subcorp is
duly qualified to do business and in good standing in each jurisdiction in which
the nature of the business conducted by it or the property it owns, leases or
operates, makes such qualification necessary, except where the failure to be so
qualified or in good standing in such jurisdiction would not have a Material
Adverse Effect (as defined in Section 8.3) on Cardinal. Cardinal is not in
default in the performance, observance or fulfillment of any provision of its
Articles of Incorporation, as amended and restated (the "Cardinal Articles"), or
Code of Regulations, as amended and restated (the "Cardinal Code of
Regulations"), and Subcorp is not in default in the performance, observance or
fulfillment of any provisions of its Articles of Incorporation or Bylaws.
Cardinal has heretofore furnished to Owen a complete and correct copy of the
Cardinal Articles and Cardinal Code of Regulations.
 
     3.2 Corporate Power and Authority.  Each of Cardinal and Subcorp has all
requisite corporate power and authority to enter into and deliver this
Agreement, to perform its obligations hereunder and to
 
                                       A-5
<PAGE>   69
 
consummate the transactions contemplated by this Agreement. The execution and
delivery of this Agreement and the consummation of the transactions contemplated
hereby have been duly authorized by all necessary corporate action on the part
of each of Cardinal and Subcorp. This Agreement has been duly executed and
delivered by each of Cardinal and Subcorp, and constitutes the legal, valid and
binding obligation of each of Subcorp and Cardinal enforceable against each of
them in accordance with its terms.
 
     3.3 Capitalization of Cardinal and Subcorp.
 
     (a) As of November 22, 1996, Cardinal's authorized capital stock consisted
solely of (a) 150,000,000 common shares, without par value ("Cardinal Common
Shares"), of which (i) 66,815,619 shares were issued and outstanding, (ii)
228,631 shares were issued and held in treasury (which does not include the
shares reserved for issuance as set forth in clause (a)(iii) below) and (iii)
4,356,571 shares were reserved for issuance upon the exercise or conversion of
options, warrants or convertible securities granted or issuable by Cardinal, (b)
5,000,000 Class B common shares, without par value, none of which was issued and
outstanding or reserved for issuance, and (c) 500,000 Non-Voting Preferred
Shares, without par value, none of which was issued and outstanding or reserved
for issuance. Each outstanding share of Cardinal capital stock is, and all
Cardinal Common Shares to be issued in connection with the Merger will be, duly
authorized and validly issued, fully paid and nonassessable, and each
outstanding share of Cardinal capital stock has not been, and all Cardinal
Common Shares to be issued in connection with the Merger will not be, issued in
violation of any preemptive or similar rights. As of the date hereof, other than
as set forth in the first sentence hereof or in Section 3.3 to the disclosure
schedule delivered by Cardinal to Owen and dated the date hereof (the "Cardinal
Disclosure Schedule"), there are no outstanding subscriptions, options,
warrants, puts, calls, agreements, understandings, claims or other commitments
or rights of any type relating to the issuance, sale, transfer or registration
by Cardinal of any equity securities of Cardinal, nor are there outstanding any
securities which are convertible into or exchangeable for any shares of capital
stock of Cardinal and Cardinal has no obligation of any kind to issue any
additional securities. The Cardinal Common Shares (including those shares to be
issued in the Merger) are registered under the Securities Exchange Act of 1934,
as amended (together with the rules and regulations thereunder, the "Exchange
Act").
 
     (b) Subcorp's authorized capital stock consists solely of 1,000 shares of
Common Stock, par value $.01 per share ("Subcorp Common Stock"), of which, as of
the date hereof, 100 were issued and outstanding and none were reserved for
issuance. As of the date hereof, all of the outstanding shares of Subcorp Common
Stock are owned free and clear of any liens, claims or encumbrances by Cardinal.
 
     3.4 Conflicts; Consents and Approval.  Neither the execution and delivery
of this Agreement by Cardinal or Subcorp nor the consummation of the
transactions contemplated hereby will:
 
          (a) conflict with, or result in a breach of any provision of the
     Cardinal Articles or Cardinal Code of Regulations or the Articles of
     Incorporation or Bylaws of Subcorp;
 
          (b) violate, or conflict with, or result in a breach of any provision
     of, or constitute a default (or an event which, with the giving of notice,
     the passage of time or otherwise, would constitute a default) under, or
     entitle any party (with the giving of notice, the passage of time or
     otherwise) to terminate, accelerate, modify or call a default under, or
     result in the creation of any lien, security interest, charge or
     encumbrance upon any of the properties or assets of Cardinal or any of its
     subsidiaries under, any of the terms, conditions or provisions of any note,
     bond, mortgage, indenture, deed of trust, license, contract, undertaking,
     agreement, lease or other instrument or obligation to which Cardinal or any
     of its subsidiaries is a party;
 
          (c) violate any order, writ, injunction, decree, statute, rule or
     regulation applicable to Cardinal or any of its subsidiaries or their
     respective properties or assets; or
 
          (d) require any action or consent or approval of, or review by, or
     registration or filing by Cardinal or any of its affiliates with, any third
     party or any local, domestic, foreign or multi-national court, arbitral
     tribunal, administrative agency or commission or other governmental or
     regulatory body, agency, instrumentality or authority (a "Governmental
     Authority"), other than (i) authorization for inclusion of the Cardinal
     Common Shares to be issued in the Merger and the transactions contemplated
     hereby on
 
                                       A-6
<PAGE>   70
 
     the NYSE, subject to official notice of issuance, (ii) actions required by
     the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and
     the rules and regulations promulgated thereunder (the "HSR Act"), (iii)
     registrations or other actions required under federal and state securities
     laws as are contemplated by this Agreement, or (iv) consents or approvals
     of any Governmental Authority set forth in Section 3.4 to the Cardinal
     Disclosure Schedule;
 
except in the case of (b), (c) and (d) for any of the foregoing that would not,
individually or in the aggregate, have a Material Adverse Effect on Cardinal or
upon the ability of the parties to consummate the transactions contemplated
hereby.
 
     3.5 Brokerage and Finder's Fees.  Except for Cardinal's obligation to
Montgomery Securities ("Montgomery"), neither Cardinal nor any shareholder,
director, officer or employee thereof has incurred or will incur on behalf of
Cardinal any brokerage, finder's or similar fee in connection with the
transactions contemplated by this Agreement.
 
     3.6 Accounting Matters; Reorganization.  Neither Cardinal nor any of its
affiliates has taken or agreed to take any action that (without giving effect to
any actions taken or agreed to be taken by Owen or any of its affiliates) would
(a) prevent Cardinal from accounting for the business combination to be effected
by the Merger as a pooling-of-interests for financial reporting purposes or (b)
prevent the Merger from constituting a reorganization qualifying under the
provisions of Section 368(a) of the Code.
 
     3.7 Cardinal SEC Documents.  Cardinal has timely filed with the Commission
all forms, reports, schedules, statements and other documents required to be
filed by it since December 31, 1993 under the Exchange Act or the Securities Act
(such documents, as supplemented and amended since the time of filing,
collectively, the "Cardinal SEC Documents"). The Cardinal SEC Documents,
including, without limitation, any financial statements or schedules included
therein, at the time filed (and, in the case of registration statements and
proxy statements, on the dates of effectiveness and the dates of mailing,
respectively) (a) 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 therein, in light of the circumstances under which
they were made, not misleading, and (b) complied in all material respects with
the applicable requirements of the Exchange Act and the Securities Act, as the
case may be. The financial statements of Cardinal included in the Cardinal SEC
Documents at the time filed (and, in the case of registration statements and
proxy statements, on the dates of effectiveness and the dates of mailing,
respectively) complied as to form in all material respects with applicable
accounting requirements and with the published rules and regulations of the
Commission with respect thereto, were prepared in accordance with generally
accepted accounting principles applied on a consistent basis during the periods
involved (except as may be indicated in the notes thereto or, in the case of
unaudited statements, as permitted by Form 10-Q of the Commission), and fairly
present (subject in the case of unaudited statements to normal, recurring audit
adjustments) the consolidated financial position of Cardinal and its
consolidated subsidiaries as at the dates thereof and the consolidated results
of their operations and cash flows for the periods then ended.
 
     3.8 Registration Statement.  None of the information provided by Cardinal
in writing for inclusion in the registration statement on Form S-4 (such
registration statement as amended, supplemented or modified, the "Registration
Statement") to be filed with the Commission by Cardinal under the Securities
Act, including the prospectus relating to Cardinal Common Shares to be issued in
the Merger (as amended, supplemented or modified, the "Prospectus") and the
proxy statement and form of proxy relating to the vote of Owen Shareholders with
respect to the Merger (as amended, supplemented or modified, the "Proxy
Statement") at the time the Registration Statement becomes effective or, in the
case of the Proxy Statement, at the date of mailing and at the date of the Owen
Shareholders Meeting (as hereinafter defined) to consider the Merger, will
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 are made, not
misleading. Each of the Registration Statement and Proxy Statement, except for
such portions thereof that relate only to Owen, will comply as to form in all
material respects with the provisions of the Securities Act and Exchange Act.
 
                                       A-7
<PAGE>   71
 
     3.9 No Material Adverse Change.  Except as set forth in Section 3.9 to the
Cardinal Disclosure Schedule, as contemplated by or resulting from the execution
of this Agreement or as disclosed in the Cardinal SEC Documents, since September
30, 1996, there has been no material adverse change in the assets, liabilities,
results of operations, business or financial condition of Cardinal taken as a
whole or any event, occurrence or development which may reasonably be expected
to have such a change or a material adverse effect on the ability of Cardinal to
consummate the transactions contemplated hereby.
 
                                   ARTICLE IV
 
                     REPRESENTATIONS AND WARRANTIES OF OWEN
 
     In order to induce Subcorp and Cardinal to enter into this Agreement, Owen
hereby represents and warrants to Cardinal and Subcorp that the statements
contained in this Article IV are true, correct and complete.
 
     4.1 Organization and Standing.  Owen is a corporation duly organized,
validly existing and in good standing under the laws of the State of Texas with
full corporate power and authority to own, lease, use and operate its properties
and to conduct its business as and where now owned, leased, used, operated and
conducted. Owen is duly qualified to do business and in good standing in each
jurisdiction in which the nature of the business conducted by it or the property
it owns, leases or operates requires it to so qualify, except where the failure
to be so qualified or in good standing in such jurisdiction would not have a
Material Adverse Effect on Owen. Owen is not in default in the performance,
observance or fulfillment of any provision of its Articles of Incorporation, as
amended and restated (the "Owen Articles"), or its Bylaws, as in effect on the
date hereof (the "Owen Bylaws"). Owen has heretofore furnished to Cardinal a
complete and correct copy of the Owen Articles and the Owen Bylaws. Listed in
Section 4.1 to the disclosure schedule delivered by Owen to Cardinal and dated
the date hereof (the "Owen Disclosure Schedule") is each jurisdiction in which
Owen is qualified to do business and in good standing as of the date of the
Agreement.
 
     4.2 Subsidiaries.  Owen does not own, directly or indirectly, any equity or
other ownership interest in any corporation, partnership, joint venture or other
entity or enterprise, except for the subsidiaries set forth in Section 4.2 to
the Owen Disclosure Schedule. Except as set forth in Section 4.2 to the Owen
Disclosure Schedule, Owen is not subject to any obligation or requirement to
provide funds to or make any investment (in the form of a loan, capital
contribution or otherwise) in any such entity. Owen owns directly or indirectly
each of the outstanding shares of capital stock (or other ownership interests
having by their terms ordinary voting power to elect a majority of directors or
others performing similar functions with respect to such subsidiary) of each of
Owen's subsidiaries. Each of the outstanding shares of capital stock of each of
Owen's subsidiaries is duly authorized, validly issued, fully paid and
nonassessable, and is owned, directly or indirectly, by Owen free and clear of
all liens, pledges, security interests, claims or other encumbrances. The
following information for each subsidiary of Owen is set forth in Section 4.2 to
the Owen Disclosure Schedule, as applicable: (i) its name and jurisdiction of
incorporation or organization; (ii) its authorized capital stock or share
capital; and (iii) the number of issued and outstanding shares of capital stock
or share capital and the record owner(s) thereof. Other than as set forth in
Section 4.2 to the Owen Disclosure Schedule, there are no outstanding
subscriptions, options, warrants, puts, calls, agreements, understandings,
claims or other commitments or rights of any type relating to the issuance, sale
or transfer of any securities of any subsidiary of Owen, nor are there
outstanding any securities which are convertible into or exchangeable for any
shares of capital stock of any subsidiary of Owen, and no subsidiary of Owen has
any obligation of any kind to issue any additional securities or to pay for
securities of any subsidiary of Owen or any predecessor thereof.
 
     4.3 Corporate Power and Authority.  Owen has all requisite corporate power
and authority to enter into and deliver this Agreement, to perform its
obligations hereunder and, subject to authorization of the Merger and the
transactions contemplated hereby by Owen Shareholders, to consummate the
transactions contemplated by this Agreement. The execution and delivery of this
Agreement by Owen have been duly authorized by all necessary corporate action on
the part of Owen, subject to authorization of the Merger and the
 
                                       A-8
<PAGE>   72
 
transactions contemplated hereby by Owen Shareholders. This Agreement has been
duly executed and delivered by Owen and constitutes the legal, valid and binding
obligation of Owen enforceable against it in accordance with its terms.
 
     4.4 Capitalization of Owen.  As of November 27, 1996, Owen's authorized
capital stock consisted solely of (a) 40,000,000 shares of common stock, without
par value ("Owen Common Stock"), of which (i) 17,069,094 shares were issued and
outstanding, (ii) 1,776,654 shares were issued and held in treasury (which does
not include the shares reserved for issuance set forth in clause (iii) below)
and (iii) 1,586,213 shares were reserved for issuance upon the exercise or
conversion of outstanding options granted or issued by Owen and (b) 1,000,000
shares of preferred stock, $0.01 par value per share ("Owen Preferred Stock"),
none of which was issued and outstanding or reserved for issuance. Each
outstanding share of Owen capital stock is duly authorized and validly issued,
fully paid and nonassessable, and has not been issued in violation of any
preemptive or similar rights. Other than as set forth in the first sentence
hereof, in Section 4.4 to the Owen Disclosure Schedule or as contemplated by the
Owen Stock Option Agreement (as defined in Section 4.26), there are no
outstanding subscriptions, options, warrants, puts, calls, agreements,
understandings, claims or other commitments or rights of any type relating to
the issuance, sale or transfer of any securities of Owen, nor are there
outstanding any securities which are convertible into or exchangeable for any
shares of capital stock of Owen, and Owen has no obligation of any kind to issue
any additional securities or to pay for securities of Owen or any predecessor.
The issuance and sale of all of the shares of capital stock described in this
Section 4.4 have been in compliance with federal and state securities laws. The
Owen Disclosure Schedule accurately sets forth the names of, and the number of
shares of each class (including the number of shares issuable upon exercise of
Owen Options and the exercise price with respect thereto) and the number of
options held by, all holders of options to purchase Owen capital stock. Except
as set forth in Section 4.4 to the Owen Disclosure Schedule, Owen has not agreed
to register any securities under the Securities Act or under any state
securities law or granted registration rights to any person or entity.
 
     4.5 Conflicts; Consents and Approvals.  Neither the execution and delivery
of this Agreement by Owen, nor the consummation of the transactions contemplated
hereby will:
 
          (a) conflict with, or result in a breach of any provision of, the Owen
     Articles or the Owen Bylaws;
 
          (b) violate, or conflict with, or result in a breach of any provision
     of, or constitute a default (or an event which, with the giving of notice,
     the passage of time or otherwise, would constitute a default) under, or
     entitle any party (with the giving of notice, the passage of time or
     otherwise) to terminate, accelerate, modify or call a default under, or
     result in the creation of any lien, security interest, charge or
     encumbrance upon any of the properties or assets of Owen under, any of the
     terms, conditions or provisions of any note, bond, mortgage, indenture,
     deed of trust, license, contract, undertaking, agreement, lease or other
     instrument or obligation to which Owen or any of its subsidiaries is a
     party;
 
          (c) violate any order, writ, injunction, decree, statute, rule or
     regulation applicable to Owen or any of its subsidiaries or any of their
     respective properties or assets; or
 
          (d) require any action or consent or approval of, or review by, or
     registration or filing by Owen or any of its affiliates with, any third
     party or any Governmental Authority, other than (i) authorization of the
     Merger and the transactions contemplated hereby by Owen Shareholders, (ii)
     actions required by the HSR Act, (iii) registrations or other actions
     required under federal and state securities laws as are contemplated by
     this Agreement and (iv) consents or approvals of any Governmental Authority
     set forth in Section 4.5 to the Owen Disclosure Schedule;
 
except in the case of (b) for any of the foregoing that are set forth in Section
4.5 of the Owen Disclosure Schedule and in the case of (b), (c) and (d) for any
of the foregoing that would not, individually or in the aggregate, have a
Material Adverse Effect on Owen.
 
     4.6 No Material Adverse Change.  Except as set forth in Section 4.6 to the
Owen Disclosure Schedule as contemplated by or resulting from the execution of
this Agreement or disclosed in the Owen SEC Documents (as defined in Section 4.7
hereof), since August 31, 1996, there has been no material adverse change in the
assets, liabilities, results of operations, business or financial condition of
Owen and its
 
                                       A-9
<PAGE>   73
 
subsidiaries taken as a whole or any event, occurrence or development which may
reasonably be expected to have such a change or a material adverse effect on the
ability of Owen to consummate the transactions contemplated hereby.
 
     4.7 Owen SEC Documents.  Owen has timely filed with the Commission all
forms, reports, schedules, statements and other documents required to be filed
by it since November 30, 1993 under the Exchange Act or the Securities Act (such
documents, as supplemented and amended since the time of filing, collectively,
the "Owen SEC Documents"). The Owen SEC Documents, including, without
limitation, any financial statements or schedules included therein, at the time
filed (and, in the case of registration statements and proxy statements, on the
dates of effectiveness and the dates of mailing, respectively) (a) 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
therein, in light of the circumstances under which they were made, not
misleading, and (b) complied in all material respects with the applicable
requirements of the Exchange Act and the Securities Act, as the case may be. The
financial statements of Owen included in the Owen SEC Documents at the time
filed (and, in the case of registration statements and proxy statements, on the
dates of effectiveness and the dates of mailing, respectively) complied as to
form in all material respects with applicable accounting requirements and with
the published rules and regulations of the Commission with respect thereto, were
prepared in accordance with generally accepted accounting principles applied on
a consistent basis during the periods involved (except as may be indicated in
the notes thereto or, in the case of unaudited statements, as permitted by Form
10-Q of the Commission), and fairly present (subject in the case of unaudited
statements to normal, recurring audit adjustments) the consolidated financial
position of Owen and its consolidated subsidiaries as at the dates thereof and
the consolidated results of their operations and cash flows for the periods then
ended.
 
     4.8 Taxes.
 
     (a) Owen and its subsidiaries have duly filed all material federal, state,
local and foreign income, franchise, excise, real and personal property and
other Tax Returns and reports (including, but not limited to, those filed on a
consolidated, combined or unitary basis) required to have been filed by Owen or
its subsidiaries prior to the date hereof. All of the foregoing Tax Returns and
reports are true and correct (except for such inaccuracies which are
individually, or in the aggregate, not material), and Owen and its subsidiaries
have within the time and manner prescribed by Applicable Law paid or, prior to
the Effective Time, will pay all Taxes, interest and penalties required to be
paid in respect of the periods covered by such returns or reports or otherwise
due to any federal, state, foreign, local or other taxing authority. Except as
disclosed on Schedule 4.8 to the Owen Disclosure Schedule, neither Owen nor any
of its subsidiaries have any material liability for any Taxes in excess of the
amounts so paid or reserves so established and neither Owen nor any of its
subsidiaries is delinquent in the payment of any material Tax. None of them has
requested or filed any document having the effect of causing any extension of
time within which to file any returns in respect of any fiscal year which have
not since been filed. No deficiencies for any material Tax have been proposed in
writing, asserted or assessed (tentatively or definitely), in each case, by any
taxing authority, against Owen or any of its subsidiaries for which there are
not adequate reserves. Except as set forth in Section 4.8 to the Owen Disclosure
Schedule, neither Owen nor any of its subsidiaries is the subject of any
currently ongoing Tax audit. As of the date of this Agreement, there are no
pending requests for waivers of the time to assess any material Tax, other than
those made in the ordinary course and for which payment has been made or there
are adequate reserves. With respect to any taxable period ended prior to May
1992, all federal income Tax Returns including Owen or any of its subsidiaries
have been audited by the Internal Revenue Service or are closed by the
applicable statute of limitations. Neither Owen nor any of its subsidiaries has
waived any statute of limitations in respect of Taxes or agreed to any extension
of time with respect to a Tax assessment or deficiency. There are no liens with
respect to Taxes upon any of the properties or assets, real or personal,
tangible or intangible of Owen or any of its subsidiaries (other than liens for
Taxes not yet due). No claim has ever been made in writing by an authority in a
jurisdiction where none of Owen and its subsidiaries files Tax Returns that Owen
or any of its subsidiaries is or may be subject to taxation by that
jurisdiction. Owen has not filed an election under Section 341(f) of the Code to
be treated as a consenting corporation.
 
                                      A-10
<PAGE>   74
 
     (b) Neither Owen nor any of its subsidiaries is obligated by any contract,
agreement or other arrangement to indemnify any other person with respect to
material Taxes. Neither Owen nor any of its subsidiaries are now or have ever
been a party to or bound by any agreement or arrangement (whether or not written
and including, without limitation, any arrangement required or permitted by law)
binding Owen or any of its subsidiaries which (i) requires Owen or any of its
subsidiaries to make any Tax payment to or for the account of any other person,
(ii) affords any other person the benefit of any net operating loss, net capital
loss, investment Tax credit, foreign Tax credit, charitable deduction or any
other credit or Tax attribute which could reduce Taxes (including, without
limitation, deductions and credits related to alternative minimum Taxes) of Owen
or any of its subsidiaries, or (iii) requires or permits the transfer or
assignment of income, revenues, receipts or gains to Owen or any of its
subsidiaries, from any other person.
 
     (c) Owen and its subsidiaries have withheld and paid all material Taxes
required to have been withheld and paid in connection with amounts paid or owing
to any employee, independent contractor, creditor, shareholder or other third
party.
 
     (d) "Tax Returns" means returns, reports and forms required to be filed
with any Governmental Authority of the United States or any other jurisdiction
responsible for the imposition or collection of Taxes.
 
     (e) "Taxes" means (i) all Taxes (whether federal, state, local or foreign)
based upon or measured by income and any other Tax whatsoever, including,
without limitation, gross receipts, profits, sales, use, occupation, value
added, ad valorem, transfer, franchise, withholding, payroll, employment,
excise, or property Taxes, together with any interest or penalties imposed with
respect thereto and (ii) any obligations under any agreements or arrangements
with respect to any Taxes described in clause (i) above.
 
     4.9 Compliance with Law.
 
     (a) Except as set forth in Section 4.9 to the Owen Disclosure Schedule,
Owen is in compliance with all applicable laws, statutes, orders, rules,
regulations, policies or guidelines promulgated, or judgments, decisions or
orders entered by any Governmental Authority (collectively, "Applicable Laws")
relating to Owen or its business or properties, including, without limitation,
laws regarding the provision of insurance, third party administration and
primary health care services, the Prescription Drug Marketing Act, the Federal
Controlled Substances Act of 1970, the Food, Drug and Cosmetic Act, any federal
or state pharmacy practice acts, the Good Manufacturing Practices standards of
the Food and Drug Administration, federal Medicare and Medicaid statutes,
including, without limitation, 42 U.S.C. Section 1320a-7b and 42 U.S.C. Section
1395nn or related state or local statutes or regulations, applicable state laws
regulating pharmacy practice, the Occupational Safety and Health Act and the
regulations promulgated thereunder and all rules of professional conduct
applicable to Owen or by which any of its properties are bound or subject,
except where the failure to be in compliance with such Applicable Laws
(individually or in the aggregate) could not reasonably be expected to have a
Material Adverse Effect on Owen. Except as disclosed in Section 4.9 to the Owen
Disclosure Schedule, no investigation or review by any Governmental Authority,
including, without limitation, applicable state insurance and health
commissions, with respect to Owen is pending, or, to the knowledge of Owen,
threatened, nor has any Governmental Authority, including, without limitation,
applicable state insurance and health commissions, indicated in writing an
intention to conduct the same, other than those the outcome of which could not
reasonably be expected to have a Material Adverse Effect on Owen.
 
     4.10 Intellectual Property.
 
     (a) As set forth in Section 4.10 to the Owen Disclosure Schedule is a true
and complete list of (i) all of Owen's foreign and domestic material patents,
patent applications, invention disclosures, trademarks, service marks,
tradenames (and any registrations or applications for registration for any of
the foregoing trademarks, service marks and tradenames) and all material
copyright applications and registrations and (ii) all agreements to which Owen
is a party which concern any of the material Intellectual Property
("Intellectual Property" shall mean all intellectual property or other
proprietary rights of every kind, including, all domestic or foreign patents,
domestic or foreign patent applications, inventions (whether or not patentable),
processes, products, technologies, discoveries, copyrightable and copyrighted
works, apparatus, trade secrets, trademarks and trademark registration and
trademark registration applications, service marks and service mark registra-
 
                                      A-11
<PAGE>   75
 
tions and service mark registration applications, tradenames, trade dress,
copyright registrations, customer lists, marketing and customer information,
mask works rights, know-how, licenses, technical information (whether
confidential or otherwise), software, and all documentation thereof). Other than
the Intellectual Property set forth in Section 4.10 of the Owen Disclosure
Schedule, no name, patent, invention, tradesecret, proprietary right, computer
software, trademark, tradename, service mark, logo, copyright, franchise,
license, sublicense, or other such right is necessary for the operation of the
business of Owen in substantially the same manner as such business is presently
conducted. Except as set forth in Section 4.10 to the Owen Disclosure Schedule
(i) Owen owns, free and clear of any liens, claims or encumbrances, the material
Intellectual Property listed thereon; (ii) no claim of invalidity of the
patents, trademark registrations, service mark registrations, and copyright
registrations included in the Intellectual Property has been made by a third
party; (iii) no claim of infringement of any now existing domestic or foreign
patent, trademark, service mark, tradename, copyright or design right has been
made by any third party; (iv) no person or entity has asserted that, with
respect to the material Intellectual Property, Owen or a licensee of Owen is
infringing or has infringed any domestic or foreign patent, trademark, service
mark, tradename, or copyright or design right, or has misappropriated or
improperly used or disclosed any trade secret, confidential information or
know-how; (v) to Owen's knowledge none of the Intellectual Property, its use or
operation infringe any foreign or domestic patent, trademark, service mark,
tradename or copyright of any entity or have involved the misappropriation or
improper use or disclosure of any trade secrets, confidential information or
know-how of any entity; (vi) to Owen's knowledge all fees, annuities, and other
payments which are due from Owen on or before the effective date of this
Agreement for any of the Intellectual Property have been paid; (vii) the making,
using, selling, manufacturing, marketing, licensing, reproduction, distribution,
or publishing of any process, machine, manufacture, composition of matter, or
material pursuant to any part of the Intellectual Property, does not and will
not infringe any domestic or foreign patent, trademark, service mark, tradename,
copyright or other intellectual property right; (viii) no unexpired foreign or
domestic patents or patent applications exist that are adverse to the material
interests of Owen; (ix) the Intellectual Property is not the subject to any
pending Action; (x) to Owen's knowledge there exists no (a) prior act that would
void or invalidate any of the Intellectual Property or (b) conduct or use by
Owen or any third party that would void or invalidate any of the Intellectual
Property; (xi) the execution, delivery and performance of this Agreement by
Owen, and the consummation of the transactions contemplated thereby, will not
breach, violate or conflict with any instrument or agreement governing or
contained within any of the Intellectual Property, will not cause the forfeiture
or termination or give rise to a right of forfeiture or termination of any of
the Intellectual Property or in any way impair the right of Red or Subcorp to
use, sell, license or dispose of, or to bring any action for the infringement
of, any Intellectual Property; (xii) there are no royalties, honoraria, fees or
other payments payable to any third party by reason of the ownership, use,
license, sale or disposition of the Intellectual Property; (xiii) no substantial
part of the source or object code, algorithms or structure included in any of
the Intellectual Property is copied from, based upon or derived from any source
or object code, algorithm or structure included in any computer software product
owned by any third party nor does any substantial similarity of any of such
source or object code, algorithms or structure being copied from, based upon or
derived from any computer software product owned by any third party.
 
     (a) Owen has taken reasonable and appropriate steps to safeguard and
maintain the secrecy and confidentiality of all material trade secrets,
copyrights and patents contained in the Intellectual Property (including,
entering into appropriate confidentiality, nondisclosure and noncompetition
agreements with all officers, directors, employees and third-party consultants
of Owen).
 
     4.11 Title to and Condition of Properties.  Owen owns or holds under valid
leases all real property, plants, machinery and equipment necessary for the
conduct of the business of Owen as presently conducted, except where the failure
to own or hold such property, plants, machinery and equipment would not have a
Material Adverse Effect on Owen.
 
     4.12 Registration Statement; Proxy Statement.  None of the information
provided in writing by Owen for inclusion in the Registration Statement at the
time it becomes effective or, in the case of the Proxy Statement, at the date of
mailing and at the date of the meeting of the Owen Shareholders to consider the
Merger, will contain any untrue statement of a material fact or omit to state a
material fact required to be
 
                                      A-12
<PAGE>   76
 
stated therein or necessary in order to make the statements therein, in light of
the circumstances under which they were made, not misleading. The Registration
Statement and Proxy Statement, except for such portions thereof that relate only
to Cardinal and its subsidiaries, will each comply as to form in all material
respects with the provisions of the Securities Act and the Exchange Act.
 
     4.13 Litigation.  Except as set forth in Section 4.13 to the Owen
Disclosure Schedule, there is no suit, claim, action, proceeding or, to the
knowledge of Owen, investigation (an "Action") pending or, to the knowledge of
Owen (or its executive officers or directors), threatened against Owen or any
executive officer or director of Owen which, individually or in the aggregate,
if adversely determined, would have a Material Adverse Effect on Owen or a
Material Adverse Effect on the ability of Owen to consummate the transactions
contemplated hereby. Owen is not subject to any outstanding order, writ,
injunction or decree which, individually or in the aggregate, insofar as can be
reasonably foreseen, could have a Material Adverse Effect on Owen or a material
adverse effect on the ability of Owen to consummate the transactions
contemplated hereby. Except as set forth in Section 4.13 to the Owen Disclosure
Schedule, since November 30, 1993, Owen has not been subject to any outstanding
order, writ, injunction or decree relating to Owen's method of doing business or
its relationship with past, existing or future customers, lessees, users,
purchasers or licensees of any Intellectual Property, goods or services of Owen.
 
     4.14 Brokerage and Finder's Fees; Expenses.  Except for Owen's obligations
to Smith Barney Inc. ("Smith Barney") and to Rauscher Pierce Refsnes, Inc.
("RPR") (copies of the written agreements relating to such obligations having
previously been provided to Cardinal), neither Owen nor any stockholder,
director, officer or employee thereof, has incurred or will incur on behalf of
Owen, any brokerage, finder's or similar fee in connection with the transactions
contemplated by this Agreement. Section 4.14 to the Owen Disclosure Schedule
discloses the maximum aggregate amount of all fees and expenses which will be
paid or will be payable by Owen to all attorneys, accountants and investment
bankers in connection with the Merger ("Merger Fees").
 
     4.15 Accounting Matters; Reorganization.  Neither Owen nor any of its
affiliates has taken or agreed to take any action that (without giving effect to
any actions taken or agreed to be taken by Cardinal or any of its affiliates)
would (a) prevent Cardinal from accounting for the business combination to be
effected by the Merger as a pooling-of-interests for financial reporting
purposes or (b) prevent the Merger from constituting a reorganization qualifying
under the provisions of Section 368(a) of the Code.
 
     4.16 Employee Benefit Plans.
 
     (a) For purposes of this Section 4.16, the following terms have the
definitions given below:
 
          "Controlled Group Liability" means any and all liabilities under (i)
     Title IV of ERISA, (ii) section 302 of ERISA, (iii) sections 412 and 4971
     of the Code, (iv) the continuation coverage requirements of section 601 et
     seq. of ERISA and section 4980B of the Code, and (v) corresponding or
     similar provisions of foreign laws or regulations, in each case other than
     pursuant to the Plans.
 
          "ERISA" means the Employee Retirement Income Security Act of 1974, as
     amended, and the regulations thereunder.
 
          "ERISA Affiliate" means, with respect to any entity, trade or
     business, any other entity, trade or business that is a member of a group
     described in Section 414(b), (c), (m) or (o) of the Code or Section
     4001(b)(1) of ERISA that includes the first entity, trade or business, or
     that is a member of the same "controlled group" as the first entity, trade
     or business pursuant to Section 4001(a)(14) of ERISA.
 
          "Plans" means all employee benefit plans, programs and other
     arrangements providing benefits to any employee or former employee in
     respect of services provided to Owen or beneficiary or dependent thereof,
     and whether covering one person or more than one person, sponsored or
     maintained by Owen or any of its subsidiaries or to which Owen or any of
     its subsidiaries contributes or is obligated to contribute. Without
     limiting the generality of the foregoing, the term "Plans" includes all
     employee welfare benefit plans within the meaning of Section 3(1) of ERISA
     and all employee pension benefit plans within the meaning of Section 3(2)
     of ERISA.
 
                                      A-13
<PAGE>   77
 
          "Withdrawal Liability" means liability to a Multiemployer Plan as a
     result of a complete or partial withdrawal from such Multiemployer Plan, as
     those terms are defined in Part I of Subtitle E of Title IV of ERISA.
 
     (b) Section 4.16 to the Owen Disclosure Schedule lists all Plans. With
respect to each Plan, Owen has made available to Cardinal a true, correct and
complete copy of the following (where applicable): (i) each writing constituting
a part of such Plan, including without limitation all plan documents, benefit
schedules, trust agreements, and insurance contracts and other funding vehicles;
(ii) the most recent Annual Report (Form 5500 Series) and accompanying schedule,
if any; (iii) the current summary plan description, if any; (iv) the most recent
annual financial report, if any; and (v) the most recent determination letter
from the Internal Revenue Service, if any.
 
     (c) The Internal Revenue Service has issued a favorable determination
letter with respect to each Plan that is intended to be a "qualified plan"
within the meaning of Section 401(a) of the Code (a "Qualified Plan") and to the
knowledge of Owen there are no existing circumstances nor any events that have
occurred that could adversely affect the qualified status of any Qualified Plan
or the related trust.
 
     (d) All contributions required to be made to any Plan by Applicable Laws or
by any plan document or other contractual undertaking, and all premiums due or
payable with respect to insurance policies funding any Plan, for any period
through the date hereof have been timely made or paid in full and through the
Closing Date will be timely made or paid in full.
 
     (e) Owen and its subsidiaries have complied, and are now in compliance, in
all material respects, with all provisions of ERISA, the Code and all laws and
regulations applicable to the Plans. Each Plan has been operated in material
compliance with its terms. There is not now, and to the knowledge of Owen there
are no existing circumstances that could reasonably be expected to give rise to,
any requirement for the posting of security with respect to a Plan or the
imposition of any lien on the assets of Owen or any of its subsidiaries under
ERISA or the Code.
 
     (f) No Plan is subject to Title IV or Section 302 of ERISA or Section 412
or 4971 of the Code. No Plan is a "multiemployer plan" within the meaning of
Section 4001(a)(3) of ERISA (a "Multiemployer Plan") or a plan that has two or
more contributing sponsors at least two of whom are not under common control,
within the meaning of Section 4063 of ERISA (a "Multiple Employer Plan"), nor
has Owen or any of its subsidiaries or any of their respective ERISA Affiliates,
at any time within five years before the date hereof, contributed to or been
obligated to contribute to any Multiemployer Plan or Multiple Employer Plan.
With respect to each Multiemployer Plan: (i) Neither Owen nor any of its ERISA
Affiliates has incurred any Withdrawal Liability that has not been satisfied in
full; (ii) if Owen or any of its ERISA Affiliates were to experience a
withdrawal or partial withdrawal from such plan, no Withdrawal Liability would
be incurred; and (iii) neither Owen nor any ERISA Affiliate has received any
notification, nor has any reason to believe, that any such plan is in
reorganization, has been terminated, or may reasonably be expected to be in
reorganization or to be terminated.
 
     (g) There does not now exist, and to the knowledge of Owen there are no
existing circumstances that could reasonably be expected to result in any
material Controlled Group Liability that would be a liability of Owen or any of
its subsidiaries following the Closing. Without limiting the generality of the
foregoing, neither Owen nor any of its subsidiaries nor any of their respective
ERISA Affiliates has engaged in any transaction described in Section 4069 or
Section 4204 of ERISA.
 
     (h) Except for health continuation coverage as required by Section 4980B of
the Code or Part 6 of Title I of ERISA, neither Owen nor any of its subsidiaries
has any material liability for life, health, medical or other welfare benefits
to former employees or beneficiaries or dependents thereof.
 
     (i) Except with respect to the acceleration of the non-employee director
options granted under the 1992 Non-Employee Director Stock Option Plan, neither
the execution and delivery of this Agreement nor the consummation of the
transactions contemplated hereby will result in, cause the accelerated vesting
or delivery of, or increase the amount or value of, any payment or benefit to
any employee, officer, director or consultant of Owen or any of its
subsidiaries. Without limiting the generality of the foregoing, no amount paid
or payable
 
                                      A-14
<PAGE>   78
 
by Owen or any of its subsidiaries in connection with the transactions
contemplated hereby either solely as a result thereof or as a result of such
transactions in conjunction with any other events will be an "excess parachute
payment" within the meaning of Section 280G of the Code.
 
     (j) Except as disclosed in Section 4.16(j) to the Owen Disclosure Schedule,
there are no pending or to the knowledge of Owen threatened claims (other than
claims for benefits in the ordinary course), lawsuits or arbitrations which have
been asserted or instituted against the Plans, any fiduciaries thereof with
respect to their duties to the Plans or the assets of any of the trusts under
any of the Plans which could reasonably be expected to result in any material
liability of Owen or any of its subsidiaries to the Pension Benefit Guaranty
Corporation, the Department of Treasury, the Department of Labor or any
Multiemployer Plan.
 
     (k) Section 4.16(k) to the Owen Disclosure Schedule sets forth the names of
all directors and officers of Owen, the total salary, bonus, fringe benefits and
perquisites each will receive in the fiscal year ending November 30, 1996, and
any changes to the foregoing which will occur subsequent to November 30, 1996;
Section 4.16(k) to the Owen Disclosure Schedule also lists and describes the
current compensation of any other employee of Owen whose total current salary
and maximum bonus opportunity exceeds $100,000 annually. Except as disclosed in
Section 4.16(k) to the Owen Disclosure Schedule, there are no other material
forms of compensation paid to any such director, officer or employee of Owen.
Except as set forth in Section 4.16(k) to the Owen Disclosure Schedule, no
officer, director, or employee of Owen or any other affiliate of Owen, or any
immediate family member of any of the foregoing, provides or causes to be
provided to Owen any material assets, services or facilities and Owen does not
provide or cause to be provided to any such officer, director, employee or
affiliate, or any immediate family member of any of the foregoing, any material
assets, services or facilities.
 
     4.17 Contracts.  Section 4.17 to the Owen Disclosure Schedule lists as of
the date hereof all written or oral contracts, agreements, guarantees, leases
and executory commitments other than Plans (each a "Contract") to which Owen is
a party and which fall within any of the following categories: (a) Contracts not
entered into in the ordinary course of Owen's business other than those that are
not material to the business of Owen, (b) joint venture, partnership and like
agreements, (c) Contracts which are service contracts or equipment leases
involving payments by Owen of more than $100,000 per year, (d) Contracts
containing covenants purporting to limit the freedom of Owen to compete in any
line of business in any geographic area or to hire any individual or group of
individuals except for confidentiality agreements executed in connection with
potential business combination or sale of any business division with such
covenants consistent with the Confidentiality Agreement (as defined in Section
5.2(j), (e) Contracts which after the Effective Time would have the effect of
limiting the freedom of Cardinal or its subsidiaries (other than Owen and its
subsidiaries) to compete in any line of business in any geographic area or to
hire any individual or group of individuals, except for confidentiality
agreements executed in connection with potential business combination or sale of
any business division with such covenants consistent with the Confidentiality
Agreement (f) Contracts which contain minimum purchase conditions (other than
such Contracts with manufacturers of pharmaceutical products) in excess of
$100,000 or requirements or other terms that restrict or limit the purchasing
relationships of Owen or its affiliates, or any customer, licensee or lessee
thereof, (g) Contracts relating to any outstanding commitment for capital
expenditures in excess of $300,000, (h) Contracts relating to the lease or
sublease of or sale or purchase of real or personal property involving any
annual expense or price in excess of $250,000 and not cancellable by Owen
(without premium or penalty) within one month, (i) Contracts with any labor
organization, (j) indentures, mortgages, promissory notes, loan agreements,
guarantees of borrowed money in excess of $50,000, letters of credit or other
agreements or instruments of Owen or commitments for the borrowing or the
lending of amounts in excess of $50,000 by Owen or providing for the creation of
any charge, security interest, encumbrance or lien upon any of the assets of
Owen, (k) Contracts involving annual revenues or expenditures to the business of
Owen in excess of 2.5% of Owen's annual revenues, (l) Contracts providing for
"earn-outs" or other contingent payments by Owen involving more than $20,000
over the term of the Contract and (m) Contracts with or for the benefit of any
affiliate of Owen or immediate family member thereof (other than subsidiaries of
Owen) involving more than $60,000 in the aggregate per affiliate. All such
Contracts are valid and binding obligations of Owen and, to the knowledge of
Owen, the valid and binding obligation of each other party thereto except such
Contracts which if not so valid and binding would not,
 
                                      A-15
<PAGE>   79
 
individually or in the aggregate, have a Material Adverse Effect on Owen.
Neither Owen nor, to the knowledge of Owen, any other party thereto is in
violation of or in default in respect of, nor has there occurred an event or
condition which with the passage of time or giving of notice (or both) would
constitute a default under or permit the termination of, any such Contract
except for payment defaults by client hospitals in the ordinary course of
business except such violations or defaults under or terminations which,
individually or in the aggregate, would not have a Material Adverse Effect on
Owen.
 
     4.18 Labor Matters.  Except as set forth in Section 4.18 to the Owen
Disclosure Schedule, neither Owen nor any of its subsidiaries has any labor
contracts, collective bargaining agreements or employment or consulting
agreements with any persons employed by Owen or any persons otherwise performing
services primarily for Owen or any of its subsidiaries (the "Owen Business
Personnel"). There is no labor strike, dispute or stoppage pending or, to the
knowledge of Owen, threatened against Owen or any of its subsidiaries, and
neither Owen nor any of its subsidiaries has experienced any labor strike,
dispute or stoppage or other material labor difficulty involving its employees
since November 30, 1993.
 
     4.19 Operation of Owen's Business; Relationships.
 
     (a) Since August 31, 1996 through the date of this Agreement, neither Owen
nor its subsidiaries has engaged in any transaction which, if done after
execution of this Agreement, would violate Section 5.3(c) hereof except as set
forth in Section 4.20 to the Owen Disclosure Schedule.
 
     (b) The relationships of Owen with its customers and suppliers are
satisfactory as of the date of this Agreement.
 
     (c) No product produced by Owen or produced for Owen by a third party and
bearing an Owen trademark or other Proprietary Right of Owen has been recalled
voluntarily or involuntarily since November 30, 1995, no such recall is being
considered by Owen, and, to the knowledge of Owen, no such recall is being
considered by or has been requested or ordered by any Governmental Authority.
 
     4.20 Permits; Compliance.  Owen is in possession of all material
franchises, grants, authorizations, licenses, permits, easements, variances,
exemptions, consents, certificates, approvals and orders necessary to own, lease
and operate its properties and to carry on its business as it is now being
conducted (collectively, the "Owen Permits"), and there is no Action pending or,
to the knowledge of Owen, threatened regarding any of the Owen Permits. Owen is
not in conflict with, or in default or violation of any of the Owen Permits,
except for any such conflicts, defaults or violations which, individually or in
the aggregate, could not reasonably be expected to have a Material Adverse
Effect on Owen.
 
     4.21 Product Warranties and Liabilities.  Except as listed in Section 4.21
to the Owen Disclosure Schedule, Owen has no forms of warranties or guarantees
of its products and services that are in effect or proposed to be used by it.
 
     4.22 Environmental Matters.  Except for matters disclosed in Schedule 4.22
of the Owen Disclosure Schedule, (a) the properties, operations and activities
of Owen and its subsidiaries are in compliance in all material respects with all
applicable Environmental Laws (as defined below); (b) Owen and its subsidiaries
and the properties and operations of Owen and its subsidiaries are not subject
to any existing, pending or, to the knowledge of Owen, threatened action, suit,
investigation, inquiry or proceeding by or before any court or governmental
authority under any Environmental Law; (c) there has been no material release of
any hazardous substance, pollutant or contaminant into the environment by Owen
or its subsidiaries or in connection with their properties or operations; (d)
there has been no material exposure of any person or property to any hazardous
substance, pollutant or contaminant in connection with the properties,
operations and activities of Owen and its subsidiaries; and (e) Owen and its
subsidiaries or their counsel have made available to the Purchaser all internal
and external audits (in each case relevant to Owen or any of its subsidiaries)
in the possession of Owen or its subsidiaries or their counsel. The term
"Environmental Laws" means all federal, state, local or foreign laws relating to
pollution or protection of human health or the environment (including, without
limitation, ambient air, surface water, groundwater, land surface or subsurface
strata), including, without limitation, laws relating to emissions, discharges,
releases or threatened releases of chemicals, pollutants, contaminants, or
industrial, toxic or hazardous substances or wastes
 
                                      A-16
<PAGE>   80
 
(collectively, "Hazardous Materials") into the environment, or otherwise
relating to the manufacture, processing, distribution, use, treatment, storage,
disposal, transport or handling of Hazardous Materials, as well as all
authorizations, codes, decrees, demands or demand letters, injunctions,
judgments, licenses, notices or notice letters, orders, permits, plans or
regulations issued, entered, promulgated or approved thereunder.
 
     4.23 Opinion of Financial Advisors.  Owen has received the opinion of each
of Smith Barney and RPR, its financial advisors, to the effect that, as of the
date of this Agreement, the Exchange Ratio is fair to the Owen Shareholders from
a financial point of view, Owen has heretofore provided copies of such opinions
to Cardinal and neither of such opinions have been withdrawn or revoked or
modified in any material respect.
 
     4.24 Board Recommendation.  The Board of Directors of Owen, at a meeting
duly called and held, has by unanimous vote of those directors present (who
constituted 100% of the directors then in office) (i) determined that this
Agreement and the transactions contemplated hereby, including the Merger, and
the Owen Stock Option Agreement and the transactions contemplated thereby, taken
together, are fair to and in the best interests of the Owen Shareholders, and
(ii) resolved to recommend that the holders of the shares of Owen Common Stock
approve this Agreement and the transactions contemplated herein, including the
Merger (the "Owen Board Recommendation").
 
     4.25 State Takeover Laws.  No state takeover law or other state law
(including, without limitation, under the TBCA) that purports to limit or
restrict business combinations or the ability to acquire or vote shares nor the
provisions of Article 10 of the Owen Articles are applicable to: (i) the
execution of this Agreement, the Stock Option Agreement dated November 27, 1996
between Cardinal and Owen (the "Owen Stock Option Agreement") and the
Support/Voting Agreements dated as of November 27, 1996 between Cardinal and
certain Owen Shareholders (collectively, the "Support Agreements"), (ii) the
Merger and (iii) the transactions contemplated hereby and by the Owen Stock
Option Agreement and the Support Agreements.
 
     4.26 Lease Arrangements.
 
     (a) Except as set forth in Section 4.26 to the Owen Disclosure Schedule,
there are no lessees ("Master Lessees") who have been granted the right to use,
purchase, lease or license Intellectual Property, goods or services from Owen
and to provide, resell, sublease or relicense same to other authorized lessees
or third parties. The identity of each Master Lessee and a description of all
lessees and third parties to whom such Master Lessee is entitled to provide,
resell, sublease or relicense Intellectual Property, goods and services of Owen
are set forth in Section 4.26 to the Owen Disclosure Schedule. There are no
material agreements between Owen and any Master Lessee other than those in
writing that are set forth in Section 4.26 to the Owen Disclosure Schedule.
 
     (b) The relationships of Owen with its lessees and licensees are
satisfactory as of the date of this Agreement.
 
     (c) Owen is not a party to any vendor financing arrangement which (i)
requires Owen to use such financing for any particular transaction, or (ii)
cannot be terminated (without premium or penalty) upon less than one month's
notice. Any Meditrol unit that is subject to any vendor financing arrangement
shall, upon expiration of the term of such financing arrangement (assuming all
Owen's obligations thereunder have been met), be owned by Owen free and clear of
any liens, security interests, encumbrances and restrictions of any kind.
 
                                   ARTICLE V
 
                            COVENANTS OF THE PARTIES
 
     The parties hereto agree as follows with respect to the period from and
after the execution of this Agreement.
 
                                      A-17
<PAGE>   81
 
     5.1 Mutual Covenants.
 
     (a) General.  Each of the parties shall use its reasonable efforts to take
all action and to do all things necessary, proper or advisable to consummate the
Merger and the transactions contemplated by this Agreement (including, without
limitation, using its reasonable efforts to cause the conditions set forth in
Article VI for which they are responsible to be satisfied as soon as reasonably
practicable and to prepare, execute and deliver such further instruments and
take or cause to be taken such other and further action as any other party
hereto shall reasonably request).
 
     (b) HSR Act.  As soon as practicable, and in any event no later than
fifteen business days after the date hereof, each of the parties hereto will
file any Notification and Report Forms and related material required to be filed
by it with the Federal Trade Commission and the Antitrust Division of the United
States Department of Justice under the HSR Act with respect to the Merger, will
use its reasonable efforts to obtain an early termination of the applicable
waiting period, and shall promptly make any further filings pursuant thereto
that may be necessary, proper or advisable. Cardinal and Owen agree to cooperate
with respect to, and shall cause each of their respective subsidiaries to
cooperate with respect to, and agree to use all reasonable efforts to contest
and resist, any Action, including legislative, administrative or judicial
Action, and to have vacated, lifted, reversed or overturned any decree,
judgment, injunction or other order (whether temporary, preliminary or
permanent) (an "Order") of any Governmental Authority that is in effect and that
restricts, prevents or prohibits the consummation of the Merger or any other
transactions contemplated by this Agreement, including, without limitation, by
pursuing all available avenues of administrative and judicial appeal and all
available legislative action. Upon the terms and subject to the conditions set
forth in this Agreement, in connection with the HSR Act, each of Owen and
Cardinal agrees to take, or cause to be taken, all actions, and to do, or cause
to be done, and to assist and cooperate with the other parties in doing, all
things necessary, proper or advisable to consummate and make effective, in the
most expeditious manner practicable, the Merger and the other transactions
contemplated by this Agreement, including the obtaining of all necessary actions
or nonactions, waivers, consents and approvals from Governmental Authorities and
the making of all necessary registrations and filings (including filings with
Governmental Authorities, if any) and the taking of all reasonable steps as may
be necessary to obtain an approval or waiver from, or to avoid an action or
proceeding by, any Governmental Authority; provided, however, that a party shall
not be obligated to take any action pursuant to the foregoing if the taking of
such action or the obtaining of any waiver, consent, approval or exemption is
reasonably likely (x) to impact in a materially adverse manner the economic or
business benefits of the transactions contemplated by this Agreement so as to
render inadvisable the consummation of the Merger or (y) to result in an Order
(i) prohibiting or limiting the ownership or operation by Cardinal of any
material portion of the business or assets of Owen or compelling Cardinal to
dispose of or hold separate any of the business or assets of Cardinal or any
material portion of the business or assets of Owen as a result of the Merger or
any of the other transactions contemplated by this Agreement, (ii) imposing
limitations on the ability of Cardinal to acquire or hold, or exercise full
rights of ownership of, any shares of capital stock of Owen, including, without
limitation, the right to vote such capital stock on all matters properly
presented to the Owen Shareholders, or (iii) prohibiting Cardinal from
effectively controlling in any material respect the business or operations of
Owen.
 
     (c) Other Governmental Matters.  Each of the parties shall use its
reasonable efforts to take any additional action that may be necessary, proper
or advisable in connection with any other notices to, filings with, and
authorizations, consents and approvals of any Governmental Authority that it may
be required to give, make or obtain.
 
     (d) Pooling-of-Interests.  Each of the parties shall use its best efforts
to cause the Merger to qualify for pooling-of-interests accounting treatment for
financial reporting purposes, including without limitation, appropriate
representation letters to Cardinal's accountants.
 
     (e) Tax-Free Treatment.  Each of the parties shall use its best efforts to
cause the Merger to constitute a tax-free "reorganization" under Section 368(a)
of the Code and to permit Vinson & Elkins L.L.P. and Wachtell, Lipton, Rosen &
Katz to issue their opinions provided herein.
 
                                      A-18
<PAGE>   82
 
     (f) Public Announcements.  Unless otherwise required by Applicable Laws or
requirements of the NYSE (and in that event only if time does not permit), at
all times prior to the earlier of the Effective Time or termination of this
Agreement pursuant to Section 7.1, Cardinal and Owen shall consult with each
other before issuing any press release with respect to the Merger and shall not
issue any such press release prior to such consultation.
 
     5.2 Covenants of Cardinal.
 
     (a) Preparation of Registration Statement.  Cardinal shall, as soon as is
reasonably practicable, prepare the Proxy Statement for filing by Owen with the
Commission on a confidential basis. Cardinal shall prepare and file the
Registration Statement with the Commission as soon as is reasonably practicable
following clearance of the Proxy Statement by the Commission and shall use all
reasonable efforts to have the Registration Statement declared effective by the
Commission as promptly as practicable and to maintain the effectiveness of the
Registration Statement through the Effective Time. If, at any time prior to the
Effective Time, Cardinal shall obtain knowledge of any information pertaining to
Cardinal contained in or omitted from the Registration Statement that would
require an amendment or supplement to the Registration Statement or the Proxy
Statement, Cardinal will so advise Owen in writing and will promptly take such
action as shall be required to amend or supplement the Registration Statement.
Cardinal shall promptly furnish to Owen all information concerning it as may be
required for supplementing the Proxy Statement. Cardinal shall cooperate with
Owen in the preparation of the Proxy Statement in a timely fashion and shall use
all reasonable efforts to assist Owen in clearing the Proxy Statement with the
Staff of the Commission. Cardinal also shall take such other reasonable actions
(other than qualifying to do business in any jurisdiction in which it is not so
qualified) required to be taken under any applicable state securities laws in
connection with the issuance of Cardinal Common Shares in the Merger.
 
     (b) Indemnification.  From and after the Effective Time, Cardinal shall
cause (including, providing adequate funding), the Surviving Corporation to
indemnify and hold harmless the present and former officers and directors of
Owen in respect of acts or omissions occurring prior to the Effective Time to
the extent provided under the Owen Certificate of Incorporation, as amended and
restated, and Bylaws in effect on the date hereof.
 
     (c) Insurance.  From and after this Effective Time Cardinal shall maintain
the current policies of directors' and officers' liability insurance through the
remainder of its term which ends in June 1997.
 
     (d) Employee Benefits.  Cardinal covenants and agrees that, for a period of
one year from and after the Effective Time, it will cause the Surviving
Corporation to provide for the benefit of employees of the Surviving Corporation
benefits that are no less favorable, in the aggregate, than those provided to
employees of Owen immediately prior to the date of this Agreement. In the event
Cardinal satisfies its obligations under this Section 5.2(c) by adding employees
of Owen to Cardinal's medical plan (the "Cardinal Medical Plan"), then
eligibility of such employees for medical benefits under the Cardinal Medical
Plan will not be subject to standard exclusions for pre-existing conditions.
 
     (e) Notification of Certain Matters.  Cardinal shall give prompt notice to
Owen of (i) the occurrence or non-occurrence of any event the occurrence or
non-occurrence of which would cause any Cardinal or Subcorp representation or
warranty contained in this Agreement to be untrue or inaccurate at or prior to
the Effective Time in any material respect and (ii) any material failure of
Cardinal to comply with or satisfy any covenant, condition or agreement to be
complied with or satisfied by it hereunder; provided, however, that the delivery
of any notice pursuant to this Section 5.2(d) shall not limit or otherwise
affect the remedies available hereunder to Owen.
 
     (f) Pooling Press Release.  Cardinal shall use its best efforts to prepare
and publicly release as soon as practicable (but in any event within fifteen
days) following the end of the first full calendar month completed after the
Effective Time, a report in the form of a quarterly earnings report,
registration statement filed with the Commission, a report filed with the
Commission on Form 10-K, 10-Q or 8-K or any other public filing, statement or
announcement which includes the combined financial results (including combined
sales and net
 
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<PAGE>   83
 
income) of Cardinal and Owen for a period of at least 30 days of combined
operations of Cardinal and Owen following the Effective Time.
 
     (g) Merger Sub.  Prior to the Effective Time, Subcorp shall not conduct any
business or make any investments other than as specifically contemplated by this
Agreement and will not have any assets (other than a de minimis amount of cash
paid to Subcorp for the issuance of its stock to Cardinal) or any material
liabilities.
 
     (h) NYSE Listing.  Cardinal shall use its reasonable efforts to cause the
Cardinal Common Shares issuable pursuant to the Merger to be approved for
listing on the NYSE, subject to official notice of issuance, prior to the
Effective Time.
 
     (i) Affiliates of Cardinal.  Cardinal shall cause each such person who may
be at the Effective Time or was on the date hereof an "affiliate" of Cardinal
for purposes of Rule 145 under the Securities Act, to execute and deliver to
Cardinal no less than 30 days prior to the date of the Owen Shareholders
Meeting, the written undertakings in the form attached hereto as Exhibit A-2.
 
     (j) Access.  Cardinal shall permit representatives of Owen to have
appropriate access at all reasonable times to Cardinal's premises, properties,
books, records, contracts, tax records, documents, customers and suppliers.
Information obtained by Owen pursuant to this Section 5.2(i) shall be subject to
the provisions of the confidentiality agreement between Cardinal and Owen dated
November 12, 1996 (the "Confidentiality Agreement"), which agreement remains in
full force and effect.
 
     5.3 Covenants of Owen.
 
     (a) Owen Shareholders Meeting.  Owen shall take all action in accordance
with the federal securities laws, the TBCA and the Owen Articles and the Owen
Bylaws necessary to convene a special meeting of Owen Shareholders to be held on
the earliest practicable date (the "Owen Shareholders Meeting") to consider and
vote upon approval of the Merger, this Agreement and the transactions
contemplated hereby.
 
     (b) Information for the Registration Statement and Preparation of Proxy
Statement.  Owen shall promptly furnish Cardinal with all information concerning
it as may be required for inclusion in the Registration Statement. Owen shall
cooperate with Cardinal in the preparation of the Registration Statement in a
timely fashion and shall use all reasonable efforts to assist Cardinal in having
the Registration Statement declared effective by the Commission as promptly as
practicable. If, at any time prior to the Effective Time, Owen obtains knowledge
of any information pertaining to Owen that would require any amendment or
supplement to the Registration Statement or the Proxy Statement, Owen shall so
advise Cardinal and shall promptly furnish Cardinal with all information as
shall be required for such amendment or supplement and shall promptly supplement
the Proxy Statement. Owen shall use all reasonable efforts to cooperate with
Cardinal in the preparation and filing of the Proxy Statement with the
Commission on a confidential basis. Owen shall use all reasonable efforts to
mail at the earliest practicable date to Owen Shareholders the Proxy Statement,
which shall include all information required under Applicable Law to be
furnished to Owen Shareholders in connection with the Merger and the
transactions contemplated thereby and shall include the Owen Board
Recommendation to the extent not previously withdrawn in compliance with Section
5.3(e).
 
     (c) Conduct of Owen's Operations.  Owen shall conduct its operations in the
ordinary course except as expressly contemplated by this Agreement and the
transactions contemplated hereby and shall use its reasonable best efforts to
maintain and preserve its business organization and its material rights and
franchises and to retain the services of its officers and key employees and
maintain relationships with customers, suppliers, lessees, licensees and other
third parties, and to maintain all of its operating assets in their current
condition (normal wear and tear excepted), to the end that their goodwill and
ongoing business shall not be impaired in any material respect. Without limiting
the generality of the foregoing, during the period from the date of this
Agreement to the Effective Time, Owen shall not, except as otherwise expressly
contemplated by
 
                                      A-20
<PAGE>   84
 
this Agreement and the transactions contemplated hereby or as set forth in
Section 5.3(c) to the Owen Disclosure Schedule, without the prior written
consent of Cardinal:
 
          (i) do or effect any of the following actions with respect to its
     securities: (A) adjust, split, combine or reclassify its capital stock, (B)
     make, declare or pay any dividend or distribution on, or directly or
     indirectly redeem, purchase or otherwise acquire, any shares of its capital
     stock or any securities or obligations convertible into or exchangeable for
     any shares of its capital stock, (C) grant any person any right or option
     to acquire any shares of its capital stock, (D) issue, deliver or sell or
     agree to issue, deliver or sell any additional shares of its capital stock
     or any securities or obligations convertible into or exchangeable or
     exercisable for any shares of its capital stock or such securities (except
     pursuant to the exercise of Owen Options which are outstanding as of the
     date hereof), or (E) enter into any agreement, understanding or arrangement
     with respect to the sale or voting of its capital stock;
 
          (ii) directly or indirectly sell, transfer, lease, pledge, mortgage,
     encumber or otherwise dispose of any of its property or assets other than
     in the ordinary course of business;
 
          (iii) make or propose any changes in the Owen Articles or the Owen
     Bylaws;
 
          (iv) merge or consolidate with any other person or acquire a material
     amount of assets or capital stock of any other person (other than as
     permitted, in each case, by Section 5.3(e));
 
          (v) incur, create, assume or otherwise become liable for any
     indebtedness for borrowed money or assume, guarantee, endorse or otherwise
     as an accommodation become responsible or liable for the obligations of any
     other individual, corporation or other entity, other than in the ordinary
     course of business, consistent with past practice not in excess of $8
     million in the aggregate;
 
          (vi) create any subsidiaries;
 
          (vii) enter into or modify any employment, severance, termination or
     similar agreements or arrangements with, or grant any bonuses, salary
     increases, severance or termination pay to, any officer, director,
     consultant or employee other than in the ordinary course of business
     consistent with past practice, or otherwise increase the compensation or
     benefits provided to any officer, director, consultant or employee except
     as may be required by Applicable Law or in the ordinary course of business
     consistent with past practice;
 
          (viii) enter into, adopt or amend any employee benefit or similar plan
     except as may be required by Applicable Law;
 
          (ix) change any method or principle of accounting in a manner that is
     inconsistent with past practice except to the extent required by generally
     accepted accounting principles;
 
          (x) settle any Actions, whether now pending or hereafter made or
     brought involving, individually or in the aggregate, an amount in excess of
     $500,000;
 
          (xi) write up, write down or write off the book value of any assets,
     individually or in the aggregate, in excess of $250,000 except for
     depreciation and amortization in accordance with generally accepted
     accounting principles consistently applied;
 
          (xii) incur or commit to any capital expenditures, obligations or
     liabilities in respect thereof which in the aggregate exceed or would
     exceed $3 million;
 
          (xiii) pay (or agree to become obligated to pay) any Merger Fees in
     excess of the amount set forth in Section 4.14 to the Owen Disclosure
     Schedule;
 
          (xiv) take any action to exempt or make not subject to the provisions
     of Article 10 of the Owen Articles any person or entity (other than
     Cardinal or its subsidiaries) or any action taken thereby, which person,
     entity or action would have otherwise been subject to such restrictive
     provisions and not exempt therefrom;
 
                                      A-21
<PAGE>   85
 
          (xv) take any action that could likely result in the representations
     and warranties set forth in Article IV becoming false or inaccurate in any
     material respect;
 
          (xvi) permit or cause any subsidiary to do any of the foregoing or
     agree or commit to do any of the foregoing; or
 
          (xvii) agree in writing or otherwise to take any of the foregoing
     actions.
 
     (d) Intellectual Property Matters.  Owen shall use its reasonable efforts
consistent with its past practices to preserve its ownership rights to the
Intellectual Property free and clear of any liens, claims or encumbrances.
 
     (e) No Solicitation.  Owen agrees that, during the term of this Agreement,
it shall not, and shall not authorize or permit any of its subsidiaries or any
of its or its subsidiaries' directors, officers, employees, agents or
representatives, directly or indirectly, to solicit, initiate, encourage or
facilitate, or furnish or disclose non-public information in furtherance of, any
inquiries or the making of any proposal with respect to any recapitalization,
merger, consolidation or other business combination involving Owen, or
acquisition of any capital stock (other than upon exercise of Owen Options which
are outstanding as of the date hereof) or any material portion of the assets
(except for acquisition of assets in the ordinary course of business consistent
with past practice) of Owen, or any combination of the foregoing (a "Competing
Transaction"), or negotiate, explore or otherwise engage in discussions with any
person (other than Cardinal, Subcorp or their respective directors, officers,
employees, agents and representatives) with respect to any Competing Transaction
or enter into any agreement, arrangement or understanding requiring it to
abandon, terminate or fail to consummate the Merger or any other transactions
contemplated by this Agreement; provided that, at any time prior to the approval
of the Merger by the Owen Shareholders, Owen may furnish information to, and
negotiate or otherwise engage in discussions with, any party who delivers a
written proposal for a Competing Transaction which was not solicited or
encouraged after the date of this Agreement if and so long as the Board of
Directors of Owen determines in good faith by a majority vote, based upon
consultation and advice from its outside legal counsel that failing to take such
action is reasonably likely to constitute a breach of the fiduciary duties of
the Board of Directors of Owen under Applicable Law and determines that such a
proposal is, after consulting with Smith Barney or RPR (or any other nationally
recognized investment banking firm), more favorable to Owen's Stockholders from
a financial point of view than the transactions contemplated by this Agreement
(including any adjustment to the terms and conditions proposed by Cardinal in
response to such Competing Transaction). Owen will immediately cease all
existing activities, discussions and negotiations with any parties conducted
heretofore with respect to any proposal for a Competing Transaction. In the
event that prior to the approval of the Merger by the Owen Shareholders the
Board of Directors of Owen receives advice of outside legal counsel that failure
to do so is reasonably like to result in breach of the fiduciary duties of the
Owen Board of Directors under Applicable Law, the Board of Directors of Owen may
(subject to this and the following sentences) withdraw or modify the Owen Board
Recommendation and/or comply with Rule 14e-2 promulgated under the Exchange Act
with respect to a Competing Transaction, provided that it gives Cardinal two
business days prior written notice of its intention to do so (provided that the
foregoing shall no way limit or otherwise affect Cardinal's right to terminate
this Agreement pursuant to Section 7.1(d)). Any such withdrawal or modification
of the Owen Board Recommendation shall not change the approval of the Board of
Directors of Owen for purposes of causing either the provisions of Article 10 of
the Owen Articles or any state takeover statute or other state law to be
inapplicable to the transactions contemplated hereby, including the Merger, the
Owen Stock Option Agreement or the Support Agreements or change the obligation
of Owen to present the Merger for approval at a duly called Owen Shareholders
Meeting on the earliest practicable date. From and after the execution of this
Agreement, Owen shall immediately advise Cardinal in writing of the receipt,
directly or indirectly, of any inquiries, discussions, negotiations, or
proposals relating to a Competing Transaction (including the specific terms
thereof and the identity of the other party or parties involved) and promptly
furnish to Cardinal a copy of any such written proposal in addition to any
information provided to or by any third party relating thereto.
 
     (f) Termination Right.  If prior to the approval of the Merger by the Owen
Shareholders the Board of Directors of Owen shall determine in good faith, after
consultation with its financial and legal advisors, that
 
                                      A-22
<PAGE>   86
 
any written proposal from a third party for a Competing Transaction received
after the date hereof that was not solicited or encouraged by Owen or any of its
subsidiaries or affiliates in violation of this Agreement is more favorable to
the Owen Shareholders from a financial point of view than the transactions
contemplated by this Agreement (including any adjustment to the terms and
conditions of such transaction proposed in writing by Cardinal in response to
such Competing Transaction) and is in the best interest of the Owen Shareholders
and Owen has received (x) advice of its outside legal counsel that failure to
enter into such a Competing Transaction is reasonably likely to constitute a
breach of the Board of Directors' fiduciary duties under Applicable Law and (y)
a written opinion (a copy of which has been delivered to Cardinal) from Smith
Barney or RPR that the Competing Transaction is more favorable from a financial
point of view to the Owen Shareholders than the transactions contemplated by
this Agreement (including any adjustment to the terms and conditions of such
transaction proposed in writing by Cardinal), Owen may terminate this Agreement
and enter into a letter of intent, agreement-in-principle, acquisition agreement
or other similar agreement (each, an "Acquisition Agreement") with respect to
such Competing Transaction provided that, prior to any such termination, (i)
Owen has provided Cardinal written notice that it intends to terminate this
Agreement pursuant to this Section 5.3(f), identifying the Competing Transaction
then determined to be more favorable and the parties thereto and delivering a
copy of the Acquisition Agreement for such Competing Transaction in the form to
be entered into, and (ii) at least two full business days after Owen has
provided the notice referred to in clause (i) above (provided that the opinions
referred to in clauses (x) and (y) above shall continue in effect without
revision or modification), Owen delivers to Cardinal (A) a written notice of
termination of this Agreement pursuant to this Section 5.3(f), (B) a check in
the amount of Cardinal's Costs (as defined in Section 7.2) as the same may have
been estimated by Cardinal in good faith prior to the date of such delivery
(subject to an adjustment payment between the parties upon Cardinal's definitive
determination of such Costs), plus the amount of the termination fee as provided
in Section 7.2, (C) a written acknowledgment from Owen that (x) the termination
of this Agreement and the entry into the Acquisition Agreement for the Competing
Transaction will be a "Purchase Event" as defined in the Owen Stock Option
Agreement and (y) the Owen Stock Option Agreement shall be honored in accordance
with its terms and (D) a written acknowledgment from each other party to such
Competing Transaction that it is aware of the substance of Owen's acknowledgment
under clause (C) above and waives any right it may have to contest the matters
thus acknowledged by Owen.
 
     (g) Affiliates of Owen.  Owen shall cause each such person who may be at
the Effective Time or was on the date hereof an "affiliate" of Owen for purposes
of Rule 145 under the Securities Act, to execute and deliver to Cardinal no less
than 30 days prior to the date of the Owen Shareholders Meeting, the written
undertakings in the form attached hereto as Exhibit A-1. On or prior to such
date, Owen, after consultation with its outside counsel, shall provide Cardinal
with a letter (reasonably satisfactory to counsel to Cardinal) specifying all of
the persons or entities who, in Owen's view, may be deemed to be "affiliates" of
Owen under the preceding sentence.
 
     (h) Access.  Owen shall permit representatives of Cardinal to have
appropriate access at all reasonable times to Owen's premises, properties,
books, records, contracts, tax records, documents, customers and suppliers.
Proprietary information obtained by Cardinal pursuant to this Section 5.3(h)
shall be subject to the provisions of the Confidentiality Agreement, which
agreement remains in full force and effect.
 
     (i) Notification of Certain Matters.  Owen shall give prompt notice to
Cardinal of (i) the occurrence or non-occurrence of any event the occurrence or
non-occurrence of which would cause any Owen representation or warranty
contained in this Agreement to be untrue or inaccurate at or prior to the
Effective Time in any material respect and (ii) any material failure of Owen to
comply with or satisfy any covenant, condition or agreement to be complied with
or satisfied by it hereunder; provided, however, that the delivery of any notice
pursuant to this Section 5.3(h) shall not limit or otherwise affect the remedies
available hereunder to Cardinal.
 
     (j) Subsequent Financial Statements.  Owen shall consult with Cardinal
prior to making publicly available its financial results for any period.
 
                                      A-23
<PAGE>   87
 
                                   ARTICLE VI
 
                                   CONDITIONS
 
     6.1 Mutual Conditions.  The obligations of the parties hereto to consummate
the Merger shall be subject to fulfillment of the following conditions:
 
          (a) No temporary restraining order, preliminary or permanent
     injunction or other order or decree which prevents the consummation of the
     Merger shall have been issued and remain in effect, and no statute, rule or
     regulation shall have been enacted by any Governmental Authority which
     prevents the consummation of the Merger.
 
          (b) All waiting periods applicable to the consummation of the Merger
     under the HSR Act shall have expired or been terminated.
 
          (c) The Merger and the transactions contemplated hereby shall have
     been approved by the Owen Shareholders in the manner required by any
     Applicable Law.
 
          (d) The Commission shall have declared the Cardinal Registration
     Statement effective. On the Closing Date and at the Effective Time, no stop
     order or similar restraining order shall have been entered by the
     Commission or proceeding for that purpose initiated or any state securities
     administrator prohibiting the Merger.
 
          (e) No Action shall be instituted by any Governmental Authority which
     seeks to prevent consummation of the Merger or seeking material damages in
     connection with the transactions contemplated hereby which continues to be
     outstanding.
 
          (f) Cardinal shall have received a letter, in form and substance
     reasonably satisfactory to Cardinal, from Deloitte & Touche L.L.P. dated
     the date of the Proxy Statement and confirmed in writing at the Effective
     Time stating that the Merger will qualify as a pooling of interests
     transaction under Opinion 16 of the Accounting Principles Board.
 
     6.2 Conditions to Obligations of Owen.  The obligations of Owen to
consummate the Merger and the transactions contemplated hereby shall be subject
to the fulfillment of the following conditions unless waived by Owen:
 
          (a) The representations and warranties of each of Cardinal and Subcorp
     set forth in Article III shall be true and correct on the date hereof and
     on and as of the Closing Date as though made on and as of the Closing Date
     (except for representations and warranties made as of a specified date,
     which need be true and correct only as of the specified date), except for
     such inaccuracies which have not had and could not reasonably be expected
     to have in the reasonably foreseeable future a Material Adverse Effect on
     Cardinal.
 
          (b) Each of Cardinal and Subcorp shall have performed in all material
     respects each obligation and agreement and shall have complied in all
     material respects with each covenant to be performed and complied with by
     it hereunder at or prior to the Effective Time.
 
          (c) Each of Cardinal and Subcorp shall have furnished Owen with a
     certificate dated the Closing Date signed on behalf of it by the Chairman,
     President or any Vice President to the effect that the conditions set forth
     in Sections 6.2(a) and (b) have been satisfied.
 
          (d) Owen shall have received the legal opinions, dated the Closing
     Date, of Wachtell, Lipton, Rosen & Katz in substantially the form attached
     hereto as Exhibit B.
 
          (e) The Cardinal Common Shares to be issued in the Merger and the
     transactions contemplated hereby shall have been authorized for inclusion
     on the NYSE, subject to official notice of issuance.
 
          (f) Owen shall have received the opinion of Vinson & Elkins LLP, dated
     on or prior to the effective date of the Registration Statement, to the
     effect that (i) the Merger will constitute a reorganization
 
                                      A-24
<PAGE>   88
 
     under section 368(a) of the Code, (ii) Owen, Cardinal and Subcorp will each
     be a party to that reorganization, and (iii) no gain or loss will be
     recognized by the shareholders of Owen upon the receipt of Cardinal Common
     Shares in exchange for shares of Owen Common Stock pursuant to the Merger
     except with respect to cash received in lieu of fractional share interests
     in Cardinal Common Shares.
 
     6.3 Conditions to Obligations of Cardinal and Subcorp.  The obligations of
Cardinal to consummate the Merger and the other transactions contemplated hereby
shall be subject to the fulfillment of the following conditions unless waived by
Cardinal:
 
          (a) The representations and warranties of Owen set forth in Article IV
     shall be true and correct on the date hereof and on and as of the Closing
     Date as though made on and as of the Closing Date (except for
     representations and warranties made as of a specified date, which need be
     true and correct only as of the specified date), except for such
     inaccuracies which have not had and could not reasonably be expected to
     have in the reasonably foreseeable future a Material Adverse Effect on
     Owen.
 
          (b) Owen shall have performed in all material respects each obligation
     and agreement and shall have complied in all material respects with each
     covenant to be performed and complied with by it hereunder at or prior to
     the Effective Time.
 
          (c) Owen shall have furnished Cardinal with a certificate dated the
     Closing Date signed on its behalf by its Chairman, President or any Vice
     President to the effect that the conditions set forth in Sections 6.3(a)
     and (b) have been satisfied.
 
          (d) Cardinal shall have received the legal opinion, dated the Closing
     Date, of Vinson & Elkins, substantially in the form attached hereto as
     Exhibit C.
 
          (e) Cardinal shall have received the opinion of Wachtell, Lipton,
     Rosen & Katz, dated on or prior to the effective date of the Registration
     Statement, to the effect that (i) the Merger will constitute a
     reorganization under section 368(a) of the Code, (ii) Cardinal, Subcorp and
     Owen will each be a party to that reorganization, and (iii) no gain or loss
     will be recognized by Cardinal, Subcorp or Owen by reason of the Merger.
 
          (f) There shall not have been a breach of the Owen Stock Option
     Agreement.
 
                                  ARTICLE VII
 
                           TERMINATION AND AMENDMENT
 
     7.1 Termination.  This Agreement may be terminated at any time prior to the
Effective Time, whether before or after approval and adoption of this Agreement
by Owen Shareholders:
 
          (a) by mutual consent of Cardinal and Owen;
 
          (b) by either Cardinal or Owen if any permanent injunction or other
     order of a court or other competent Governmental Authority preventing the
     consummation of the Merger shall have become final and nonappealable;
 
          (c) by either Cardinal or Owen if the Merger shall not have been
     consummated before May 31, 1997, unless extended by the Boards of Directors
     of both Cardinal and Owen (provided that the right to terminate this
     Agreement under this Section 7.1(c) shall not be available to any party
     whose failure to perform any material covenant or obligation under this
     Agreement has been the cause of or resulted in the failure of the Merger to
     occur on or before such date);
 
          (d) by Cardinal if the Board of Directors of Owen shall withdraw,
     modify or change the Owen Board Recommendation in a manner adverse to
     Cardinal, or if the Board of Directors of Owen shall have refused to affirm
     the Owen Board Recommendation within two business days of any written
     request from Cardinal;
 
                                      A-25
<PAGE>   89
 
          (e) by Cardinal or Owen if at the Owen Shareholders Meeting (including
     any adjournment or postponement thereof) the requisite vote of the Owen
     Shareholders to approve the Merger and the transactions contemplated hereby
     shall not have been obtained;
 
          (f) by Owen, pursuant to Section 5.3(f);
 
          (g) by Owen, no earlier than the fifth trading day or later than the
     third full trading day immediately preceding the date of the Owen
     Stockholders Meeting at which the vote to approve the Merger will be taken,
     if the Average Share Price is less than $69.20, provided that Owen will
     have no right to terminate pursuant to this paragraph (g) unless (x) Owen
     shall have given, during the three trading day period referred to above,
     one full trading day's prior written notice of its intention to terminate
     pursuant to this Section 7.1(g) and (y) Cardinal during such one full
     trading day notice period shall not have given written notice (an
     "Adjustment Election") to Owen that the Exchange Ratio shall be calculated
     pursuant to clause (b) of Section 2.2;
 
          (h) by Cardinal if Owen shall have breached any of its obligations
     under the Owen Stock Option Agreement or if Dian G. Owen shall have
     breached any of her obligations under the Support Agreement with Cardinal;
 
     7.2 Effect of Termination.  In the event of the termination of this
Agreement pursuant to Section 7.1, this Agreement, except for the provisions of
the last sentence of each of Section 5.2(j) and Section 5.3(h) and the
provisions of Sections 7.2 and 8.11, shall become void and have no effect,
without any liability on the part of any party or its directors, officers or
stockholders. Notwithstanding the foregoing, nothing in this Section 7.2 shall
relieve any party to this Agreement of liability for a material breach of any
provision of this Agreement and provided, further, however, that if it shall be
judicially determined that termination of this Agreement was caused by an
intentional breach of this Agreement, then, in addition to other remedies at law
or equity for breach of this Agreement, the party so found to have intentionally
breached this Agreement shall indemnify and hold harmless the other parties for
their respective out-of-pocket costs, fees and expenses of their counsel,
accountants, financial advisors and other experts and advisors as well as fees
and expenses incident to negotiation, preparation and execution of this
Agreement and related documentation and shareholders' meetings and consents
("Costs"). If this Agreement is terminated for any reason pursuant to Section
7.1 (other than a termination pursuant to Section 7.1(a) (prior to the public
announcement of a Competing Transaction), 7.1(b), 7.1(c) (other than a
termination by Cardinal pursuant to Section 7.1(c) if Owen's failure to perform
any material covenant or obligation under this Agreement has been the cause of
or resulted in the failure of the Merger to occur on or before May 31, 1997),
7.1(e), 7.1(g)) or this Agreement is terminated pursuant to Section 7.1(e) and
within 12 months after the date of termination Owen enters into an Acquisition
Agreement for a Business Combination (as defined herein) or consummates a
Business Combination Owen will, in the case of a termination by Cardinal, within
three business days following any such termination or, in the case of a
termination by Owen, (except in each case, if the termination is pursuant to
Section 7.1(e), then, prior to consummation of a Business Combination herein) or
execution of the definitive agreement with respect thereto) concurrently with
such termination, pay to Cardinal in cash by wire transfer in immediately
available funds to an account designated by Cardinal (i) in reimbursement for
Cardinal's expenses an amount in cash equal to the aggregate amount of
Cardinal's Costs incurred in connection with pursuing the transactions
contemplated by this Agreement, including, without limitation, legal, accounting
and investment banking fees, up to but not in excess of an amount equal to $1.8
million in the aggregate and (ii) a termination fee in an amount equal to $13
million. For the purposes of this Section 7.2, "Business Combination" means (i)
a merger, consolidation, share exchange, business combination or similar
transaction involving Owen as a result of which the Owen Shareholders prior to
such transaction in the aggregate cease to own at least a majority of the voting
securities of the entity surviving or resulting from such transaction (or the
ultimate parent entity thereof), (ii) a sale, lease, exchange, transfer or other
disposition of more than 50% of the assets of Owen and its subsidiaries, taken
as a whole, in a single transaction or a series of related transactions, or
(iii) the acquisition, by a person (other than Cardinal or any affiliate
thereof) or group (as such term is defined under Section 13(d) of the Exchange
Act and the rules and regulations thereunder) of beneficial ownership (as
defined in Rule 13d-3 under the Exchange Act) of more than 50% of the Owen
Common Stock whether by tender or exchange offer or otherwise.
 
                                      A-26
<PAGE>   90
 
     7.3 Amendment.  This Agreement may be amended by the parties hereto, by
action taken or authorized by their respective Boards of Directors, at any time
before or after adoption of this Agreement by Owen Shareholders, but after any
such approval, no amendment shall be made which by law requires further approval
or authorization by the Owen Shareholders without such further approval or
authorization. Notwithstanding the foregoing, this Agreement may not be amended
except by an instrument in writing signed on behalf of each of the parties
hereto.
 
     7.4 Extension; Waiver.  At any time prior to the Effective Time, Cardinal
(with respect to Owen) and Owen (with respect to Cardinal and Subcorp) by action
taken or authorized by their respective Boards of Directors, may, to the extent
legally allowed, (a) extend the time for the performance of any of the
obligations or other acts of such party, (b) waive any inaccuracies in the
representations and warranties contained herein or in any document delivered
pursuant hereto and (c) waive compliance with any of the agreements or
conditions contained herein. Any agreement on the part of a party hereto to any
such extension or waiver shall be valid only if set forth in a written
instrument signed on behalf of such party.
 
                                  ARTICLE VIII
 
                                 MISCELLANEOUS
 
     8.1 Survival of Representations and Warranties.  The representations and
warranties made herein by the parties hereto shall not survive the Effective
Time. This Section 8.1 shall not limit any covenant or agreement of the parties
hereto, which by its terms contemplates performance after the Effective Time or
after the termination of this Agreement.
 
     8.2 Notices.  All notices and other communications hereunder shall be in
writing and shall be deemed given if delivered personally, telecopied (which is
confirmed) or dispatched by a nationally recognized overnight courier service to
the parties at the following addresses (or at such other address for a party as
shall be specified by like notice):
 
        (a) if to Cardinal or Subcorp:
 
          Cardinal Health, Inc.
          5555 Glendon Court
          Dublin, Ohio 43016
          Attention: Robert D. Walter
          Telecopy No.: (614) 717-8919
 
          with a copy to
 
          David A. Katz
          Wachtell, Lipton, Rosen & Katz
          51 West 52nd Street
          New York, New York 10019
          Telecopy No.: (212) 403-2000
 
                                      A-27
<PAGE>   91
 
        (b) if to Owen:
 
            Owen Healthcare, Inc.
            9800 Centre Parkway, Suite 1100
            Houston, Texas 77036-8279
            Attention: Carl Isgren
            Telecopy No.: (713) 777-5417
 
            with a copy to
 
            Jeffery B. Floyd
            Vinson & Elkins L.L.P.
            1001 Fannin
            3300 First City Tower
            Houston, Texas 77002-6760
            Telecopy No.: (713) 615-5660
 
     8.3 Interpretation.  When a reference is made in this Agreement to an
Article or Section, such reference shall be to an Article or Section of this
Agreement unless otherwise indicated. The headings and the table of contents
contained in this Agreement are for reference purposes only and shall not affect
in any way the meaning or interpretation of this Agreement. When a reference is
made in this Agreement to Owen, such reference shall be deemed to include any
and all subsidiaries of Owen, individually and in the aggregate, except for
Sections 4.1, 4.2, 4.3, 4.4, 4.6, 4.8, 4.16, 4.19 and 4.23. For the purposes of
any provision of this Agreement, a "Material Adverse Effect" with respect to any
party shall be deemed to occur if (i) in any individual representation or
warranty in this Agreement, if the aggregate consequences of breaches and
inaccuracies of such representation and warranty would have a material adverse
effect on the assets, liabilities, business, results of operations or financial
condition of such party and its subsidiaries taken as a whole, and (ii)
elsewhere in the Agreement, the aggregate consequences of all breaches and
inaccuracies of covenants and representations of such party under this
Agreement, when read without any exception or qualification for a material
adverse effect, would have a material adverse effect on the assets, liabilities,
business, results of operations or financial condition of such party and its
subsidiaries taken as a whole. For purposes of this Agreement, a "subsidiary" of
any person means another person, an amount of the voting securities or other
voting ownership or voting partnership interests of which is sufficient to elect
at least a majority of its Board of Directors or other governing body (or, if
there are no such voting securities or interests, 50% or more of the equity
interests of which) is owned directly or indirectly by such first person.
 
     8.4 Counterparts.  This Agreement may be executed in counterparts, which
together shall constitute one and the same Agreement. The parties may execute
more than one copy of the Agreement, each of which shall constitute an original.
 
     8.5 Entire Agreement.  This Agreement (including the documents and the
instruments referred to herein), the Support Agreements, the Owen Stock Option
Agreement and the Confidentiality Agreement constitute the entire agreement
among the parties and supersede all prior agreements and understandings,
agreements or representations by or among the parties, written and oral, with
respect to the subject matter hereof and thereof.
 
     8.6 Third Party Beneficiaries.  Except for the agreements set forth in
Section 5.2(b) and 5.2(c) nothing in this Agreement, express or implied, is
intended or shall be construed to create any third party beneficiaries.
 
     8.7 Governing Law.  Except to the extent that the laws of the jurisdiction
of organization of any party hereto, or any other jurisdiction, are mandatorily
applicable to the Merger or to matters arising under or in connection with this
Agreement, this Agreement shall be governed by the laws of the State of
Delaware. All actions and proceedings arising out of or relating to this
Agreement shall be heard and determined in any Delaware state or federal court
sitting in the City of Wilmington.
 
                                      A-28
<PAGE>   92
 
     8.8 Consent to Jurisdiction; Venue.
 
     (a) Each of the parties hereto irrevocably submits to the exclusive
jurisdiction of the state courts of Delaware and to the jurisdiction of the
United States District Court for the District of Delaware, for the purpose of
any action or proceeding arising out of or relating to this Agreement and each
of the parties hereto irrevocably agrees that all claims in respect to such
action or proceeding may be heard and determined exclusively in any Delaware
state or federal court sitting in the City of Wilmington. Each of the parties
hereto agrees that a final judgment in any action or proceeding shall be
conclusive and may be enforced in other jurisdictions by suit on the judgment or
in any other manner provided by law.
 
     (b) Each of the parties hereto irrevocably consents to the service of any
summons and complaint and any other process in any other action or proceeding
relating to the Merger, on behalf of itself or its property, by the personal
delivery of copies of such process to such party. Nothing in this Section 8.8
shall affect the right of any party hereto to serve legal process in any other
manner permitted by law.
 
     8.9 Specific Performance.  The transactions contemplated by this Agreement
are unique. Accordingly, each of the parties acknowledges and agrees that, in
addition to all other remedies to which it may be entitled, each of the parties
hereto is entitled to a decree of specific performance, provided such party is
not in material default hereunder.
 
     8.10 Assignment.  Neither this Agreement nor any of the rights, interests
or obligations hereunder shall be assigned by any of the parties hereto (whether
by operation of law or otherwise) without the prior written consent of the other
parties. Subject to the preceding sentence, this Agreement shall be binding
upon, inure to the benefit of and be enforceable by the parties and their
respective successors and assigns.
 
     8.11 Expenses.  Subject to the provisions of Section 7.2 and the Owen Stock
Option Agreement, all costs and expenses incurred in connection with this
Agreement and the transactions contemplated hereby and thereby shall be paid by
the party incurring such expenses, except that those expenses incurred in
connection with filing, printing and mailing the Registration Statement and the
Proxy Statement (including filing fees related thereto) will be shared equally
by Cardinal and Owen.
 
     IN WITNESS WHEREOF, Cardinal, Subcorp and Owen have signed this Agreement
as of the date first written above.
 
                                          CARDINAL HEALTH, INC.
 
                                          By: /s/ ROBERT D. WALTER
                                            ------------------------------------
                                            Name: Robert D. Walter
                                            Title: Chairman
 
                                          OWL MERGER CORP.
 
                                          By: /s/ ROBERT D. WALTER
                                            ------------------------------------
                                            Name: Robert D. Walter
                                            Title: Chairman
 
                                          OWEN HEALTHCARE, INC.
 
                                          By: /s/ CARL E. ISGREN
                                            ------------------------------------
                                            Name: Carl E. Isgren
                                            Title: President and CEO
 
                                      A-29
<PAGE>   93
 
                                                                         ANNEX B
 
[SMITH BARNEY LETTERHEAD]
 
November 27, 1996
 
The Board of Directors
Owen Healthcare, Inc.
9800 Centre Parkway
Houston, Texas 77036
 
Members of the Board:
 
You have requested our opinion as to the fairness, from a financial point of
view, to the holders of the common stock of Owen Healthcare, Inc. ("Owen") of
the consideration to be received by such holders pursuant to the terms and
subject to the conditions set forth in the Agreement and Plan of Merger, dated
as of November 27, 1996 (the "Merger Agreement"), by and among Owen, Cardinal
Health, Inc. ("Cardinal") and Owl Merger Corp., a wholly owned subsidiary of
Cardinal ("Subcorp"). As more fully described in the Merger Agreement, (i)
Subcorp will be merged with and into Owen (the "Merger") and (ii) each
outstanding share of the common stock, without par value, of Owen (the "Owen
Common Stock") will be converted into the right to receive that number of shares
of the common stock, without par value, of Cardinal (the "Cardinal Common
Stock") equal to (A) the quotient obtained by dividing (x) $27.25 by (y) the
average of the closing prices per share of Cardinal Common Stock as reported on
the New York Stock Exchange Composite Tape on each of the last 10 trading days
ending on the sixth trading day prior to the stockholders' meeting of Owen to
approve the Merger (the "Average Share Price" and, the number of shares of
Cardinal Common Stock into which such shares of Owen Common Stock will be so
converted, the "Exchange Ratio"); provided that (i) the Average Share Prices is
less than $82.175, then the Exchange Ratio will be 0.3316 or (ii) if the Average
Share Price is greater than $90.825, then the Exchange Ratio will be 0.3000 or
(B) if Cardinal has made an Adjustment Election (as defined in the Merger
Agreement), then the product of (x) 0.3316 and (y) the quotient obtained by
dividing $69.20 by the Average Share Price.
 
In arriving at our opinion, we reviewed the Merger Agreement and held
discussions with certain senior officers, directors and other representatives
and advisors of Owen and certain senior officers and other representatives of
Cardinal concerning the businesses, operations and prospects of Owen and
Cardinal. We examined certain publicly available business and financial
information relating to Owen and Cardinal as well as certain financial forecasts
and other data for Owen and Cardinal which were provided to or otherwise
discussed with us by the respective management of Owen and Cardinal, including
information relating to certain strategic implications and operational benefits
anticipated to result from the Merger. We reviewed the financial terms of the
Merger as set forth in the Merger Agreement in relation to, among other things:
current and historical market prices and trading volumes of Owen Common Stock
and Cardinal Common Stock; the respective companies' historical and projected
earnings and other operating data; and the capitalization and financial
condition of Owen and Cardinal. We also considered, to the extent publicly
available, the financial terms of certain other similar transactions recently
effected which we considered relevant in evaluating the Merger and analyzed
certain financial, stock market and other publicly available information
relating to the businesses of other companies whose operations we considered
relevant in evaluating those of Owen and Cardinal. We also evaluated the
potential pro forma financial impact of the Merger on Cardinal. In connection
with our engagement, we were requested to approach, and held discussions with,
certain third parties to solicit indications of interest in a possible
acquisition of Owen. In addition to the foregoing, we conducted such other
<PAGE>   94
 
The Board of Directors Owen Healthcare, Inc.
November 27, 1996 - Page 2
 
analyses and examinations and considered such other financial, economic and
market criteria as we deemed appropriate in arriving at our opinion.
 
In rendering our opinion, we have assumed and relied, without independent
verification, upon the accuracy and completeness of all financial and other
information and data publicly available or furnished to or otherwise reviewed by
or discussed with us. With respect to financial forecasts and other information
and data provided to or otherwise reviewed by or discussed with us, we have been
advised by the respective managements of Owen and Cardinal that such forecasts
and other information and data were prepared on bases reflecting reasonable
estimates and judgments as to the future financial performance of Owen and
Cardinal and the strategic implications and operational benefits anticipated to
result from the Merger. We assumed, with your consent, that the Merger will be
treated as a pooling of interests in accordance with generally accepted
accounting principles and as a tax-free reorganization for federal income tax
purposes. Our opinion, as set forth herein, relates to the relative values of
Owen and Cardinal. We are not expressing any opinion as to what the value of the
Cardinal Common Stock actually will be when issued to Owen stockholders pursuant
to the Merger or the price at which the Cardinal Common Stock will trade
subsequent to the Merger. We have not made or been provided with an independent
evaluation or appraisal of the assets or liabilities (contingent or otherwise)
of Owen or Cardinal nor have we made any physical inspection of the properties
or assets of Owen or Cardinal. Our opinion is necessarily based upon information
available to us, and financial, stock market and other conditions and
circumstances existing and disclosed to us, as of the date hereof.
 
Smith Barney has been engaged to render financial advisory services to Owen in
connection with the Merger and will receive a fee for our services, a
significant portion of which is contingent upon the consummation of the Merger.
We also will receive a fee upon the delivery of this opinion. In the ordinary
course of our business, we and our affiliates may actively trade or hold the
securities of Owen and Cardinal for our own account or for the account of our
customers and, accordingly, may at any time hold a long or short position in
such securities. We have in the past provided investment banking and financial
advisors services to Owen and Cardinal unrelated to the proposed merger, for
which services we have received compensation. In addition, Smith Barney and its
affiliates (including Travelers Group Inc. and its affiliates) may maintain
relationships with Owen and Cardinal.
 
Our advisory services and the opinion expressed herein are provided for the
information of the Board of Directors of Owen in its evaluation of the proposed
Merger, and our opinion is not intended to be and does not constitute a
recommendation to any stockholder as to how such stockholder should vote on the
proposed Merger. Our opinion may not be published or otherwise used or referred
to, nor shall any public reference to Smith Barney be made, without our prior
written consent.
 
Based upon and subject to the foregoing, our experience as investment bankers,
our work as described above and other factors we deemed relevant, we are of the
opinion that, as of the date thereof, the Exchange Ratio is fair, from a
financial point of view, to the holders of Owen Common Stock.
 
Very truly yours,
 
/s/ Smith Barney Inc.
 
SMITH BARNEY INC.
<PAGE>   95
 
                                                                         ANNEX C
 
                   [RAUSCHER PIERCE REFSNES, INC. LETTERHEAD]
 
                                                               November 27, 1996
Board of Directors
Owen Healthcare, Inc.
9800 Centre Parkway, Suite 1100
Houston, Texas 77036
Ladies and Gentlemen:
 
You have asked our opinion as to the fairness from a financial point of view to
the holders of Owen Healthcare, Inc. ("Owen") outstanding common stock, no par
value per share, of the proposed merger of Owen with a subsidiary (the "Cardinal
Subsidiary") of Cardinal Health, Inc. ("Cardinal"). Such terms are included in
the Agreement and Plan of Merger among Owen, the Cardinal Subsidiary and
Cardinal, and the related merger agreements (together, the "Merger Agreement").
Under the terms of the Merger Agreement and subject to the approval of the
stockholders of Owen and the satisfaction of certain other conditions, Owen will
be merged with the Cardinal Subsidiary with Owen being the surviving corporation
(the "Merger"). As a result of the Merger, each share of Owen's common stock
("Owen Common Stock") outstanding immediately prior to the Merger will be
converted into the right to receive that number of shares of Cardinal's common
stock, without par value. ("Cardinal Common Stock") equal to the quotient
obtained by dividing (x) $27.25 by (y) the average of the closing prices of
Cardinal Common Stock as reported on the New York Stock Exchange Composite Tape
on each of the last 10 trading days ending on the sixth trading day prior to the
stockholders' meeting of Owen to approve the Merger (the "Average Share Price"
and, the number of shares of Cardinal Common Stock into which such shares of
Owen Common Stock will be so converted, the "Exchange Ratio"); provided that (i)
if the Average Share Price is less than $82.175, then the Exchange Ratio will be
 .3316 or (ii) if the Average Share Price is greater than $90.825, then the
Exchange Ratio will be .3000.
 
In connection with the opinion described below, we have reviewed publicly
available business and financial information relating to Owen and Cardinal. We
also have, among other things, reviewed the Merger Agreement and discussed with
certain members of senior management of Owen and Cardinal the past and current
business operations, financial condition and future prospects of Owen and
Cardinal. We have reviewed certain financial analyses and forecasts of Owen and
Cardinal which were provided to or otherwise discussed with us by the companies'
respective managements. We reviewed the financial terms of the Merger as set
forth in the Merger Agreement in relation to, among other things: current and
historical market prices and trading volumes of Owen Common Stock and Cardinal
Common Stock; the respective companies' historical and projected earnings and
operating data; and the capitalization and financial condition of Owen and
Cardinal. We compared certain financial and stock market information for Owen
and Cardinal with similar information for certain other companies the securities
of which are publicly traded. We reviewed the financial terms of certain recent
business combinations in the healthcare industry specifically and in other
industries generally whose operations we considered relevant in evaluating those
of Owen and Cardinal. We also evaluated the potential pro forma financial impact
of the Merger on Cardinal. In connection with our engagement, we were requested
to approach, and prior to the date of the Merger Agreement held discussions
with, certain third parties to solicit indications of interest in a possible
acquisition of Owen.
<PAGE>   96
 
Board of Directors
November 27, 1996 - Page 2
 
In addition, we have considered such other information and financial, economic
and market criteria which we deemed relevant, and have conducted such other
analyses as we deemed appropriate under the circumstances. In connection with
our review, we have relied upon and assumed the accuracy and completeness of the
financial and other information publicly available or furnished to us by Owen
and Cardinal or their representatives. We have not independently verified the
accuracy or completeness of such information. With respect to the financial
forecasts provided to or otherwise reviewed by or discussed with us, we have
assumed that they have been prepared on bases reflecting reasonable estimates
and judgments as to the future performance of Owen and Cardinal, respectively.
In addition, we have not made an independent evaluation or appraisal of the
assets of Owen or Cardinal, nor were we furnished with any such appraisals. We
assumed, with your consent, that the Merger will be treated as a pooling of
interests in accordance with generally accepted accounting principles and as a
tax-free reorganization for federal income tax purposes.
 
Rauscher Pierce Refsnes, Inc., as part of its investment banking activities, is
continually engaged in the valuation of businesses and their securities in
connection with mergers and acquisitions, negotiated underwritings, secondary
distributions of listed and unlisted securities, private placements and
valuations for estate and other purposes. We are familiar with Owen and have
rendered certain investment banking services to Owen in recent years, including
acting as agent in the private placement in December 1991 of $10,000,000
principal amount of Convertible Subordinated Notes, rendering a fairness opinion
in connection with Owen's acquisition of Meditrol, Inc. in April 1994, acting as
manager in the public offering of 6,656,000 shares of Owen Common Stock in
August 1995, as well as providing certain valuation services to Owen. In
addition, Rauscher Pierce Refsnes, Inc. has been engaged to render financial
advisory services to Owen in connection with the Merger and will receive a fee
for our services, a significant portion is contingent upon the consummation of
the Merger. We will also receive a fee upon delivery of this opinion. In the
ordinary course of our business, we may actively trade or hold the securities of
Owen for our own account or for the account of our customers and, accordingly,
may at any time hold a long or short position in such securities.
 
Our advisory services and the opinion expressed herein are provided for the
information of the Board of Directors of Owen in its evaluation of the proposed
Merger, and our opinion is not intended to be and does not constitute a
recommendation to any stockholder as to how such stockholder should vote on the
proposed Merger. Further, we are not expressing any opinion as to what the value
of the Cardinal Common Stock actually will be when issued to Owen stockholders
pursuant to the Merger or the price at which the Cardinal Common Stock will
trade subsequent to the Merger. Our opinion may not be published or otherwise
used or referred to, nor shall any public reference be made, without our prior
written consent.
 
Based upon and subject to the foregoing and based upon our experience as
investment bankers, the matters described above and other factors we deemed
relevant, we are of the opinion that, as of the date hereof, the Exchange Ratio
is fair from a financial point of view to the stockholders of Owen.
 
                                          Very truly yours,
 
                                          RAUSCHER PIERCE REFSNES, INC.
 
                                          /s/ Rauscher Pierce Refsnes, Inc.
<PAGE>   97

                            FRONT SIDE OF PROXY CARD

                                     PROXY
                             OWEN HEALTHCARE, INC.
                SPECIAL MEETING OF SHAREHOLDERS - MARCH 18, 1997
                   PROXY SOLICITED BY THE BOARD OF DIRECTORS

        The undersigned hereby appoints Carl E. Isgren, Harlan C. Stai and
Stephen A. Drury as Proxies, each with the power to appoint his substitute, and
hereby authorizes each of them to represent and to vote as designated on the
reverse, all the shares of Common Stock of Owen Healthcare, Inc. (the
"Corporation"), held of record by the undersigned on February 10, 1997, at the
Special Meeting of Shareholders of the Corporation to be held on March 18, 1997
at 9800 Centre Parkway, Suite 1100, Houston, Texas, commencing at 10:00 a.m.,
local time, or any adjournment or postponement thereof.

        The undersigned hereby revokes any proxy to vote said shares heretofore
given. THE UNDERSIGNED ACKNOWLEDGES THAT THIS PROXY WHEN PROPERLY EXECUTED WILL
BE VOTED IN THE MANNER DIRECTED HEREIN BY THE UNDERSIGNED SHAREHOLDER AND THAT
IF NO DIRECTION IS MADE, THIS PROXY WILL BE VOTED IN FAVOR OF PROPOSAL 1.
RECEIPT OF THE NOTICE OF SPECIAL MEETING AND THE RELATED PROXY
STATEMENT/PROSPECTUS IS HEREBY ACKNOWLEDGED.

                           (continued on reverse side)


                           REVERSE SIDE OF PROXY CARD


1.      Approval of the Agreement and Plan of Merger dated as of November 27,
        1996, by and among the Corporation, Cardinal Health, Inc., an Ohio
        corporation ("Cardinal") and Owl Merger Corp., a Texas corporation
        and wholly-owned subsidiary of Cardinal ("Subcorp"), providing for the
        merger of Subcorp with and into the Corporation on the terms and subject
        to the conditions set forth therein. 

              / /  FOR          / /  AGAINST          / /  ABSTAIN


2.      In their discretion, the Proxies are authorized to vote upon such other
        business as may properly come before the meeting or any adjournment or
        postponement thereof.

If you receive more than one proxy card, please sign and return all cards in the
accompanying envelope.


This proxy may be revoked at any time prior to the voting of the proxy by the
execution and submission of a revised proxy, by written notice to the Secretary
of the Company or by voting in person at the meeting.

                   PROXY SOLICITED BY THE BOARD OF DIRECTORS
                 PLEASE MARK, SIGN, DATE AND RETURN THIS PROXY
                      PROMPTLY USING THE ENCLOSED ENVELOPE

                                                        Date              , 1997
- ----------------------     --------------------------        -------------
Signature                  Signature, if held jointly


        Please sign exactly as name appears on your stock certificate. When
shares are held by joint tenants, both should sign. When signing as attorney,
executor, administrator, trustee or guardian, please give full title as such.
If a corporation, please sign in full corporate name by President or other
authorized officer. If a partnership, please sign in partnership name by
authorized person.




<PAGE>   98


                     FRONT SIDE OF VOTING INSTRUCTION CARD

                            VOTING INSTRUCTION CARD
                             OWEN HEALTHCARE, INC.
                SPECIAL MEETING OF SHAREHOLDERS - MARCH 18, 1997

     The undersigned hereby instructs Texas Commerce Bank National
Association, as Trustee under the Owen Healthcare, Inc. Employee Stock Ownership
Plan (the "ESOP"), to vote as designated on the reverse, all the shares of
Common Stock of Owen Healthcare, Inc. (the "Corporation"), held in the ESOP in
which the undersigned has a beneficial interest on February 10, 1997, at the
Special Meeting of Shareholders of the Corporation to be held on March 18, 1997
at 9800 Centre Parkway, Suite 1100, Houston, Texas, commencing at 10:00 a.m.,
local time, or any adjournment or postponement thereof.

     THE UNDERSIGNED ACKNOWLEDGES THAT THIS VOTING INSTRUCTION WHEN PROPERLY
EXECUTED WILL (SUBJECT TO THE FIDUCIARY DUTIES OF THE TRUSTEE) BE VOTED IN THE
MANNER DIRECTED HEREIN BY THE UNDERSIGNED AND THAT IF THIS CARD IS EXECUTED AND
RETURNED BUT NO DIRECTION IS MADE, THE SHARES TO WHICH THIS VOTING INSTRUCTION
APPLIES WILL BE VOTED IN FAVOR OF PROPOSAL 1. RECEIPT OF THE NOTICE OF SPECIAL
MEETING AND THE RELATED PROXY STATEMENT/PROSPECTUS IS HEREBY ACKNOWLEDGED.

                          (continued on reverse side)



                    REVERSE SIDE OF VOTING INSTRUCTION CARD


1.   Approval of the Agreement and Plan of Merger dated as of November 27, 1996,
     by and among the Corporation, Cardinal Health, Inc., an Ohio corporation
     ("Cardinal") and Owl Merger Corp., a Texas corporation and wholly-owned 
     subsidiary of Cardinal ("Subcorp"), providing for the merger of Subcorp 
     with and into the Corporation on the terms and subject to the conditions 
     set forth therein.

            / /    FOR        / /    AGAINST         / /    ABSTAIN


2.   In its discretion, the Trustee is authorized to vote upon such other
     business as may properly come before the meeting or any adjournment or
     postponement thereof.

This voting instruction may be changed or withdrawn at any time before the
Special Meeting by delivering a written revocation or a duly executed voting
instruction card bearing a later date.




        PLEASE MARK, SIGN, DATE AND RETURN THIS VOTING INSTRUCTION CARD
                      PROMPTLY USING THE ENCLOSED ENVELOPE.

                                                           Date:         , 1997
- --------------  --------------------------  --------------      ---------
  Signature     Signature, if held jointly  Print Name(s)   

     Please sign your name exactly as it appears hereon. Joint owners must each
sign. When signing as attorney, executor, administrator, trustee or guardian,
please give full title as such.
<PAGE>   99
 
                              TEXAS COMMERCE BANK
 
                              NATIONAL ASSOCIATION
 
RETIREMENT AND                                                    P. O. BOX 2558
INVESTMENT MANAGEMENT SERVICES                         HOUSTON, TEXAS 77252-8315
 
                                          February 17, 1997
 
Dear Owen Healthcare, Inc. ESOP Beneficiary:
 
     Our records indicate that you are the beneficial owner of certain of the
shares of Common Stock of Owen Healthcare, Inc. ("Owen") held by Texas Commerce
Bank National Association, as Trustee for the Owen Employee Stock Ownership Plan
(the "ESOP"). As the record owner of the shares held in the ESOP (the "ESOP
shares"), we are required to vote the ESOP shares at the Special Meeting of
Shareholders of Owen to be held on March 18, 1997 with respect to the proposed
merger with Cardinal Health, Inc. (the "Special Meeting"). Subject to the
fiduciary duty requirements imposed under the Employee Retirement Income
Security Act of 1974, as amended, the terms of the ESOP require that we vote the
ESOP shares in the manner directed by the beneficial owners of such shares.
 
     In order for you to instruct us how to vote the ESOP shares beneficially
owned by you, please complete the enclosed BLUE voting instruction form and
return it to American Stock Transfer & Trust Company in the accompanying
postage-paid envelope.
 
     If American Stock Transfer & Trust Company does not receive a duly executed
voting instruction form from you prior to March 18, 1997, subject to the
Trustee's fiduciary duty, the ESOP shares that you beneficially own will be
voted by the Trustee in the same proportion as the Trustee will vote the ESOP
shares for which voting instructions are received. Owen has provided us with the
enclosed copy of the Proxy Statement/Prospectus related to the Special Meeting.
The matters to be presented and voted on at the meeting are described in the
Proxy Statement/Prospectus, and you should read these materials carefully before
deciding how you wish to instruct the Trustee to vote.
 
     Except as required by law, your individual voting instructions will not be
disclosed to the Company. Only aggregate voting totals from all ESOP
participants will be disclosed to the Company.
 
     You should be aware that the voting instruction form only relates to the
shares held in the ESOP and does not authorize the voting of any other shares of
Owen Common Stock you may own. You will receive a separate WHITE proxy card
(which you should also return) with respect to shares of Owen Common Stock held
by you directly or in other forms. If you have any questions, you may call
Morrow & Co., who are acting as proxy solicitors with respect to the Special
Meeting, at (800) 607-0088.
 
                                          Texas Commerce Bank National
                                          Association,
                                               as Trustee
 
Owens Healthcare, Inc. believes that it is important that your shares be voted
at the Special Meeting. Please complete, sign and mail the enclosed BLUE voting
instruction card in the accompanying envelope promptly. You may change or
withdraw your voting instruction at any time before the Special Meeting by
delivering a written revocation or a duly executed voting instruction card
bearing a later date.


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