PROCEPT INC
SC 13D/A, 1998-04-21
BIOLOGICAL PRODUCTS, (NO DIAGNOSTIC SUBSTANCES)
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                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                  SCHEDULE 13D

                    Under the Securities Exchange Act of 1934
                               (Amendment No. 2)*

                                  Procept, Inc.
                                (Name of Issuer)

                     Common Stock, par value $.01 per share
                         (Title of Class of Securities)

                                  742 683 10 5
                                 (CUSIP Number)

                    Paramount Capital Asset Management, Inc.
                         c/o Lindsay A. Rosenwald, M.D.
                               787 Seventh Avenue
                               New York, NY 10019
                                 (212) 554-4300

                                 with a copy to:

  Michael S. Weiss, Esq.                              Monica C. Lord, Esq.
  Paramount Capital Asset                     Kramer, Levin, Naftalis & Frankel
    Management, Inc.                                    919 Third Avenue
  787 Seventh Avenue                                   New York, NY  10022  
   New York, NY 10019                                     (212) 715-9100    
    (212) 554-4372 

(Name,  Address and Telephone Number of Person Authorized to Receive Notices and
Communications)

                                  April 9, 1998
             (Date of Event which Requires Filing of this Statement)

If the filing person has previously  filed a statement on Schedule 13G to report
the  acquisition  which is the subject of this  Schedule 13D, and is filing this
schedule because of Rule 13d-1(b)(3) or (4), check the following:
   [_]

Note: Six copies of this statement, including all exhibits, should be filed with
the  Commission.  See Rule 13d- 1(a) for other  parties to whom copies are to be
sent.

*The  remainder of this cover page shall be filled out for a reporting  person's
initial filing on this form with respect to the subject class of securities, and
for  any  subsequent   amendment   containing   information  which  would  alter
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the  Securities  Exchange  Act of
1934 ("Act") or otherwise  subject to the liabilities of that section of the Act
but  shall be  subject  to all other  provisions  of the Act  (however,  see the
Notes).


                               Page 1 of 11 pages


<PAGE>

CUSIP No. 742 683 10 5                 13 D                  Page 2 of  11 Pages
- --------------------------------------------------------------------------------
1)       NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

         Paramount Capital Asset Management, Inc.
- --------------------------------------------------------------------------------
2)       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP     (a)     [ ]

                                                              (b)     [ ]
- --------------------------------------------------------------------------------
3)       SEC USE ONLY

- --------------------------------------------------------------------------------
4)       SOURCE OF FUNDS*
         00 (see Item 3 below)
- --------------------------------------------------------------------------------
5)       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEM 2(d) OR 2(e)
                                                                       [_]
- --------------------------------------------------------------------------------
6)       CITIZENSHIP OR PLACE OF ORGANIZATION
         Delaware
- --------------------------------------------------------------------------------
                               7)     SOLE VOTING POWER
                                      None
         NUMBER                -------------------------------------------------
         OF                    8)     SHARED VOTING POWER
         SHARES                       26,892,059**
         BENEFICIALLY          -------------------------------------------------
         OWNED BY              9)     SOLE DISPOSITIVE POWER
         EACH                         None
         REPORTING             -------------------------------------------------
         PERSON                10)    SHARED DISPOSITIVE POWER
         WITH                         26,892,059**

- --------------------------------------------------------------------------------
11)      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING
         PERSON

         26,892,059**
- --------------------------------------------------------------------------------
12)      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
         SHARES                                                    [ ]

- --------------------------------------------------------------------------------
13)      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
         69.9%

- --------------------------------------------------------------------------------
14)      TYPE OF REPORTING PERSON
         CO
- --------------------------------------------------------------------------------



**  Consists  of (i)  13,416,800  shares of  Common  Stock  which are  presently
votable,  and (ii)  13,475,259  shares of Common Stock issuable upon exercise of
warrants, which, accordingly, are not presently votable.


<PAGE>

CUSIP No. 742 683 10 5                  13 D                 Page 3 of  11 Pages
- --------------------------------------------------------------------------------
1)       NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

         Aries Domestic Fund, L.P.
- --------------------------------------------------------------------------------
2)       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP     (a)     [ ]

                                                              (b)     [ ]
- --------------------------------------------------------------------------------
3)       SEC USE ONLY

- --------------------------------------------------------------------------------
4)       SOURCE OF FUNDS*
         00 (see Item 3 below)
- --------------------------------------------------------------------------------
5)       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEM 2(d) OR 2(e)
                                                                       [_]
- --------------------------------------------------------------------------------
6)       CITIZENSHIP OR PLACE OF ORGANIZATION
         Delaware
- --------------------------------------------------------------------------------
                               7)     SOLE VOTING POWER
                                      None
         NUMBER                -------------------------------------------------
         OF                    8)     SHARED VOTING POWER
         SHARES                       9,209,298**
         BENEFICIALLY          -------------------------------------------------
         OWNED BY              9)     SOLE DISPOSITIVE POWER
         EACH                         None
         REPORTING             -------------------------------------------------
         PERSON                10)    SHARED DISPOSITIVE POWER
         WITH                         9,209,298**

- --------------------------------------------------------------------------------
11)      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING
         PERSON

         9,209,298**
- --------------------------------------------------------------------------------
12)      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
         SHARES                                                    [ ]

- --------------------------------------------------------------------------------
13)      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
         23.9%

- --------------------------------------------------------------------------------
14)      TYPE OF REPORTING PERSON
         PN
- --------------------------------------------------------------------------------

** Consists of (i) 4,595,880 shares of Common Stock which are presently votable,
and (ii)  4,613,418  shares of Common Stock  issuable upon exercise of warrants,
which, accordingly, are not presently votable.


<PAGE>

CUSIP No. 742 683 10 5                  13 D                 Page 4 of  11 Pages
- --------------------------------------------------------------------------------
1)       NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

         The Aries Trust
- --------------------------------------------------------------------------------
2)       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP     (a)     [ ]

                                                              (b)     [ ]
- --------------------------------------------------------------------------------
3)       SEC USE ONLY

- --------------------------------------------------------------------------------
4)       SOURCE OF FUNDS*
         00 (see Item 3 below)
- --------------------------------------------------------------------------------
5)       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEM 2(d) OR 2(e)
                                                                       [_]
- --------------------------------------------------------------------------------
6)       CITIZENSHIP OR PLACE OF ORGANIZATION
         Cayman Islands
- --------------------------------------------------------------------------------
                               7)     SOLE VOTING POWER
                                      None
         NUMBER                -------------------------------------------------
         OF                    8)     SHARED VOTING POWER
         SHARES                       17,682,761**
         BENEFICIALLY          -------------------------------------------------
         OWNED BY              9)     SOLE DISPOSITIVE POWER
         EACH                         None
         REPORTING             -------------------------------------------------
         PERSON                10)    SHARED DISPOSITIVE POWER
         WITH                         17,682,761**

- --------------------------------------------------------------------------------
11)      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING
         PERSON

         17,682,761**
- --------------------------------------------------------------------------------
12)      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
         SHARES                                                    [ ]

- --------------------------------------------------------------------------------
13)      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
         46.0%

- --------------------------------------------------------------------------------
14)      TYPE OF REPORTING PERSON
         OO (see Item 2)
- --------------------------------------------------------------------------------

** Consists of (i) 8,820,920 shares of Common Stock which are presently votable,
and (ii)  8,861,841  shares of Common Stock  issuable upon exercise of warrants,
which, accordingly, are not presently votable.


<PAGE>

CUSIP No. 742 683 10 5                  13 D                 Page 5 of  11 Pages
- --------------------------------------------------------------------------------
1)       NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

         Lindsay A. Rosenwald, M.D.
- --------------------------------------------------------------------------------
2)       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP     (a)     [ ]

                                                              (b)     [ ]
- --------------------------------------------------------------------------------
3)       SEC USE ONLY

- --------------------------------------------------------------------------------
4)       SOURCE OF FUNDS*
         00 (see Item 3 below)
- --------------------------------------------------------------------------------
5)       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEM 2(d) OR 2(e)
                                                                       [_]
- --------------------------------------------------------------------------------
6)       CITIZENSHIP OR PLACE OF ORGANIZATION
         United States
- --------------------------------------------------------------------------------
                               7)     SOLE VOTING POWER
                                      None
         NUMBER                -------------------------------------------------
         OF                    8)     SHARED VOTING POWER
         SHARES                       26,892,059**
         BENEFICIALLY          -------------------------------------------------
         OWNED BY              9)     SOLE DISPOSITIVE POWER
         EACH                         None
         REPORTING             -------------------------------------------------
         PERSON                10)    SHARED DISPOSITIVE POWER
         WITH                         26,892,059**

- --------------------------------------------------------------------------------
11)      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING
         PERSON

         26,892,059**
- --------------------------------------------------------------------------------
12)      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
         SHARES                                                    [ ]

- --------------------------------------------------------------------------------
13)      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
         69.9%

- --------------------------------------------------------------------------------
14)      TYPE OF REPORTING PERSON
         IN
- --------------------------------------------------------------------------------


**  Consists  of (i)  13,416,800  shares of  Common  Stock  which are  presently
votable,  and (ii)  13,475,259  shares of Common Stock issuable upon exercise of
warrants, which, accordingly, are not presently votable.


<PAGE>



                                  SCHEDULE 13D


         This  Amendment  No. 2 (the  "Amendment")  amends and  supplements  the
following Items of the Reporting  Persons' Statement on Schedule 13D, dated July
10, 1997, as amended (the "Schedule").

ITEM 3.  SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.

         The disclosure  under Item 3 of the Schedule is incorporated  herein by
reference.  All amounts  reported in this  Amendment  have been adjusted and all
amounts  previously  reported should be adjusted,  as necessary,  to reflect the
one-for-seven  reverse  split of the  Common  Stock of the Issuer  which  became
effective October 14, 1997. In addition,  the information contained in Item 3 to
the Schedule is hereby amended and supplemented by adding the following:

         The A Notes,  Class A Warrants,  Class B Warrants and Purchased  Common
acquired by Aries  Domestic and Aries Trust  converted  into, or were  exchanged
for, 30,060 shares of Series A Preferred Stock and warrants (the "New Warrants")
to purchase 3,283,132 shares of Common Stock, at various times prior to November
14, 1997.

         Pursuant to Subscription Agreements dated as of April 9, 1998, the form
of which is attached  hereto as Exhibit O (each,  a  "Subscription  Agreement"),
Aries Domestic used $717,750 of its general funds to purchase  1,650,000  shares
of Common Stock of the Issuer and Class C Warrants for the purchase of 1,650,000
shares of Common Stock of the Issuer at an exercise price of $.50 per share, and
the Aries  Trust used  $1,457,250  of its general  funds to  purchase  3,350,000
shares of Common  Stock of the Issuer and Class C Warrants  for the  purchase of
3,350,000 shares of Common Stock of the Issuer at an exercise price of $0.50 per
share (subject to certain antidilution adjustments). 

         On April 9, 1998, pursuant to a Letter Agreement dated January 13, 1998
between the Issuer,  Aries  Domestic and Aries Trust (the  "Letter  Agreement"),
Aries Domestic and Aries Trust exchanged (the "Exchange") their shares of Series
A Preferred  Stock and New Warrants  for an  aggregate  of  8,416,800  shares of
Common Stock (the "Exchange Common Stock") and Class C Warrants for the purchase
of an aggregate of 8,416,800 shares of Common Stock at an initial exercise price
of $.50 per share (subject to certain antidilution adjustments).

         The Aries Trust and Aries  Domestic are entitled to receive  additional
shares of Common  Stock of the Issuer  upon the  occurrence  of  certain  events
described  in  Article  VI of  the  Subscription  Agreement  in  respect  of the
13,416,800  shares of Common Stock  referred to in the preceding two  paragraphs
(such rights to receive additional Common Stock, the "Article VI Rights").


                               page 6 of 11 pages


<PAGE>

ITEM 4. PURPOSE OF TRANSACTION.

         The  information  contained in Item 4 to the Schedule is hereby amended
and restated to read in its entirety as follows:

         The  Reporting  Persons  acquired   securities  of  the  Issuer  as  an
Investment  in the  Issuer.  Except  as  indicated  in this  Schedule  13D,  the
Reporting  Persons  currently have no plans or proposals that relate to or would
result in any of the matters  described in subparagraphs (a) through (j) of Item
4 of Schedule  13D.  Pursuant to Section  7.19 of the  Purchase  Agreement,  the
Reporting  Persons  have the right to appoint a majority  of the  members of the
Board of Directors  of the Issuer.  In  connection  with the  transactions  (the
"Transactions")  contemplated by the Purchase Agreement and the Letter of Intent
between the Issuer, Paramount Capital, Inc., Aries Trust and Aries Domestic (the
"Letter of Intent"), Mr. Michael S. Weiss joined the Issuer's Board of Directors
pursuant to the Purchase Agreement and the Letter of Intent and has been elected
by the Board of Directors of the Issuer to serve as the Chairman of the Issuer's
Board of  Directors.  On December 22,  1997,  Mr.  Weiss  recommended  that Mark
Rogers, a consultant to Paramount Capital,  and Elliott Vernon be elected to the
Issuer's  Board of  Directors,  and they were so  elected.  On February 9, 1998,
Stanley C. Erck resigned as the Issuer's  Chief  Executive  Officer and from the
Issuer's Board, Mr. Weiss  recommended  that John F. Dee be appointed  President
and Chief  Executive  Officer of the Issuer and be elected to join the  Issuer's
Board and Mr. Dee was so appointed and elected.  Pursuant to Section 7.31 of the
Purchase  Agreement,  the Issuer has  covenanted  to keep  available  sufficient
authorized but unissued shares of Common Stock to fulfill its obligations  under
the Purchase Agreement, and it appears the Issuer will need to take such actions
as are necessary in order to comply with this  covenant.  The Reporting  Persons
may from  time to time  acquire,  or  dispose  of,  Common  Stock  and/or  other
securities  of the Issuer if and when they deem it  appropriate.  The  Reporting
Persons may formulate other purposes, plans or proposals relating to any of such
securities  of the  Issuer to the  extent  deemed  advisable  in light of market
conditions, investment policies and other factors.

ITEM 5.  INTEREST IN SECURITIES OF ISSUER.

         All  amounts  reported in this  Amendment  have been  adjusted  and all
amounts  previously  reported should be adjusted,  as necessary,  to reflect the
one-for-seven  reverse  split of the  Common  Stock of the Issuer  which  became
effective October 14, 1997.

         The  information  contained in Item 5 to the Schedule is hereby amended
and supplemented to read in its entirety as follows:

                  (a)      As of April 9,  1998,  Dr.  Rosenwald  and  Paramount
                           Capital,  through  acquisition of the shares by Aries
                           Trust and Aries Domestic,  may be deemed beneficially
                           to own  26,892,059  shares  or 69.9% of the  Issuer's
                           Common Stock,  and Aries Domestic and Aries Trust may
                           be deemed to beneficially own the following number of
                           shares of Common Stock:

                           Aries Domestic            9,209,298/1/
                           Aries Trust              17,682,761/2/
- --------
/1/  Includes  warrants to purchase 17,538 shares of Common Stock at an exercise
     price of $17.50 per share, acquired in May 1996.
/2/  Includes  warrants to purchase 40,921 shares of Common Stock at an exercise
     price of $17.50 per share, acquired in May 1996.


                               page 7 of 11 pages


<PAGE>

                           Each Reporting Person disclaims  beneficial ownership
                           of all the Common  Stock  other  than the  respective
                           Purchased  Common,  if  any,  actually  held  by such
                           Reporting Person.

                  (b)      Dr.  Rosenwald and Paramount  Capital share the power
                           to vote or to  direct  the  vote,  to  dispose  or to
                           direct the  disposition of those shares  beneficially
                           owned by each of Aries Domestic and Aries Trust.

                  (c)      Other than the  exchange of Series A Preferred  Stock
                           and  New  Warrants  for  Common  Stock  and  Class  C
                           Warrants,  pursuant to the Letter  Agreement  and the
                           purchases  of  Common  Stock  and  Class  C  Warrants
                           purchased  pursuant to the  Subscription  Agreements,
                           the  Reporting   Persons  have  not  engaged  in  any
                           transactions in the Common Stock of the Issuer in the
                           past 60 days. See Item 3.

                  (d) & (e)         Not applicable.

ITEM 6.  CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR  RELATIONSHIPS  WITH RESPECT
         TO SECURITIES OF THE ISSUER.

         The disclosure  under Item 6 of the Schedule is incorporated  herein by
reference.  All amounts  reported in this  Amendment  have been adjusted and all
amounts  previously  reported should be adjusted,  as necessary,  to reflect the
one-for-seven  reverse  split of the  Common  Stock of the Issuer  which  became
effective October 14, 1997.

         In  addition,  the  information  contained in Item 6 to the Schedule is
hereby amended and supplemented by adding the following:

         The Issuer,  Aries  Trust and Aries  Domestic  entered  into the Letter
Agreement  described in Item 3, pursuant to which Aries Trust and Aries Domestic
exchanged  their Series A Preferred Stock and New Warrants for a number of Units
of Common Stock and Class C Warrants  having an  aggregate  price in the Private
Placement  equal to $140 per share of  Series A  Preferred  Stock so  exchanged.
Thus, pursuant to the Letter Agreement, Aries Domestic and Aries Trust exchanged
their  Series A Preferred  Stock and New  Warrants for an aggregate of 8,416,800
shares of Common Stock and Class C Warrants for the purchase of 8,416,800 shares
of Common Stock at an exercise price of $.50 per share.

         The  Article  VI  Rights,  contained  in  the  Subscription  Agreements
referred to in Item 3 provide for additional  issuances of Common Stock (x) upon
the  occurrence  of  dilution  events,  such as  issuances  of Common  Stock (or
securities  convertible  into, or exercisable  for, Common Stock) at a price per
share less than the  then-current  market price or the  then-effective  Dilution
Value (as defined in the Subscription Agreement; initially $0.50), to compensate
for such  dilution  and (y) if the market  price of the Common Stock on the date
that is 12 months after April 9, 1998 (such date, the "Reset Date") is less than
140% of the then-applicable


                               page 8 of 11 pages


<PAGE>

Dilution  Value,  to the  extent  provided  in Section  6.2 of the  Subscription
Agreement. The Article VI Rights also provide for additional issuances of Common
Stock on each six month anniversary of the Reset Date. Furthermore,  the Article
VI Rights  include a right to "put" the Common Stock to which they relate to the
Issuer for 140% of the Dilution  Value.  The  Subscription  Agreement,  however,
contains a  covenant  on the part of each  holder of  Article VI Rights  only to
exercise such "put" under certain circumstances.

         Pursuant to a Placement  Agency Agreement dated as of October 26, 1997,
attached hereto as Exhibit P, Paramount Capital,  Inc. (the "Placement  Agent"),
an NASD member broker dealer and an affiliate of Aries  Domestic and Aries Trust
has acted as placement  agent for the Issuer,  and will receive certain fees for
such  services  including  options (the  "Placement  Options") to purchase up to
1,920,000  shares of Common  Stock of the issuer and an equal  number of Class C
Warrants.  The Placement  Options are  exerciseable at an initial exercise price
equal to the product of $0.55 multiplied by the number of shares of Common Stock
so purchased (subject to certain antidilution adjustments). As of June 30, 1997,
the  Issuer  and the  Placement  Agent  entered  into a  twenty-four  (24) month
engagement  agreement (the "Financial Advisory  Agreement"),  attached hereto as
Exhibit Q, pursuant to which the  Placement  Agent is entitled to receive a cash
retainer  and  standard  success  fees in  addition  to options  (the  "Advisory
Options") upon the occurrence of certain events.  In connection with the Private
Placement and pursuant to the Financial Advisory Agreement,  the Placement Agent
is entitled to receive  Advisory  Options to purchase up to 2,880,000  shares of
Common Stock of the Issuer and an equal number of Class C Warrants. The Advisory
Options are  exerciseable  at an initial  exercise price equal to the product of
$0.55  multiplied by the number of shares of Common Stock so purchased  (subject
to certain  antidilution  adjustments).  Upon exercise of the Placement  Options
and/or Advisory Options, the exercising holder shall have Article VI Rights with
respect to the shares of Common Stock issued upon such  exercise.  The Placement
Options and Advisory Options will become exercisable on October 9, 1998.

ITEM 7.  MATERIAL TO BE FILED AS EXHIBITS

         The  information  contained in Item 7 to the Schedule is hereby amended
and supplemented to read in its entirety as follows:

Exhibit A:        Agreement of Joint Filing of Schedule 13D dated as of July 9, 
                  1997.

Exhibit B:        List  of   executive   officers  and  directors  of  Paramount
                  Capital  and  information  called  for by  Items  2-6 of  this
                  statement relating to said officers and directors.

Exhibit C:        List of  executive  officers and  directors  of Aries Domestic
                  and  information  called  for by Items  2-6 of this  statement
                  relating to said officers and directors.

Exhibit D:        List  of executive  officers and  directors of Aries Trust and
                  information called for by Items 2-6 of this statement relating
                  to said officers and directors.

Exhibit E:        Securities Purchase Agreement dated as of June 30, 1997.


                               page 9 of 11 pages


<PAGE>

Exhibit F:        Senior   Convertible  Note  for   $70,000  issued   to   Aries
                  Domestic dated June 30, 1997.

Exhibit G:        Senior  Convertible  Note  for $130,000  issued to Aries Trust
                  dated June 30, 1997.

Exhibit H:        Class  A  Warrant  for  the  Purchase   of  959,944  shares of
                  Common Stock issued to Aries Domestic dated June 30, 1997.

Exhibit I:        Class  A  Warrant  for  the  Purchase of  1,782,752  shares of
                  Common Stock issued to Aries Trust dated June 30, 1997.

Exhibit J:        Class  B  Warrant  for  the  Purchase of  2,660,746  shares of
                  Common Stock issued to Aries Domestic dated June, 1997.

Exhibit K:        Class  B  Warrant  for  the  Purchase of  4,941,386  shares of
                  Common Stock issued to Aries Trust dated June 30, 1997.

Exhibit L:        Letter of Intent dated June 29, 1997.

Exhibit M:        Certificate of Designation for Series A Convertible Preferred
                  Stock of Procept, Inc.

Exhibit N:        Letter Agreement dated January 13, 1998.

Exhibit O:        Form of Subscription Agreement.

Exhibit P:        Placement Agency Agreement, dated October 26, 1997.

Exhibit Q:        Financial Advisory Agreement, dated June 30, 1997.

Exhibit R:        Form  of   Unit Purchase  Option  for  the Purchase of   Units
                  Consisting of Shares of Common Stock and Warrants.


                               page 10 of 11 pages

<PAGE>

                                   SIGNATURES

         After  reasonable  inquiry and to the best  knowledge and belief of the
undersigned,  the  undersigned  certify that the  information  set forth in this
statement is true, complete and correct.

                                 PARAMOUNT CAPITAL ASSET MANAGEMENT, INC.

Dated:   April 20, 1997
         New York, NY            By: /s/ Lindsay A. Rosenwald, M.D.
                                    -----------------------------------------
                                      Lindsay A. Rosenwald, M.D.
                                      President

                                 ARIES DOMESTIC FUND, L.P.
                                 By: Paramount Capital Asset Management, Inc.
                                       General Partner

Dated:   April 20, 1997
         New York, NY            By: /s/ Lindsay A. Rosenwald, M.D.
                                    -----------------------------------------
                                      Lindsay A. Rosenwald, M.D.
                                      President


                                 THE ARIES TRUST
                                 By: Paramount Capital Asset Management, Inc.
                                       Investment Manager

Dated:   April 20, 1997
         New York, NY            By: /s/ Lindsay A. Rosenwald, M.D.
                                    -----------------------------------------
                                      Lindsay A. Rosenwald, M.D.
                                      President
Dated:   April 20, 1997
         New York, NY            By: /s/ Lindsay A. Rosenwald, M.D.
                                    -----------------------------------------
                                      Lindsay A. Rosenwald, M.D.
                                      President


                               page 11 of 11 pages

<PAGE>

                                                                       EXHIBIT 0

                                    FORM OF
                             SUBSCRIPTION AGREEMENT


                  SUBSCRIPTION  AGREEMENT (this "Agreement") made as of the date
set  forth on the  signature  page  hereof  between  Procept,  Inc.  a  Delaware
Corporation (the "Company") and the undersigned (the "Subscriber").

                              W I T N E S S E T H:

                  WHEREAS, the Company has retained Paramount Capital, Inc. (the
"Placement  Agent") as Placement  Agent, on a "best efforts" basis, in a private
placement offering (the "Offering") of Units (the "Units") of the Company;

                  WHEREAS,  the  Company  desires to issue a minimum of ten (10)
Units (the "Minimum  Offering")  and a maximum of sixty (60) Units (the "Maximum
Offering"),  with an  option in favor of the  Placement  Agent to offer up to an
additional  sixty (60) Units to cover  over-allotments,  each Unit consisting of
(A) a number (the "Offering Quantity") of shares of common stock (rounded to the
nearest whole share,  with  one-half (.5) of one share being rounded  upward) of
the  Company,  par value  $.01 per share (the  "Common  Stock"),  determined  by
dividing one hundred thousand dollars  ($100,000) by the lesser of (a) $0.50 and
(b)  seventy-five  percent (75%) of the Trading Price (as defined  below) of the
Common  Stock  immediately  preceding  (i) the Initial  Closing Date (as defined
below),  (ii) any Interim  Closing Date (as defined  below),  or (iii) the Final
Closing  Date (as  defined  below) of this  Offering,  whichever  is lowest (the
lesser of (a) and (b) being the "Offering Price") and (B) warrants (the "Class C
Warrants") to purchase at any time prior to the fifth  anniversary  of the Final
Closing Date, a number of shares of Common Stock, per share equal to the product
of (x) the  Offering  Quantity  multiplied  by (y) 1.0,  (the Common Stock to be
issued pursuant to this Agreement and the Placement Agency Agreement (as defined
below),  including  the Common Stock  issuable  upon  exercise of the  Placement
Options and the Advisory Options, the Common Stock issuable as a Reset Issuance,
Semi-Annual Issuance,  Dilution Issuance or Qualified Offering Issuance (each as
defined in Article VI below)  and,  together  with the Class C Warrants  and the
Common Stock issuable upon exercise of the Class C Warrants  being  collectively
referred to herein as the "Subscription Common" or the "Securities");

                  WHEREAS,  the  Subscriber  desires to purchase  that number of
Units  set forth on the  signature  page  hereof  on the  terms  and  conditions
hereinafter set forth;

                  NOW,  THEREFORE,  in  consideration  of the  promises  and the
mutual  representations and covenants  hereinafter set forth, the parties hereto
do hereby agree as follows:


                                        1


<PAGE>

I.       SUBSCRIPTION FOR UNITS AND REPRESENTATIONS BY SUBSCRIBER

                  1.1 Subject to the terms and conditions hereinafter set forth,
the  Subscriber  hereby  subscribes for and shall purchase from the Company such
number of Units or  fractions  thereof and the Company  shall sell such Units to
the  Subscriber as is set forth upon the signature  page hereof at a price equal
to one hundred  thousand  dollars  ($100,000)  per Unit (the  "Initial  Offering
Price").  The  purchase  price is payable by personal or  business  check,  wire
transfer of  immediately  available  funds or money order made payable to "Fleet
National Bank, Escrow Agent,  F/B/O Procept,  Inc."  contemporaneously  with the
execution and delivery of this  Agreement by the  Subscriber.  The  certificates
representing  the  Securities  underlying  the Units  will be  delivered  by the
Company at each  closing  of the  Offering  (each,  a  "Closing")  to which such
certificates  relate  as  set  forth  in  Article  III  hereof.  The  Subscriber
understands, however, that this purchase of Units is contingent upon the Company
making  sales of a minimum of  twenty-five  (25) Units prior to the  termination
date of the Offering.

                  1.2 The  Subscriber  recognizes  that  the  purchase  of Units
involves a high degree of risk including, but not limited to, the following: (i)
the Company remains a development  stage business with limited operating history
and requires substantial funds in addition to the proceeds of the Offering; (ii)
an investment in the Company is highly  speculative,  and only investors who can
afford the loss of their  entire  investment  should  consider  investing in the
Company and the Units;  (iii) the  Subscriber  may not be able to liquidate  his
investment;  (iv) transferability of the Securities is extremely limited; (v) in
the event of a disposition of the Securities,  the Subscriber  could sustain the
loss of his entire  investment  and (vi) the Company has not paid any  dividends
since  inception  and  does not  anticipate  the  payment  of  dividends  in the
foreseeable  future.  Such  risks are more fully set forth in the Term Sheet (as
defined below) furnished by the Company to the Subscriber.

                  1.3  The  Subscriber  represents  that  the  Subscriber  is an
"accredited  investor"  as such  term is  defined  in Rule 501 of  Regulation  D
promulgated  under the  Securities  Act of 1933,  as  amended  (the  "Act"),  as
indicated by the  Subscriber's  responses to the questions  contained in Article
VIII hereof,  and that the  Subscriber  is able to bear the economic  risk of an
investment in the Units.

                  1.4 The Subscriber hereby acknowledges and represents that (i)
the  Subscriber  has  prior  investment  experience,   including  investment  in
securities  that are non-listed,  unregistered  and are not traded on the Nasdaq
National or SmallCap  Market,  nor on the  National  Association  of  Securities
Dealers,  Inc.'s (the "NASD") automated  quotation system, or the Subscriber has
employed,  at its own  expense,  and relied upon the  services of an  investment
advisor,  attorney and/or  accountant to read all of the documents  furnished or
made available by the Company to the Subscriber and to evaluate the  investment,
tax and legal merits and the consequences and risks of such a transaction on the
Subscriber's  behalf and that such person has such  knowledge and  experience in
financial and business  matters is capable of evaluating the merits and risks of
the  prospective  investment and satisfies the conditions set out in Rule 501(h)
under the Act; (ii) the


                                        2


<PAGE>

Subscriber  recognizes the highly  speculative  nature of this  investment;  and
(iii) the  Subscriber  is able to bear the  economic  risk which the  Subscriber
hereby assumes.

                  1.5 The  Subscriber  hereby  acknowledges  receipt and careful
review  of  (a)  the  Confidential   Term  Sheet  dated  November  14,  1997  as
supplemented and amended, and the attachments and exhibits thereto, all of which
constitute an integral  part thereof (the "Term  Sheet") and (b) this  Agreement
and all  attachments to it, and hereby  represents  that the Subscriber has been
furnished  by the  Company  during  the  course  of this  transaction  with  all
information  regarding the Company which the Subscriber has requested or desired
to know,  has been afforded the  opportunity to ask questions of, and to receive
answers from, duly authorized  officers or other  representatives of the Company
concerning  the terms and  conditions  of the  Offering  and the  affairs of the
Company and has received any  additional  information  which the  Subscriber has
requested.

                  1.6 (a) The Subscriber has relied solely upon the  information
provided  by the Company in the Term Sheet and in this  Agreement  in making the
decision to invest in the Units.  To the extent  necessary,  the  Subscriber has
retained,  at the sole expense of the  Subscriber,  and relied upon  appropriate
professional  advice  regarding  the  investment,   tax  and  legal  merits  and
consequences  of this  Agreement  and its purchase of the Units  hereunder.  The
Subscriber  acknowledges  and agrees that (i) the Company has  prepared the Term
Sheet and that no other person,  including,  without  limitation,  the Placement
Agent,  has supplied any  information for inclusion in the Term Sheet other than
information  furnished  in  writing  to  the  Company  by  the  Placement  Agent
specifically  for inclusion in the Term Sheet  relating to the Placement  Agent,
(ii) the Placement Agent has no responsibility  for the accuracy or completeness
of the Term Sheet and (iii) the Subscriber  has not relied upon the  independent
investigation  or  verification,  if any, which may have been  undertaken by the
Placement Agent.

                  (b) The  Subscriber  represents  that (i) the  Subscriber  was
contacted  regarding  the  sale  of the  Units  by the  Placement  Agent  (or an
authorized agent or representative thereof) with whom the Subscriber had a prior
substantial pre-existing  relationship and (ii) no Units were offered or sold to
it by means of any form of general solicitation or general  advertising,  and in
connection   therewith  the  Subscriber  did  not  (A)  receive  or  review  any
advertisement,  article,  notice or other communication published in a newspaper
or magazine or similar  media or  broadcast  over  television  or radio  whether
closed  circuit,  or generally  available;  or (B) attend any seminar meeting or
industry  investor  conference  whose  attendees  were  invited  by any  general
solicitation or general advertising.

                  1.7 The  Subscriber  hereby  represents  that  the  Subscriber
either by reason of the Subscriber's  business or financial  experience,  or the
business or financial experience of the Subscriber's  professional advisors (who
are  unaffiliated  with  and who  are  not  compensated  by the  Company  or any
affiliate  or selling  agent of the  Company,  including  the  Placement  Agent,
directly  or  indirectly),  has the  capacity to protect  the  Subscriber's  own
interests in connection with the transaction contemplated hereby.


                                        3


<PAGE>

                  1.8 The Subscriber  hereby  acknowledges that the Offering has
not been reviewed by the United States  Securities and Exchange  Commission (the
"SEC" or the "Commission") or any state regulatory authority, since the Offering
is intended to be exempt from the registration  requirements of Section 5 of the
Act pursuant to Regulation D promulgated under the Act. The Subscriber shall not
sell or otherwise  transfer the Securities  unless they are registered under the
Act or unless an exemption from such registration is available.

                  1.9 The Subscriber  understands that the Securities comprising
the  Units  have  not been  registered  under  the Act by  reason  of a  claimed
exemption  under the  provisions  of the Act which  depends,  in part,  upon the
Subscriber's  investment  intention.  In this connection,  the Subscriber hereby
represents that the Subscriber is purchasing the Securities comprising the Units
for the  Subscriber's  own account for investment and not with a view toward the
resale or distribution to others.  The Subscriber,  if an entity, was not formed
for the purpose of purchasing the Securities.

                  1.10 The Subscriber understands that there is no public market
for the Units or the  Securities  underlying  the Units  (other  than the Common
Stock) and that no market may develop for any such  securities.  The  Subscriber
understands  that even if a public  market  develops  for such  securities,  and
although there currently is a public market for the Common Stock,  reliance upon
Rule  144  under  the  Act,  as  amended,  for  resales  requires,  among  other
conditions,  a one-year  holding period prior to the resale (in limited amounts)
of securities  acquired in a non-public  offering  without having to satisfy the
registration  requirements under the Act. The Subscriber  understands and hereby
acknowledges  that the Company is under no  obligation  to  register  any of the
Units or any of the  Securities  comprising the Units under the Act or any state
securities  or  "blue  sky"  laws  other  than as set  forth in  Article  V. The
Subscriber  shall  hold the  Company  and its  directors,  officers,  employees,
controlling  persons and agents (including the Placement Agent and its officers,
directors,  employees,  counsel,  controlling  persons  and  agents)  and  their
respective  heirs,  representatives,  successors and assigns  harmless from, and
shall indemnify them against,  all liabilities,  costs and expenses  incurred by
them as a result of (i) any  misrepresentation  made by the Subscriber contained
in this Agreement (including the Confidential Investor  Questionnaire  contained
in Article VIII  herein),  (ii) any sale or  distribution  by the  Subscriber in
violation of the Act or any  applicable  state  securities or "blue sky" laws or
(iii)  any  untrue  statement  of a  material  fact made by the  Subscriber  and
contained  herein or omission to state herein a material fact necessary in order
to make the statements  contained herein,  in light of the  circumstances  under
which they were made, not misleading.

                  1.11 The  Subscriber  consents to the placement of a legend on
any certificate or other document evidencing the Securities that such Securities
have not been  registered  under the Act or any state  securities  or "blue sky"
laws and setting forth or referring to the  restrictions on transfer ability and
sale  thereof  contained in this  Agreement.  The  Subscriber  is aware that the
Company  will make a notation in its  appropriate  records  with  respect to the
restrictions on the transferability of such Securities.


                                        4


<PAGE>

                  1.12 The Subscriber  understands  that the Company will review
this  Agreement  and is  hereby  given  authority  by  the  Subscriber  to  call
Subscriber's  bank or place of  employment  or  otherwise  review the  financial
standing of the Subscriber;  and it is further agreed that the Company (with the
consent of the Placement Agent) and the Placement Agent, at its sole discretion,
reserves the unrestricted right,  without further  documentation or agreement on
the part of the  Subscriber,  to  reject or limit  any  subscription,  to accept
subscriptions  for fractional  Units and to close the Offering to the Subscriber
at any time.

                  1.13 The Subscriber  hereby represents that the address of the
Subscriber  furnished  by  Subscriber  on  the  signature  page  hereof  is  the
Subscriber's principal residence if Subscriber is an individual or its principal
business address if it is a corporation or other entity.

                  1.14 The  Subscriber  represents  that the Subscriber has full
power and authority (corporate,  statutory and otherwise) to execute and deliver
this  Agreement  and to purchase the Units and the  Securities.  This  Agreement
constitutes  the  legal,   valid  and  binding  obligation  of  the  Subscriber,
enforceable against the Subscriber in accordance with its terms.

                  1.15 If the Subscriber is a corporation,  partnership, limited
liability company,  trust, employee benefit plan, individual retirement account,
Keogh Plan, or other entity,  then (a) it is authorized  and qualified to become
an investor in the Company and the person  signing  this  Agreement on behalf of
such entity has been duly authorized by such entity to do so, and (b) it is duly
organized,  validly  existing  and  in  good  standing  under  the  laws  of the
jurisdiction of its organization.

                  1.16  The  Subscriber  acknowledges  that  if he or  she  is a
registered  representative of an NASD member firm, he or she must give such firm
the notice required by the NASD's Rules of Fair Practice,  receipt of which must
be acknowledged by such firm in Section 8.4 below.

                  1.17 The Subscriber  acknowledges  that at such time, if ever,
as the Securities  are  registered,  sales of the Securities  will be subject to
state securities laws,  including those of the State of New Jersey which require
any securities sold in New Jersey to be sold through a registered  broker-dealer
or in reliance upon an exemption from registration.

                  1.18  Subject to the proviso  below,  from the date hereof and
continuing  for a period of nine (9)  months  (the  "Lock-Up  Period")  from the
effective date of the Registration  Statement (as defined in Section 5.2 hereof)
(the  "Effective  Date"),  the Subscriber  shall not,  without the prior written
consent of the Placement Agent, offer, pledge, sell, contract to sell, grant any
option for the sale of, or otherwise dispose of, directly or indirectly,  75% of
the Registrable  Securities (as defined in Section 5.1) purchased or acquired by
the Subscriber; provided, however, that, following each three month period after
the Effective  Date,  an amount of  Registrable  Securities  equal to 25% of the
number of Registrable  Securities  purchased or acquired by the Subscriber shall
become exempt from the lock-up  provisions  contained in this sentence.  For the
sake of clarity, 25% of the Registrable


                                        5


<PAGE>

Securities  will not be subject to any lock-up.  In addition,  during the period
from the date  that the  Subscriber  was first  contacted  with  respect  to the
potential  purchase of  Securities  through the last date upon which  Subscriber
holds any  Securities  or  Registrable  Securities,  the  Subscriber  shall not,
directly or indirectly  through  related  parties,  affiliates or otherwise sell
"short" or "short against the box" (as those terms are generally  understood) or
otherwise  engage  in any  "hedging"  transaction  with  respect  to any  equity
security of the Company; provided,  however, that it shall not be a violation of
this  Section  1.18,  if the  Subscriber  places a sell  order  for  Registrable
Securities  underlying the Class C Warrants prior to the exercise  thereof or at
the time the  exercise  is  requested,  relies on the  Company to  deliver  such
Registrable  Securities in accordance with Section 5.4(h) and completes the sale
of such  Registrable  Securities  before the Company  delivers  the  Registrable
Securities to the Subscriber.

                  1.19 The  Subscriber  represents  and warrants that it has not
engaged,  consented to nor authorized any broker,  finder or intermediary to act
on its behalf,  directly or indirectly,  as a broker,  finder or intermediary in
connection with the transactions  contemplated by this Agreement. The Subscriber
shall  indemnify  and hold  harmless  the  Company  from and  against  all fees,
commissions  or other payments owing to any such person or firm acting on behalf
of such Subscriber hereunder.

                  1.20 The  Subscriber  acknowledges  that (a) the  Company  has
engaged,  consented to and authorized the Placement Agent in connection with the
transactions  contemplated  by this  Agreement,  (b) the  Company  shall pay the
Placement  Agent a commission  and reimburse the Placement  Agent's  expenses in
accordance with the Placement Agency Agreement,  and the Company shall indemnify
and hold harmless the Subscriber from and against all fees, commissions or other
payments owing by the Company to the Placement Agent or any other person or firm
acting on behalf of the Company hereunder and (c) registered  representatives of
the  Placement  Agent  and/or  its  designees  (including,  without  limitation,
registered  representatives  of the  Placement  Agent and/or its  designees  who
participate  in the Offering and sale of the  securities  sold in the  Offering)
will be paid a portion of the commissions  paid to the Placement Agent including
a portion of the Placement Options (as defined in Section 5.1(c) below).

                  1.21 The Subscriber,  whose name appears on the signature line
below, shall be the beneficial owner of the Securities for which such Subscriber
subscribes.

II.      REPRESENTATIONS, WARRANTIES AND COVENANTS OF THE COMPANY

         Except as set forth on the Schedule of  Exceptions  attached  hereto as
Exhibit  A,  the  Company  hereby  represents,  warrants  and  covenants  to the
Subscriber that:

                  2.1 Organization, Good Standing and Qualification. The Company
is a corporation duly organized, validly existing and in good standing under the
laws of the State of Delaware and has full corporate power and lawful  authority
to conduct its business as described in


                                        6


<PAGE>

the Term  Sheet.  The  Company is duly  qualified  to do  business  as a foreign
corporation and is in good standing in Massachusetts and in each jurisdiction in
which the nature of the  business  conducted,  or as proposed to be conducted in
the Term Sheet, by it or the properties  owned,  leased or operated by it, makes
such  qualification  or  licensing  necessary  and  where the  failure  to be so
qualified or licensed  would have a material  adverse  effect upon the business,
prospects and financial condition of the Company.  The Company is duly qualified
to do  business  as a  foreign  corporation  and is in  good  standing  in  each
jurisdiction  in which the laws  require the Company to be so  qualified  and/or
authorized to do business.

                  2.2 Capitalization  and Voting Rights. The authorized,  issued
and  outstanding  capital stock of the Company is as set forth in the Term Sheet
under the heading "Equity Capitalization";  all issued and outstanding shares of
capital stock of the Company are validly issued,  fully paid and  nonassessable.
The Securities  comprising the Units have been duly and validly  authorized and,
when issued and paid for  pursuant to this  Agreement,  will be validly  issued,
fully paid and  nonassessable.  Except as set forth in the Term Sheet, there are
no outstanding options, warrants, agreements, convertible securities, preemptive
rights or other  rights to  subscribe  for or to purchase  any shares of capital
stock of the Company.  Except as set forth in the Term Sheet,  in this Agreement
and as otherwise  required by law, there are no restrictions  upon the voting or
transfer  of  the   Securities   pursuant  to  the  Company's   Certificate   of
Incorporation, as amended (the "Certificate of Incorporation"), By-laws or other
governing  documents or any agreement or other  instruments to which the Company
is a party or by which the Company is bound.

                  2.3  Authorization;   Enforceability.   The  Company  has  all
corporate  right,  power  and  authority  to enter  into this  Agreement  and to
consummate the  transactions  contemplated  hereby.  All corporate action on the
part  of  the  Company,  its  directors  and  stockholders   necessary  for  the
authorization,  execution,  delivery and  performance  of this  Agreement by the
Company,  the  authorization,  sale,  issuance and delivery of the  Subscription
Common and Class C Warrants  contemplated hereby and the Common Stock underlying
such Class C Warrants and the performance of the Company's obligations hereunder
has been taken.  This  Agreement  has been duly  executed  and  delivered by the
Company and  constitutes a legal,  valid and binding  obligation of the Company,
enforceable against the Company in accordance with its terms, subject to laws of
general application relating to bankruptcy, insolvency and the relief of debtors
and rules of law  governing  specific  performance,  injunctive  relief or other
equitable  remedies,  and to limitations of public policy. Upon the issuance and
delivery of the  Subscription  Common and Class C Warrants,  as  contemplated by
this Agreement,  such securities will be duly and validly authorized and issued,
fully paid and nonassessable. Upon the issuance and delivery of the Common Stock
underlying the Class C Warrants,  and upon compliance by the Subscriber with the
terms hereof,  the Common Stock will be duly authorized,  validly issued,  fully
paid and  nonassessable.  The issuance and sale of the  Securities  contemplated
hereby will not give rise to any preemptive rights or rights of first refusal on
behalf of any person.

                  2.4      No Conflict; Governmental Consents.


                                        7


<PAGE>

                  (a)  The  execution  and  delivery  by  the  Company  of  this
Agreement and the consummation of the transactions  contemplated hereby will not
result in the violation of any law,  statute,  rule,  regulation,  order,  writ,
injunction,  judgment or decree of any court or governmental  authority to or by
which  the  Company  is  bound,  or of  any  provision  of  the  Certificate  of
Incorporation  or By-laws of the Company,  and will not conflict with, or result
in a breach or violation  of, any of the terms or  provisions  of, or constitute
(with due  notice or lapse of time or both) a default  under,  any  lease,  loan
agreement,  mortgage,  security agreement, trust indenture or other agreement or
instrument  to which the  Company is a party or by which it is bound or to which
any of its  properties  or assets is  subject,  nor  result in the  creation  or
imposition of any lien upon any of the properties or assets of the Company.

                  (b) No consent, approval,  authorization or other order of any
governmental  authority or other  third-party  is required to be obtained by the
Company in  connection  with the  authorization,  execution and delivery of this
Agreement  or with the  authorization,  issuance  and  sale of the  Units or the
Securities  comprising  the Units,  except such filings as may be required to be
made with the  Commission,  the NASD and the National  Association of Securities
Dealers Automated Quotation System ("Nasdaq") and with any state or foreign blue
sky or securities regulatory authority.

                  2.5  Licenses.  Except  as set  forth in the Term  Sheet,  the
Company  has  all  licenses,  permits  and  other  governmental   authorizations
currently  required for the conduct of its  business or ownership of  properties
and is in all material respects complying therewith.

                  2.6  Litigation.  Except as set forth in the Term  Sheet,  the
Company  knows of no pending or  threatened  legal or  governmental  proceedings
against  the Company  which  could  materially  adversely  affect the  business,
property, financial condition, operations or prospects of the Company.

                  2.7 Accuracy of Reports.  All material  reports required to be
filed by the Company  within the three years prior to the date of this Agreement
under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), have
been duly filed  with the SEC,  complied  at the time of filing in all  material
respects with the  requirements  of their  respective  forms and,  except to the
extent updated or superseded by the Term Sheet or any subsequently filed report,
to the  best of the  Company's  knowledge,  were  complete  and  correct  in all
material  respects as of the dates at which the information  was furnished,  and
contained  (as of such dates) no untrue  statement of a material fact or omitted
to state a material  fact  necessary in order to make the  statements  contained
therein,  in  light  of the  circumstances  under  which  they  were  made,  not
misleading.

                  2.8 Term Sheet;  Disclosure.  No information  set forth in the
Term Sheet contains any untrue  statement of a material fact or omits to state a
material fact necessary in order to make the statements  contained  therein,  in
light of the circumstances under which they were made, not misleading.


                                        8


<PAGE>

                  2.9  Investment  Company.  The  Company is not an  "investment
company"  within the  meaning of such term under the  Investment  Company Act of
1940, as amended, and the rules and regulations of the Commission thereunder.

                  2.10 Listing.  The Company shall  promptly file an Application
for Listing of Additional  Shares with the Nasdaq National Market (the "Nasdaq")
and hereby  represents  and warrants to the Placement  Agent and the  Subscriber
that it will take any other necessary action in accordance with the rules of the
Nasdaq to  enable  the (a)  Subscription  Common  (including  the  Common  Stock
issuable  upon exercise of the Class C Warrants) and (b) the Class C Warrants to
trade on the Nasdaq.

                  2.11 Reservation of Shares;  Transfer Taxes,  Etc. The Company
shall  at all  times  reserve  and keep  available,  out of its  authorized  and
unissued  shares of Common  Stock,  solely  for the  purpose  of  effecting  any
exercises  of Class C  Warrants,  and any Reset  Issuance  (as  defined  below),
Semi-Annual Issuance (as defined below), Qualified Offering Issuance (as defined
below)  and  Dilution  Issuance  (as  defined  below  and,  together  with Reset
Issuances,  Qualified Offering Issuances and Semi-Annual Issuances,  referred to
herein as "Article  VI  Issuances"),  such number of shares of its Common  Stock
free of preemptive  rights as shall be  sufficient to effect such  exercises and
Article VI Issuances from time to time required or reasonably  anticipated.  The
Company  shall use its best efforts from time to time,  in  accordance  with the
laws of the State of  Delaware to increase  the  authorized  number of shares of
Common  Stock if at any time the number of shares of  authorized,  unissued  and
unreserved  Common  Stock  shall not be  sufficient  to permit any  required  or
reasonably anticipated exercises of Class C Warrants or Article VI Issuances. In
the  event,  and to the  extent,  that the  company  does  not  have  sufficient
authorized but unissued shares of Common Stock to effect any exercise of Class C
Warrants or any Article VI Issuance  (collectively a "Common  Issuance  Event"),
the Company shall pay the Subscriber cash in an amount per share of Common Stock
that would have been issued to such Subscriber  pursuant to such Common Issuance
Event but for the lack of sufficient  authorized but unissued Common Stock equal
to the greater of (i) 1.40 times the Dilution  Value (as defined  below) (or, in
the case of  shares  of  Common  Stock  issuable  upon  exercise  of the Class C
Warrants,  1.40 times the exercise  price) and (ii) the Market Price,  in either
case  determined as of the date of the event giving rise to such Common Issuance
Event.

          The  Company  shall pay any and all issue or other  taxes  that may be
payable in respect of any Article VI Issuance.

III.     TERMS OF SUBSCRIPTION

                  3.1 The Company  shall issue a minimum of ten (10) Units and a
maximum of sixty (60) Units. The Placement Agent, at its sole option,  may offer
and sell up to an  additional  sixty  (60) Units to cover  over-allotments.  The
offering  period (the "Offering  Period") shall begin on November 14, 1997. Upon
receipt of the  Minimum  Offering  amount,  the  Placement  Agent may  conduct a
closing  (the date of which being the  "Initial  Closing  Date") and may conduct
subsequent


                                        9

<PAGE>

Closings on an interim basis until the Maximum  Offering and any  over-allotment
amount has been  reached or the  Termination  Date (as  defined  below) has been
reached (the "Final Closing Date"). The Offering Period shall terminate at 11:59
p.m. New York City time on March 13, 1998, subject to an extension,  at the sole
option  of  the  Placement  Agent,  for  an  additional  sixty  (60)  days  (the
"Termination  Date").  The Units will be offered on a "best efforts" basis.  The
purchase  price is payable by  personal  or  business  check,  wire  transfer of
immediately available funds or money order made payable to "Fleet National Bank,
Escrow Agent, F/B/O Procept, Inc."

                  3.2  Placement  of the  Units  will be  made by the  Placement
Agent, who will receive certain  compensation as described in the Term Sheet and
the Placement Agency Agreement.

                  3.3  Pending the sale of the Units,  all funds paid  hereunder
shall be deposited by the Company in escrow with Fleet National  Bank,  having a
branch at 345 Park Avenue,  New York,  New York 10022.  If the Company shall not
have obtained  subscriptions  (including this subscription) for purchases of the
minimum ten (10) Units on or before the Termination Date, then this subscription
shall be void and all funds paid hereunder by the  Subscriber  shall be promptly
returned to the Subscriber, with interest, subject to paragraph 3.5 hereof.

                  3.4 The Subscriber  hereby  authorizes and directs the Company
to  deliver  the  Securities  to be issued to the  Subscriber  pursuant  to this
Agreement  directly to the  Subscriber's  account  maintained  by the  Placement
Agent,  if any, or, if no such account  exists,  to the  residential or business
address indicated on the signature page hereto.

                  3.5 The Subscriber  hereby  authorizes and directs the Company
to return any funds for unaccepted  subscriptions to the same account from which
the funds  were  drawn,  including  any  customer  account  maintained  with the
Placement Agent.

IV.      CONDITIONS TO OBLIGATIONS OF THE SUBSCRIBER

                  4.1 The  Subscriber's  obligation to purchase the Units at any
Closing  is  subject  to the  fulfillment  on or  prior to each  Closing  of the
following  conditions,  which  conditions  may be  waived  at the  option of the
Subscriber to the extent permitted by law:

                           (a)  Representations  and  Warranties  Correct.   The
representations and warranties made by the Company in Article II hereof shall be
true and  correct in all  material  respects  when  made,  and shall be true and
correct in all material  respects on each Closing with the same force and effect
as if they had been made on and as of such Closing.

                           (b)   Covenants.   All   covenants,   agreements  and
conditions  contained  in this  Agreement  to be  performed by the Company on or
prior to such  purchase  shall  have  been  performed  or  complied  with in all
material respects.


                                       10


<PAGE>

                           (c) No Legal Order  Pending.  There shall not then be
in effect any legal or other order  enjoining or  restraining  the  transactions
contemplated by this Agreement.

                           (d) No Law  Prohibiting  or  Restricting  Such  Sale.
There  shall  not be in  effect  any  law,  rule or  regulation  prohibiting  or
restricting  such sale or requiring  any consent or approval of any person which
shall not have  been  obtained  to issue the  Securities  (except  as  otherwise
provided in this Agreement).

                           (e) Minimum  Subscriptions.  The  Company  shall have
received binding subscriptions for at least twenty-five (25) Units.

                           (f) Legal Opinion.  On each Closing,  if requested by
the  Placement  Agent,  at each  Closing,  counsel  to the  Company  shall  have
delivered to the Placement Agent, for the benefit of the Placement Agent and the
Subscriber,  a legal opinion concerning legal matters relating to this Agreement
and the Term Sheet as the Placement Agent may require.

                           (g) Comfort Letter. On each Closing,  if requested by
the Placement Agent, the Company's auditors,  Coopers & Lybrand, LLP, shall have
delivered to the Placement  Agent for the benefit of the Placement Agent and the
Subscriber, a comfort letter to such effect as the Placement Agent may require.

V.       REGISTRATION RIGHTS

                  5.1 As used in this Agreement,  the following terms shall have
the following meanings:

                           (a)  "Affiliate"  shall  mean,  with  respect  to any
Person (as defined below), any other Person controlling, controlled by, or under
direct or indirect  common  control with,  such Person (for the purposes of this
definition "control," when used with respect to any specified Person, shall mean
the power to direct the  management  and  policies of such  person,  directly or
indirectly,  whether  through  ownership  of voting  securities,  by contract or
otherwise;  and the terms  "controlling"  and  "controlled"  shall have meanings
correlative to the foregoing).

                           (b)  "Business  Day" shall mean a day Monday  through
Friday on which banks are generally open for business in New York.

                           (c)  "Holders"  shall  mean  the  Subscriber  and any
person holding  Registrable  Securities  (including the  Registrable  Securities
underlying  the  placement  options (the  "Placement  Options") and the advisory
options (the "Advisory Options") to be granted to the Placement Agent and/or its
designees pursuant to the Placement Agency Agreement between the Company and the
Placement Agent dated October 26, 1997 (the "Placement Agency Agreement")),


                                       11


<PAGE>

or any  person to whom the  rights  under  Article V have  been  transferred  in
accordance with Section 5.9 hereof.

                           (d)  "Person"  shall  mean  any  person,  individual,
corporation,   limited   liability   company,   partnership,   trust   or  other
nongovernmental  entity or any governmental  agency,  court,  authority or other
body (whether foreign, federal, state, local or otherwise).

                           (e)   The   terms   "register,"    "registered"   and
"registration"  refer to the  registration  effected by  preparing  and filing a
registration  statement  in  compliance  with the Act,  and the  declaration  or
ordering of the effectiveness of such registration statement.

                           (f)  "Registrable  Securities"  shall  mean  (i)  the
Subscription  Common (including the Subscription Common underlying the Placement
Options and Advisory Options), (ii) the shares of Common Stock issuable upon the
exercise of the Class C Warrants  (including the shares of Common Stock issuable
upon exercise of the Class C Warrants  underlying the Placement  Options and the
Advisory  Options),  (iii) the Class C Warrants  (including the Class C Warrants
issuable upon exercise of the Placement and Advisory Options),  (iv) a number of
shares of Common  Stock  issuable  upon  issuances  pursuant  to Article VI with
respect any Reset Issuance (as defined below) and the first two (2)  Semi-Annual
Issuances  (as defined  below) and (v) any shares of Common  Stock issued as (or
issuable upon the  conversion of any warrant,  right or other  security which is
issued as) a dividend or other distribution with respect to or in replacement of
the Securities;  provided,  however,  that  securities  shall only be treated as
Registrable  Securities  if and  only  for so long as they  (A)  have  not  been
disposed of pursuant  to a  registration  statement  declared  effective  by the
Commission, (B) have not been sold in a transaction exempt from the registration
and  prospectus   delivery   requirements  of  the  Act  so  that  all  transfer
restrictions  and restrictive  legends with respect thereto are removed upon the
consummation of such sale or (C) are held by a Holder or a permitted  transferee
pursuant to Section 5.9.

                           (g)  "Registration  Expenses" shall mean all expenses
incurred by the Company in complying with Section 5.2 hereof, including, without
limitation, all registration,  qualification and filing fees, printing expenses,
escrow fees,  fees and  expenses of counsel for the  Company,  blue sky fees and
expenses and the expense of any special audits  incident to, or required by, any
such registration (but excluding the fees of legal counsel for any Holder).

                           (h)  "Registration  Statement" shall have the meaning
ascribed to such term in Section 5.2.

                           (i)  "Registration  Period"  shall  have the  meaning
ascribed to such term in Section 5.4.


                                       12


<PAGE>

                           (j) "Selling  Expenses"  shall mean all  underwriting
discounts  and  selling  commissions  applicable  to  the  sale  of  Registrable
Securities and all fees and expenses of legal counsel for any Holder.

                  5.2 No later than  thirty  (30) days  after the Final  Closing
Date  (the  "Filing  Date"),  the  Company  shall  file a  "shelf"  registration
statement  on the  appropriate  form  (the  "Registration  Statement")  with the
Commission and use its best efforts to effect the  registration,  qualifications
or compliances  (including,  without  limitation,  the execution of any required
undertaking to file  post-effective  amendments,  appropriate  qualifications or
exemptions  under  applicable  blue  sky or  other  state  securities  laws  and
appropriate   compliance  with  applicable  securities  laws,   requirements  or
regulations)  of the Registrable  Securities  prior to the date which is 75 days
after the Final Closing Date.  Notwithstanding the foregoing,  the Company shall
not be obligated to enter into any underwriting agreement for the sale of any of
the Registrable Securities.

                  5.3 All Registration  Expenses incurred in connection with any
registration,  qualification,  exemption or  compliance  pursuant to Section 5.2
shall be borne by the  Company.  All  Selling  Expenses  relating to the sale of
securities  registered by or on behalf of Holders shall be borne by such Holders
pro rata on the basis of the number of securities so  registered;  provided that
if a Holder uses its own legal counsel in addition to one counsel for all of the
Holders of  securities  registered  on behalf of the Holders,  such Holder shall
bear the cost of such counsel.

                  5.4 In the case of the registration,  qualification, exemption
or compliance  effected by the Company  pursuant to this Agreement,  the Company
shall,  upon  reasonable  request,  inform  each Holder as to the status of such
registration,  qualification,  exemption  and  compliance.  At its  expense  the
Company shall:

                           (a) use its best  efforts to keep such  registration,
and any qualification, exemption or compliance under state securities laws which
the Company determines to obtain,  continuously effective until the Holders have
completed the  distribution  described in the  registration  statement  relating
thereto.  The period of time during  which the Company is required  hereunder to
keep  the  Registration  Statement  effective  is  referred  to  herein  as "the
Registration Period."  Notwithstanding the foregoing, at the Company's election,
the Company may cease to keep such  registration,  qualification,  exemption  or
compliance  effective  with  respect  to any  Registrable  Securities,  and  the
registration rights of a Holder shall expire, at such time as the Holder (who is
not an affiliate of the Company) may sell under Rule 144 under the Act (or other
exemption from registration  acceptable to the Company) in a three-month  period
all Registrable Securities then held by such Holder, but this sentence shall not
relieve the Company of any  obligation  to comply with this  Article V as to any
Subscription Common thereafter issued; and

                           (b) advise the Holders:


                                       13


<PAGE>

                                    (i) when the  Registration  Statement or any
amendment  thereto has been filed with the Commission and when the  Registration
Statement or any post-effective amendment thereto has become effective;

                                    (ii) of any  request by the  Commission  for
amendments  or  supplements  to the  Registration  Statement  or the  prospectus
included therein or for additional information;

                                    (iii) of the issuance by the  Commission  of
any stop order suspending the effectiveness of the Registration Statement or the
initiation of any proceedings for such purpose;

                                    (iv) of the  receipt  by the  Company of any
notification  with  respect  to  the  suspension  of  the  qualification  of the
Registrable  Securities  included  therein for sale in any  jurisdiction  or the
initiation or threatening of any proceeding for such purpose; and

                                    (v)  of the  happening  of  any  event  that
requires  the  making  of any  changes  in  the  Registration  Statement  or the
prospectus so that, as of such date, the  statements  therein are not misleading
and do not omit to state a  material  fact  required  to be  stated  therein  or
necessary to make the statements therein (in the case of the prospectus,  in the
light of the circumstances under which they were made) not misleading;

                           (c)  make  every  reasonable  effort  to  obtain  the
withdrawal  of any  order  suspending  the  effectiveness  of  any  Registration
Statement at the earliest possible time;

                           (d) furnish to each Holder,  without charge, at least
one  copy of  such  Registration  Statement  and  any  post-effective  amendment
thereto,  including  financial  statements and schedules,  and, if the Holder so
requests in writing, all exhibits (including those incorporated by reference) in
the form filed with the Commission;

                           (e) during the Registration  Period,  deliver to each
Holder,  without  charge,  as many  copies of the  prospectus  included  in such
Registration  Statement and any  amendment or supplement  thereto as such Holder
may reasonably request; and the Company consents to the use, consistent with the
provisions  hereof, of the prospectus and any amendment or supplement thereto by
each of the selling  Holders of  Registrable  Securities in connection  with the
offering and sale of the  Registrable  Securities  covered by the prospectus and
any amendment or supplement thereto. In addition, upon the reasonable request of
the Holder and subject in all cases to  confidentiality  protections  reasonably
acceptable  to  the  Company,   the  Company  will  meet  with  a  Holder  or  a
representative  thereof at the Company's headquarters to discuss all information
relevant for disclosure in the Registration  Statement  covering the Registrable
Securities,   and  will  otherwise  cooperate  with  any  Holder  conducting  an
investigation for the purpose of reducing or eliminating


                                       14


<PAGE>

such Holder's  exposure to liability  under the Act,  including  the  reasonable
production of information at the Company's headquarters;

                           (f) during the Registration  Period,  deliver to each
Holder,  without  charge,  (i) as soon as  practicable  (but in the  case of the
annual report of the Company to its stockholders,  within 120 days after the end
of each fiscal year of the  Company)  one copy of: (A) its annual  report to its
stockholders,  if any (which annual report shall  contain  financial  statements
audited in  accordance  with  generally  accepted  accounting  principles in the
United States of America by a firm of certified public accountants of recognized
standing);   (B)  if  not  included  in  substance  in  its  annual   report  to
stockholders,  its annual report on Form 10-K (or similar form); (C) each of its
quarterly reports to its stockholders, if any, and, if not included in substance
in its quarterly reports to stockholders,  its quarterly report on Form 10-Q (or
similar form), and (D) a copy of the full Registration Statement (the foregoing,
in each  case,  excluding  exhibits);  and (ii)  upon  reasonable  request,  all
exhibits excluded by the parenthetical to the immediately  preceding clause (D),
and all other information that is generally available to the public;

                           (g)  prior  to any  public  offering  of  Registrable
Securities pursuant to any Registration Statement, register or qualify or obtain
an exemption  for offer and sale under the  securities  or blue sky laws of such
jurisdictions as any such Holders reasonably  request in writing,  provided that
the Company  shall not for any such purpose be required to qualify  generally to
transact business as a foreign  corporation in any jurisdiction  where it is not
so  qualified  or  to  consent  to  general  service  of  process  in  any  such
jurisdiction,  and do any and all other acts or things  reasonably  necessary or
advisable to enable the offer and sale in such  jurisdictions of the Registrable
Securities covered by such Registration Statement;

                           (h)  cooperate  with the  Holders to  facilitate  the
timely  preparation  and  delivery  of  certificates   representing  Registrable
Securities  to be  sold  pursuant  to any  Registration  Statement  free  of any
restrictive  legends  to the  extent  not  required  at  such  time  and in such
denominations and registered in such names as Holders may request at least three
(3)  business  days prior to sales of  Registrable  Securities  pursuant to such
Registration Statement;

                           (i) upon the occurrence of any event  contemplated by
Section  5.4(b)(v)  above,  the Company shall promptly  prepare a post-effective
amendment  to  the  Registration  Statement  or  a  supplement  to  the  related
prospectus, or file any other required document so that, as thereafter delivered
to purchasers of the Registrable  Securities  included  therein,  the prospectus
will not include any untrue  statement  of a material  fact or omit to state any
material  fact  necessary to make the  statements  therein,  in the light of the
circumstances under which they were made, not misleading; and

                           (j)  use  its  best   efforts  to  comply   with  all
applicable  rules and  regulations  of the  Commission,  and will make generally
available  to the  Holders  not  later  than 45 days  (or 90 days if the  fiscal
quarter is the fourth  fiscal  quarter)  after the end of its fiscal  quarter in
which the


                                       15


<PAGE>

first  anniversary  date of the  effective  date of the  Registration  Statement
occurs, an earnings statement  satisfying the provisions of Section 11(a) of the
Act.

                  5.5 The  Holders  shall  have no right to take any  action  to
restrain,  enjoin or otherwise  delay any  registration  pursuant to Section 5.2
hereof  as a result  of any  controversy  that may  arise  with  respect  to the
interpretation or implementation of this Agreement.

                  5.6 (a) To the extent  permitted  by law,  the  Company  shall
indemnify each Holder,  each underwriter of the Registrable  Securities and each
person controlling such Holder within the meaning of Section 15 of the Act, with
respect to which any registration, qualification or compliance has been effected
pursuant to this Agreement,  against all claims, losses, damages and liabilities
(or action in respect  thereof),  including  any of the  foregoing  incurred  in
settlement of any litigation, commenced or threatened (subject to Section 5.6(c)
below),  arising out of or based on (i) any untrue  statement (or alleged untrue
statement)  of  a  material  fact  contained  in  any  registration   statement,
prospectus  or  offering  circular,  or any  amendment  or  supplement  thereof,
incident to any such registration,  qualification or compliance, or based on any
omission (or alleged  omission) to state  therein a material fact required to be
stated therein or necessary to make the statements  therein not  misleading,  in
light of the  circumstances  in which they were made,  or (ii) any  violation or
alleged  violation by the Company of the Act,  the Exchange  Act, or any rule or
regulation  promulgated  under the Act, or the Exchange Act, and shall reimburse
each Holder,  each  underwriter  of the  Registrable  Securities and each person
controlling  such Holder,  for legal and other expenses  reasonably  incurred in
connection  with  investigating  or  defending  any such  claim,  loss,  damage,
liability or action as incurred;  provided  that the Company shall not be liable
in any such  case to the  extent  that  any  untrue  statement  or  omission  or
allegation  thereof is made in  reliance  upon and in  conformity  with  written
information  furnished  to the Company by or on behalf of such Holder and stated
to be  specifically  for  use in  preparation  of such  registration  statement,
prospectus or offering  circular;  provided that the Company shall not be liable
in any such case where the claim,  loss, damage or liability arises out of or is
related to the failure of the Holder to comply with the covenants and agreements
contained in this  Agreement  respecting  sales of Registrable  Securities,  and
except that the foregoing  indemnity agreement is subject to the condition that,
insofar as it relates to any such untrue  statement or alleged untrue  statement
or  omission  or  alleged  omission  made  in  the  preliminary  prospectus  but
eliminated or remedied in the amended  prospectus on file with the Commission at
the  time  the  registration  statement  becomes  effective  or in  the  amended
prospectus  filed with the  Commission  pursuant to Rule 424(b) of the Act or in
the  prospectus  subject to completion and term sheet under Rule 434 of the Act,
which  together  meet the  requirements  of Section 10(a) of the Act (the "Final
Prospectus"),  such  indemnity  agreement  shall not inure to the benefit of any
such Holder,  any such underwriter or any such controlling  person, if a copy of
the Final Prospectus furnished by the Company to the Holder for delivery was not
furnished to the person or entity asserting the loss, liability, claim or damage
at or prior to the time such  furnishing  is  required  by the Act and the Final
Prospectus  would  have cured the defect  giving  rise to such loss,  liability,
claim or damage.


                                       16


<PAGE>

                           (b)  Each  Holder  will  severally,   if  Registrable
Securities  held by such Holder are included in the  securities as to which such
registration,  qualification  or  compliance  is being  effected,  indemnify the
Company, each of its directors and officers, each underwriter of the Registrable
Securities  and each  person who  controls  the  Company  within the  meaning of
Section 15 of the Act, against all claims,  losses,  damages and liabilities (or
actions  in  respect  thereof),  including  any of  the  foregoing  incurred  in
settlement of any litigation, commenced or threatened (subject to Section 5.6(c)
below),  arising  out of or based on any untrue  statement  (or  alleged  untrue
statement)  of  a  material  fact  contained  in  any  registration   statement,
prospectus  or  offering  circular,  or any  amendment  or  supplement  thereof,
incident to any such  registration,  qualification or compliance or based on any
omission (or alleged  omission) to state  therein a material fact required to be
stated therein or necessary to make the statements  therein not  misleading,  in
light of the  circumstances  in which they were  made,  and will  reimburse  the
Company,  such  directors  and officers,  each  underwriter  of the  Registrable
Securities and each person  controlling the Company for reasonable legal and any
other expenses reasonably incurred in connection with investigating or defending
any such claim, loss, damage,  liability or action as incurred,  in each case to
the extent,  but only to the extent,  that such untrue  statement or omission or
allegation  thereof is made in reliance  upon, and in conformity  with,  written
information furnished to the Company by or on behalf of the Holder and stated to
be  specifically  for  use  in  preparation  of  such  registration   statement,
prospectus or offering circular;  provided that the indemnity shall not apply to
the extent that such claim, loss, damage or liability results from the fact that
a current copy of the prospectus or offering  circular was not made available to
the Holder and such current copy of the  prospectus or offering  circular  would
have cured the defect  giving  rise to such loss,  claim,  damage or  liability.
Notwithstanding the foregoing, in no event shall a Holder be liable for any such
claims,  losses,  damages or liabilities  in excess of the proceeds  received by
such Holder in the offering, except in the event of fraud by such Holder.

                           (c) Each party entitled to indemnification under this
Section 5.6 (the "Indemnified Party") shall give notice to the party required to
provide   indemnification   (the  "Indemnifying   Party")  promptly  after  such
Indemnified Party has actual knowledge of any claim as to which indemnity may be
sought,  and shall  permit the  Indemnifying  Party to assume the defense of any
such claim or any litigation resulting therefrom,  provided that counsel for the
Indemnifying  Party,  who shall conduct the defense of such claim or litigation,
shall  be  approved  by  the   Indemnified   Party  (whose  approval  shall  not
unreasonably  be withheld),  and the  Indemnified  Party may participate in such
defense at such  Indemnified  Party's  expense,  and  provided  further that the
failure of any  Indemnified  Party to give notice as provided  herein  shall not
relieve the Indemnifying  Party of its obligations under this Agreement,  unless
such failure is materially  prejudicial to the  Indemnifying  Party in defending
such claim or  litigation.  An  Indemnifying  Party  shall not be liable for any
settlement of an action or claim  effected  without its written  consent  (which
consent will not be unreasonably withheld).

                           (d)  If the  indemnification  provided  for  in  this
Section 5.6 is held by a court of competent jurisdiction to be unavailable to an
Indemnified Party with respect to any loss,


                                       17


<PAGE>

liability,  claim, damage or expense referred to therein,  then the Indemnifying
Party,  in  lieu  of  indemnifying  such  Indemnified  Party  thereunder,  shall
contribute to the amount paid or payable by such  Indemnified  Party as a result
of such loss,  liability,  claim,  damage or expense  in such  proportion  as is
appropriate to reflect the relative fault of the  Indemnifying  Party on the one
hand and of the Indemnified Party on the other in connection with the statements
or omissions which resulted in such loss, liability, claim, damage or expense as
well as any other relevant equitable  considerations.  The relative fault of the
Indemnifying Party and of the Indemnified Party shall be determined by reference
to,  among other  things,  whether the untrue or alleged  untrue  statement of a
material  fact or the omission to state a material  fact relates to  information
supplied by the Indemnifying  Party or by the Indemnified Party and the parties'
relative intent, knowledge,  access to information and opportunity to correct or
prevent such statement or omission.

                  5.7 (a) Upon  receipt  of any notice  from the  Company of the
happening of any event requiring the preparation of a supplement or amendment to
a prospectus relating to Registrable Securities so that, as thereafter delivered
to the  Holders,  such  prospectus  will not  contain an untrue  statement  of a
material fact or omit to state any material  fact required to be stated  therein
or necessary to make the statements  therein not  misleading,  each Holder shall
forthwith  discontinue  disposition  of Registrable  Securities  pursuant to the
registration  statement  contemplated by Section 5.2 until its receipt of copies
of the  supplemented or amended  prospectus from the Company and, if so directed
by the Company,  each Holder shall deliver to the Company all copies, other than
permanent  file  copies  then in such  Holder's  possession,  of the  prospectus
covering  such  Registrable  Securities  current  at the time of receipt of such
notice.

                           (b) Each Holder  shall  suspend,  upon request of the
Company, any disposition of Registrable  Securities pursuant to the Registration
Statement and prospectus  contemplated  by Section 5.2 during (i) any period not
to exceed two 30-day periods within any one 12-month period the Company requires
in connection with a primary underwritten offering of equity securities and (ii)
any period,  not to exceed one 45-day period per  circumstance  or  development,
when the Company determines in good faith that offers and sales pursuant thereto
should  not  be  made  by  reason  of  the  presence  of  material   undisclosed
circumstances or developments with respect to which the disclosure that would be
required in such a prospectus is premature,  would have an adverse effect on the
Company or is otherwise inadvisable.

                           (c)  As  a  condition   to  the   inclusion   of  its
Registrable   Securities,   each  Holder  shall  furnish  to  the  Company  such
information   regarding  such  Holder,  the  Securities  of  the  Company  owned
beneficially or of record by such holder and the  distribution  proposed by such
Holder  as the  Company  may  request  in  writing  or as shall be  required  in
connection with any  registration,  qualification  or compliance  referred to in
this Article V.

                           (d) Each Holder hereby covenants with the Company (i)
not to make any sale of the Registrable  Securities without  effectively causing
the prospectus delivery requirements under the Act to be satisfied,  and (ii) if
such Registrable Securities are to be sold by any method or


                                       18


<PAGE>

in any  transaction  other than on a national  securities  exchange,  the Nasdaq
National Market,  Nasdaq SmallCap Market or in the  over-the-counter  market, in
privately  negotiated  transactions,  or in a combination  of such  methods,  to
notify the  Company at least five (5)  business  days prior to the date on which
the Holder first offers to sell any such Registrable Securities.

                           (e) Each  Holder  acknowledges  and  agrees  that the
Registrable  Securities sold pursuant to the Registration Statement described in
this Section are not  transferable  on the books of the Company unless the stock
certificate   submitted  to  the  transfer  agent  evidencing  such  Registrable
Securities  is  accompanied  by a  certificate  reasonably  satisfactory  to the
Company  to the effect  that (i) the  Registrable  Securities  have been sold in
accordance  with  such  Registration  Statement  and  (ii)  the  requirement  of
delivering a current prospectus has been satisfied.

                           (f)  Each  Holder  shall  not take  any  action  with
respect to any  distribution  deemed to be made  pursuant  to such  registration
statement, which would constitute a violation of Regulation M under the Exchange
Act or any other applicable rule, regulation or law.

                           (g) At the end of the period during which the Company
is  obligated  to keep the  Registration  Statement  current  and  effective  as
described  above,  the  Holders  of  Registrable   Securities  included  in  the
Registration  Statement  shall  discontinue  sales of  shares  pursuant  to such
Registration  Statement upon receipt of notice from the Company of its intention
to remove from  registration the shares covered by such  Registration  Statement
which remain unsold,  and such Holders shall notify the Company of the number of
shares  registered  which remain unsold  immediately upon receipt of such notice
from the Company.

                  5.8  With a view  to  making  available  to  the  Holders  the
benefits of certain rules and  regulations of the  Commission  which at any time
permit  the  sale  of  the   Registrable   Securities  to  the  public   without
registration, the Company shall use its reasonable best efforts:

                           (a) to make and keep public information available, as
those terms are understood and defined in Rule 144 under the Act, at all times;

                           (b) to file with the  Commission  in a timely  manner
all reports and other documents  required of the Company under the Exchange Act;
and

                           (c)  so  long  as  a  Holder  owns  any  unregistered
Registrable Securities,  to furnish to such Holder upon any reasonable request a
written  statement by the Company as to its  compliance  with Rule 144 under the
Act,  and of the  Exchange  Act, a copy of the most recent  annual or  quarterly
report of the Company,  and such other  reports and  documents of the Company as
such Holder may reasonably  request in availing itself of any rule or regulation
of the  Commission  allowing  a  Holder  to sell  any  such  securities  without
registration.


                                       19


<PAGE>

                  5.9 The rights to cause the  Company to  register  Registrable
Securities  granted  to the  Holders by the  Company  under  Section  5.1 may be
assigned in full by a Holder in connection with a transfer by such Holder of its
Registrable  Securities,  provided  that (i) such  transfer  shall  otherwise be
effected in accordance  with  applicable  securities  laws and Section 6.9; (ii)
such Holder gives prior written notice to the Company; and (iii) such transferee
agrees to  comply  with the terms and  provisions  of this  Agreement,  and such
transfer is otherwise in compliance with this Agreement.  Except as specifically
permitted  by  this  Section  5.9,  the  rights  of a  Holder  with  respect  to
Registrable  Securities as set out herein shall not be transferable to any other
Person, and any attempted transfer shall cause all rights of such Holder therein
to be forfeited.

                  5.10 With the  written  consent of the Company and the Holders
holding  at  least a  majority  of the  Registrable  Securities  that  are  then
outstanding,  any provision of this Article V may be waived (either generally or
in a particular instance, either retroactively or prospectively and either for a
specified period of time or  indefinitely) or amended.  Upon the effectuation of
each such waiver or amendment,  the Company shall  promptly give written  notice
thereof to the Holders,  if any, who have not previously received notice thereof
or consented thereto in writing.

VI.      ADDITIONAL CONTRACTUAL RIGHTS

                  6.1  Definitions.  As used in this  Agreement,  the  following
terms shall have the following meanings, unless the context otherwise requires:

                           (a)  "Article  VI  Rights"  shall  mean the rights to
receive all Reset  Issuances,  Semi-Annual  Issuances,  Dilution  Issuances  and
Qualified  Offering  Issuances and the right to exercise the Liquidation Put and
the Exchange Right, as provided herein.

                           (b)  "Change  of  Shares"  shall  mean any event that
necessitates  an adjustment to the Dilution Value (as defined below) pursuant to
Section 6.7 below.

                           (c) The "Closing Bid Price" of any security,  for any
trading day (as defined  below),  shall be the  reported  per share  closing bid
price,  regular way, of such  security on the relevant  Stock Market (as defined
below) on such  trading day or, if there were no  transactions  on such  trading
day, the average of the reported  closing bid and asked prices,  regular way, of
such security on the relevant Stock Market on such trading day.

                           (d)  "Dilution  Event"  shall  mean  any  event  that
necessitates  an adjustment to the Dilution Value (as defined below) pursuant to
Section 6.6 below.

                           (e)  The  "Dilution  Value"  initially  shall  be the
lesser of (i) $0.50 and (ii) seventy-five percent (75%) of the Trading Price (as
defined  below)  immediately  preceding (A) the Initial  Closing  Date,  (B) any
interim  closing date or (C) the Final  Closing Date,  whichever is lowest.  The
Dilution  Value is subject to adjustment  pursuant to Sections 6.2, 6.6, 6.7 and
6.15.


                                       20


<PAGE>

                           (f) "Fair Market Value" of any asset  (including  any
security)  means the fair market  value  thereof as mutually  determined  by the
Company and the  Placement  Agent.  If the Company and the  Placement  Agent are
unable to reach  agreement on any  valuation  matter,  such  valuation  shall be
submitted to and determined by a nationally  recognized  independent  investment
bank selected by the Board of Directors of the Company and the  Placement  Agent
(or, if such selection  cannot be agreed upon  promptly,  or in any event within
ten  days,  then  such  valuation  shall  be  made  by a  nationally  recognized
independent  investment  banking  firm  selected  by  the  American  Arbitration
Association in New York City in accordance  with its rules),  the costs of which
valuation shall be paid for by the Company.

                           (g) The "Issuance Base Amount" for the Subscriber, at
any time, means the sum of (i) the product of the Offering  Quantity  multiplied
by the number of Units the  Subscriber  has  subscribed  for, (ii) the number of
shares  of any  Reset  Issuances  (as  defined  below)  made to such  Subscriber
occurring  before  such  time,  (iii) the  number  of shares of any  Semi-Annual
Issuances (as defined below) made to such Subscriber occurring before such time,
(iv) the number of shares of any Dilution  Issuances (as defined  below) made to
such Subscriber  occurring  before such time and (v) the number of shares of any
Qualified Offering Issuances (as defined below) made to such subscriber ocucring
before  such time  (with  appropriate  adjustments  for any Change of Shares and
subject to  reduction  pursuant  to Section  6.10).  For any  transferee  Rights
Holder,  the Issuance Base Amount, at any time, shall be the number of shares of
Common  Stock  related  to such  Article VI Rights as were  transferred  to such
Rights  Holder  plus the  number of shares  of any  Reset  Issuance,  SemiAnnual
Issuance,  Dilution Issuance and Qualified Offering Issuance made to such Rights
Holder occurring  subsequent to such transfer but before such time. The Issuance
Base Amount shall include Dilution  Issuances which would have been required but
for the operation of Paragraph 6.6(b)(i).

                           (h)   "Liquidation   Event"   shall   mean   any  (i)
liquidation,  dissolution  or winding up of the  Company,  whether  voluntary or
involuntary,  (ii) sale or other  disposition of all or substantially all of the
assets  of  the  Company  or  (iii)  any  consolidation,   merger,  combination,
reorganization  or other  transaction  in which the Company is not the surviving
entity or shares of Common Stock  constituting  more than fifty percent (50%) of
the voting  power of the  Company  are  exchanged  for or changed  into stock or
securities of another  entity,  cash and/or any other property  (clause (iii) of
this Subsection  being referred to as a "Merger  Transaction").  Notwithstanding
the above,  any  consolidation,  merger,  combination,  reorganization  or other
transaction  in  which  the  Company  is  not  the  surviving   entity  but  the
stockholders of the Company  immediately prior to such transaction own in excess
of 50% of the voting power of the corporation surviving such transaction and own
such  interest  in   substantially   the  same  proportions  as  prior  to  such
transaction,   shall  not  be  considered  a  Liquidation   Event  or  a  Merger
Transaction,  provided  that the  surviving  corporation  has  made  appropriate
provisions  acceptable  to the  Placement  Agent to ensure  that the  Article VI
Rights survive any such transaction.

                           (i)  "Market  Price" per share of Common  Stock shall
mean the average Closing Bid Price (adjusted, where appropriate,  for any Change
of Shares) for twenty (20)


                                       21


<PAGE>

consecutive  trading days,  ending with the trading day immediately prior to the
date as of which the Market Price is being determined;  provided,  however, that
if the prices  referred  to in the  definition  of Closing  Bid Price  cannot be
determined on any trading day, "Market Price" shall mean the Fair Market Value.

                           (j) The  "Post-Dilution  Common  Quantity"  means the
quotient of the Pre-  Dilution  Common Value (as defined  below)  divided by the
Dilution Value immediately following the relevant Dilution Event, Reset Event or
Qualified Offering Adjustment Event (as defined below).

                           (k) The "Pre-Dilution Common Value" means the product
of the  Issuance  Base  Amount  multiplied  by the  Dilution  Value  immediately
preceding  the  relevant  Dilution  Event,  Reset  Event or  Qualified  Offering
Adjustment Event (as defined below).

                           (l) "Rights  Holder" shall mean the Subscriber or any
Person who succeeds to such  Subscriber's  Article VI Rights pursuant to Section
6.9.

                           (m) The "Stock  Market"  shall mean,  with respect to
any security,  the principal national securities exchange on which such security
is listed or admitted to trading or, if such  security is not listed or admitted
to trading on any national securities  exchange,  shall mean The Nasdaq National
Market System or The Nasdaq SmallCap Market (collectively, "Nasdaq") or, if such
security is not quoted on Nasdaq,  shall mean the OTC Bulletin Board or, if such
security   is  not   quoted  on  the  OTC   Bulletin   Board,   shall  mean  the
over-the-counter  market as furnished by any NASD member firm selected from time
to time by the Company for that purpose.

                           (n) A  "trading  day"  shall  mean a day on which the
Stock Market is open for the transaction of business.

                           (o)  "Trading  Price" shall mean the lower of (i) the
average  Closing Bid Price of the Common  Stock for the thirty (30)  consecutive
trading days  immediately  preceding  the date as of which the Trading  Price is
being  determined  (with  appropriate  adjustments for any Change of Shares) and
(ii) the average  Closing Bid Price of the Common Stock for five (5) consecutive
trading days  immediately  preceding  the date as of which the Trading  Price is
being determined (with appropriate adjustments for any Change of Shares).

                           (p) The "Transfer  Agent"shall  mean  American  Stock
Transfer & Trust Company or the duly appointed  successor thereto serving as the
transfer agent for the Common Stock.

                  6.2 Reset. (a) The Dilution Value in effect  immediately prior
to the date that is 12 months after the Final  Closing  Date (the "Reset  Date")
shall be adjusted  and reset  effective as of the Reset Date if the Market Price
of the Common Stock as of the Reset Date (the "12-Month  Trading Price") is less
than 140% of the then applicable Dilution Value (a "Reset Event"). Upon the


                                       22


<PAGE>

occurrence of a Reset Event,  the Dilution Value shall be reduced to be equal to
the greater of (A) the 12-Month  Trading Price  divided by 1.40,  and (B) 25% of
the then applicable Dilution Value.

                           (b) Within  fifteen (15) days of the Reset Date,  the
Company  shall prepare a certificate  signed by the Chief  Executive  Officer or
President, and by the Treasurer or an Assistant Treasurer or the Secretary or an
Assistant  Secretary,  of the Company setting forth the Dilution Value as of the
Reset  Date,  showing in  reasonable  detail the facts upon which such  Dilution
Value is based, and such certificate  shall forthwith be filed with the Transfer
Agent. A notice  stating that the Dilution  Value has been adjusted  pursuant to
this  paragraph,  or that no  adjustment  is  necessary,  and setting  forth the
Dilution  Value in effect as of the Reset  Date shall be mailed as  promptly  as
practicable  after the Reset Date by the Company to all Rights  Holders at their
last addresses as they shall appear in the Transfer Agent's record books.

                  6.3 Reset  Issuance.  If there is any  change in the  Dilution
Value as a result of Subsection  6.2(a),  then, on such date,  the Company shall
issue to the  Rights  Holder a number  of shares of  Common  Stock  (the  "Reset
Issuance")  equal to the difference  between the  Post-Dilution  Common Quantity
minus the Issuance Base Amount.

                  6.4 Semi-Annual  Issuances.  On each six month  anniversary of
the Reset Date (or the next  succeeding  business  day), the Company shall issue
(each a  "Semi-Annual  Issuance")  to the  Rights  Holder a number  of shares of
Common Stock equal to 5% of the Issuance Base Amount on the applicable six month
anniversary date.

                  6.5 Dilution  Issuances.  Upon the  occurrence of any Dilution
Event, the Company shall issue (each a "Dilution Issuance") to the Rights Holder
a number of shares of Common Stock equal to the difference of the  Post-Dilution
Common Quantity minus the Issuance Base Amount.

                  6.6      Anti-Dilution Adjustments.

                           (a)  Except  as  otherwise   provided  in  Subsection
6.6(c),  in the event the Company shall,  at any time or from time to time after
the date hereof,  sell or issue any shares of Common  Stock for a  consideration
per share less than either (i) the Dilution  Value in effect on the date of such
sale or issuance or (ii) the Market  Price of the Common Stock as of the date of
the sale or issuance  (any such sale or issuance a "Dilutive  Issuance"),  then,
and thereafter upon each further Dilutive Issuance, the Dilution Value in effect
immediately prior to such Dilutive Issuance shall be changed to a price (rounded
to the nearest cent)  determined  by  multiplying  the Dilution  Value in effect
immediately prior thereto by a fraction, the numerator of which shall be the sum
of the number of shares of Common  Stock  outstanding  immediately  prior to the
Dilutive  Issuance and the number of shares of Common Stock which the  aggregate
consideration received (determined as provided in Paragraph 6.6(b)(v) below) for
the issuance of such additional  shares would purchase at the greater of (x) the
Dilution Value in effect on the date of such issuance or (y) the Market Price of
the Common  Stock as of such date,  and the  denominator  of which  shall be the
number of shares of


                                       23


<PAGE>

Common  Stock  outstanding   immediately  after  the  Dilutive  Issuance.   Such
adjustment shall be made successively whenever such an issuance is made.

                           (b) For purposes of Subsection  6.6(a), the following
Paragraphs (i) to (v) shall also be applicable:

                                    (i)  No  adjustment  of the  Dilution  Value
shall be made unless such adjustment  would require a decrease of at least $.01;
provided that any  adjustments  which by reason of this Paragraph  6.6(b)(i) are
not  required to be made shall be carried  forward and shall be made at the time
of and  together  with the  next  subsequent  adjustment  which,  together  with
adjustments so carried forward, shall require a decrease of at least $.01 in the
Dilution Value then in effect hereunder.

                                    (ii)  In  case  of (A)  the  sale  or  other
issuance by the Company  (including  as a component  of a unit) of any rights or
warrants to  subscribe  for or  purchase,  or any options for the  purchase  of,
Common Stock or any securities convertible into or exchangeable for Common Stock
(such  securities  convertible,  exercisable or  exchangeable  into Common Stock
being  herein  called  "Convertible  Securities"),  or (B) the  issuance  by the
Company,  without the receipt by the Company of any consideration  therefor,  of
any rights or  warrants to  subscribe  for or  purchase,  or any options for the
purchase of, Common Stock or Convertible Securities, whether or not such rights,
warrants  or  options,  or the right to convert  or  exchange  such  Convertible
Securities,  are immediately  exercisable,  and the  consideration per share for
which  Common Stock is issuable  upon the  exercise of such rights,  warrants or
options  or upon the  conversion  or  exchange  of such  Convertible  Securities
(determined by dividing (x) the minimum aggregate consideration, as set forth in
the instrument  relating thereto,  without regard to any antidilution or similar
provisions contained therein for a subsequent adjustment of such amount, payable
to the Company upon the exercise of such rights,  warrants or options,  plus the
consideration  received by the Company for the  issuance or sale of such rights,
warrants or  options,  plus,  in the case of such  Convertible  Securities,  the
minimum  aggregate  amount,  as set forth in the  instrument  relating  thereto,
without regard to any antidilution or similar provisions contained therein for a
subsequent adjustment of such amount, of additional consideration, if any, other
than such  Convertible  Securities,  payable  upon the  conversion  or  exchange
thereof,  by (y) the  total  maximum  number,  as set  forth  in the  instrument
relating  thereto,  without  regard to any  antidilution  or similar  provisions
contained  therein for a  subsequent  adjustment  of such  amount,  of shares of
Common Stock  issuable upon the exercise of such rights,  warrants or options or
upon the conversion or exchange of such Convertible Securities issuable upon the
exercise of such  rights,  warrants or options) is less than either the Dilution
Value or the Market  Price of the Common Stock as of the date of the issuance or
sale of such  rights,  warrants or options,  then such total  maximum  number of
shares of Common Stock  issuable  upon the exercise of such rights,  warrants or
options or upon the conversion or exchange of such Convertible Securities (as of
the date of the issuance or sale of such rights,  warrants or options)  shall be
deemed to be  "Common  Stock" for  purposes  of  Subsection  6.6(a) and shall be
deemed to have been sold for an amount equal


                                       24


<PAGE>

to such  consideration  per share and shall  cause an  adjustment  to be made in
accordance with Subsection 6.6(a).

                                    (iii) In case of the sale or other  issuance
by the  Company  of any  Convertible  Securities,  whether  or not the  right of
conversion or exchange thereunder is immediately exercisable,  and the price per
share for which Common Stock is issuable upon the conversion or exchange of such
Convertible   Securities  (determined  by  dividing  (x)  the  total  amount  of
consideration  received  by  the  Company  for  the  sale  of  such  Convertible
Securities,  plus the minimum  aggregate  amount, as set forth in the instrument
relating  thereto,  without  regard to any  antidilution  or similar  provisions
contained  therein for a subsequent  adjustment  of such amount,  of  additional
consideration,  if any, other than such Convertible Securities, payable upon the
conversion or exchange thereof, by (y) the total maximum number, as set forth in
the instrument  relating  thereto without regard to any  antidilution or similar
provisions  contained  therein for a subsequent  adjustment  of such amount,  of
shares  of  Common  Stock  issuable  upon the  conversion  or  exchange  of such
Convertible  Securities)  is less than either the  Dilution  Value or the Market
Price of the Common  Stock as of the date of the sale or other  issuance of such
Convertible Securities, then such total maximum number of shares of Common Stock
issuable upon the conversion or exchange of such  Convertible  Securities (as of
the date of the sale of such  Convertible  Securities)  shall  be  deemed  to be
"Common  Stock" for  purposes of  Subsection  6.6(a) and shall be deemed to have
been sold for an amount equal to such consideration per share and shall cause an
adjustment to be made in accordance with Subsection 6.6(a).

                                    (iv) In case the  Company  shall  modify the
rights of conversion,  exchange or exercise of any of the securities referred to
in Paragraphs (ii) or (iii) of this Subsection 6.6(b) or any other securities of
the Company convertible, exchangeable or exercisable for shares of Common Stock,
for any reason  other than an event that  would  require  adjustment  to prevent
dilution, so that the consideration per share received by the Company after such
modification  is less than either the Dilution  Value or the Market Price of the
Common Stock as of the date prior to such modification, then such securities, to
the extent not theretofore exercised, converted or exchanged, shall be deemed to
have expired or terminated  immediately  prior to the date of such  modification
and the Company  shall be deemed for  purposes of  calculating  any  adjustments
pursuant to this  Section 6.6 to have issued such new  securities  upon such new
terms on the date of modification.  Such adjustment shall become effective as of
the date upon which such  modification  shall take effect.  On the expiration or
cancellation  of any  such  right,  warrant  or  option  or the  termination  or
cancellation  of any such  right to  convert or  exchange  any such  Convertible
Securities,  the  Dilution  Value then in effect  hereunder  shall  forthwith be
readjusted to such Dilution Value as would have obtained (A) had the adjustments
made upon the issuance or sale of such rights, warrants,  options or Convertible
Securities been made upon the basis of the issuance of only the number of shares
of Common Stock  theretofore  actually  delivered  (and the total  consideration
received therefor) upon the exercise of such rights, warrants or options or upon
the  conversion  or  exchange  of  such  Convertible   Securities  and  (B)  had
adjustments  been  made on the basis of the  Dilution  Value as  adjusted  under
clause (A) of this sentence for all transactions (which would have affected such


                                       25


<PAGE>

adjusted  Dilution  Value)  made  after  the  issuance  or sale of such  rights,
warrants, options or Convertible Securities.

                                    (v) In case of the  sale  of any  shares  of
Common Stock,  any Convertible  Securities,  any rights or warrants to subscribe
for or purchase, or any options for the purchase of, Common Stock or Convertible
Securities,  the consideration  received by the Company therefor shall be deemed
to be the gross sales price  therefor  without  deducting  therefrom any expense
paid or incurred by the Company or any underwriting  discounts or commissions or
concessions paid or allowed by the Company in connection therewith. In the event
that any securities  shall be issued in connection with any other  securities of
the Company,  together comprising one integral  transaction in which no specific
consideration  is allocated among the  securities,  then each of such securities
shall be deemed  to have  been  issued  for such  consideration  as the Board of
Directors of the Company determines in good faith; provided, however that if the
Placement Agent disagrees with such determination,  the Company shall retain, at
its own  expense,  an  independent  investment  banking firm  acceptable  to the
Placement Agent for the purpose of obtaining an appraisal.

                           (c)  Notwithstanding  any other provision  hereof, no
adjustment to the Dilution Value will be made:

                                    (i) upon the  exercise of any of the options
outstanding on the date hereof under the Company's  existing stock option plans;
or

                                    (ii)  upon  the   issuance  or  exercise  of
options  which  may  hereafter  be  granted  with the  approval  of the Board of
Directors,  or  exercised,  under any  employee  benefit  plan of the Company to
officers,  directors,  consultants  or employees,  but only with respect to such
options as are exercisable at prices no lower than the Closing Bid Price (or, if
the  prices  referenced  in the  definition  of  Closing  Bid  Price  cannot  be
determined,  the Fair Market  Value) of the Common Stock as of the date of grant
thereof; or

                                    (iii)  upon  issuance  or  exercise  of  the
Placement Options or the Advisory Options,  upon the conversion the New Warrants
(as defined in Exhibits B and C to the Securities Purchase Agreement dated as of
June 30, 1997), upon the issuance or exercise of the Subscription  Common or the
Class C Warrants to be issued (i) on or prior to the Final  Closing Date or (ii)
pursuant to the  exercise of the  Placement  and Advisory  Options,  or upon the
issuance,  conversion  or the  exercise of any Series A  Preferred  Stock or New
Warrants or Class C Warrants approved in writing by the Placement Agent; or

                                    (iv)  upon the  issuance  or sale of  Common
Stock or Convertible  Securities pursuant to the exercise of any rights, options
or  warrants  to  receive,  subscribe  for or  purchase,  or any options for the
purchase of, Common Stock or Convertible Securities, whether or not such rights,
warrants  or  options  were  outstanding  on the  Final  Closing  Date  or  were
thereafter


                                       26


<PAGE>

issued or sold,  provided that an adjustment  was either made or not required to
be made in accordance with Subsection  6.6(a) in connection with the issuance or
sale of such securities or any modification of the terms thereof; or

                                    (v)  upon  the  issuance  or sale of  Common
Stock upon conversion or exchange of any Convertible  Securities,  provided that
any  adjustments  required  to be  made  upon  the  issuance  or  sale  of  such
Convertible  Securities or any  modification  of the terms thereof were so made,
and whether or not such  Convertible  Securities  were  outstanding on the Final
Closing Date or were thereafter issued or sold; or

                                    (vi)  upon the  issuance  of stock  that may
hereafter  be  purchased  or sold with the  approval of the Board of  Directors,
under  the  1993  Employee  Stock  Purchase  Plan of the  Company  to  officers,
directors, consultants or employees, but only with respect to such shares as are
purchased  and/or sold in accordance  with the current plan and at the prices no
lower than eighty-five percent (85%) of the Closing Bid Price (or, if the prices
referenced in the definition of Closing Bid Price cannot be  determined,  85% of
the Fair Market  Value) of the Common  Stock as of the date of  purchase  and/or
sale thereof;

                           Paragraph  6.6(b)(iv) shall nevertheless apply to any
modification  of the rights of  conversion,  exchange  or exercise of any of the
securities  referred  to  in  this  Subsection  6.6(c),  except  that  Paragraph
6.6(b)(iv)  shall not apply to any  modification  of the  rights of  conversion,
exchange or  exercise of the  securities  excepted  by  Paragraph  (iii) of this
Subsection  6.6(c) that are required by the original  terms of those  respective
instruments.

                           (d) As used in this  Section  6.6,  the term  "Common
Stock" shall mean and include the Company's  Common Stock authorized on the date
of the first  original  issue of the Units and shall also  include  any  capital
stock of any  class of the  Company  thereafter  authorized  which  shall not be
limited to a fixed sum or  percentage  in  respect of the rights of the  holders
thereof to participate in dividends and in the  distribution  of assets upon the
voluntary liquidation, dissolution or winding up of the Company.

                           (e) The Company  from time to time may  decrease  the
Dilution Value by any amount for any period of time if the period is at least 20
days and if the decrease is irrevocable during the period. Whenever the Dilution
Value is so decreased,  the Company shall mail to the Rights Holders a notice of
the decrease at least 15 days before the date the decreased Dilution Value takes
effect,  and such notice shall state the decreased Dilution Value and the period
it will be in effect.

                           The Company may make such  decreases  in the Dilution
Value,  in addition to those required or allowed by this Article VI, as shall be
determined by it, as evidenced by a resolution of the Board of Directors,  to be
advisable  in order to avoid or  diminish  any  income  tax to holders of Common
Stock resulting from any dividend or distribution of stock or issuance of


                                       27


<PAGE>

rights or warrants to purchase or subscribe  for stock or from any event treated
as such for income tax purposes.

                  6.7  Change of Shares  Adjustments.  In the event the  Company
shall,  at any time or from  time to time  after the date  hereof  (i) issue any
shares of Common  Stock as a stock  dividend to the  holders of Common  Stock or
(ii) subdivide or combine the outstanding  shares of Common Stock into a greater
or lesser number of shares (any such issuance,  subdivision or combination being
herein called a "Change of Shares"), then the Dilution Value shall be changed to
a price  (rounded to the nearest cent)  determined by  multiplying  the Dilution
Value in effect  immediately  prior to such Change of Shares by a fraction,  the
numerator  of which  shall be the number of shares of Common  Stock  outstanding
immediately  prior to the Change of Shares and the denominator of which shall be
the  number of shares of Common  Stock  outstanding  immediately  following  the
Change of Shares.

                  6.8  Liquidation  Put.  (a) The Rights  Holder may require the
Company to repurchase  with cash any number (not to exceed such Rights  Holder's
Issuance Base Amount) of shares of Common Stock then owned by such Rights Holder
for 140% of the aggregate Dilution Value of such shares;  provided,  however, in
the event of a Merger  Transaction,  any repurchase pursuant to this Section 6.8
may be paid in cash,  property (valued as provided in Subsection 6.8 (d)) and/or
securities  (valued as provided in Subsection  6.8 (d)) of the entity  surviving
such Merger Transaction.  Notwithstanding the foregoing,  the Company shall have
no obligation to repurchase Common Stock owned by the Rights Holders,  if and to
the extent  that the  Company is not  permitted  to do so under the terms of the
Series A Preferred Stock.

                           (b) The Rights  Holder  covenants not to exercise the
Liquidation Put unless a Liquidation Event has occurred.

                           (c) The Rights  Holder's  Article VI Rights  shall be
terminated  to the pro rata  extent  of any  exercise  of such  Rights  Holder's
Liquidation Put.

                           (d) Any  securities or other property to be delivered
to the Rights Holder pursuant to this Section 6.8 shall be valued as follows:

                                    (i)  Securities not subject to an investment
letter or other similar restriction on free marketability:

                                    (A)     If  actively  traded  on  the  Stock
                                            Market, the value shall be deemed to
                                            be  the   Market   Price   of   such
                                            securities as of the third day prior
                                            to the date of valuation.

                                    (B)     If not actively  traded on the Stock
                                            Market,  the value shall be the Fair
                                            Market Value of such securities.


                                       28


<PAGE>

                                    (ii) For  securities  for which  there is an
active  public  market but which are  subject to an  investment  letter or other
restrictions  on free  marketability,  the value shall be the Fair Market  Value
thereof, determined by discounting appropriately the Market Price thereof.

                                    (iii)  For all other  securities,  the value
shall be the Fair Market Value thereof.

                  6.9  Transfer  of Rights  Under  This  Article  VI. The Rights
Holder's  Article VI Rights are not  transferable  unless the transferee will be
both the record and  beneficial  owner of the related  Common Stock and executes
and delivers to the Company a counterpart to this Agreement agreeing to be bound
by the obligations of the Subscriber hereunder. Any such transferee must provide
his or her  name  and  address,  which  name  and  address  must  be that of the
beneficial  owner,  to the  Company.  Any  transfer of Common  Stock and related
Article VI Rights must be performed in  accordance  with  applicable  securities
laws and  regulations,  and the  transferor  must  provide the  Company  with an
opinion of counsel, satisfactory to the Company, to that effect. Furthermore, no
transfer  of Article VI Rights may be made  relating  to fewer  shares of Common
Stock than the quotient of $25,000 divided by the Dilution Value.  ANY PURPORTED
TRANSFER OF ARTICLE VI RIGHTS NOT IN  COMPLIANCE  WITH THIS SECTION 6.9 SHALL BE
NULL AND VOID AND THE RIGHTS HOLDER SHALL FORFEIT ALL ARTICLE VI RIGHTS  RELATED
TO SUCH  TRANSFERRED  COMMON STOCK.  Upon, and to the extent of, any transfer of
Common Stock  without the related  Article VI Rights,  such  related  Article VI
Rights shall terminate.

                  6.10 Adjustments to Issuance Base Amount. Upon the termination
of any of the Rights Holder's Article VI Rights,  such Rights Holder's  Issuance
Base Amount shall be proportionally reduced.

                  6.11     Notices.

                           (a)  After  each  adjustment  of the  Dilution  Value
pursuant to Sections 6.2, 6.6, 6.7 and 6.15 the Company will promptly  prepare a
certificate  signed by the Chief  Executive  Officer  or  President,  and by the
Treasurer or an Assistant Treasurer or the Secretary or an Assistant  Secretary,
of the Company  setting forth:  (i) the Dilution Value as so adjusted and (ii) a
brief statement of the facts  accounting for such  adjustment.  The Company will
promptly file such certificate with the Transfer Agent and cause a brief summary
thereof to be sent by ordinary  first class mail to each Rights Holder at his or
her last address as it shall appear on the Transfer  Agent's  record  books.  No
failure to mail such  notice nor any defect  therein or in the  mailing  thereof
shall affect the validity of such adjustment. The affidavit of an officer of the
Transfer  Agent or the  Secretary or an Assistant  Secretary of the Company that
such  notice has been  mailed  shall,  in the  absence of fraud,  be prima facie
evidence  of the  facts  therein  stated.  The  Transfer  Agent  may rely on the
information  in the  certificate  as  true  and  correct  and  has no  duty  nor
obligation  independently  to verify the  amounts or  calculations  therein  set
forth.


                                       29


<PAGE>

                           (b) After any  adjustment in the Issuance Base Amount
resulting  from  (i)  any  Reset  Issuances,   Semi-Annual  Issuances,  Dilution
Issuances or Qualified  Offering Issuance (ii) any Change in Shares or (iii) any
termination  of  Article  VI  Rights,   the  Company  will  promptly  prepare  a
certificate  signed by the Chief  Executive  Officer  or  President,  and by the
Treasurer or an Assistant Treasurer or the Secretary or an Assistant  Secretary,
of the Company setting forth: (x) the Issuance Base Amount immediately preceding
and succeeding such adjustment and (y) a brief statement of the facts accounting
for such  adjustment.  The Company will promptly file such  certificate with the
Transfer  Agent and cause a brief summary  thereof to be sent by ordinary  first
class mail to each Rights  Holder at his or her last  address as it shall appear
on the Transfer  Agent's  record  books.  No failure to mail such notice nor any
defect  therein or in the  mailing  thereof  shall  affect the  validity of such
adjustment.  The affidavit of an officer of the Transfer  Agent or the Secretary
or an Assistant Secretary of the Company that such notice has been mailed shall,
in the absence of fraud,  be prima facie  evidence of the facts therein  stated.
The Transfer Agent may rely on the  information  in the  certificate as true and
correct and has no duty nor  obligation  independently  to verify the amounts or
calculations therein set forth.

                  6.12 Treasury Stock. Any Reset Issuance,  Semi-Annual Issuance
and  Dilution  Issuance  shall be made  with  duly  authorized,  fully-paid  and
non-assessable  shares of Common  Stock,  in  accordance  with Delaware Law, and
shall be drawn from the treasury  stock of the Company to the extent  available.
The Company shall  promptly  furnish to the Placement  Agent,  upon request,  an
opinion of  counsel  reasonably  satisfactory  to the  Placement  Agent that the
requirements  of this Section 6.12 have been met as to any issuance  referred to
herein. The Company shall not otherwise sell, issue,  cancel or otherwise impair
any of its treasury stock without the Placement Agent's prior written consent.

                  6.13 Mandatory  Termination of Article VI Rights.  At any time
on or after the Reset Date, the Company may cause the Rights Holder's Article VI
Rights to be  terminated  if the  Market  Price of the Common  Stock  shall have
exceeded 300% of the then applicable Dilution Value as of the third business day
prior to the date of notice of termination. No greater than 60 nor fewer than 20
days prior to the date of any such mandatory termination,  notice by first class
mail, postage prepaid,  shall be given to the Rights Holders,  addressed to such
Rights  Holders at their last  addresses  as they shall  appear in the  Transfer
Agent's  record  books.  Each  such  notice  shall  specify  the date  fixed for
termination. Any notice which is mailed as herein provided shall be conclusively
presumed  to have been duly given by the  Company on the date  deposited  in the
mail,  whether  or not the Rights  Holder  receives  such  notice;  and  failure
properly  to give such  notice by mail,  or any  defect in such  notice,  to any
Rights  Holders  shall  not  affect  the  validity  of the  proceedings  for the
termination of any other Rights Holders' Article VI Rights.

                  6.14 With the  written  consent of the  Company and the Rights
Holders holding at least a majority of the issued and  outstanding  Common Stock
subject to Article VI Rights,  any  provision  of this  Article VI may be waived
(either  generally  or  in  a  particular  instance,   either  retroactively  or
prospectively  and either for a  specified  period of time or  indefinitely)  or
amended.


                                       30


<PAGE>

Upon the  effectuation  of each such  waiver or  amendment,  the  Company  shall
promptly give written notice thereof to the Rights Holders, if any, who have not
previously received notice thereof or consented thereto in writing.

                  6.15  Optional   Exchange/Reset.   (a)  Upon  the  receipt  of
requisite approvals, if any, from the stockholders of the Company, the shares of
Common Stock acquired hereunder may be exchanged (the "Exchange Right"),  at the
option of each Rights Holder,  upon the  completion of a Qualified  Offering (as
defined  below) into Qualified  Offering  Securities  (as defined  below).  Upon
exchange of their shares of Common Stock,  up to the Issuance  Base Amount,  the
exchanging  Rights  Holders  shall  receive  an  amount  of  Qualified  Offering
Securities equal to the quotient of (i) the Issuance Base Amount being exchanged
multiplied by the Dilution Value at the time of the Qualified Offering,  divided
by (ii) the Qualified Offering Securities Price (as defined below) multiplied by
 .75 (the  "Exchange  Price");  provided,  however,  that in the  event  that the
Exchange Price divided by the Underlying  Common Stock Amount (as defined below)
is less than the  greater  of (a) 50% of the  Offering  Price and (b) 50% of the
average  closing  bid price of the  Common  Stock for the  twenty  trading  days
immediately  preceding the date of such exchange (the "Floor  Price"),  then the
Exchange Price shall equal the Floor Price  multiplied by the Underlying  Common
Stock Amount.

As used herein the following terms shall have the following meanings:

(i)      "Underlying  Common Stock  Amount"  shall equal the number of shares of
         Common  Stock  and  Common  Stock  underlying   Convertible  Securities
         included  as part of each  Qualified  Offering  Security  but shall not
         include Common Stock underlying  warrants or options to purchase Common
         Stock  or to  purchase  a  Convertible  Security,  whether  or not such
         warrant or option  contains a right to exercise  such warrant or option
         by the  delivery  of shares  deemed  purchased  thereunder,  including,
         without limitation, by a cashless exercise.

(ii)     "Qualified Offering Security" and "Qualified Offering Securities" shall
         mean  the  security  or  securities  (whether  they are  Common  Stock,
         Convertible  Securities,  units  of  Common  Stock  and/or  Convertible
         Securities  (as defined  below) and warrants or other  similar  rights)
         issued or sold in the Qualified  Offering  (including  any  contractual
         rights granted to investors in connection with the Qualified Offering).

(iii)    "Qualified  Offering"  shall mean the sale or series of sales of equity
         securities of the Company next  occurring  after the Final Closing Date
         of  this  Offering,   including,  without  limitation,   Common  Stock,
         warrants,   units  of  Common  Stock  and  warrants,  other  securities
         exchangeable,  convertible or exercisable for Common Stock, alone or in
         units, whether in a public offering or private placement, raising gross
         proceeds in excess of $2,500,000;  excluding, however, at the Company's
         option, a firm commitment underwritten public offering.


                                       31


<PAGE>

(iv)     "Qualified  Offering  Securities Price" shall mean the selling price to
         investors for each Qualified Offering Security.

(v)      "Convertible  Security"  and  "Convertible  Securities"  shall mean any
         security  convertible  into or  exchangeable  for a share or  shares of
         Common Stock  without the payment of any  additional  consideration  in
         such  conversion or exchange  other than the delivery of such security,
         but shall not include a warrant or option to purchase  Common  Stock or
         to  purchase a  Convertible  Security,  whether or not such  warrant or
         option  contains  a right to  exercise  such  warrant  or option by the
         delivery of shares  deemed  purchased  thereunder,  including,  without
         limitation, by a cashless exercise.

                  (b) Upon and to the  extent  of any  exchange  into  Qualified
Offering securities as set forth in Section 6.15(a) above, the Article VI Rights
related to the exchanged Common Stock shall terminate.

                  (c) Upon the receipt of requisite approvals,  if any, from the
stockholders  of the  Company,  holders who elect not to exchange  their  Common
Stock upon a Qualified  Offering for Qualified Offering  Securities,  shall have
the  Dilution  Value  with  respect  to their  Article  VI  Rights  adjusted  (a
"Qualified  Offering  Adjustment  Event") to equal the Exchange  Price and shall
receive an additional  number of shares (the "Qualified  Offering  Issuance") of
Common  Stock  equal  to the  difference  between  (i) the  quotient  of (a) the
Issuance  Base Amount  multiplied  by the Dilution  Value in effect prior to the
date of  adjustment  divided by (b) the (x)  Exchange  Price  divided by (y) the
Underlying  Common Stock Amount,  and (ii) the Issuance Base Amount prior to the
date of adjustment;  provided,  however,  that no adjustment shall be made if it
would result in an increase in the Dilution Value.  Holders receiving  Qualified
Offering Issuance shall have Article VI Rights with respect to such shares.

VII.     MISCELLANEOUS

                  7.1 Any notice or other communication given hereunder shall be
deemed sufficient if in writing and sent by registered or certified mail, return
receipt  requested,  or  delivered  by hand against  written  receipt  therefor,
addressed to Procept, Inc., 840 Memorial Drive, Cambridge,  Massachusetts 02139,
Attn:  Stanley C. Erck, and to the Subscriber at the  Subscriber's  address indi
cated on the signature  page of this  Agreement and to any Rights Holders at his
or her last  address as it shall appear in the Transfer  Agent's  record  books.
Notices  shall be deemed to have been given or delivered on the date of mailing,
except notices of change of address, which shall be deemed to have been given or
delivered when received.

                  7.2 Except as provided in Section 5.10 above,  this  Agreement
shall not be  changed,  modified  or amended  except by a writing  signed by the
parties  to be  charged,  and this  Agreement  may not be  discharged  except by
performance in accordance  with its terms or by a writing signed by the party to
be charged.


                                       32


<PAGE>

                  7.3 Subject to the  provisions  of Sections  1.6, 5.9, 6.9 and
7.12,  this  Agreement  shall be  binding  upon and inure to the  benefit of the
parties hereto and to their respective heirs, legal representatives,  successors
and assigns.  In addition,  the  Placement  Agent is intended to be and shall be
third-party  beneficiary of the provisions hereof. This Agreement sets forth the
entire agreement and understanding  between the parties as to the subject matter
hereof  and  merges  and  supersedes  all  prior  discussions,   agreements  and
understandings of any and every nature among them.

                  7.4 Upon the execution  and delivery of this  Agreement by the
Subscriber,  this Agreement shall become a binding  obligation of the Subscriber
with respect to the purchase of Units as herein provided,  subject,  however, to
the right hereby  reserved by the Company to enter into the same agreements with
other subscribers and to add and/or delete other persons as subscribers.

                  7.5  NOTWITHSTANDING  THE PLACE  WHERE THIS  AGREEMENT  MAY BE
EXECUTED BY ANY OF THE PARTIES HERETO,  THE PARTIES EXPRESSLY AGREE THAT ALL THE
TERMS AND PROVISIONS  HEREOF SHALL BE CONSTRUED IN ACCORDANCE WITH, AND GOVERNED
BY, THE LAWS OF THE STATE OF NEW YORK WITHOUT  REGARD TO PRINCIPLES OF CONFLICTS
OF LAW. IN THE EVENT THAT A JUDICIAL PROCEEDING IS NECESSARY, THE EXCLUSIVE FORA
FOR RESOLVING DISPUTES ARISING OUT OF, OR RELATING TO, THIS AGREEMENT ARE EITHER
THE SUPREME  COURT OF THE STATE OF NEW YORK IN AND FOR THE COUNTY OF NEW YORK OR
THE FEDERAL COURTS FOR SUCH STATE AND COUNTY,  AND ALL RELATED APPELLATE COURTS,
THE PARTIES HEREBY  IRREVOCABLY  CONSENT TO THE  JURISDICTION OF SUCH COURTS AND
AGREE TO SAID VENUE.

                  7.6 In order to discourage frivolous claims, unless a claimant
in any proceeding  arising out of this Agreement  succeeds in  establishing  his
claim and  recovering a judgment  against  another party  (regardless of whether
such claimant succeeds against one of the other parties to the action), then the
other party shall be entitled to recover  from such  claimant  all of  its/their
reasonable legal costs and expenses  relating to such proceeding and/or incurred
in preparation therefor.

                  7.7 The  holding  of any  provision  of this  Agreement  to be
invalid or unenforceable by a court of competent  jurisdiction  shall not affect
any other  provision  of this  Agreement,  which shall  remain in full force and
effect.  If any  provision  of this  Agreement  shall be  declared by a court of
competent jurisdiction to be invalid,  illegal or incapable of being enforced in
whole  or in  part,  such  provision  shall  be  interpreted  so  as  to  remain
enforceable to the maximum extent permissible consistent with applicable law and
the remaining  conditions and provisions or portions thereof shall  nevertheless
remain in full force and effect and  enforceable  to the extent  they are valid,
legal and en forceable,  and no provisions  shall be deemed  dependent  upon any
other covenant or provision unless so expressed herein.

                  7.8 A waiver by either  party of a breach of any  provision of
this Agreement shall not operate, or be construed, as a waiver of any subsequent
breach by that same party.


                                       33


<PAGE>

                  7.9 The parties  shall  execute  and deliver all such  further
documents,  agreements  and  instruments  and shall take such other and  further
action as may be necessary or  appropriate  to carry out the purposes and intent
of this Agreement.

                  7.10  This   Agreement   may  be   executed  in  two  or  more
counterparts  each of which shall be deemed an original,  but all of which shall
together constitute one and the same instrument.

                  7.11 (a) The Subscriber  shall not issue any public  statement
with  respect to the  Subscriber's  investment  or  proposed  investment  in the
Company or the terms of any  agreement or covenant  between them and the Company
without the Company's prior written  consent,  except such disclosures as may be
required under applicable law or under any applicable order, rule or regulation.

                           (b)  The  Company   shall  not  disclose  the  names,
addresses or any other information  about the Subscriber,  except as required by
law;  provided,  that the Company may use the name (but not the  address) of the
Subscriber in the Registration Statement.

                  7.12  Nothing in this  Agreement  shall create or be deemed to
create any rights in any person or entity not a party to this Agreement,  except
(a) for the holders of Registrable  Securities,  and (b) for the Placement Agent
pursuant to Section  1.6(a) and where  otherwise  explicitly  noted,  including,
without limitation,  the provisions of Article V and Section 7.3 and (c) for any
Rights Holders to whom Article VI Rights were transferred pursuant to 6.9.

                  7.13 The  Company  acknowledges  and agrees  that  irreparable
damage  would  occur in the event  that any of the  provisions  of Article V and
Article VI of this Agreement were not performed in accordance  with its specific
terms or were  otherwise  breached and that such damage would not be compensable
in money damages and that it would be extremely  difficult or  impracticable  to
measure the resultant damages.  Accordingly, the Subscriber shall be entitled to
an injunction or  injunctions  with respect to the  provisions of this Agreement
and to enforce  specifically the terms and provisions hereof, in addition to any
other  remedy to which it may be entitled  at law or in equity,  and the Company
expressly  waives any defense  that a remedy in damages  would be  adequate  and
expressly  waives any requirement in an action for specific  performance for the
posting of a bond by the Subscriber bringing such action.

                  7.14 For Missouri Residents Only: the Units are not registered
under the laws of the state of  Missouri  and may only be  disposed of through a
licensed  broker-dealer.  It is a felony to sell  securities in violation of the
Missouri Securities Act.


                                       34


<PAGE>

VIII.    CONFIDENTIAL INVESTOR QUESTIONNAIRE

                  8.1 The Subscriber  represents and warrants that he, she or it
comes within one cate gory marked below, and that for any category  marked,  he,
she or it has  truthfully  set forth,  where  applicable,  the factual  basis or
reason the Subscriber comes within that category. ALL INFORMATION IN RESPONSE TO
THIS SECTION WILL BE KEPT STRICTLY  CONFIDEN  TIAL.  The  undersigned  agrees to
furnish any additional  information  which the Company deems neces sary in order
to verify the answers set forth below.

Category                   A  The   undersigned   is  an   individual   (not   a
                           partnership,  corporation, etc.) whose individual net
                           worth,  or joint  net worth  with his or her  spouse,
                           presently exceeds $1,000,000.

                           Explanation. In calculating net worth you may include
                           equity  in  personal   property   and  real   estate,
                           including your principal residence,  cash, short-term
                           investments, stock and securities. Equity in personal
                           property and real estate  should be based on the fair
                           market  value of such  property  less debt secured by
                           such property.

Category B                 The  undersigned is an individual (not a partnership,
                           corporation,  etc.) who had an  individual  income in
                           excess  of  $200,000  in each of the two most  recent
                           years,  or joint  income  with his or her  spouse  in
                           excess of  $300,000  in each of those  years (in each
                           case including foreign income,  tax exempt income and
                           full amount of capital gains and losses but excluding
                           any income of other family members and any unrealized
                           capital  appreciation)  and  has a  reasonable  expec
                           tation  of  reaching  the  same  income  level in the
                           current year.

Category                   C The undersigned is a director or executive  officer
                           of the  Company  which is  issuing  and  selling  the
                           Units.

Category D                 The  undersigned  is  a  bank;  a  savings  and  loan
                           association; insurance company; registered investment
                           company;  registered  business  development  company;
                           licensed small business  investment company ("SBIC");
                           or employee  benefit plan within the meaning of Title
                           1 of ERISA and (a) the investment decision is made by
                           a plan fiduciary which is either a bank,  savings and
                           loan  association,  insurance  company or  registered
                           investment  advisor, or (b) the plan has total assets
                           in excess of  $5,000,000  or is a self  directed plan
                           with investment decisions made solely by persons that
                           are accredited investors.


                                       35


<PAGE>

                                                              (describe entity)

Category                   E The undersigned is a private  business  development
                           company  as  defined  in  section  202(a)(22)  of the
                           Investment Advisors Act of 1940.



                                                              (describe entity)

Category                   F  The   undersigned   is   either   a   corporation,
                           partnership,   Massachusetts   business   trust,   or
                           non-profit organization within the meaning of Section
                           501(c)(3) of the Internal  Revenue Code, in each case
                           not formed for the specific  purpose of acquiring the
                           Units and with total assets in excess of $5,000,000.


                                                              (describe entity)

Category                   G The  undersigned  is a trust with  total  assets in
                           excess of  $5,000,000,  not formed  for the  specific
                           purpose of acquiring the Units, where the purchase is
                           directed  by a  "sophisticated  person" as defined in
                           Regulation 506(b)(2)(ii) under the Act.

Category                   H The  undersigned  is an entity (other than a trust)
                           all  the  equity  owners  of  which  are  "accredited
                           investors"   within   one  or  more   of  the   above
                           categories. If relying upon this Category alone, each
                           equity  owner must  complete a sepa rate copy of this
                           Agreement.



                                                              (describe entity)

Category                   I The undersigned is not within any of the categories
                           above and is therefore not an accredited investor.

The undersigned  agrees that the undersigned will notify the Company at any time
on or prior to the Final Closing Date in the event that the  representations and
warranties in this Agreement shall cease to be true, accurate and complete.


                                       36

<PAGE>

         8.2      SUITABILITY (please answer each question)

(a) For an  individual  Subscriber,  please  describe  your current  employment,
including the company by which you are employed and its principal business:

(b) For an  individual  Subscriber,  please  describe  any  college or  graduate
degrees held by you:

(c) For all Subscribers, please list types of prior investments:

(d) For all Subscribers, please state whether you have you participated in other
private placements before:

                   YES_______                         NO_______

(e) If your answer to question (d) above was "YES", please indicate frequency of
such prior participation in private placements of:

                              Public        Private      Public or Private
                             Companies     Companies     Biotechnology Companies

         Frequently
         Occasionally
         Never

(f) For  individual  Subscribers,  do you expect your current level of income to
significantly decrease in the foreseeable future:

                   YES_______                         NO_______

(g) For trust, corporate,  partnership and other institutional  Subscribers,  do
you expect  your  total  assets to  significantly  decrease  in the  foreseeable
future:


                                       37


<PAGE>


                   YES_______                         NO_______

(h) For all  Subscribers,  do you  have  any  other  investments  or  contingent
liabilities which you reasonably  anticipate could cause you to need sudden cash
requirements in excess of cash readily available to you:

                    YES_______                         NO_______

(i)  For all  Subscribers,  are you  familiar  with  the  risk  aspects  and the
non-liquidity  of  investments  such as the  securities  for  which  you seek to
subscribe?

                    YES_______                         NO_______

(j) For all  Subscribers,  do you  understand  that  there  is no  guarantee  of
financial  return on this  investment  and that you run the risk of losing  your
entire investment?

                    YES_______                         NO_______


         8.3      MANNER IN WHICH TITLE IS TO BE HELD. (circle one)

                             (a)    Individual Ownership
                             (b)    Community Property
                             (c)    Joint Tenant with Right of
                                    Survivorship (both parties
                                    must sign)
                             (d)    Partnership*
                             (e)    Tenants in Common
                             (f)    Company*
                             (g)    Trust*
                             (h)    Other

         *If  Units  are  being  subscribed  for  by  an  entity,  the  attached
Certificate of Signatory must also be completed.


                                       38


<PAGE>

                  8.4      NASD AFFILIATION.

Are you affiliated or associated with an NASD member firm (please check one):

Yes _________                       No __________

If Yes, please describe:

*If Subscriber is a Registered Representative with an NASD member firm, have the
following acknowledgment signed by the appropriate party:

The undersigned NASD member firm acknowledges  receipt of the notice required by
Article 3, Sections 28(a) and (b) of the Rules of Fair Practice.

- ---------------------------------
Name of NASD Member Firm

By:
   ------------------------------
         Authorized Officer

Date:
     ----------------------------




                  8.5 The  undersigned  is informed of the  significance  to the
Company  of  the  forego  ing  representations  and  answers  contained  in  the
Confidential Investor Questionnaire contained in this Section 7 and such answers
have been provided under the assumption that the Company will rely on them.


                                       39


<PAGE>

                                [SIGNATURE PAGE]

NUMBER OF UNITS               X $100,000 =                (THE "PURCHASE PRICE")
                -------------              ---------------


Signature                                    Signature (if purchasing jointly)


Name Typed or Printed                        Name Typed or Printed


Entity Name                                  Entity Name


Address                                      Address


City, State and Zip Code                     City, State and Zip Code


Telephone-Business                           Telephone--Business


Telephone-Residence                          Telephone--Residence


Facsimile-Business                           Facsimile--Business


Facsimile-Residence                          Facsimile--Residence


Tax ID # or Social Security #                Tax ID # or Social Security #

Name in which securities should be issued:

CHECK THE BOX MARKED YES IF YOU WOULD LIKE THE SECURITIES
TO BE DELIVERED TO YOUR ACCOUNT WITH PARAMOUNT CAPITAL, INC.  YES ___    NO ___

(IF YOU CHECK "NO",  SECURITIES WILL BE DELIVERED TO YOU AT THE ADDRESS PROVIDED
ABOVE)

Dated:                              , 1998

         This   Subscription   Agreement   is  agreed  to  and  accepted  as  of
___________________________ , 1998.
                                PROCEPT, INC.

                                By:  
                                   ----------------------------
                                        Name:
                                        Title:


                                       40

<PAGE>

                            CERTIFICATE OF SIGNATORY

                          (To be completed if Units are
                       being subscribed for by an entity)


  I,___________________________________, am the_______________________________
of

_____________________________________________ (the "Entity").

         I certify  that I am  empowered  and duly  authorized  by the Entity to
execute and carry out the terms of the  Subscription  Agreement  and to purchase
and hold the Units, and certify further that the Subscription Agreement has been
duly and validly  executed on behalf of the Entity and  constitutes  a legal and
binding obligation of the Entity.

         IN   WITNESS   WHEREOF,   I  have  set  my  hand   this________day   of
_________________, 1998.


                                    ---------------------------------------
                                    (Signature)


                                       41

<PAGE>

                                                                       EXHIBIT P
                                  PROCEPT, INC.

                           PLACEMENT AGENCY AGREEMENT


                                                                October 26, 1997

Paramount Capital, Inc.
787 Seventh Avenue
New York, New York  10019

Dear Sirs:

                  Procept, Inc., a Delaware corporation (the "Company"),  hereby
confirms its agreement to retain Paramount Capital, Inc. (the "Placement Agent")
on an exclusive basis to introduce the Company to, and to procure  subscriptions
from,"accredited  investors"  as that term is defined in  Regulation D under the
Securities  Act of 1933,  as  amended  (the  "Act")  as  prospective  purchasers
("Purchasers")  of a minimum (the "Minimum  Offering") of twenty-five (25) Units
(the "Units") and a maximum (the "Maximum Offering") of one hundred (100) Units,
with an option in favor of the Placement  Agent to offer up to an additional one
hundred  fifty  (150)  Units to cover  over-allotments  at a  purchase  price of
$100,000  per Unit,  with each  "Unit"  consisting  of (a) a number of shares of
Common Stock  (rounded to the nearest whole share,  with  one-half  (0.5) of one
share being rounded upward) (the "Offering  Quantity") of the Company, par value
$.01 per share (the "Common Stock"), determined by dividing one hundred thousand
dollars ($100,000) by the lesser of (A) $2.00 and (B) fifty percent (50%) of the
Trading Price (as defined in the  Subscription  Agreement (as defined below)) of
the Common Stock on the Nasdaq  National  Market  immediately  preceding (i) the
Initial  Closing  Date (as defined  below),  (ii) any Interim  Closing  Date (as
defined  below),  or (iii) the Final  Closing  Date (as  defined  below) of this
Offering,  whichever  is lowest (the  "Offering  Price") and (b)  warrants  (the
"Class C Warrants")  to purchase at any time prior to the fifth  anniversary  of
the Final  Closing  Date,  a number of shares of Common  Stock  equal to (x) the
Offering  Quantity  multiplied  by (y) 0.5 (rounded to the nearest  whole share,
with one-half  (00.5) of one share being rounded  upward).  The Units shall have
the terms set forth in the Term Sheet (as defined below).

                  The  sale to such  Purchasers  (the  "Offering")  will be made
through a private


<PAGE>

Paramount Capital, Inc.
Page 2



placement by the Placement Agent (or its designated selected dealers) on a "best
efforts" basis pursuant to the Confidential  Term Sheet dated November 14, 1997,
and all supplements,  amendments and exhibits thereto and documents incorporated
therein by  reference,  all of which  constitute  an integral  part thereof (the
"Term Sheet"),  separate  subscription  agreements  between the Company and each
purchaser  of Units in the  Offering  (collectively  "Purchasers")  and  related
documents (the "Subscription Agreements") in accordance with Section 4(2) of the
Act and Regulation D promulgated thereunder.

                  The  Term  Sheet  and  the  exhibits  attached  thereto,   the
Subscription  Agreements,  the  exhibits  to the  Subscription  Agreements,  the
Warrant Agreement to be entered into by and between the Company,  American Stock
Transfer and Trust  Company,  as warrant  agent,  and the  Placement  Agent (the
"Warrant  Agreement"),  the Escrow Agreement (the "Escrow  Agreement") among the
Company,  the Placement  Agent and Fleet Bank,  N.A. (the "Escrow  Agent"),  the
Financial  Advisory  Agreement (as defined in Section 5(k) below), the Placement
Options (as defined in Section 4(d) below),  the Advisory Options (as defined in
Section  5(k)  below ) and this  Placement  Agency  Agreement  are  collectively
referred to herein as the "Offering Documents."

                  The Company,  at its sole cost,  shall  prepare and deliver to
the Placement Agent a reasonable  number of copies of the Offering  Documents in
form and substance satisfactory to the Placement Agent.

                  Each prospective  investor subscribing to purchase Units shall
be required to deliver,  among other things,  a  Subscription  Agreement,  which
shall  include a  Confidential  Investor  Questionnaire  ("Questionnaire").  The
Company shall make available to each prospective  purchaser at a reasonable time
prior to the purchase of the Units the  opportunity  to ask questions of, and to
receive  answers from,  the Company  concerning  the terms and conditions of the
Offering  and the  opportunity  to obtain  additional  information  necessary to
verify the accuracy of the documents  delivered in connection  with the purchase
of the Units to the  extent it  possesses  such  information  or can  acquire it
without  unreasonable  effort or expense.  After the investors shall have had an
opportunity to review the Offering  Documents,  and have had the  opportunity to
address all inquiries to the Company,  separate Subscription Agreements shall be
completed by each  prospective  investor.  The Company,  with the consent of the
Placement Agent, and the Placement Agent, in its sole discretion, shall have the
right to reject  subscriptions  in whole or in part.  The Company shall evidence
its  acceptance of a  subscription  by  countersigning  a copy of the applicable
Subscription Agreement and returning the same to the Placement Agent.

                  Capitalized  terms used in this  Agreement,  unless  otherwise
defined herein or


<PAGE>

Paramount Capital, Inc.
Page 3



unless the context otherwise indicates, shall have the same meanings provided in
the Offering Documents.

                  1.       Appointment of Placement Agent.

                           (a) The Placement Agent is hereby appointed exclusive
placement agent of the Company  (subject to the Placement  Agent's right to have
Selected  Dealers,  as  defined  in  Section  1(c)  hereof,  participate  in the
Offering)  during the  Offering  Period  herein  specified  for the  purposes of
assisting the Company in finding qualified  subscribers pursuant to the Offering
described in the Offering Documents.  The Placement Agent shall not be deemed an
agent of the Company for any other purpose. The "Offering Period" shall commence
on the day the Offering  Documents  are first made  available  to the  Placement
Agent by the Company for delivery in  connection  with the offering for the sale
of the Units (the  "Commencement  Date").  Upon receipt of the Minimum  Offering
amount,  the Placement Agent may conduct a closing (the "Initial  Closing Date")
and may  conduct  subsequent  closings  on an interim  basis  until the  Maximum
Offering amount (and any over-allotment amount) has been reached or the Offering
is terminated (the "Final Closing  Date").  Each such closing may be referred to
herein as a "Closing". If not terminated earlier pursuant to this Agreement, the
Offering Period shall terminate at 11:59 p.m. New York City Time on January, [ ]
1998,  subject to an  extension,  at the option of the Placement  Agent,  for an
additional sixty (60) days (the "Termination Date"),  accordingly,  the Offering
Period shall terminate on the Final Closing Date or the Termination Date, as the
case may be. If  subscriptions  for the Minimum  Offering amount of 25 Units are
not received  prior to the end of the  Offering  Period,  the  Offering  will be
terminated and all funds  received from  Subscribers  will be returned,  without
interest and without any deduction.

                           (b) Subject to the  performance by the Company of all
of its obligations to be performed under this Agreement and to the  completeness
and accuracy of all  representations  and warranties of the Company contained in
this Agreement, the Placement Agent hereby accepts such agency and agrees to use
its best efforts to assist the Company in finding qualified subscribers pursuant
to the Offering described in the Offering  Documents.  It is understood that the
Placement  Agent has no  commitment  to sell the Units.  The  Placement  Agent's
agency  hereunder is not terminable by the Company prior to the Termination Date
except as set forth in Section 8(g).

                           (c) The  Placement  Agent may engage  other  persons,
selected  by it in  its  sole  discretion,  who  are  members  of  the  National
Association of Securities Dealers, Inc., ("NASD") or who are located outside the
United States and that have  executed a Selected  Dealers  Agreement  (each such
person being hereinafter  referred to as a "Selected  Dealer") and the Placement
Agent may allow such persons such part of the compensation and payment of


<PAGE>

Paramount Capital, Inc.
Page 4



expenses  payable to the Placement  Agent hereunder as the Placement Agent shall
determine;  provided,  however,  that any such  compensation  shall be  received
pursuant to Section 4(d) hereof.

                           (d) Subscriptions for Units shall be evidenced by the
execution by qualified subscribers of a Subscription  Agreement. No Subscription
Agreement  shall be  effective  unless and until it is accepted by the  Company.
Until a closing is held, all subscription funds received shall be held in escrow
as described in the Escrow  Agreement.  The  Placement  Agent shall not have any
independent obligation to verify the accuracy or completeness of any information
contained in any Subscription  Agreement or the  authenticity,  sufficiency,  or
validity  of any check  delivered  by any  prospective  investor  in payment for
Units,  nor shall the Placement  Agent incur any  liability  with respect to any
such check.

                  2.  Representations and Warranties of the Company. The Company
represents and warrants to the Placement Agent and each Selected Dealer, if any,
as follows:

                           (a)   Securities   Law   Compliance.   The   Offering
Documents, as of their respective dates do, and as of the date of the Term Sheet
and each Closing,  shall  describe the material  aspects of an investment in the
Company and conform in all respects with the requirements of Section 4(2) of the
Act and  Regulation D promulgated  thereunder and with the  requirements  of all
other published rules and regulations of the Securities and Exchange  Commission
(the  "Commission")  currently  in effect  relating  to "private  offerings"  to
"accredited  investors"(as  that term is defined in Regulation D under the Act).
The  Offering  Documents  shall  not,  as of the date of the Term Sheet and each
Closing,  contain any untrue  statement of a material  fact or omit to state any
material fact necessary in order to make the statements therein, in light of the
circumstances  under which they were made, not  misleading;  provided,  however,
that no  representation  is made with  respect to  information  relating  to the
Placement  Agent  which is  provided  in writing by the  Placement  Agent to the
Company  specifically  for inclusion in the Offering  Documents.  If at any time
prior to the  completion of the Offering or other  termination of this Agreement
any event shall occur as a result of which it might become necessary to amend or
supplement  the  Offering  Documents  so that  they do not  include  any  untrue
statement of any material fact or omit to state any material  fact  necessary in
order to make the statements  therein,  in the light of the  circumstances  then
existing,  not misleading,  the Company will promptly notify the Placement Agent
and will supply the Placement Agent (or the prospective Purchasers designated by
the Placement Agent) with amendments or supplements correcting such statement or
omission. The Company shall also provide the Placement Agent for delivery to all
offerees and  Purchasers  and their  representatives,  if any, any  information,
documents and instruments  which the Placement  Agent and the Company's  counsel
reasonably deem necessary to comply


<PAGE>

Paramount Capital, Inc.
Page 5



with applicable state and federal law.

                  The Company  acknowledges that the Placement Agent (i) has not
supplied any  information  for  inclusion in the Offering  Documents  other than
information  relating to the Placement Agent furnished in writing to the Company
by the Placement  Agent  specifically  for inclusion in the Offering  Documents;
(ii) has no obligation  independently  to verify any of the  information  in the
Offering  Documents;  and  (iii)  has no  responsibility  for  the  accuracy  or
completeness of the Offering Documents, except for the information,  relating to
the Placement Agent,  furnished in writing by the Placement Agent to the Company
specifically for inclusion in the Offering Documents.

                           (b)  Organization.  The Company is a corporation duly
incorporated,  validly existing and in good standing under the laws of the State
of  Delaware,  is  duly  qualified  or  licensed  to do  business  as a  foreign
corporation and is in good standing in Massachusetts and in each jurisdiction in
which the nature of the  business  conducted,  or as proposed to be conducted in
the Term Sheet, by it or the properties  owned,  leased or operated by it, makes
such  qualification  or  licensing  necessary  and  where the  failure  to be so
qualified or licensed  would have a material  adverse  effect upon the business,
prospects and financial condition of the Company and has all requisite corporate
power and authority to own and lease its respective properties,  to carry on its
respective business as currently  conducted and as proposed to be conducted,  to
execute  and  deliver  this   Agreement  and  to  carry  out  the   transactions
contemplated by this Agreement, as appropriate and is duly licensed or qualified
to do  business  as a  foreign  corporation  in each  jurisdiction  in which the
conduct of its business or ownership or leasing of its properties requires it to
be so  qualified,  except where the failure to be so qualified  would not have a
material adverse effect on the business, financial condition or prospects of the
Company.

                           (c)  Capitalization.   The  authorized,   issued  and
outstanding  capital  stock  of the  Company  prior to the  consummation  of the
transactions  contemplated  hereby is as set forth in the Term Sheet. All issued
and  outstanding  shares of the  Company  are  validly  issued,  fully  paid and
nonassessable  and have not been issued in violation of the preemptive rights of
any  stockholder of the Company.  The Common Stock,  when issued,  will have the
rights,   preferences  and  privileges   substantially   as  set  forth  in  the
Subscription  Agreements.  All prior sales of  securities  of the  Company  were
either  registered  under the Act and applicable state securities laws or exempt
from such  registration,  and no security holder has any rescission  rights with
respect thereto. Except as set forth in the Term Sheet, there are no outstanding
options,  warrants,  agreements,  convertible  securities,  preemptive rights or
other rights to subscribe  for or to purchase any shares of capital stock of the
Company. Except as set forth in the Term Sheet and as otherwise required by law,
there are no restrictions on the voting or transfer of any


<PAGE>

Paramount Capital, Inc.
Page 6



shares of the Company's  capital stock pursuant to the Company's  Certificate of
Incorporation,  By-laws or other  governing  documents or any agreement or other
instruments to which the Company is a party or by which the Company is bound.

                           (d) Warrants,  Preemptive Rights,  Etc. Except as set
forth in or  contemplated  by the Term Sheet,  there are not,  nor will there be
immediately  after  any  Closing  (as  hereinafter  defined),   any  outstanding
warrants, options, agreements,  convertible securities, rights of first refusal,
rights of first offer,  preemptive rights or other rights to subscribe for or to
purchase or other  commitments  pursuant to which the Company is, or may become,
obligated to issue any shares of its capital  stock or other  securities  of the
Company and this Offering will not cause any  anti-dilution  adjustments to such
securities or commitments except as reflected in the Term Sheet.

                           (e)  Subsidiaries  and  Investments.  Other  than  as
disclosed in the Term Sheet and 225,000 shares of common stock of VacTex,  Inc.,
a Delaware  corporation,  the  Company  does not own,  directly  or  indirectly,
capital stock or other equity  ownership or  proprietary  interests in any other
corporation, association, trust, partnership, joint venture or other entity.

                           (f) Financial  Statements.  The financial information
contained in the Offering  Documents is accurate in all material  respects.  The
Company's  financial  statements have been prepared in conformity with generally
accepted  accounting  principles  consistently  applied  and show  all  material
liabilities,  absolute or  contingent,  of the  Company  required to be recorded
thereon and present  fairly the financial  position and results of operations of
the Company as of the dates and for the periods  indicated,  subject in the case
of unaudited interim financial statements, to normal year-end adjustments.

                           (g)  Absence of  Changes.  Since the date of the Term
Sheet,  except as has been or will be  reflected in the Term Sheet prior to each
Closing, the Company has not incurred any liabilities or obligations,  direct or
contingent,  other than  those  that were  incurred  in the  ordinary  course of
business,  nor has the Company entered into any transaction  that is material to
the  business of the  Company,  and there has not been any change in the capital
stock of, or any incurrence of long-term  debt by, the Company,  or any issuance
of options,  warrants  or other  rights to  purchase  the  capital  stock of the
Company,  or any  adverse  change or any  development  involving  a  prospective
adverse change in the condition (financial or otherwise),  net worth, results of
operations, business, key personnel or properties which would be material to the
business,  prospects or financial condition of the Company,  and the Company has
not become a party to, and neither the  business nor the property of the Company
has  become  the  subject  of,  any  material  litigation  whether or not in the
ordinary course of business.


<PAGE>

Paramount Capital, Inc.
Page 7




                           (h) Title.  The Company has good and marketable title
to all tangible  properties and assets owned by it, free and clear of all liens,
charges,  encumbrances  or  restrictions,  except  such  as are  not  materially
significant  or important in relation to the Company's  business.  Except as has
been or will be  reflected in the Term Sheet prior to each  Closing,  all of the
material leases and subleases under which the Company is the lessor or sublessor
of properties or assets or under which the Company holds properties or assets as
lessee or  sublessee  are in full force and  effect,  and the  Company is not in
default in any material  respect with respect to any of the terms or  provisions
of any of such leases or subleases,  and no material  claim has been asserted by
anyone  adverse  to  rights  of the  Company  as  lessor,  sublessor,  lessee or
sublessee under any of the leases or subleases  mentioned above, or affecting or
questioning  the right of the Company to continued  possession  of the leased or
subleased premises or assets under any such lease or sublease.  The Company owns
or leases all such tangible properties as are necessary to its operations as now
conducted and proposed to be conducted and except to the extent described in the
Term Sheet,  the Company  presently does not anticipate the need for any capital
expenditures.

                           (i) Proprietary Rights. Except as has been or will be
reflected in the Term Sheet prior to each Closing, the Company owns or possesses
adequate  and  enforceable  rights  to use  all  patents,  patent  applications,
trademarks,  service marks,  trade names,  corporate  names,  copyrights,  trade
secrets, processes, mask works, licenses, inventions,  formulations,  technology
and know-how and other  intangible  property  used or proposed to be used in the
conduct of its business as described in or  contemplated  by the Term Sheet (the
"Proprietary Rights"). Except as has been or will be reflected in the Term Sheet
prior to each  Closing,  the Company or the  entities  from whom the Company has
acquired rights,  has taken all necessary action to protect all of the Company's
Proprietary  Rights.  Except as set forth in the Term Sheet, the Company has not
received  any notice of, and there are not any facts known to the  Company  that
indicate the existence of (i) any infringement or  misappropriation by any third
party  of any of the  Proprietary  Rights  or (ii) any  claim  by a third  party
contesting the validity of any of the  Proprietary  Rights;  the Company has not
received any notice of any  infringement,  misappropriation  or violation by the
Company or any of its employees of any Proprietary Rights of third parties, and,
to the best of the Company's knowledge, the Company nor any of its employees has
infringed,  misappropriated  or otherwise violated any Proprietary Rights of any
third parties;  and, to the best of the Company's  knowledge,  no  infringement,
illicit  copying,  misappropriation  or violation of any  intellectual  property
rights of any  third  party has  occurred  or will  occur  with  respect  to any
products  currently  being sold by the Company or with  respect to any  products
currently under development by the Company or with respect to the conduct of the
Company's  business as currently  contemplated.  Except as described in the Term
Sheet,  the Company is not aware that any of its employees  are obligated  under
any contract (including


<PAGE>

Paramount Capital, Inc.
Page 8



licenses, covenants or commitments of any nature) or other agreement, or subject
to any judgment,  decree or order of any court or  administrative  agency,  that
would  interfere  with the use of the  employee's  best  efforts to promote  the
interests of the Company or that would  conflict with the Company's  business as
currently conducted or as proposed to be conducted. To the best of the Company's
knowledge,  neither  the  execution  nor  delivery  of this  Agreement,  nor the
carrying on of the Company's  business by the employees of the Company,  nor the
conduct of the Company's  business,  as currently conducted or as proposed to be
conducted,  will conflict with or result in a breach of the terms, conditions or
provisions  of, or  constitute  a  default  under,  any  contract,  covenant  or
instrument under which any such employee is now obligated.

                           (j)  Litigation.  Except  as set  forth  in the  Term
Sheet,  there is no material  action,  suit,  claim or  proceeding  at law or in
equity, or to the Company's knowledge,  investigation or customer complaint,  by
or before  any  arbitrator,  governmental  instrumentality  or other  agency now
pending or, to the knowledge of the Company,  threatened against the Company (or
basis  therefor  known to the Company which the Company  believes will result in
the foregoing) the adverse outcome of which would  materially  adversely  affect
the Company's  business,  prospects or financial  condition.  The Company is not
subject to any  judgment,  order,  writ,  injunction  or decree of any  Federal,
state, municipal or other governmental  department,  commission,  board, bureau,
agency or instrumentality,  domestic or foreign which would materially adversely
affect the Company's business, prospects or financial condition.

                           (k) Non-Defaults,  Non-Contravention.  The Company is
not in violation of or default  under,  nor will the  execution  and delivery of
this  Agreement  or  any of  the  Offering  Documents,  or  consummation  of the
transactions  contemplated  herein  or  therein  result  in a  violation  of  or
constitute a default in the  performance  or  observance of any  obligation  (i)
under its Certificate of Incorporation, its By-laws, or any indenture, mortgage,
material purchase order or other agreement or instrument to which the Company is
a party or by which it or its property is bound or affected or (ii) with respect
to any material order,  writ,  injunction or decree of any court of any Federal,
state, municipal or other governmental  department,  commission,  board, bureau,
agency  or  instrumentality,  domestic  or  foreign,  and  there is no  existing
condition, event or act which constitutes,  nor which after notice, the lapse of
time or both, could constitute,  a default under any of the foregoing,  which in
either case would have a material  adverse effect on the business,  prospects or
financial condition of the Company.

                           (l) Taxes. The Company has filed all Federal,  state,
local and foreign tax  returns  required to be filed by it and all such  returns
are true and correct in all  material  respects.  The Company has paid all taxes
pursuant to such returns or pursuant to any assessments  received by it or which
it is obligated to withhold from amounts owing to any


<PAGE>

Paramount Capital, Inc.
Page 9



employee,  creditor or third party.  The Company has properly  accrued all taxes
required to be accrued.  The tax returns of the Company  have never been audited
by any  state,  local or Federal  authorities.  The  Company  has not waived any
statute of limitations  with respect to taxes or agreed to any extension of time
with respect to any tax assessment or deficiency.

                           (m) Compliance With Laws, Licenses,  Etc. The Company
has not  received  notice of any  violation  of,  or  non-compliance  with,  any
Federal,  state,  local or foreign,  laws,  ordinances,  regulations  and orders
applicable to its business, the violation of, or noncompliance with which, would
have a materially adverse effect on the business, financial condition, prospects
or  operations  of the Company.  The Company has all  governmental  licenses and
permits  and other  governmental  certificates,  authorizations  and permits and
approvals (collectively,  "Licenses") required by every Federal, state and local
government  or  regulatory  body for the  operation of its business as currently
conducted and the use of its properties, except where the failure to be licensed
would not have a material  adverse  effect on the business of the  Company.  The
Company's  Licenses are in full force and effect and no  violations  are or have
been  recorded in respect of any License and no proceeding is pending or, to the
best knowledge of the Company, threatened to revoke or limit any thereof.

                           (n) Authorization of Documents and Units. Each of the
Offering Documents,  has been, or prior to any Closing will be, duly and validly
authorized,  executed and delivered by the Company and the  execution,  delivery
and  performance  by the  Company  of  the  Offering  Documents  has  been  duly
authorized by all requisite  corporate action by the Company and when delivered,
constitute or will constitute  (assuming that such agreements are countersigned,
if  necessary)  the  legal,  valid  and  binding  obligations  of  the  Company,
enforceable  in  accordance  with  their  respective   terms,   subject  to  the
availability  and   enforceability  of  equitable  remedies  and  to  applicable
bankruptcy  and other laws  relating to the rights of  creditors  generally  and
except as the  enforcement  of the rights to  indemnification  and  contribution
hereunder  and under any other  Offering  Documents may be limited by federal or
state securities laws or public policy. The Company has full corporate power and
lawful  authority  to  authorize,  issue  and sell  the  Units to be sold to the
Purchasers  and the  securities  underlying  the Units (as  defined  below).  No
consent is required by the Company or from any third party  (other than the SEC,
but only insofar as such consent relates to the Company's obligation to register
the Registrable Securities (as defined below)) to perform any of its obligations
under this  Agreement  or any of the  Offering  Documents.  Any  increase to the
number of authorized  shares of Common Stock will  require,  among other things,
the approval of the holders of a majority of the outstanding Common Stock of the
Company.

                           (o)  Exemption  from  Registration.  Assuming (i) the
accuracy of the


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Paramount Capital, Inc.
Page 10



information   provided  by  the  respective   Purchasers  in  the   Subscription
Agreements, and (ii) the timely filing of a Form D by the Company, the offer and
sale of the Units and the  granting of the  Placement  Options and the  Advisory
Options (as defined  below)  pursuant to the terms of this  Agreement are exempt
from the  registration  requirements  of the Act and the rules  and  regulations
promulgated thereunder (the "Regulations"). The Company is not disqualified from
the exemption under Regulation D by virtue of the disqualification  contained in
Rule 507 promulgated  thereunder.  There exists no fact or set of facts known to
the Company or its counsel that might cause the Offering to be  integrated  with
any other offering of the Company's  securities  which would cause this offering
to lose its exemption under Regulation D.

                           (p) Registration  Rights.  Except as set forth in the
Term Sheet or Section 5 of the Subscription  Agreement,  no person has any right
to cause the Company to effect the registration  under the Act of any securities
of the Company.

                           (q)  Brokers.  Neither  the  Company  nor  any of its
officers, directors, employees or stockholders has employed any broker or finder
in connection  with the  transactions  contemplated by this Agreement other than
the Placement Agent.

                           (r) Title to Units.  When  certificates  representing
the Common  Stock and Class C Warrants  shall  have been duly  delivered  to the
Purchasers  and  payment  shall  have  been  made  for the  Units,  the  several
Purchasers  shall have good and valid title to the Common  Stock and the Class C
Warrants and,  upon exercise of such Class C Warrants,  will have good and valid
title to the Common Stock issuable upon such exercise (the "Conversion Shares"),
in each case, free and clear of all liens,  encumbrances  and claims and adverse
claims,  whatsoever  (except  as  arising  from  applicable  Federal  and  state
securities  laws), and the Company shall have paid all taxes, if any, in respect
of the original issuance thereof.  When certificates  representing the Placement
Options and Advisory  Options  shall have been duly  delivered to the  Placement
Agent,  the Placement  Agent or its designees shall have good and valid title to
the Placement  Options and Advisory  Options,  upon  exercise of such  Placement
Options and/or  Advisory  Options,  will have good and valid title to the Common
Stock and Class C Warrants  issuable  upon such  exercise,  and upon exercise of
such Class C Warrants  issuable upon exercise of such  Placement  Options and/or
Advisory Options,  will have good and valid title to the Common Stock into which
such Class C Warrants are converted,  in each case, free and clear of all liens,
encumbrances and adverse claims,  whatsoever  (except as arising from applicable
Federal and state  securities  laws), and the Company shall have paid all taxes,
if  any,  in  respect  of  the  original  issuance  thereof.  When  certificates
representing   the  Common  Stock  issuable   pursuant  to  Article  VI  of  the
Subscription  Agreement  (the  "Article  VI  Issuances")  shall  have  been duly
delivered to the Purchasers,  the several  Purchasers  shall have good and valid
title to the


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Paramount Capital, Inc.
Page 11



Common Stock constituting such Article VI Issuances free and clear of all liens,
encumbrances and claims and adverse claims,  whatsoever  (except as arising from
applicable  Federal and state securities  laws), such Common Stock shall be duly
authorized, validly issued, fully paid and non-assessable, and the Company shall
have paid all taxes, if any, in respect of the original issuances thereof.

                           (s) Non-Affiliated  Directors. The Company's Board of
Directors  has not less than two (2)  directors who are  independent  from,  and
unaffiliated with, management of the Company.

                           (t)  Accuracy  of  Reports.   All  material   reports
required  to be filed by the  Company  within the two years prior to the date of
this  Agreement  under the  Securities  and Exchange Act of 1934 as amended (the
"Exchange  Act"),  have been duly  filed with the SEC,  complied  at the time of
filing in all material  respects with the requirements of their respective forms
and,  except  to the  extent  updated  or  superseded  by the Term  Sheet or any
subsequently filed report, were complete and correct in all material respects as
of the dates at which the information  was furnished,  and contained (as of such
dates) no untrue  statement  of a  material  fact or omitted to state a material
fact necessary in order to make the statements  contained  therein,  in light of
the circumstances under which they were made, not misleading.

                           (u) Reservation of Shares;  Transfer Taxes,  Etc. The
Company shall at all times reserve and keep available, out of its authorized and
unissued  shares of Common  Stock,  solely  for the  purpose  of  effecting  any
exercises  of Class C  Warrants,  and any  Reset  Issuance  (as  defined  in the
Subscription  Agreement),  Semi-Annual  Issuance (as defined in the Subscription
Agreement)  and Dilution  Issuance (as defined  below and,  together  with Reset
Issuances  and  Semi-Annual  Issuances,   referred  to  herein  as  "Article  VI
Issuances"), such number of shares of its Common Stock free of preemptive rights
as shall be  sufficient to effect such  exercises and Article VI Issuances  from
time to time required or reasonably anticipated.  The Company shall use its best
efforts from time to time, in accordance  with the laws of the State of Delaware
to increase the  authorized  number of shares of Common Stock if at any time the
number of shares of authorized,  unissued and unreserved  Common Stock shall not
be  sufficient  to permit any required or  reasonably  anticipated  exercises of
Class C Warrants or Article VI Issuances.  In the event, and to the extent, that
the company does not have  sufficient  authorized but unissued  shares of Common
Stock to effect any  exercise  of Class C Warrants  or any  Article VI  Issuance
(collectively a "Common Issuance  Event"),  the Company shall pay the Subscriber
cash.

                  3.  Representations and Warranties of the Placement Agent. The
Placement


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Paramount Capital, Inc.
Page 12



Agent represents and warrants as follows:

                           (a) The Placement Agent is duly organized and validly
existing and in good  standing as a  corporation  under the laws of the State of
New York with full and  adequate  power and  authority to enter into and perform
this Agreement.

                           (b) In offering the Units,  the Placement Agent shall
deliver (or direct the Company to deliver) to each prospective purchaser,  prior
to the Company's acceptance of any subscription from such prospective purchaser,
the  appropriate  Offering  Documents.  The Placement Agent will not engage in a
general  solicitation  or employ  general  advertising  in  connection  with the
Offering.

                           (c) The  Placement  Agent  shall  use its  reasonable
efforts to conduct the Offering in material  compliance with applicable  federal
and state  securities  laws so as to preserve the exemption  provided in Section
4(2) of the Act and any applicable rules or regulations  promulgated  thereunder
or under such state  securities  laws. The Placement  Agent shall use reasonable
efforts to make offers only to persons who the  Placement  Agent has  reasonable
grounds to believe are "accredited  investors" (as defined in Regulation D under
the Act). The final acceptance of any subscription  shall be made only after the
Company  has  reviewed  the  Subscription  Agreement  and  agreed to such  final
acceptance  and  determination  as to the status of such  subscriber  which such
acceptance  and  determination  shall remain  solely the  responsibility  of the
Company.

                           (d) The Placement Agent is, and at each closing shall
be,  (i) a  securities  broker-dealer  registered  with the  Commission  and any
jurisdiction  where  broker-dealer  registration  is  required  in order for the
Company  to sell the  Units  in such  jurisdiction  and  (ii) a  member  in good
standing of the NASD.


                  4.       Closing; Placement and Fees.

                           (a) Closing.  Provided that the  Placement  Agent has
received  subscriptions for the Minimum Offering amount, the Placement Agent may
conduct, in its sole discretion, closings (the date of each a "Closing Date") at
the offices of the Placement  Agent,  787 Seventh  Avenue,  New York,  New York,
until the Final Closing Date. On each Closing Date, payment for the Units issued
and sold by the Company  shall be made to the Company in  immediately  available
funds against  delivery of certificates  evidencing the Common Stock and Class C
Warrants comprising such Units.


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Paramount Capital, Inc.
Page 13




                           (b) Conditions to Placement Agent's Obligations.  The
obligations of the Placement  Agent hereunder are subject to the accuracy of the
representations  and warranties of the Company  herein  contained as of the date
hereof and as of each Closing  Date,  to the  performance  by the Company of its
obligations hereunder and to the following additional conditions:

                                      (i) Due  Qualification  or Exemption.  (A)
The Offering  contemplated by this Agreement shall become qualified or be exempt
from  qualification  under the securities laws of the several states pursuant to
paragraph 4(c) below not later than the Closing Date,  subject to any filings to
be made  thereafter,  and (B) at the Closing Date, no stop order  suspending the
sale of the Units shall have been  issued,  and no  proceeding  for that purpose
shall have been initiated or threatened;

                                      (ii) No  Material  Misstatements.  Neither
the Blue Sky  qualification  materials,  the  Offering  Documents,  nor the Term
Sheet,  nor any supplement  thereto,  will contain an untrue statement of a fact
which in the  opinion of the  Placement  Agent is  material,  or omit to state a
fact, which in the opinion of the Placement Agent is material and is required to
be stated therein,  or is, in the opinion of the Placement  Agent,  necessary to
make the statements therein, in light of the circumstances under which they were
made, not misleading;

                                      (iii)  Compliance  with  Agreements.   The
Company shall have complied with all  agreements and satisfied all conditions on
its part to be  performed  or  satisfied  hereunder  and under the  Subscription
Agreements at or prior to each Closing;

                                      (iv) Corporate  Action.  The Company shall
have  taken  all  corporate  action  necessary  to permit  the valid  execution,
delivery and  performance of the Offering  Documents by the Company,  including,
without  limitation,  obtaining the approval of the Company's board of directors
for the execution and delivery of the Offering  Documents and the performance by
the Company of its obligations hereunder and the offering contemplated hereby;

                                      (v) Opinion of Counsel to the Company. The
Placement  Agent shall  receive  the opinion of counsel to the Company  (stating
that each of the  Purchasers  may rely thereon as though  addressed  directly to
such  Purchaser),  dated as of each Closing  Date,  substantially  to the effect
that:

                                             (A)    the    Company    is    duly
incorporated, validly existing



<PAGE>

Paramount Capital, Inc.
Page 14



and in corporate good standing under the laws of the State of Delaware,  has all
requisite  corporate  power and lawful  authority  necessary  to own or hold its
properties  and conduct its  business as described in the Term Sheet and is duly
qualified  or licensed to do  business as a foreign  corporation  and is in good
standing in  Massachusetts  and in each  jurisdiction in which the nature of the
business  conducted,  or as proposed to be conducted in the Term Sheet, by it or
the  properties  owned,  leased or operated by it, makes such  qualification  or
licensing  necessary and where the failure to be so qualified or licensed  would
have a material  adverse  effect  upon the  business,  prospects  and  financial
condition of the Company.  To such  counsel's  knowledge  except with respect to
VacTex,  Inc.,  the Company does not own,  directly or  indirectly,  any capital
stock  or  other  equity  ownership  or  proprietary   interests  in  any  other
corporation, association, trust, partnership, joint venture or other entity;

                                             (B)  the  execution,  delivery  and
performance  of each  of the  Offering  Documents  to  which  the  Company  is a
signatory,  and the  issuance  of (I) the Units,  the  Common  Stock and Class C
Warrants included in the Units and the Placement and Advisory Options,  (II) the
Common Stock and Class C Warrants  issuable  upon  exercise of the Placement and
Advisory  Options and (III) the shares of Common Stock issuable upon exercise of
the Class C Warrants (the  "Exercise  Shares")  (including  the Exercise  Shares
underlying  the Class C Warrants  issuable  upon  exercise of the  Placement and
Advisory Options),  have been duly authorized by all necessary  corporate action
on the part of the  Company;  provided,  however,  that  shareholder  consent is
required for any increase in authorized  shares.  Each of the Offering Documents
to which the Company is a signatory  has been duly executed and delivered by the
Company and  constitutes  a legal,  valid and binding  obligation of the Company
enforceable  in  accordance  with its  terms,  subject  to such  limitations  on
enforceability  as such counsel  shall  specify in the opinion and that shall be
acceptable to the Placement Agent;

                                             (C)  the  authorized,   issued  and
outstanding  capital  stock of the  Company  as of the date  set  forth  therein
(before giving effect to the transactions  contemplated by this Agreement) is as
set  forth  in the  Term  Sheet.  To  such  counsel's  knowledge,  there  are no
outstanding warrants, options,  agreements,  convertible securities,  preemptive
rights or other  commitments  pursuant  to which the  Company is, or may become,
obligated to issue any shares of its capital  stock or other  securities  of the
Company other than as set forth in the Term Sheet. To such counsel's  knowledge,
all of the issued  shares of  capital  stock of the  Company  have been duly and
validly  authorized and issued,  are fully paid and  nonassessable  and have not
been issued in violation of the preemptive rights of any security holder;

                                             (D)  assuming  (x) the  accuracy of
the information


<PAGE>

Paramount Capital, Inc.
Page 15



provided by the  Subscribers  in the  Subscription  Documents and (y) the timely
filing with the  Securities and Exchange  Commission  and any  applicable  state
securities  authorities of a Form D and amendments thereto  containing  accurate
and  complete  information,  the  issuance  and sale of the Units is exempt from
registration  under the Act and Rule 506 of Regulation D promulgated  thereunder
and is not  subject to  integration  with any other  offering  of the  Company's
securities which will undermine the exempt status of the Offering;

                                             (E)  neither  the   execution   and
delivery of the  Offering  Documents  nor  compliance  with the terms  hereof or
thereof,   nor  the   consummation  of  the   transactions   herein  or  therein
contemplated,  has,  conflicts  with,  results in a breach of, or  constitutes a
default under the Certificate of  Incorporation  (provided that such counsel may
note that the Company may not issue shares in excess of the  authorized  capital
stock) or  By-laws of the  Company,  or any  material  contract,  instrument  or
document  known to such  counsel  after due  inquiry  to which the  Company is a
party,  or by which it or any of its properties is bound  (provided such counsel
need  express no opinion  with respect to the  satisfaction  of the  stockholder
approval  requirement under the Company's existing agreement with Nasdaq) or, to
the best knowledge of such counsel,  violate any  applicable  order or decree of
any governmental  agency or court having jurisdiction over the Company or any of
its properties or business;

                                             (F) except as disclosed in the Term
Sheet, to such counsel's best knowledge and without conducting a search of court
documents,  there are no claims, actions,  suits,  investigations or proceedings
before or by any arbitrator,  court,  governmental  authority or instrumentality
pending or threatened against the Company which could, if adversely  determined,
materially and adversely affect the business,  properties or financial condition
of the Company,  the  transactions  or other acts  contemplated  by the Offering
Documents or the validity or enforceability of the Offering Documents. Except as
disclosed in the Term Sheet, to such counsel's  knowledge,  the Company is not a
party or subject to the provisions of any order, writ,  injunction,  judgment or
decree  of any court or  government  agency or  instrumentality  that  names the
Company;

                                             (G) upon the issuance of the Units,
the Common Stock (including the Common Stock issuable pursuant to any Article VI
Issuances)  and Class C Warrants  (including  the shares of Common Stock and the
Class C Warrants issuable upon exercise of the Placement and Advisory  Options),
the  Placement  and Advisory  Options and the  Exercise  Shares  (including  the
Exercise  Shares  underlying  the Class C Warrants  issuable  upon  exercise  of
Placement and Advisory  Options),  each of the Purchasers or the Placement Agent
and its designees,  as the case may be, shall acquire such securities,  free and
clear of all pledges, liens, claims, encumbrances,  preemptive rights, rights of
first offer or right of first refusal and


<PAGE>

Paramount Capital, Inc.
Page 16



restrictions  known to such counsel  after due inquiry,  except for the transfer
restrictions  set forth in the  Subscription  Agreements and any action taken to
encumber such securities by the holders thereof;

                                             (H) the Common  Stock  included  in
the  Units,  when  issued  in  accordance  with the  terms  of the  Subscription
Agreement  for  the   consideration   expressed  therein  will  have  been  duly
authorized, fully paid, validly issued and non-assessable. The Class C Warrants,
the Placement Options and the Advisory  Options,  when issued in accordance with
the terms of this Agreement  and/or the Subscription  Agreement,  as applicable,
for the consideration  expressed therein, will have been validly issued and will
constitute  legal,  valid and binding  obligations  of the  Company  enforceable
against the Company in accordance with their respective  terms,  subject to such
limitations on  enforceability  as such counsel shall specify in the opinion and
that  shall  be  acceptable  to  the  Placement  Agent.  The  Common  Stock  (x)
constituting  Article VI Issuances and (y) issuable upon exercise of the Class C
Warrants and the Placement and Advisory Options  (including the shares of Common
Stock  issuable upon exercise of the Class C Warrants  underlying  the Placement
and Advisory  Options) (the securities  referred to in clauses (x) and (y) above
collectively the "Additional Shares"),  when issued in accordance with the terms
thereof for the consideration expressed therein, will have been duly authorized,
validly issued, fully paid, and non-assessable.  The Additional Shares have been
duly  authorized  by all necessary  corporate  action on the part of the Company
and, to the extent such shares are  available  and as such shares  become,  from
time to  time  available,  shall  be  reserved  for  issuance  by the  Board  of
Directors.

                                             (I)    the    Company's    Restated
Certificate of  Incorporation  provides that the Company  shall,  to the fullest
extent  permitted by Section 145 of the General  Corporation Law of the State of
Delaware,  as amended from time to time,  indemnify  each person who was or is a
party  or is  threatened  to be  made a  party  to any  threatened,  pending  or
completed action, suit or proceeding, whether civil, criminal, administrative or
investigative,  by reason of the fact that he is or was, or has agreed to become
a director of the Company.  The Company's Restated  Certificate of Incorporation
also provides that no director shall be personally  liable to the Company or its
stockholders  for  monetary  damages for any breach of a fiduciary  duty by such
director as a director,  to the fullest extent permitted by the Delaware General
Corporation Law, as from time to time amended.

                                             Such  counsel   shall   state,   in
opining on any matter  stated to be subject to the  knowledge  of such  counsel,
that such knowledge shall include the actual  knowledge of such counsel who have
given  substantive  attention to the Company's  affairs in  connection  with the
Offering and that such counsel has made due inquiry, including, but not


<PAGE>

Paramount Capital, Inc.
Page 17



limited to, appropriate inquiries of officers of the Company with respect to the
subject  matter of such opinion and has reviewed all  documents the existence of
which is disclosed by such inquiries or of which such counsel is otherwise aware
of as a result of its representation of the Company.

                                             In  addition,  such  counsel  shall
state that in the course of the  preparation  of the Offering  Documents,  which
involved,  among other things,  discussions and inquiries concerning the various
legal  matters  and the  review of  certain  corporate  records,  documents  and
proceedings, counsel participated in conferences with certain officers and other
representatives of the Company and the Placement Agent during which the contents
of the Offering Documents and related matters were discussed. Such counsel shall
advise  the  Placement  Agent in the form of an  opinion  of  counsel  that such
counsel has no reason to believe that, as of the date of such opinion,  the Term
Sheet  including any document  incorporated by reference  therein  contained any
untrue  statement of a material fact relating to the Company or omitted to state
a  material  fact  relating  to the  Company  required  to be stated  therein or
necessary  to make the  statements  therein not  misleading  in the light of the
circumstances under which they were made.

                                    (vi)   Opinion   of  Patent   Counsel.   The
Placement Agent shall receive (unless waived in writing by the Placement  Agent)
the  opinion of patent  counsel to the  Company  (which  such  counsel  shall be
satisfactory  to the  Placement  Agent),  dated the Closing Date in the form and
substance satisfactory to counsel for the Placement Agent.

                                    (vii)  Comfort  Letter.  The  Company  shall
cause Coopers & Lybrand,  L.L.P., the Company's  independent public accountants,
to  address  and  deliver to the  Company  and the  Placement  Agent a letter or
letters (which letters are frequently referred to as "Comfort Letters") dated as
of each  Closing  Date  and the  effective  date of the  registration  statement
required to be filed in connection with the Subscription Agreements.

                                    (viii) Officer's Certificate.  The Placement
Agent  shall  receive  an  Officer's  Certificate  substantially  in the form of
Exhibit A hereto  and a  Secretary's  Certificate  substantially  in the form of
Exhibit B hereto, signed by the appropriate parties and dated as of each Closing
Date.   These   certificates   shall  state,   among  other  things,   that  the
representations  and  warranties  contained  in  Section  2 hereof  are true and
accurate in all  material  respects at such Closing Date with the same effect as
though expressly made at such Closing Date.

                                    (ix) Escrow  Agreement.  The Placement Agent
shall receive a copy of a duly executed Escrow Agreement with Fleet Bank, N.A.


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Paramount Capital, Inc.
Page 18



                                    (x) Transmittal Letters. The Placement Agent
shall  receive  copies  of  all  letters  from  the  Company  to  the  investors
transmitting  the Common Stock and Class C Warrants  and shall  receive a letter
from the Company confirming transmittal of the securities to the investors.

                           (c) Blue Sky. A summary blue sky survey,  at the sole
cost  of  the  Company  (including,  without  limitation,  the  legal  fees  and
disbursements  in  connection  therewith),  shall be  prepared by counsel to the
Placement Agent stating the extent to which and the conditions upon which offers
and sales of the Units may be made in certain  jurisdictions.  It is  understood
that such  survey may be based on or rely upon (i) the  representations  of each
Subscriber set forth in the Subscription Agreement delivered by such Subscriber,
(ii) the representations,  warranties and agreements of the Company set forth in
Section 2 of this  Agreement,  (iii) the  representations  and warranties of the
Placement  Agent, and (iv) the  representations  of the Company set forth in the
certificate  to be  delivered at each  Closing  pursuant to paragraph  (viii) of
Section 4(b).

                           (d) Placement Fees and Expenses.  (i)  Simultaneously
with  payment  for and  delivery  of the Units at each  Closing as  provided  in
paragraph  4(a) above,  the Company  shall at such Closing pay to the  Placement
Agent (i) a commission (the "Cash Commission") equal to nine percent (9%) of the
aggregate  purchase price of the Units sold and (ii) a  non-accountable  expense
allowance (the "Expense  Allowance") equal to four percent (4%) of the aggregate
purchase  price of the Units sold.  The Company  shall also pay all  expenses in
connection with the  qualification of the Units under the securities or Blue Sky
laws of the states which the Placement Agent shall designate.  In addition,  the
Company shall pay to the Placement  Agent a commission of five percent (5%) upon
the exercise of the Class C Warrants. In addition, upon each Closing of the sale
of the Units being offered,  the Company will sell to the Placement Agent and/or
its  designees,  for $.001 per option,  options  (the  "Placement  Options")  to
acquire a number of newly issued Units equal to ten percent  (10%) of the number
of Units  issued  in the  Offering,  exercisable  for a period of five (5) years
commencing  six (6) months  after the Final  Closing  Date at an exercise  price
equal to one  hundred ten percent  (110%) of the initial  offering  price of the
Units.  The  Company  agrees with the  Placement  Agent and its  successors  and
assigns that the securities underlying the Placement Options will not be subject
to  redemption  by  the  Company  nor  will  they  be  callable  or  mandatorily
convertible by the Company.  The Placement Options cannot be transferred,  sold,
assigned  or  hypothecated  for six months  except  that they may be assigned in
whole or in part  during such  period to any NASD  member  participating  in the
Offering  or any officer or  employee  of the  Placement  Agent or any such NASD
member.  The  Placement  Options will  contain a cashless  exercise  feature,  a
provision  for payment of the exercise  price by promissory  note,  antidilution
provisions and the


<PAGE>

Paramount Capital, Inc.
Page 19


right to have the Common Stock  issuable upon exercise of the Placement  Options
included on the Shelf Registration Statement.

                                    (ii) The Cash Commission, Expense Allowance,
and Placement  Options and Advisory Options as set forth in this Agreement shall
be paid to the Placement  Agent with respect to any  investment by any investors
introduced to the Company by the Placement  Agent  ("Covered  Investors") in the
event that any such  Covered  Investor  purchases  securities  from the  Company
during the twelve (12) months following the Final Closing Date of the Offering.

                           (e)  No  Adverse   Changes.   There  shall  not  have
occurred,  at any time prior to the  Closing (i) any  domestic or  international
event,  act or occurrence  which has materially  disrupted,  or in the Placement
Agent's  determination  will in the immediate  future  materially  disrupt,  the
securities  markets of the United  States;  (ii) a general  suspension  of, or a
general  limitation  on prices for,  trading in securities on the New York Stock
Exchange,  the American Stock Exchange,  the NASDAQ National Market,  the NASDAQ
SmallCap Market, or in the over-the-counter  market; (iii) any outbreak of major
hostilities  or other  national  or  international  calamity;  (iv) any  banking
moratorium declared by a state or federal authority; (v) any moratorium declared
in foreign exchange trading by major international banks or other persons;  (vi)
any material  interruption  in the mail service or other means of  communication
within the United  States;  (vii) any material  adverse  change in the business,
properties,  assets, results of operations,  financial condition or prospects of
the Company;  or (viii) any change in the market for securities in general or in
political,  financial,  or economic  conditions  which, in the Placement Agent's
reasonable  judgment,  makes it inadvisable to proceed with the offering,  sale,
and delivery of the Units.

                  5. Covenants of the Company.

                           (a) Use of Proceeds. The net proceeds of the Offering
will be used by the Company  substantially  as set forth in the Term Sheet.  The
Company  shall not use any of the  proceeds  from this  Offering to  repurchase,
redeem or otherwise  acquire any shares of capital stock of the Company or repay
any indebtedness of the Company including but not limited to any indebtedness to
current  executive  officers  or  principal  stockholders  of the  Company,  but
excluding accounts payable to non-affiliates  incurred in the ordinary course of
business, without the prior written consent of the Placement Agent.

                           (b)  Expenses  of  Offering.  The  Company  shall  be
responsible  for and shall bear all  expenses  incurred in  connection  with the
proposed Offering, including but not


<PAGE>


Paramount Capital, Inc.
Page 20


limited  to,  the costs of  preparing  and  duplicating  the Term  Sheet and all
exhibits  thereto;  the  costs  of  preparing,  printing  and  filing  with  the
Securities and Exchange Commission (the "SEC") the Shelf Registration  Statement
and amendments,  post-effective  amendments and supplements thereto;  preparing,
duplicating and delivering exhibits thereto and copies of the preliminary, final
and supplemental prospectus; preparing, duplicating and delivering (including by
facsimile) all selling  documents,  including but not limited to the Term Sheet,
the Placement Agency Agreement,  Subscription  Agreements,  Warrant  agreements,
blue sky memorandum and stock and warrant  certificates;  blue sky fees,  filing
fees and legal  fees and  disbursements  of the  Placement  Agent's  counsel  in
connection  with blue sky matters;  fees and  disbursements  of the transfer and
warrant agent;  the cost of a total of two sets of bound closing volumes for the
Placement Agent and its counsel; and the cost of three tombstone advertisements,
at least one of which shall appear in a national  business  newspaper and one of
which  shall  appear in a major New York  newspaper  (or,  at the  option of the
Placement Agent,  forty (40) lucite deal mementos)  (collectively,  the "Company
Expenses").  The Company  agrees to use a printer  designated  by the  Placement
Agent and which is reasonably  acceptable to the Company.  The Company shall pay
to the Placement Agent a  non-accountable  expense  allowance equal to 4% of the
total  proceeds of the  Offering  (the  "Expense  Allowance"),  of which  twenty
thousand dollars ($20,000) shall be due and payable upon the date the Term Sheet
is completed,  to cover the cost of the Placement  Agent's  mailing,  telephone,
telecopy,  travel to due diligence meetings and other similar expenses including
legal fees of the Placement Agent's counsel (other than legal fees in connection
with blue sky matters as to which fees the Company shall be responsible  and any
items designated  above as Company  Expenses).  Such prepaid expense  allowances
shall be non-refundable.  If the proposed financing is not completed because the
Company  prevents  it or  because of a breach by the  Company of any  covenants,
representations  or warranties  contained herein,  then the Company shall pay to
the Placement Agent a fee of one hundred  thousand  dollars  ($100,000)  against
which the $20,000,  if  previously  paid,  shall be credited (in addition to the
Company Expenses for which the Company shall in all events remain liable).

                           (c)  Notification.   The  Company  shall  notify  the
Placement  Agent  immediately,  and in  writing,  (A) when any event  shall have
occurred during the period commencing on the date hereof and ending on the Final
Closing  Date as a result of which the  Offering  Documents  would  include  any
untrue  statement of a material fact or omit to state any material fact required
to be stated therein or necessary to make the statements  therein not misleading
in light of the circumstances  under which they were made and (B) of the receipt
of any notification with respect to the modification,  rescission, withdrawal or
suspension  of  the  qualification  or  registration  of  the  Units,  or of any
exemption from such  registration or  qualification,  in any  jurisdiction.  The
Company  will  use  its  best  efforts  to  prevent  the  issuance  of any  such
modification,   rescission,   withdrawal   or   suspension   and,  if  any  such
modification,


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Paramount Capital, Inc.
Page 21



rescission,  withdrawal  or  suspension  is issued  and the  Placement  Agent so
requests, to obtain the lifting thereof as promptly as possible.

                           (d) Blue Sky.  The Company  will use its best efforts
to qualify the Units for offering and sale under  exemptions from  qualification
or  registration  requirements  under the  securities or "blue sky" laws of such
jurisdictions as the Placement Agent may reasonably  request;  provided however,
that the Company will not be obligated to qualify as a dealer in  securities  in
any  jurisdiction  in  which  it is not  so  qualified.  The  Company  will  not
consummate any sale of Units in any jurisdiction in which it is not so qualified
or in any manner in which such sale may not be lawfully made.

                           (e) Registration  Statement Filing. The Company will,
as soon as  practicable,  but not later  than  thirty  (30) days after the Final
Closing Date, (i) file a shelf registration  statement (the "Shelf  Registration
Statement")  with respect to the resale of (A) the Common Stock  underlying  the
Units  (including the Units issuable upon exercise of the Placement  Options and
Advisory  Options,  (B) the Class C  Warrants  (including  the Class C  Warrants
underlying  the  Placement  and  Advisory  Options,   (C)  the  Exercise  Shares
(including the Exercise  Shares  underlying  the Class C Warrants  issuable upon
exercise of Placement  Options and the  Advisory  Options) and (D) the shares of
Common Stock  constituting  any Article VI Issuances  (together the "Registrable
Capital  Stock")  with  the SEC and use its  best  efforts  to have  such  Shelf
Registration  Statement  declared effective by the SEC prior to the date that is
seventy-five  (75) days after the Final  Closing Date  (subject to penalties for
failure to effect such  registration in the time frames  required) and (b) cause
such Shelf  Registration  Statement to remain  effective  until such date as the
holders of the securities  (including the securities  issued or then required to
be issued by the Company pursuant to any Article VI Issuances,  whether pursuant
to Reset  Issuances  (as  defined in the  Subscription  Agreement),  Semi-Annual
Issuances (as defined in the Subscription  Agreements) or Dilution Issuances (as
defined in the Subscription Agreement) have completed the distribution described
in the Shelf  Registration  Statement  or at such time that such  shares  are no
longer,  by reason of Rule 144(k) under the Act,  required to be registered  for
the sale thereof by such holders who are not  affiliates of the Company.  In the
event that the Shelf Registration Statement is not declared effective within the
75 day period  described  above,  the  Company  shall  declare  and pay,  for no
additional  consideration,  to the Purchasers additional Units, equal to .25% of
the Units,  then held by such  Purchaser for each whole month in which the Shelf
Registration Statement remains ineffective. If requested by the Placement Agent,
and in  accordance  with  applicable  securities  laws,  the Shelf  Registration
Statement shall cover the direct sale of such Registerable  Capital Stock to the
holders of such securities.  The Registerable Capital Stock will be subject to a
staggered "lock-up" as may be deemed advisable by the Placement Agent.


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Paramount Capital, Inc.
Page 22



                           (f) Form D Filing.  The  Company  shall file five (5)
copies of a Notice of Sales of Securities on Form D with the Commission no later
than  fifteen (15) days after the first  Closing  Date.  The Company  shall file
promptly such amendments to such Notices on Form D as shall become necessary and
shall also comply with any filing  requirement  imposed by the laws of any state
or  jurisdiction  in which offers and sales are made.  The Company shall furnish
the Placement Agent with copies of all such filings.

                           (g) Press Releases, Etc. Except as otherwise required
by  applicable  law or the rules of a regulatory  body,  the Company  shall not,
during the period  commencing  on the date  hereof and ending  thirty  (30) days
after the Final  Closing Date,  issue any press release or other  communication,
make any written or oral statement to any media  organization  or publication or
hold any  press  conference,  presentation  or  seminar,  or engage in any other
publicity  with  respect to the Company,  its  financial  condition,  results of
operations,  business,  properties,  assets,  or  liabilities,  or the Offering,
without the prior written  consent of the Placement  Agent.  Upon the request of
the  Placement  Agent,  the  Company  shall  make a Rule 135c  (under  the Act )
announcement with respect to the commencement of the Offering.

                           (h) Public  Documents.  Following  the Final  Closing
Date of the Offering,  the Company will furnish to the Placement  Agent:  (i) as
soon as practicable  (but in the case of the annual report of the Company to its
stockholders,  within one hundred twenty (120) days after the end of each fiscal
year of the  Company)  one copy of:  (A) its annual  report to its  stockholders
(which annual report shall contain  financial  statements  audited in accordance
with generally accepted accounting principles in the United States of America by
a firm of certified  public  accountants  of  recognized  standing),  (B) if not
included in substance in its annual report to stockholders, its annual report on
Form 10-K, (C) each of its quarterly reports to its stockholders, if any, and if
not  included  in  substance  in its  quarterly  reports  to  stockholders,  its
quarterly  report on Form 10-Q, (D) each of its current reports on Form 8-K, and
(E) a copy of the full Shelf  Registration  Statement,  (the foregoing,  in each
case,  excluding  exhibits);  and (ii) upon  reasonable  request,  all  exhibits
excluded by the parenthetical to the immediately preceding clause 5(h)(i)(E) and
any other  information that is generally  available to the public.  In addition,
the Company upon  reasonable  request will meet with the Placement  Agent or its
representatives to discuss all information  relevant for disclosure in any Shelf
Registration  Statement covering shares purchased by Purchasers from the Company
and  offered  by  them  for  resale  and  will   cooperate  in  any   reasonable
investigation  undertaken by the  Placement  Agent for the purpose of confirming
the accuracy of the Shelf  Registration  Statement,  including the production of
information at the Company's offices. (i) Restrictions on Securities. During the
thirty-six (36) months


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Paramount Capital, Inc.
Page 23



following  June 30,  1997,  the Company  shall not,  without  the prior  written
consent of the Placement Agent,  offer or sell any of its securities in reliance
on Regulation S of the Act. During the twenty-four  (24) month period  following
October 1, 1997,  the  Placement  Agent shall have the right of first refusal to
act as placement  agent for the offering of any securities of the Company issued
for fund raising  purposes.  During the thirty-six  (36) month period  following
June 30, 1997 the Company  will not extend the  expiration  date or decrease the
exercise price of any options, warrants, convertible securities or other similar
security  purchase  rights  without the prior  written  consent of the Placement
Agent.

                           (j)  Listing.   The  Company  will  take  all  action
necessary  promptly to file an Application for Listing of Additional Shares with
the New York Stock Exchange,  the American Stock  Exchange,  the NASDAQ National
Market, the NASDAQ SmallCap Market, or the OTC Electronic  Bulletin Board and/or
take any other  necessary  action to enable the (i) Common Stock  (including the
Common  Stock  issuable  (A) upon  exercise  of the Class C  Warrants,  (B) upon
exercise of the Placement and Advisory  Options  (including the shares of Common
Stock  issuable upon exercise of the Class C Warrants  underlying  the Placement
Options  and (C)  pursuant  to any  Article VI  Issuances)  and (ii) the Class C
Warrants to trade on such market.

                           (k)  Financial  Advisory  Agreement.  Upon the  Final
Closing Date,  the Company and the  Placement  Agent will enter into an advisory
agreement (the "Financial Advisory  Agreement") whereby the Placement Agent will
act as the Company's  non-exclusive  financial  advisor.  Such  engagement  will
provide that the Placement Agent receive (i) a monthly retainer of four thousand
($4,000) Dollars (minimum  engagement of 24 months and $20,000 of which shall be
payable  upon  the  execution  of  the  Financial  Advisory   Agreement),   (ii)
out-of-pocket  expenses and (iii)  standard cash and equity  success fees in the
event the  Placement  Agent  assists  the  Company in  connection  with  certain
financing and  strategic  transactions.  In addition,  upon the execution of the
Financial  Advisory  Agreement,  the Company  will sell to the  Placement  Agent
and/or its designees,  for $.001 per option, options (the "Advisory Options") to
acquire a number of newly  issued  Units equal to fifteen  percent  (15%) of the
Units  issued  in the  Offering,  exercisable  for a period  of five  (5)  years
commencing  six (6) months  after the Final  Closing  Date at an exercise  price
equal to 110% of the initial offering price of the Units. The Company has agreed
to register certain of the securities underlying the Advisory Options for resale
under the Act on the  Registration  Statement.  The  securities  underlying  the
Advisory  Options will not be subject to mandatory  conversion  or redemption by
the Company nor will they be callable by the Company.  The Advisory Options will
contain a cashless  exercise  feature,  a provision  for payment of the exercise
price by promissory note, and  antidilution  provisions.  (l) Company  Insiders.
Officers, directors or principal stockholders of


<PAGE>

Paramount Capital, Inc.
Page 24



the Company may invest in the Offering. Any such investments will be included in
calculating whether the 25 Units have been sold in the Minimum Offering, whether
the 100 Units have been sold in the Maximum Offering,  and whether the 150 Units
have been sold pursuant to the over-allotment option.

                           (m) Placement Agent Insiders.  Certain  affiliates of
the  Placement  Agent may  purchase  Units in the  Offering.  Affiliates  of the
Placement Agent will invest net of cash  commissions and expenses.  Accordingly,
the Placement  Agent will not receive a commission on the Units purchased by its
affiliates  and the Company  will  receive net  proceeds  equivalent  to the net
proceeds  received from the purchase of Units by persons not affiliated with the
Placement  Agent.  The aggregate  offering price of any such investments will be
included  in  calculating  whether  the 25 Units  have been sold in the  Minimum
Offering,  whether  the 100 Units have been sold in the  Maximum  Offering,  and
whether the 150 Units have been sold pursuant to the over-allotment option.

                           (n) Subscription  Checks. All subscription checks and
funds shall be promptly and directly  delivered  without  offset or deduction to
the bank account at the Escrow Agent described in the Escrow Agreement.

                           (o) No Offerings.  Pending  completion or termination
of the  Offering in  accordance  with the terms of this  Agreement,  the Company
agrees that it will not enter into an  agreement  (whether  binding or not) with
any other person or entity relating to a possible public or private  offering or
placement  of  its  securities  (other  than  in  connection  with  a  corporate
partnership, strategic alliance or government funding).

                           (p) Lock-Up Agreement.  If requested by the Placement
Agent,  the Company  will  obtain from its  directors,  executive  officers  and
beneficial  owners of five  percent  (5%) or more of the  Company's  outstanding
common stock,  an agreement  that, for a period of twenty-four  (24) months from
the Final  Closing  Date,  they will not sell,  assign or transfer  any of their
shares of the Company's  securities  without the Placement Agent's prior written
consent.

                           (q) No Statements. The Company shall not use the name
of the Placement Agent or any officer, director, employee or shareholder thereof
without the express  written  consent of the Placement  Agent.  In the event the
Placement  Agent has refused to give  consent  and the Company has been  advised
upon in a written  opinion of counsel that any such  disclosure is required as a
matter of law,  the  Company may make such  disclosure  (to the extent that such
opinion states that it is required) without the Placement Agent's consent.


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Paramount Capital, Inc.
Page 25



                           (r)  Company  Advisors.  The  Company  covenants  and
represents  that it shall  immediately  notify its  independent  accountants and
patent, regulatory and outside corporate counsel of the pendency of the Offering
and that  comfort  letters  and legal  opinions  will be  required  prior to any
closing.  The Company agrees and represents that it will provide (i) preliminary
drafts of the Term Sheet to such firms for their  review  and  comment  and (ii)
final drafts of the Term Sheet to such firms immediately upon its completion.

                           (s) Directors and Observers.

                                    (i) For a  period  of five (5)  years  after
June 30, 1997,  the  Placement  Agent shall be entitled to designate a number of
directors  that  would  constitute  a  majority  of the Board of  Directors  for
nomination as voting directors  ("Directors") of the Company.  In no event shall
the Board of Directors  exceed seven (7) members  without the Placement  Agent's
consent. If necessary,  the Directors of the Company will elect each such person
to the Board of Directors  of the Company (A) on the Initial  Closing  Date,  by
causing an existing  Director of the  Company to resign and (B)  thereafter,  by
creating  a new  position  on the Board of  Directors  promptly  following  such
person's  nomination  by the  Placement  Agent.  The Board of  Directors  of the
Company  shall  nominate  each such person for election in  connection  with any
stockholder  vote for  Directors,  and the Company  will use its best efforts to
ensure that the  stockholders of the Company agree to vote all their  securities
in favor of each such person's  election.  The Company agrees to vote all voting
securities for which the Company holds proxies granting it voting discretion, or
which the Company is  otherwise  entitled  to vote,  in favor of, and to use its
best  efforts in all  respect to cause,  the  election  of each such  individual
proposed by the Placement  Agent.  In the event that a vacancy is created on the
Board of Directors at any time by the death, disability,  resignation or removal
(with or without  cause) of any such  individual  proposed and  nominated by the
Placement Agent pursuant to this Agreement, the Company shall, and shall use its
best efforts to ensure that the  stockholders  of the  Company,  vote all its or
their voting securities to elect each individual proposed by the Placement Agent
and nominated for election by the Placement Agent to fill such vacancy and serve
as a voting Director.

                                    (ii) At the  Placement  Agent's  option,  in
addition to or in lieu of proposing for  nomination and election the majority of
the Directors of the Company to be proposed by the Placement  Agent as set forth
in Section  5(s)(i),  the Placement  Agent may, until such time as no Article VI
Rights (as defined in the Subscription Agreement) remain outstanding,  designate
a nonvoting  observer or observers  who shall be entitled to attend all meetings
of the  Board  of  Directors  and any of its  committees  and who  shall  be (A)
provided  reasonable  prior notice of all meetings of the Board of Directors and
any of its committees, (B)


<PAGE>

Paramount Capital, Inc.
Page 26



provided  reasonable  prior  notice of any action that the Board of Directors or
any of its committees may take by written consent, (C) promptly delivered copies
of all  minutes  and other  records of action by,  and all  written  information
furnished to, the Board of Directors or any of its committees,  and (D) promptly
furnished any other information  requested by such observer or observers which a
member of the Board of Directors  would be entitled to request to discharge  his
or her  duties.  Such  observers  shall  be  entitled  to  the  same  rights  to
reimbursement for the expense of attendance at meetings as any outside Director.

                                    (iii) If the Placement Agent gives notice to
the Company that the Placement  Agent  desires to remove a Director  proposed by
the Placement Agent pursuant to this Agreement, the Company shall, and shall use
its best effort to ensure that the  stockholders of the Company shall,  vote all
of its or their voting  securities  in favor of removing such Director if a vote
of holders of such securities shall be required to remove the Director,  and the
Company agrees to take any action necessary to facilitate such removal.

                                    (iv)   Each   Director   nominated   by  the
Placement  Agent  shall be  entitled  to the same type of  compensation,  and an
amount of  compensation  at least  equal to the highest  amount,  payable to any
other Director for serving in such capacity. As used in this paragraph 5(s)(iv),
"compensation" shall include Director and Officer insurance coverage among other
things.  The Company shall cover the Directors  nominated by the Placement Agent
with  Director  and  Officer  insurance  that is at least as  favorable  to such
persons as the most favorable (from the prospective of the insured) Director and
Officer  insurance  benefiting  any other  member of the Board of  Directors  or
management of the Company.

                                    (v) Not later than three (3)  business  days
after  the  Initial  Closing  Date,  the  Company  shall  have  (A)  caused  the
appointment  of the initial  Directors  nominated by the Placement  Agent to its
Board of Directors in  accordance  with the  provisions of this Section 5(s), to
the extent such  individuals  have been  identified in writing to the Company by
such time, and (B) taken such action as shall be necessary to cause the Board of
Directors to be composed of, and limited to, five members.  The Company will use
its best efforts to ensure continuing compliance with the terms of Clause (B) of
the  preceding  sentence  until  such  time  as  no  Article  VI  Rights  remain
outstanding.

                                    (vi) The Placement Agent's rights under this
Section  5(s) shall be  exercisable  only to the extent  that the  corresponding
rights contained in Section 7.19 of the Securities  Purchase  Agreement dated as
of June 30, 1997 have not been previously exercised by The Aries Trust, a Cayman
Islands Trust (the "Trust") or Aries Domestic Fund, L.P. (the "Partnership").


<PAGE>

Paramount Capital, Inc.
Page 27




                           (t) Board of Directors.

                                    (i) The  Company  shall  promptly  reimburse
each  Director  or  observer  of  the  Company  designated  by  the  Trust,  the
Partnership or the Placement Agent who is not an employee of the Company for all
of his  reasonable  expenses  incurred in attending each meeting of the Board of
Directors of the Company or any committee thereof.

                                    (ii) The Company shall at all times maintain
provisions in its By-laws and/or  Certificate of Incorporation  indemnifying all
directors  against  liability and absolving all directors  from liability to the
Company and its  stockholders to the maximum extent  permitted under the laws of
the State of Delaware.

                                    (iii)  The  By-laws  of  the  Company  shall
always contain  provisions  consistent  with the provisions of this Section 5(t)
except to the extent this Section 5(t) deals with the possible observers.

                           (u) Placement Agent Approval Rights.

                                    (i) Until such time as the Placement  Agent,
Partnership  and the  Trust,  and each of their  respective  affiliates,  in the
aggregate,  own less  than five  percent  (5%) of the Total  Voting  Shares  (as
defined  below) of the  Company's  capital  stock  (taking into  account  shares
issuable upon conversion or exercise of shares held by them),  the Company shall
not do any of the following without prior written consent of the Placement Agent
to the extent such  consent  right is not  exercised by the  Partnership  or the
Trust: (A) incur any indebtedness  outside the ordinary course of business,  (B)
incorporate, acquire, dissolve or dispose of any subsidiaries (C) enter into any
transactions  with  affiliates  of the Company nor (D)  increase  any  executive
compensation or bonuses,  whether in the form of cash, stock,  stock equivalents
or otherwise  (except for bonuses  guaranteed  in an employment  contract).  The
"Total Voting Shares" shall mean all outstanding  shares of any class or classes
(however designated) of capital stock entitled to vote generally in the election
of members of the Board of Directors.

                                    (ii) In addition to the approval  rights set
forth in 5(u)(i) above, so long as at least fifty percent (50%) of the shares of
Common Stock  included in the Units  (including  those issuable upon exercise of
the Placement and Advisory Options) remain outstanding and subject to Article VI
Rights, the Company will not, without the prior written consent of the Placement
Agent: (A) issue or increase the authorized amount or alter any of the terms, of
any  securities  of the Company  senior to, or on parity with,  the Common Stock
(other than Common Stock to be issued pursuant to Article VI Issuances  relating
to Common Stock


<PAGE>

Paramount Capital, Inc.
Page 28



(including  the  shares of Common  Stock  underlying  the  Units  issuable  upon
exercise of the Placement Options and Advisory Options) issued in this Offering)
with respect to voting, liquidation or dividends (except for class voting rights
required  law),  (B) alter any of the  Company's  charter  documents or take any
action  so  as  to   adversely   effect  the   relative   rights,   preferences,
qualifications,  limitations  or  restrictions  of the  Common  Stock  or of the
Article VI Rights (as defined in the Subscription Agreement), (C) enter into any
transactions  with  affiliates of the Company or (D)  incorporate or acquire any
subsidiaries.

                           (v)  Disposal  of  Assets.   Pending   completion  or
termination  of the Offering,  the Company will not dispose of any assets of the
Company  (including,  without  limitation,   creating,  suffering  to  exist  or
permitting  the  imposition  of any  liens)  other than in the  ordinary  course
consistent with past practice.

                           (w) Consultants, Etc. The Placement Agent may, at its
option, select and appoint a public relations firm and consultants to assist the
Company in its affairs, the cost of which shall be borne by the Company.

                           (x) Reports.  The Company shall provide the Placement
Agent with (i) written  business and  financial  updates on a monthly  basis and
(ii)  detailed  written  quarterly  reports  ("Quarterly   Reports")  containing
quarterly updates as to product development, financial matters, clinical trials,
corporate  partnering  matters,  and  any  other  material  events  or  business
activities.  The  Quarterly  Reports  shall  contain  sections (i) detailing the
Company's  objectives and milestones for the upcoming quarter and (ii) comparing
the  Company's  performance  in the  previous  quarter with the  milestones  and
objectives set forth for such quarter in the previous Quarterly Report.

                  6. Indemnification.

                           (a) The Company agrees to indemnify and hold harmless
the  Placement  Agent and each  Selected  Dealer,  if any, and their  respective
partners,  affiliates,  shareholders,  directors,  officers,  agents,  advisors,
representatives,  employees,  counsel and controlling persons within the meaning
of the Act (a  "Paramount  Indemnified  Party")  against  any  and  all  losses,
liabilities, claims, damages and expenses whatsoever (and all actions in respect
thereof),  and to reimburse the such Paramount  Indemnified Party for legal fees
and related  expenses as  incurred  (including,  but not limited to the costs of
giving testimony or furnishing documents in response to a subpoena or otherwise,
the costs of investigating,  preparing, pursuing or defending any such action or
claim  whether or not pending or  threatened  and  whether or not the  Placement
Agent or any Paramount Indemnified Party is a party thereto), in so far as such


<PAGE>

Paramount Capital, Inc.
Page 29



losses,  liabilities,  claims,  damages or expenses arise out of, relate to, are
incurred in connection  with or are in any way a result of (i) the engagement of
the  Placement  Agent  pursuant to this  Agreement  and in  connection  with the
transactions  contemplated  by this Agreement and the other  Offering  Documents
(the  "Engagement"),  including any  modifications  or future  additions to such
Engagement and related activities prior to the date hereof,  (ii) any act by the
Placement Agent or any Paramount  Indemnified Party taken in connection with the
Engagement,  (iii)  a  breach  of any  representation,  warranty,  covenant,  or
agreement of the Company contained in this Agreement, (iv) the employment by the
Company of any device,  scheme or artifice  to defraud,  or the  engaging by the
Company in any act,  practice  or course of  business  which  operates  or would
operate  as a fraud or  deceit,  or any  conspiracy  with  respect  thereto,  in
connection  with the sale of the Units,  or (v) any untrue  statement or alleged
untrue  statement of a material fact contained in the Offering  Documents or the
omission or alleged omission  therefrom of a material fact necessary in order to
make the statements therein, in light of the circumstances under which they were
made, not misleading,  provided, however, that the Company will not be liable in
any such case if and to the extent that any such loss, claim, damage,  liability
or expense arises out of or is based upon an untrue  statement or alleged untrue
statement or omission or alleged omission so made in conformity with information
furnished by any such Paramount  Indemnified  Party in writing  specifically for
use in the Offering Documents;

                           (b) The Company agrees to indemnify and hold harmless
a Paramount Indemnified Party to the same extent as the foregoing indemnity, and
subject  to the  limitations  set  forth  therein,  against  any and  all  loss,
liability,  claim,  damage and expense  whatsoever  directly  arising out of the
exercise  by any person of any right  under the Act or the  Exchange  Act or the
securities  or Blue  Sky laws of any  state  on  account  of  violations  of the
representations, warranties or agreements set forth in Section 2 hereof.

                           (c) The Placement  Agent agrees to indemnify and hold
harmless the Company, the Company's  directors,  officers,  employees,  counsel,
advisors,  representatives and agents and controlling persons within the meaning
of the Act (a "Company Indemnified Party") and each and all of them, to the same
extent as set forth in  Section  6(a)(v)  of the  foregoing  indemnity  from the
Company to the Placement Agent, but only with reference to information, relating
to the  Placement  Agent,  furnished in writing to the Company by the  Placement
Agent  specifically  for  inclusion  in the Offering  Documents  and only to the
extent that any losses,  claims,  damages,  and  liabilities in respect of which
indemnification  is claimed are finally  judicially  determined to have resulted
primarily and directly  from the bad faith or gross  negligence of the Placement
Agent.

                           (d) Promptly  after  receipt by a person  entitled to
indemnification


<PAGE>

Paramount Capital, Inc.
Page 30



pursuant to subsection (a), (b), or (c) (an "indemnified party") of this Section
of notice of the  commencement of any action,  the indemnified  party will, if a
claim in respect thereof is to be made against a person granting indemnification
(an "indemnifying party") under this Section, notify in writing the indemnifying
party  of  the  commencement   thereof;  but  the  omission  so  to  notify  the
indemnifying  party will not relieve it from any liability  which it may have to
the indemnified party otherwise than under this Section. In case any such action
is brought against an indemnified  party, and it notifies the indemnifying party
of the  commencement  thereof,  the  indemnifying  party  will  be  entitled  to
participate  in,  and, to the extent  that it may wish,  jointly  with any other
indemnifying party similarly notified, to assume the defense thereof, subject to
the  provisions  herein  stated,  with counsel  reasonably  satisfactory  to the
indemnified  party,  and  after  notice  from  the  indemnifying  party  to  the
indemnified  party  of its  election  so to  assume  the  defense  thereof,  the
indemnifying  party will not be liable to the indemnified party for any legal or
other expenses subsequently incurred by the indemnified party in connection with
the defense thereof other than reasonable costs of investigation incurred at the
request of the indemnifying party. The indemnified party shall have the right to
employ  separate  counsel in any such action and to  participate  in the defense
thereof,  but the fees and expenses of such counsel  shall not be at the expense
of the indemnifying  party if the indemnifying  party has assumed the defense of
the action  with  counsel  reasonably  satisfactory  to the  indemnified  party;
provided  that the fees and expenses of such counsel  shall be at the expense of
the  indemnifying  party  if  (i)  the  employment  of  such  counsel  has  been
specifically  authorized in writing by the indemnifying  party or (ii) the named
parties to any such action  (including any impleaded  parties)  include both the
indemnified  party or parties and the indemnifying  party and, in the opinion of
counsel of the  indemnified  party,  a conflict of interest  exists between such
parties in which case the indemnifying  party shall not have the right to assume
the defense of such  action on behalf of the  indemnified  party or parties,  it
being understood,  however, that the indemnifying party shall not, in connection
with any one such  action or  separate  but  substantially  similar  or  related
actions in the same jurisdiction  arising out of the same general allegations or
circumstances,  be liable for the reasonable  fees and expenses of more than one
separate firm of attorneys for the indemnified party or parties.  No settlement,
compromise,  consent to entry of  judgment  or other  termination  of any action
(collectively, "Terminations") in respect of which a Paramount Indemnified Party
may seek  indemnification  hereunder  (whether or not any Paramount  Indemnified
Party is a party thereto) shall be made without the prior written consent of the
Paramount  Indemnified  Party,  which such  consent  may be withheld at the sole
discretion of such Paramount  Indemnified  Party,  provided,  however,  that the
foregoing  requirement of prior written consent for Terminations shall not apply
to the  Placement  Agent who may agree to such  Terminations  without  the prior
written consent of any Paramount Indemnified Party.

                           (e)  Notwithstanding  any of the  provisions  of this
Agreement, the


<PAGE>

Paramount Capital, Inc.
Page 31



aggregate  indemnification  or  contribution  of the  Placement  Agent for or on
account of any  losses,  claims,  damages,  liabilities  or  actions  under this
Section 6, Section 7 or any other  applicable  section of this Agreement,  shall
not  exceed the Cash  Commissions  actually  paid to the  Placement  Agent.  The
respective  indemnity  and  contribution  agreements  by  the  Company  and  the
Placement Agent contained in subsections (a), (b), (c) and (d) of this Section 6
and Section 7, and the covenants,  representations and warranties of the Company
and the  Placement  Agent set forth in  Sections  1, 2, 3, 4 and 5 shall  remain
operative and in full force and effect regardless of (i) any investigation  made
by the Placement  Agent,  on the Placement  Agent's behalf or by or on behalf of
any person who  controls the  Placement  Agent,  the Company or any  controlling
person of the Company or any director or officer of the Company, (ii) acceptance
of any of the Units  and  payment  therefor  or (iii)  any  termination  of this
Agreement, and shall survive the delivery of the Units, and any successor of the
Placement  Agent or of the Company or of any person who controls  the  Placement
Agent or the  Company,  as the case may be,  shall be entitled to the benefit of
such respective indemnity and contribution agreements.  The respective indemnity
and contribution  agreements by the Company and the Placement Agent contained in
subsections  (a),  (b) and (c) of  this  Section  6 and  Section  7 shall  be in
addition  to any  liability  which  the  Company  and the  Placement  Agent  may
otherwise have.

                  7. Contribution.

                           (a) To provide for just and  equitable  contribution,
if (i) an  indemnified  party  makes a claim  for  indemnification  pursuant  to
Section  6 but it is  found  in a final  judicial  determination,  by a court of
competent jurisdiction, not subject to further appeal, that such indemnification
may not be enforced in such case, even though this Agreement  expressly provides
for  indemnification in such case, or (ii) any indemnified or indemnifying party
seeks  contribution  under the Act, the  Exchange  Act, or  otherwise,  then the
Company (including for this purpose any contribution made by or on behalf of any
officer, director,  employee or agent for the Company, or any controlling person
of the  Company),  on the one hand,  and the  Placement  Agent and any  Selected
Dealers  (including  for this  purpose  any  contribution  by or on behalf of an
indemnified  party),  on  the  other  hand,  shall  contribute  to  the  losses,
liabilities,  claims,  damages, and expenses whatsoever to which any of them may
be subject,  in such  proportions  as are  appropriate  to reflect the  relative
benefits  received by the Company,  on the one hand, and the Placement Agent and
the Selected Dealers, on the other hand; provided,  however,  that if applicable
law  does  not  permit   such   allocation,   then  other   relevant   equitable
considerations such as the relative fault of the Company and the Placement Agent
and the Selected  Dealers in  connection  with the facts which  resulted in such
losses, liabilities,  claims, damages, and expenses shall also be considered. In
no case shall the  Placement  Agent or a Selected  Dealer be  responsible  for a
portion of the contribution obligation


<PAGE>

Paramount Capital, Inc.
Page 32



in excess of the compensation received by it pursuant to Section 4 hereof or the
Selected Dealer Agreement,  as the case may be. No person guilty of a fraudulent
misrepresentation  shall be entitled to contribution  from any person who is not
guilty of such  fraudulent  misrepresentation.  For  purposes of this Section 7,
each  person,  if any, who controls  the  Placement  Agent or a Selected  Dealer
within the meaning of Section 15 of the Act or Section 20(a) of the Exchange Act
and each  officer,  director,  stockholder,  employee and agent of the Placement
Agent or a Selected  Dealer,  shall have the same rights to  contribution as the
Placement Agent or the Selected Dealer, and each person, if any who controls the
Company  within the  meaning  of  Section 15 of the Act or Section  20(a) of the
Exchange  Act and each  officer,  director,  employee  and agent of the Company,
shall have the same rights to contribution as the Company,  subject in each case
to the  provisions of this Section 7. Anything in this Section 7 to the contrary
notwithstanding,  no party shall be liable for contribution  with respect to the
settlement of any claim or action  effected  without its written  consent.  This
Section 7 is intended to supersede any right to contribution  under the Act, the
Exchange Act, or otherwise.

                  8. Miscellaneous.

                           (a) Survival. Any termination of the Offering without
any Closing shall be without obligation on the part of any party except that the
provisions   regarding  fees  and  expenses   contained  in  Section  5(b),  the
indemnification  provided in Section 6 hereof and the  contribution  provided in
Section 7 hereof shall survive any termination and shall survive any Closing.

                           (b)  Representations,  Warranties  and  Covenants  to
Survive   Delivery.   Except  as  provided  in  Section  8(a),   the  respective
representations,   warranties,  indemnities,  agreements,  covenants  and  other
statements  of the Company and the  Placement  Agent as of the date hereof shall
survive  execution  of  this  Agreement  and  delivery  of  the  Units  and  the
termination of this Agreement.

                           (c)  No  Other   Beneficiaries.   This  Agreement  is
intended  for the sole and  exclusive  benefit of the  parties  hereto and their
respective  successors and  controlling  persons,  and no other person,  firm or
corporation shall have any third-party beneficiary or other rights hereunder.

                           (d) Governing Law. This  Agreement  shall be governed
by and  construed  in  accordance  with the law of the State of New York without
regard to conflict of law provisions.


<PAGE>

Paramount Capital, Inc.
Page 33



                           (e)  Counterparts.  This  Agreement  may be signed in
counterparts with the same effect as if both parties had signed one and the same
instrument.

                           (f) Notices. Any communications specifically required
hereunder  to be in writing,  if sent to the  Placement  Agent,  will be mailed,
delivered and confirmed to it at Paramount  Capital,  Inc., 787 Seventh  Avenue,
48th Floor, New York, New York,  10019, Att: Michael S. Weiss and if sent to the
Company,  will be  mailed,  delivered  or  telegraphed  and  confirmed  to it at
Procept, Inc., 840 Memorial Drive,  Cambridge,  Massachusetts 02139, Attn: Chief
Executive Officer.

                           (g)  Termination.  Subject  to the  general  survival
provisions  contained  in  Sections  8(a)  and  8(b)  and,  in  the  event  of a
termination  by the  Company,  provided  that the  Company  pays the one hundred
thousand ($100,000) termination fee and expenses set forth in Section 5(b), this
Agreement  may be  terminated  by either  party prior to the end of the Offering
Period upon written notice to the other party.

                           (h) Entire Agreement.  This Agreement constitutes the
entire  agreement of the parties with respect to the matters herein referred and
supersedes all prior agreements and  understandings,  written and oral,  between
the parties with respect to the subject  matter  hereof.  Neither this Agreement
nor any term hereof may be changed,  waived or terminated orally, but only by an
instrument  in writing  signed by the party  against  which  enforcement  of the
change, waiver or termination is sought.

                           (i)  Nothing  contained  herein  or  otherwise  shall
create a  partnership  or joint  venture  between  the  Placement  Agent and the
Company.

                           (j)  The   headings   and  captions  of  the  various
subdivisions  of this Agreement are for  convenience or reference only and shall
in no way modify or affect the  meaning or  construction  of any of the terms or
provisions hereof.


<PAGE>

Paramount Capital, Inc.
Page 34



                  If  you  find  the  foregoing  is  in   accordance   with  our
understanding, kindly sign and return to us a counterpart hereof, whereupon this
instrument along with all counterparts  will become a binding  agreement between
us.

                                        Very truly yours,

                                        PROCEPT, INC.


                                        By:
                                           -------------------------------
                                        Name:
                                        Title:


Agreed to by:

PARAMOUNT CAPITAL, INC.


By:------------------------------
Name:  Lindsay A. Rosenwald, M.D.
Title: Chairman

<PAGE>


Paramount Capital, Inc.
Page 35



                                    EXHIBIT A


                                  PROCEPT, INC.

                              OFFICER'S CERTIFICATE

                                January 23, 1998

                  I,  Stanley  C.  Erck,  certify  that  I am the  President  of
Procept,  Inc., a Delaware corporation (the "Company"),  and that, as such, I am
authorized to execute this certificate on behalf of the Company. All capitalized
terms used herein but not otherwise  defined herein shall the meanings  ascribed
to such terms in the Placement Agency Agreement (as defined below). Reference is
made herein to the closing held on January 23, 1998 (the "Closing  Date").  I do
hereby certify that I have carefully  examined all of the Offering Documents (as
defined in the Placement  Agency  Agreement dated as of October 26, 1997 between
the Company and Paramount Capital, Inc. (the "Placement Agency Agreement")), and
do hereby further certify that:

                  1. All of the  representations  and  warranties of the Company
contained in the subscription agreements (the "Subscription Agreements") between
the Company and the purchasers  (the  "Purchasers")  of the Units of the Company
contemplated by the Company's  Confidential Term Sheet,  dated November 14, 1997
(as  supplemented,  the  "Term  Sheet")  are true and  correct  in all  material
respects on the Closing Date with the same force and effect as if made on and as
of the Closing Date,  and the Company has performed all covenants and agreements
and has satisfied all conditions in the Subscription  Agreements to be performed
or satisfied on its part before the Closing Date in all material respects.

                  2. The Term Sheet does not contain any untrue  statement  of a
material  fact or omit to state any fact  required to be stated in order to make
the statements  therein not misleading as of the Closing Date. Since the date of
the Term Sheet, no event has occurred  concerning which  information is required
to be contained in an amended or supplemented  Term Sheet  concerning which such
information is not contained therein.

                  3. All of the  representations  and  warranties of the Company
contained in the Placement Agency Agreement are true and correct in all material
respects on the Closing  Date,  and the Company has  performed all covenants and
agreements  and has satisfied all conditions  contained in the Placement  Agency
Agreement to be performed and satisfied on its


<PAGE>

Paramount Capital, Inc.
Page 36



part at or prior to the Closing Date in all material respects.

                  4. All of the  representations  and  warranties of the Company
contained  each of the other  Offering  Documents  are true and  correct  in all
material  respects  on the Closing  Date,  and the  Company  has  performed  all
covenants and  agreements  and has satisfied  all  conditions  contained in such
Offering  Documents to be performed and satisfied on its part at or prior to the
Closing Date in all material respects.

                  5. Since the date of the most recent financial  statements and
the information  included in the Term Sheet,  there has been no material adverse
change in the condition (financial or other), earnings, business,  properties or
prospects  of  the  Company  taken  as a  whole,  whether  or not  arising  from
transactions  in the  ordinary  course of business,  nor has there  occurred any
material  event required to be set forth in the Term Sheet,  including,  without
limitation, in accordance with Section 2(g) of the Placement Agency Agreement.

                  6. There is no litigation  pending or threatened by or against
the Company, except as disclosed in the Term Sheet.

                  7. The Company  shall  promptly  take all action  necessary to
list (i) the Common Stock  underlying the Units,  (ii) the Common Stock issuable
upon exercise of the Class C Warrants  underlying  the Units,  (iii) the Class C
Warrants  (including the Class C Warrants  underlying the Placement and Advisory
Options),  (iv) the Common Stock  constituting any Article VI Issuances relating
to Common Stock underlying the Units (including for each of (i), (ii), (iii) and
(iv) above,  the Units  issuable  upon  exercise of the  Placement  and Advisory
Options)  on the  Nasdaq  National  Market in  accordance  with the rules of the
Nasdaq National Market.

                  8. Since January 1, 1997,  the Company has not offered to sell
to or solicited any offers to buy from any person shares of capital stock of the
Company, except in connection with the Offering contemplated by the Term Sheet.

                  This  Certificate is made for the benefit of and may be relied
upon by, the Placement Agent, Kramer,  Levin,  Naftalis & Frankel, as counsel to
the Placement Agent, and each of the Purchasers.

                  IN WITNESS  WHEREOF,  I have executed this certificate on this
23rd day of January, 1998.


<PAGE>

Paramount Capital, Inc.
Page 37



                                -------------------------------------
                                Name:  Stanley C. Erck
                                Title:  President


                                                                       EXHIBIT B
<PAGE>

                                  PROCEPT, INC.

                             SECRETARY'S CERTIFICATE

                                January 23, 1998

                  I,  Lynette C.  Fallon,  certify  that I am the duly  elected,
qualified and acting  Secretary of Procept,  Inc., a Delaware  corporation  (the
"Company"),  and as such, I am duly  authorized to execute this  Certificate  on
behalf of the Company,  and that I am familiar with the facts  certified  below.
All  capitalized  terms used herein but not otherwise  defined  herein shall the
meanings  ascribed to such terms in the Placement  Agency  Agreement dated as of
October 26, 1997 between the Company and Paramount Capital, Inc. (the "Placement
Agency Agreement").  Reference is made herein to the closing held on January 23,
1998 (the "Closing Date").  In connection with the offering and sale of up to 60
units (the "Units"), each consisting of (a) the number of shares (rounded to the
nearest whole share with 0.5 of one share being rounded  upward) (the  "Offering
Quantity")  of Common  Stock of the  Company,  par value  $.01 per  share,  (the
"Common  Stock")  determined by dividing  100,000 by the lesser of (i) $0.50 and
(ii) 75% of the Trading Price (as defined  below) as of (x) the initial  closing
date (the "Initial Closing Date", (y) any interim closing date (each an "Interim
Closing  Date") or (z) the final closing date (the "Final Closing Date") of this
offering  whichever is lowest (the  "Offering  Price"),  and (b)  warrants  (the
"Class C  Warrants")  to purchase,  at an exercise  price per share equal to the
Offering Price, at any time prior to the fifth  anniversary of the Final Closing
Date (as  defined  herein)  a number of  shares  of  Common  Stock  equal to the
Offering Quantity,  for which Paramount Capital, Inc. ("Paramount") has acted as
placement agent, I do hereby further certify as follows:

                  1.  Attached  hereto as  Attachment  A is a true,  correct and
complete copy of the Company's Certificate of Incorporation,  as amended,  which
is in full force and effect,  no amendment to such certificate has been approved
by the Board of  Directors  or  stockholders  of the  Company  or filed with the
Delaware  Secretary of State since October 26, 1997. As of the Closing Date, the
Company is duly  incorporated and in good standing in its state of incorporation
and has paid all fees and taxes due and payable by it on or prior to the Closing


<PAGE>

Paramount Capital, Inc.
Page 38



Date necessary for the maintenance or  continuation of its corporate  existence.
As of the Closing  Date,  except as  disclosed  in the Term Sheet,  there are no
proceedings  or actions  contemplated  by the  Company,  relating to the merger,
liquidation, consolidation, or sale of all or substantially all of the assets or
business  of the  Company  or which  would  otherwise  threaten  or  impair  the
Company's corporate existence.

                  2.  Attached  hereto as  Attachment  B is a true,  correct and
complete copy of the By-laws of the Company,  as in full force and effect on the
Closing Date and at all times from October 26, 1997 through the Closing Date.

                  3. As of the Closing Date,  each of the Offering  Documents is
in the form authorized by the board of directors of the Company  pursuant to the
resolutions set forth in Attachment C.

                  4.  Attached  hereto as  Attachment  C is a true,  correct and
complete copy of resolutions  duly adopted at meetings of the Company's board of
directors duly called and held on January 13, 1998, which resolutions  authorize
the  issuance  and sale of the  Units and the  Placement  Options  and  Advisory
Options in accordance with the requirements of Delaware law, the Certificate and
By-laws of the Company,  are the only resolutions in effect adopted by the board
of  directors  of the  Company  or any  committee  thereof  with  respect to the
offering and sale of the units and the transactions  relating thereto, and which
have not been  revoked,  modified and amended or rescinded and are in full force
and effect on the Closing Date.

                  5.  Attached  hereto as  Attachment  D are true,  correct  and
complete copies of specimens of the  certificates  representing the Common Stock
and Class C Warrants  heretofore  approved and adopted by the board of directors
of the Company.  Each of the certificates  representing Common Stock and Class C
Warrants delivered on the Closing Date to each of the Purchasers pursuant to the
Subscription  Agreements has been executed by the genuine or facsimile signature
of officers of the Company who have been duly  elected or  appointed,  qualified
and acting as such  officers on the date such  certificates  were  executed  and
delivered, all in accordance with the Certificate and By-laws of the Company and
the requirements of applicable law.

                  6.  Attached  hereto as  Attachment  E is a true,  correct and
complete copy of the form of Placement and Advisory Options heretofore  approved
and adopted by the Board of Directors of the Company.  Each of the Placement and
Advisory Options delivered on the date hereof to each of the holders pursuant to
the  Placement  Agency  Agreement  has been executed by the genuine or facsimile
signature of officers of the Company who have been duly


<PAGE>

Paramount Capital, Inc.
Page 39



elected or  appointed,  qualified  and acting as such  officers on the date such
certificates were executed and delivered, all in accordance with the Certificate
and By-laws of the Company and the requirements of applicable law.

                  7. The minute  books and records of the  Company,  relating to
all proceedings of the  stockholders,  the Board of Directors of the Company and
the Compensation Committee,  the Audit Committee and the Nominating Committee of
such  Board  have been made  available  to  Kramer,  Levin,  Naftalis & Frankel,
counsel to  Paramount,  and, in such form,  are the  original  minute  books and
records of the  Company.  There have been no material  changes,  alterations  or
additions in such minutes or records since their  examination by Kramer,  Levin,
Naftalis & Frankel on behalf of Paramount.

                  8. Each person who, as an officer or director of the  Company,
signed any of the Offering  Documents or any other  document in connection  with
the offering and sale of the Units,  the Placement and the Advisory  Options and
the closing relating thereto was duly elected or appointed, qualified and acting
as such officer or director at the respective  times of the signing and delivery
thereof and was duly  authorized to sign such document on behalf of the Company,
and the  signature of each such person  appearing  on each such  document is the
genuine  signature of such  officer,  director or person duly  appointed for the
purpose of executing  such  documents  under valid powers of attorney,  and each
individual   who   signed   such   signature   pages,   personally   or   by  an
attorney-in-fact,  was then duly elected,  qualified and acting as an officer or
director of the Company as stated therein.

                  9. The following persons are, and have been at all times since
October 26,  1997,  duly  qualified  and acting  officers of the  Company,  duly
elected or appointed to the offices set forth opposite their  respective  names,
and the  signature  opposite  the name of each such  officer is his or her, or a
facsimile of his or her, authentic signature, and the seal affixed hereto is the
duly adopted seal of the Company:

    Name                          Office                            Signature



Stanley C. Erck      President, Chief Executive Officer
                              And Treasurer


<PAGE>

Paramount Capital, Inc.
Page 40


                  This certificate is made for the benefit of, and may be relied
upon by, Paramount,  Kramer, Levin, Naftalis & Frankel, as counsel to Paramount,
and each of the Purchasers.


                  IN WITNESS  WHEREOF,  I have  hereunto  set forth my hand this
23rd day of January, 1998.

              [SEAL]

                                          -------------------------------------
                                          Name:
                                          Title:  Secretary

                  I,  Stanley  C.  Erck,  President  of the  Company,  do hereby
certify that Lynette C. Fallon whose genuine  signature  appears above,  is, and
has been at all times since  October 26, 1997,  the duly  elected or  appointed,
qualified and acting Secretary of the Company.

                  IN WITNESS  WHEREOF,  I have  hereunto  set forth my hand this
23rd day of January, 1998.


                                          -------------------------------------
                                          Name: Stanley C. Erck
                                          Title: President

<PAGE>

                                                                       EXHIBIT Q
                                                            As of June 30, 1997



Procept, Inc.
840 Memorial Drive
Cambridge, MA 02139

Dear Sirs:

                  1.  This  is  to  confirm  our  understanding  that  Paramount
Capital,  Inc. and its affiliates and designees  ("Paramount") have been engaged
as a  non-exclusive  financial  advisor of Procept,  Inc. (the  "Company") for a
period of  twenty-four  (24) months  commencing  on the date hereof (as extended
pursuant to Paragraph 12 hereto,  or by mutual  agreement of the parties hereto,
the  "Term").  Capitalized  terms not  defined  herein  shall  have the  meaning
ascribed to such terms in the Letter of Intent (as defined below).

                  2. The Company will pay  Paramount a  non-refundable  retainer
fee for  Paramount's  services  hereunder  in an amount  equal to four  thousand
dollars ($4,000) per month,  minimum engagement of twenty-four (24) months, with
the first $20,000 of the retainer fee payable upon the Final Closing Date.

                  The  Company  also  agrees  to  pay  in  cash  all  reasonable
out-of-pocket  expenses incurred by Paramount in providing services requested by
Procept hereunder, including fees and disbursements of Paramount's counsel, such
expenses  to be paid  within ten (10) days of  submission  of a bill or bills by
Paramount from time to time.

                  3. Upon the  Closing of each  Investment  (as  defined  below)
during the Term or during the  twelve-month  period  following the expiration or
earlier  termination of the Term, the Company shall pay to Paramount a fee in an
amount  equal  to  nine  percent  (9%) of the  aggregate  dollar  value  of such
Investment  and shall  issue to  Paramount  warrants  to  purchase  an amount of
securities  equal to ten percent  (10%) of the  securities  sold as part of such
Investment at an exercise price equal to  one-hundred-ten  percent (110%) of the
price of such  securities,  exercisable  until  five (5) years  from the date of
issuance of such  warrants.  For the purposes of this  Agreement,  an Investment
shall mean any purchase of securities of the Company by an investor who is first
introduced  to the Company by or through  Paramount  and that is made during the
Term or during the twelve-month  period following the expiration of the Term. No
compensation  shall be due to  Paramount  pursuant  to this  paragraph  3 for an
Investment with respect to which Paramount is entitled to compensation  pursuant
to paragraph 4 of this Agreement or a Placement Agency Agreement (the "Placement
Agency  Agreement") to be entered into by and between  Paramount and the Company
as described in the Letter of Intent dated June 30, 1997 between  Paramount  and
the Company (the  "Letter of Intent") and provided  further that if the terms of
both the Placement  Agency  Agreement and this Agreement  would be applicable to
any particular  Investment,  the terms of the Placement  Agency  Agreement shall
govern and Paramount shall be entitled to the compensation set forth therein.

                  4. Upon  completion of the Series B Offering or the closing of
a Qualified


<PAGE>

Offering, the Company will sell to Paramount and/or its designees, for $.001 per
warrant  share,  warrants (the  "Advisory  Warrants") to purchase Units equal to
fifteen  percent  (15%) of the Units  sold in the  Series B  Offering  or of the
securities  sold in the Qualified  Offering,  which  Advisory  Warrants shall be
exercisable  for a period of five (5) years  commencing six (6) months after the
Series B Final Closing Date or the final  closing date of a Qualified  Offering,
at an exercise price equal to 110% of the initial offering price of the Series B
Units or of the initial  offering price of the securities  sold in the Qualified
Offering. The securities underlying the Advisory Warrants will not be subject to
mandatory  conversion  or redemption by the Company nor will they be callable by
the Company.  The Advisory  Warrants will contain a cashless  exercise  feature,
antidilution  provisions  and the right to have the  securities  underlying  the
Advisory Warrants included on the Shelf Registration Statement.

                  5. (a) Should the Company enter into an agreement with a party
first  introduced to the Company by or through  Paramount during or prior to the
Term pursuant to which the Company  consummates a sale,  merger,  consolidation,
tender offer,  business combination or similar transaction  involving a majority
of the business  assets or stock of the Company (a "Sale")  during the Term,  or
during the  twelve-month  period following the expiration of such Term, then the
Company  shall pay to  Paramount:  (i) a cash fee equal to eight percent (8%) of
the aggregate  consideration paid to the Company by the acquiror, such fee to be
payable in cash simultaneously with the closing of such Sale; and (ii) a warrant
(a  "Warrant")  to purchase a number of shares of Common Stock of the  surviving
entity equal to the product of (x) the quotient of the  aggregate  amount of the
aggregate  consideration  received  by the  Company or the  aggregate  amount of
equity received by the Company's shareholders as a result of the Sale divided by
the lesser of (i) the per share  value  attributed  to the  Common  Stock in the
Sale, if any (determined by dividing the aggregate consideration received by the
Company  by the  number of shares  received  by the  Company  as a result of the
Sale),  and (ii) the per share fair market value of the Common Stock at the time
of the closing of the Sale,  and (y) eight percent  (8%).  Each Warrant shall be
exercisable for at least five (5) years from the date of its respective issuance
at an exercise  price that is 110% of the fair market  value of the Common Stock
at the time each such Warrant is granted.

                           (b) Should the Company enter into an agreement with a
party first introduced to the Company by or through Paramount during or prior to
the Term pursuant to which the Company  consummates  a  transaction  wherein the
Company  acquires all or  substantially  all of the business  assets or stock of
another entity in which the Company is the surviving  entity (an  "Acquisition")
during the Term, or during the  twelve-month  period following the expiration of
such  Term,  then the  Company  shall  pay  Paramount:  (i) a fee equal to eight
percent (8%) of the  aggregate  consideration  paid by the Company to the entity
acquired, such fee to be payable in cash simultaneously with the closing of such
Acquisition;  and (ii) a warrant (a "Warrant") to purchase a number of shares of
Common  Stock of the  Company  equal to the  product of (x) the  quotient of the
aggregate  amount of the  aggregate  consideration  received by the Company as a
result of the  Acquisition  divided  by the  lesser  of (i) the per share  value
attributed  to the  Common  Stock  in the  Acquisition,  if any  (determined  by
dividing the  aggregate  consideration  received by the Company by the number of
shares received by the Company as a result of the Acquisition), and (ii) the per
share fair  market  value of the Common  Stock at the time of the closing of the
Acquisition,  and (y) eight percent (8%).  Each Warrant shall be exercisable for
at least five (5) years from the date of its respective  issuance at an exercise
price that is 110% of the fair market value of the Common Stock at the time each
such Warrant is granted.

                           (c) For purposes of calculating Paramount's fee under
this Paragraph 5, the aggregate consideration paid with respect to the business,
assets  or  stock of the  Company  shall  be  equal  to the  total of all  cash,
securities  and/or other assets paid for such  business,  assets or stock by the
acquiror. Aggregate consideration shall also include: (i)


<PAGE>

any commercial  bank or similar  indebtedness  of the Company which is repaid or
for which the  responsibility  to pay is assumed by the  acquiror in  connection
with such  transaction;  (ii) the greater of the stated value or the liquidation
value of  preferred  stock of the  Company  that is assumed or  acquired  by the
acquiror and that is not converted  into common stock upon the  consummation  of
such  transaction;  (iii)  future  payments  for which the acquiror is obligated
absolutely ("Acquiror Future Payments");  and (iv) future payments for which the
acquiror is obligated  upon the  attainment of  milestones or financial  results
("Acquiror Contingent Payments"). The fee to be paid to Paramount as a result of
Acquiror  Future  Payments  shall  be paid  upon  the  date of  closing  of such
Acquisition  and shall be valued at the  present  value of the  Acquiror  Future
Payments.  The fee to be paid to  Paramount  as a result of Acquiror  Contingent
Payments shall be paid upon the receipt of such payments by the Company.  In the
event that a Sale of the Company or an Acquisition by the Company is consummated
through a multiple-step transaction wherein the acquiror is not obligated either
absolutely or upon the  attainment  of  milestones or financial  results to make
future payments to further increase the acquiror's ownership in the Company (the
"Multiple-Step  Payments"),  the Company  agrees to pay  Paramount a fee on such
Multiple-Step  Payments which shall be calculated  pursuant to this Paragraph 5.
Such  fee  shall  be paid to  Paramount  upon  receipt  by the  Company  of such
Multiple-Step  Payments and shall be in addition to the fee paid to Paramount in
the first step of such transaction.

                  6. Should the Company enter into an agreement with an investor
first  introduced to the Company by or through  Paramount during or prior to the
Term  pursuant to which the Company  consummates  a  Strategic  Alliance(s)  (as
defined below),  or during the  twelve-month  period following the expiration of
such Term,  then the Company shall pay Paramount:  (a) a cash fee equal to eight
percent (8%) of the present  value of the  Aggregate  Consideration  (as defined
below) to be received by the Company, its shareholders or employees in each such
transaction;  and (b) a warrant (a  "Warrant") to purchase a number of shares of
Common  Stock of the  Company  equal to the  product of (x) the  quotient of the
amount of the  Aggregate  Consideration  received by the Company  divided by the
lesser  of (i) the  per  share  value  attributed  to the  Common  Stock  in the
Strategic Alliance,  if any (determined by dividing the aggregate  consideration
received  by the  Company by the number of shares  received  by the Company as a
result of the Strategic  Alliance),  and (ii) the per share fair market value of
the Common Stock at the time of the closing of the Strategic  Alliance,  and (y)
eight percent  (8%).  Each Warrant  shall be  exercisable  for at least five (5)
years from the date of its respective issuance at an exercise price that is 110%
of the fair market  value of the Common  Stock at the time each such  Warrant is
granted.  Such fee shall be paid to  Paramount in cash  simultaneously  with the
closing of each such transaction. For the purpose of calculating Paramount's fee
under this  Paragraph  6,  Aggregate  Consideration  shall  include,  but not be
limited to: (i) all payments made at the closing of such  transaction for equity
securities,  equity security rights or similar  rights;  (ii) technology  access
fees or similar  up-front  payments,  (iii)  other  future  payments,  including
without  limitation,  licensing fees, lump sum payments,  royalties and deferred
technology access fees, to be made to the Company or its employees for which the
Strategic  Alliance  partner(s) or other  counter-parties  (each a "Partner") is
obligated either absolutely ("Strategic Future Payments") or upon the attainment
of  milestones  or on a  percentage  or  royalty  basis  ("Strategic  Contingent
Payments");  (iv)  funding  provided,  arranged  or  introduced  by the  Partner
(through  reimbursement  or  otherwise)  relative to research  and  development,
testing,  clinical  trials  and  related  expenditures,  whether  such  work  is
performed,  subcontracted or managed by the Company or the Partner;  and (v) the
repayment or assumption by the Partner of obligations of the Company,  including
indebtedness  for money  borrowed or amounts owed by the Company to inventors or
owners of technology.  It is further  understood  that  Aggregate  Consideration
shall not be reduced by the amount of the fee due to  Paramount  hereunder.  Any
portion of the Aggregate  Consideration  constituting  Strategic Future Payments
shall  be paid at  closing  and  shall be  valued  at the  present  value of the
Strategic Future Payments.


<PAGE>

The fee to be paid to  Paramount as a result of  Strategic  Contingent  Payments
shall be paid upon the receipt of such  payments and shall be in addition to any
fees paid at closing. A "Strategic Alliance" may include, but is not limited to:
(i) any joint venture, partnership,  license or other contract for the research,
development,  manufacturing,  marketing,  distribution,  sale or other  activity
relating to the Company's present and/or future products;  (ii) the purchase of,
or  commitment  to  purchase  from the  Company,  less  than a  majority  of the
business, assets or stock of the Company by a Partner(s);  (iii) the sale of any
of the  Company's  assets  or any  rights in  respect  to its  products  and /or
technology;  and (iv) a  commitment  to provide  funding  for all or part of the
Company's research and development activities, whether such work is performed or
managed by the Company or the Partner.

                  For purposes of calculating the present value of any Strategic
Future  Payments,  Strategic  Contingent  Payments,  Acquiror Future Payments or
Acquiror  Contingent  Payments,  the Company and Paramount agree to discount all
such  payments by a discount  factor equal to fifteen  percent  (15%) per annum,
and,  where  necessary,  to use the  projections  which  have been  provided  to
prospective  Partners  in  the  course  of the  transaction  to  quantify  these
Strategic  Future  Payments,  Strategic  Contingent  Payments,  Acquiror  Future
Payments or  Acquiror  Contingent  Payments.  For the  purposes  of  calculating
Paramount's fee, securities  constituting part of Aggregate  Consideration which
are traded on a national or recognized foreign securities exchange or the Nasdaq
National  Market System shall be valued at the last closing bid price thereof on
the last trading date  immediately  preceeding the date of the  consummation  or
closing   of  any  such   transaction.   Such   securities   that   are   traded
over-the-counter  shall be valued at the mean  between  the latest bid and asked
prices on the last trading  date  immediately  preceeding  the  consummation  or
closing of any such transaction.

                  7.  Should  Paramount  introduce  the  Company to a  potential
product,  process,  intellectual  property or technology  which is  subsequently
licensed or otherwise  acquired by the Company,  the Company and Paramount shall
negotiate in good faith a fee for such  introduction  provided  that in no event
shall such fee be less than:  (a) $200,000 in cash; and (b) an equity payment in
an amount to be agreed upon between the parties, but in no event less than eight
percent (8%) of the total outstanding shares of common stock of the Company,  on
a fully diluted basis.

                  8. In the event that the Company,  its directors or management
initiate  any  discussions  with a  third  party  in  furtherance  of any  Sale,
Acquisition,  Investment or Strategic Alliance or receive any meaningful inquiry
or are aware of the interest of any third party concerning a Sale,  Acquisition,
Investment or Strategic  Alliance which is the subject of this  Agreement,  they
shall promptly inform Paramount of the party and its interest.

                  9. Unless required by legal  proceeding,  any financial advice
rendered by  Paramount  pursuant to this  Agreement  (and the  existence of this
Agreement)  shall not be disclosed  publicly in any manner  without  Paramount's
prior  written  approval  and shall be  treated by the  Company as  confidential
information.  The Company shall provide  Paramount  with all financial and other
information  requested by Paramount  for the purposes of rendering  its services
pursuant to this Agreement.

                  10.  All  non-public  information  given to  Paramount  by the
Company shall be treated by Paramount as confidential  information and shall not
be  used  by  Paramount  except  in  rendering  its  services  pursuant  to this
Agreement. Paramount may rely, without independent verification, on the accuracy
and  completeness  of any  information  furnished  to  Paramount by the Company,
subject to its obligations under the securities laws.

                  11.  In the  event  that  Paramount  becomes  involved  in any
capacity in any


<PAGE>

action,  proceeding,  investigation  or  inquiry in  connection  with any matter
referred to in this Agreement or arising out of the matters contemplated by this
Agreement,  the  Company  shall  reimburse  Paramount  for its  legal  and other
expenses  (including the cost of any  investigation and preparation) as they are
incurred by  Paramount  in  connection  therewith.  The  Company  also agrees to
indemnify  each of  Paramount,  the  directors,  officers,  employees and agents
thereof (the  "Indemnitees"),  pay on demand and protect,  defend, save and hold
each  Indemnitee  harmless  from and against any and all  liabilities,  damages,
losses, settlements, claims, actions, suits, penalties, fines, costs or expenses
(including,  without  limitation,  attorneys'  fees)  (any of the  foregoing,  a
"Claim")  incurred by or asserted  against any  Indemnitee  of whatever  kind or
nature,  arising  from,  in  connection  with or  occurring  as a result of this
Agreement or the matters contemplated by this Agreement. The foregoing agreement
shall be in addition to any rights that any Indemnitee may have at common law or
otherwise.

                  12.  The  Term of this  Agreement  shall be  twenty-four  (24)
months commencing on the date hereof. Thereafter,  this Agreement shall continue
on a month to month basis until  terminated  by either  party upon not less than
sixty (60) days notice with the monthly retainer fee payable on the first day of
each  month  (the  "Extended  Term");  provided,   however,  regardless  of  any
termination,  the rights to compensation  contained in Paragraphs 3, 4 and 5 and
to indemnity  and  reimbursement  contained in  Paragraph 11 shall  survive.  In
addition to any retainer fees,  Paramount shall be entitled to the reimbursement
of reasonable  expenses  incurred by Paramount as a result of services  rendered
prior to the date of the termination.

                  13.  This  Agreement  shall be governed  by and  construed  in
accordance  with the laws of the State of New York without  regard to principles
of conflicts of law. The parties hereto irrevocably  consent to the jurisdiction
of the courts of the State of New York and of any federal  court located in such
State in connection with any action or proceeding  arising out of or relating to
this Agreement,  any document or instrument delivered pursuant to, in connection
with or simultaneously with this Agreement, or a breach of this Agreement or any
such document or instrument. In any such action or proceeding, each party hereto
waives  personal  service of any summons,  complaint or other process and agrees
that service  thereof may be made in  accordance  with this  Section 13.  Within
thirty  (30) days after  such  service,  or such  other time as may be  mutually
agreed  upon in  writing by the  attorneys  for the  parties  to such  action or
proceeding,  the party so served shall appear or answer such summons,  complaint
or other process.

                  14. This  Agreement  shall be binding upon  Paramount  and the
Company and the  successors  and  assigns of  Paramount.  The Company  shall not
assign or sell all or substantially all of the Company's  business and/or assets
without  first  requiring in writing that such assignee or successor is bound by
the provisions of this Agreement.

                  15. (a) Paramount shall not have any obligation to the Company
not to (i) engage in the same or similar  activities or lines of business as the
Company or develop or market any products, services or technologies that does or
may in the future  compete,  directly or indirectly,  with those of the Company,
(ii) invest or own any interest  publicly or privately in, or develop a business
relationship  with,  any  corporation,  partnership  or other  person  or entity
engaged in the same or similar  activities or lines or business as, or otherwise
in  competition  with,  the  Company  or (iii)  do  business  with  any  client,
collaborator, licensor, consultant, vendor or customer of the Company. Paramount
and any of its officers, directors, employees or former employees and affiliates
shall not have any obligation, or be liable, to the Company solely on account of
the conduct  described in the preceding  sentence.  In the event that  Paramount
and/or any officer,  director,  employee or former employee or affiliate thereof
acquires knowledge of a potential transaction, agreement, arrangement or


<PAGE>

other matter which may be a corporate  opportunity  for both  Paramount  and the
Company,  neither  Paramount  nor any of its officers,  directors,  employees or
former  employees or affiliates shall have any duty to communicate or offer such
corporate  opportunity  to the  Company  and  neither  Paramount  nor any of its
officers, directors, employees or former employees or affiliates shall be liable
to the Company for breach of any fiduciary  duty, as a stockholder or otherwise,
solely by reason of the fact that  Paramount or any of its officers,  directors,
employees or former  employees or  affiliates  pursue or acquire such  corporate
opportunity for Paramount,  direct such corporate  opportunity to another person
or entity or communicate or fail to  communicate  such corporate  opportunity or
entity to the Company.

                  (b) The  provisions of this Section 15 shall be enforceable to
the fullest extent permitted by law.


<PAGE>

                  Please  confirm that the foregoing is in accordance  with your
understanding  by signing and  returning  to us the  enclosed  duplicate of this
letter.


                                        Sincerely yours,

                                        PARAMOUNT CAPITAL, INC.




                                  By:   
                                       ---------------------------------
                                        Name:  Lindsay A. Rosenwald, M.D.
                                        Title:    Chairman


Confirmed as of the date hereof:

PROCEPT, INC.



By:
- ------------------------
Name:  John F. Dee
Title: President and CEO


<PAGE>

                                                                       EXHIBIT R

THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE BEEN ACQUIRED FOR INVESTMENT
AND NEITHER SUCH SECURITIES NOR THE SECURITIES ISSUABLE UPON EXERCISE HEREOF NOR
THE SECURITIES  ISSUABLE UPON EXERCISE  THEREOF HAVE BEEN  REGISTERED  UNDER THE
SECURITIES ACT OF 1933, AS AMENDED OR ANY STATE  SECURITIES LAW. SUCH SECURITIES
MAY NOT BE SOLD OR  TRANSFERRED  IN THE ABSENCE OF SUCH  REGISTRATION  OR UNLESS
SUCH SALE OR TRANSFER IS EXEMPT FROM THE  REGISTRATION  AND PROSPECTUS  DELIVERY
REQUIREMENTS OF SAID ACT.



                                  PROCEPT, INC.

                                    FORM OF
          UNIT PURCHASE OPTION FOR THE PURCHASE OF UNITS CONSISTING OF
                       SHARES OF COMMON STOCK AND WARRANTS


                                                       NO. __ _____ OPTION UNITS


                      FOR VALUE RECEIVED,  Procept, Inc., a Delaware corporation
(the "COMPANY"),  hereby certifies that _______________________, or its assigns,
is  entitled  to  purchase  from the  Company,  at any time or from time to time
commencing  on OCTOBER 9, 1998 and prior to 5:00  P.M.,  New York City time,  on
OCTOBER 9, 2003, up to ______ Units,  each Unit  consisting of (a) the number of
shares  (rounded to the nearest  whole share with 0.5 of one share being rounded
upward) (the "Offering Quantity") of Common Stock of the Company, par value $.01
per share, (the "Common Stock")  determined by dividing 100,000 by the lesser of
(i) $0.50 and (ii) 75% of the  Trading  Price (as  defined  in the  Subscription
Agreement  as  hereinafter  defined)  as of (x) the  initial  closing  date (the
"Initial  Closing Date",  (y) any interim closing date (each an "Interim Closing
Date") or (z) the final closing date (the "Final  Closing Date") of the Offering
(as defined below) whichever is lowest (the "Offering Price"),  and (b) warrants
(the "Class C Warrants")  to purchase,  at an exercise  price per share equal to
the  Offering  Price,  at any time prior to the fifth  anniversary  of the Final
Closing Date (as defined herein) a number of shares of Common Stock equal to the
Offering  Quantity,  for an  aggregate  Unit  purchase  price  of  _____________
(computed on the basis of $110,000 per Unit).  (Hereinafter,  (i) said Units are
referred to as the  "UNITS",  (ii) said Class C Warrants  are referred to as the
"WARRANTS",  (iii) the Common Stock included in the Units and  purchasable  upon
exercise of the Warrants,  is referred to as the "COMMON STOCK", (iv) the shares
of the  Common  Stock  purchasable  hereunder  or under  any  other  Option  (as
hereinafter  defined) (or the shares of any capital stock purchasable  hereunder
or under  any  other  Option in lieu of Common  Stock)  are  referred  to as the
"COMMON SHARES", (v) the shares of Common Stock purchasable upon exercise of the
Warrants  hereunder  or under any other  Option  (as  hereinafter  defined)  are
referred to as the "WARRANT SHARES",  (vi) the aggregate  purchase price payable
for the Units  hereunder is referred to as the "AGGREGATE  OPTION PRICE",  (vii)
the price payable (initially  $110,000 per Unit, subject to adjustment) for each
of the Units,  hereunder  is  referred to as the "PER UNIT  PRICE",  (viii) this
Option, all similar Options issued on the date hereof and all warrants hereafter
issued in exchange or  substitution  for this Option or such similar Options are
referred to as the  "OPTIONS"  and (ix) the holder of this Option is referred to
as the "HOLDER" and the holder of this Option and all other Options are referred
to as the  "HOLDERS"  and  Holders  of more  than  fifty  percent  (50%)  of the
outstanding Options are


                                       -1-


<PAGE>

referred to as the "MAJORITY OF THE HOLDERS." The Aggregate  Option Price is not
subject  to  adjustment.  The  Per  Unit  Price  is  subject  to  adjustment  as
hereinafter provided; in the event of any such adjustment,  the number of Common
Shares or Warrant Shares, as the case may be,  deliverable upon exercise of this
Option shall be adjusted in accordance with paragraph 3(i) below.

                      This  Option,   together   with  options  of  like  tenor,
constituting in the aggregate  Options to purchase ______ Units,  was originally
issued  pursuant  to an agency  agreement  between  the  Company  and  Paramount
Capital,  Inc., as placement agent (THE "PLACEMENT  AGENT") in connection with a
private placement (THE "OFFERING") of ______ Units (THE "OFFERING UNITS"),  each
Offering  Unit  consisting of Common Stock (THE  "OFFERING  COMMON") and Class C
Warrants  (THE  "OFFERING  WARRANTS")  for which the  Placement  Agent  acted as
Placement Agent.

                      1.       EXERCISE OF OPTION.

                      (a) This Option may be exercised,  in whole at any time or
in part from time to time, commencing on OCTOBER 9, 1998 and prior to 5:00 P.M.,
New York City time, on OCTOBER 9, 2003 by the Holder:

                      (i) by the surrender of this Option (with the subscription
              form at the end hereof duly  executed) at the address set forth in
              Subsection  10(a)  hereof,  together  with  proper  payment of the
              Aggregate Option Price, or the proportionate  part thereof if this
              Option is exercised in part,  with payment for the number of Units
              made by certified or official  bank check  payable to the order of
              the Company; or

                      (ii) by the  surrender  of this Option  (with the cashless
              exercise  form at the  end  hereof  duly  executed)  (A  "CASHLESS
              EXERCISE")  at the address set forth in Subsec tion 10(a)  hereof.
              The exchange of the Option shall take place on the date  specified
              in the Cashless  Exercise Form or, if later, the date the Cashless
              Exercise Form is surrendered to the Company (THE "EXCHANGE DATE").
              Such  presentation  and surrender  shall be deemed a waiver of the
              Holder's  obligation  to pay the Aggregate  Option  Price,  or the
              proportionate part thereof if this Option is exercised in part. In
              the event of a Cashless  Exercise this Option shall  represent the
              right to subscribe for and acquire the number of Units (rounded to
              the  next  highest  integer)  equal  to (x) the  number  of  Units
              specified by the Holder in its Cashless  Exercise Form (THE "TOTAL
              NUMBER")  (such  number not to exceed the maximum  number of Units
              subject to this Option, as may be adjusted from time to time) less
              (y) the number of Units equal to the quotient obtained by dividing
              (A) the  product  of the Total  Number and the  existing  Per Unit
              Price by (B) the Market  Price Per Unit.  "MARKET  PRICE PER UNIT"
              shall mean first,  if there is a trading  market as  indicated  in
              Subsection (A) below for the Units, such Market Price Per Unit and
              if there is no such trading market in the Units, then Market Price
              Per Unit shall equal the sum of the aggregate  Market Price of all
              shares of Common Stock (on per share basis,  the "MARKET PRICE PER
              SHARE OF COMMON STOCK") and Warrants (on a per warrant basis,  the
              "MARKET  PRICE  PER  WARRANT")  which  comprise  a Unit,  with the
              meanings indicated in Subsections (B) through (G) below:

                               (A)  If  the  Units  are  listed  on  a  national
                      securities  exchange  or listed or  admitted  to  unlisted
                      trading  privileges on such exchange or listed for trading
                      on the  Nasdaq  National  Market  or the  Nasdaq  Smallcap
                      Market,  the  Market  Price  Per  Unit  shall  be the last
                      reported sale price (or if no last sale, the last


                                       -2-


<PAGE>

                      quoted  ask  price)  of the  Units on   such  exchange  or
                      market for  the trading  day   immediately  preceding  the
                      Exchange Date; or

                               (B) If the Common Stock or Warrants,  as the case
                      may be, are listed on a national  securities  exchange  or
                      admitted to unlisted  trading  privileges on such exchange
                      or listed for trading on the Nasdaq National Market or the
                      Nasdaq  Smallcap  Market,  the  Market  Price Per Share of
                      Common Stock,  or Market Price Per Warrant,  respectively,
                      shall be the last reported sale price (or if no last sale,
                      the  last  quoted  ask  price)  of  the  Common  Stock  or
                      Warrants, respectively, on such exchange or market for the
                      trading day immediately preceding the Exchange Date; or

                               (C) If the Common Stock or Warrants,  as the case
                      may be, are not so listed or admitted to unlisted  trading
                      privileges, the Market Price Per Share of Common Stock, or
                      Market Price Per Warrant, respectively,  shall be the last
                      reported  sale price (or if no last sale,  the last quoted
                      ask  price)  of  the  Common  Stock  or  Warrants  in  the
                      over-the-counter   market  as  reported  by  the  National
                      Quotation  Bureau or similar  organization  or in the Pink
                      Sheets  for the  trading  day  immediately  preceding  the
                      Exchange Date; or

                               (D) If the  Common  Stock  is  not so  listed  or
                      admitted to unlisted trading privileges and the sale price
                      is (or if no last sale,  the last quoted ask price) not so
                      reported, the Market Price Per Share of Common Stock shall
                      be the  fair  market  value  as  determined  by  agreement
                      between  the  Board  of  Directors  of the  Company  and a
                      Majority of the Holders; or

                               (E) If neither  clause (B) nor (C) applies to the
                      Warrants,  then the Market  Price Per Warrant  shall be an
                      amount  equal to the  difference  between  (i) the  Market
                      Price Per Share of Common Stock which may be received upon
                      the exercise of the Warrants,  as determined in paragraphs
                      (B),  (C) and (D) above,  and (ii) the per share  exercise
                      price of the Warrants then in effect.

                               (F)  If  the  Company  and  the  Majority  of the
                      Holders  are unable to reach  agreement  on any  valuation
                      matter,   such   valuation   shall  be  submitted  to  and
                      determined   by  a   nationally   recognized   independent
                      investment  bank selected by the Board of Directors of the
                      Company  and the  Majority  of the  Holders  (or,  if such
                      selection cannot be agreed upon promptly,  or in any event
                      within ten days,  then such  valuation  shall be made by a
                      nationally recognized  independent investment banking firm
                      selected by the American  Arbitration  Association  in New
                      York  City in  accordance  with its  rules),  the costs of
                      which valuation shall be paid for by the Company.

                      (iii)  by  the   surrender   of  this  Option   (with  the
              subscription  (promissory  note)  form  at  the  end  hereof  duly
              executed)  at the address set forth in  Subsection  10(a)  hereof,
              together with the  presentation  of a promissory note made payable
              to the Company,  duly  executed and in the form at the end hereof.
              Such promissory note shall be secured by the securities underlying
              this Option, which shall be held in safe-keeping by the Company as
              collateral for such indebtedness.



                                                  -3-


<PAGE>



                      (b) If this  Option is  exercised  in part,  the Holder is
entitled  to  receive a new  Option  covering  the  Units,  which  have not been
exercised and setting forth the proportionate part of the Aggregate Option Price
applicable to such Units.  Upon  surrender of this Option,  the Company will (i)
issue a certificate  or  certificates  in the name of the Holder for the largest
number of whole  shares of the  Common  Stock and  Warrants  to which the Holder
shall be  entitled  and, if this Option is  exercised  in whole,  in lieu of any
fractional  shares of the Common  Stock or Warrants to which the Holder shall be
entitled,  pay to the Holder  cash in an amount  equal to the fair value of such
fractional  shares  (determined  in  such  reasonable  manner  as the  Board  of
Directors of the Company shall determine), and (ii) deliver the other securities
and properties receivable upon the exercise of this Option, or the proportionate
part thereof if this Option is exercised in part,  pursuant to the provisions of
this Option;  provided,  however  that if this Option is  exercised  pursuant to
paragraph  1(a)(iii),  the Company  will issue but shall not deliver such shares
until such time as the promissory  note and all accrued  interest  thereon shall
have been paid in full, and will hold such shares in safekeeping.

                      (c) This  Option  shall  be  exercisable  only  for  Units
consisting of Warrants and Common Shares at the then  applicable  Per Unit Price
(including any adjustment pursuant to Section 3 below).

                      2.  RESERVATION  OF  WARRANT  SHARES  AND  COMMON  SHARES;
LISTING.  The Company agrees that,  prior to the expiration of this Option,  the
Company  will at all times (a) have  authorized  and in  reserve,  and will keep
available,  solely for issuance  and delivery  upon the exercise of this Option,
the Units,  the Warrants and the Common Shares  underlying  such Units and other
securities  and  properties  as from time to time shall be  receivable  upon the
exercise of this Option, free and clear of all restrictions on sale or transfer,
other than under  Federal or state  securities  laws,  and free and clear of all
preemptive  rights and rights of first  refusal and (b) have  authorized  and in
reserve, and will keep available,  solely for issuance or delivery upon exercise
of the Warrants,  the shares of Common Stock,  the Warrant Shares and the Common
Shares  and  other  securities  and  properties  as from  time to time  shall be
receivable  upon such exercise,  free and clear of all  restrictions  on sale or
transfer,  other than under Federal or state securities laws, and free and clear
of all preemptive rights and rights of first refusal;  and (c) if the Company is
listed or hereafter lists its Common Stock on any national securities  exchange,
the Nasdaq National Market or the Nasdaq Smallcap  Market,  use its best efforts
to keep the Common Shares authorized for listing on such exchange upon notice of
issuance.

                      3.       PROTECTION AGAINST DILUTION.

                      (a) The anti-dilution  provisions of the Warrant Agreement
shall protect the Holder from dilution of the purchase rights represented by the
Warrants (it being  understood  for this purpose that the Holder shall be deemed
to own the Warrants  commencing on October 9, 1998). In addition,  the following
anti-dilution  provisions shall protect the Holder from dilution  resulting from
the issuance of Common Stock and other securities:

                      (i)  If the  Company  shall  issue  or  distribute  to the
              holders of shares of Common  Stock  evidence of its  indebtedness,
              any other securities of the Company or any cash, property or other
              assets (excluding a subdivision,  combination or reclassification,
              or dividend  or  distribution  payable in shares of Common  Stock,
              referred  to in  Subsection  3(a)(ii),  and  also  excluding  cash
              dividends or cash  distributions  paid out of net profits  legally
              available therefor in the full amount thereof


                                                  -4-


<PAGE>

              (any such  non-excluded  event being herein called a "COMMON STOCK
              SPECIAL  DIVIDEND")),  the Per Unit  Price  shall be  adjusted  by
              multiplying  the Per Unit Price then in effect by a fraction,  (A)
              the numerator of which shall be (x) the then current  Market Price
              Per Share of Common  Stock in  effect on the  record  date of such
              issuance  or  distribution  less (y) the  fair  market  value  (as
              determined in good faith by the  Company's  Board of Directors) of
              the evidence of  indebtedness,  cash,  securities or property,  or
              other assets  issued or  distributed  in such Common Stock Special
              Dividend  applicable  to one  share of  Common  Stock  and (B) the
              denominator  of which shall be the then  current  Market Price Per
              Share  of  Common  Stock  in  effect  on the  record  date of such
              issuance or  distribution.  An  adjustment  made  pursuant to this
              Subsection  3(b)(i) shall become effective  immediately  after the
              record date of any such Common Stock Special Dividend.

                      (ii) If the  Company  shall (A) pay a  dividend  or make a
              distribution  on its capital stock in shares of Common Stock,  (B)
              subdivide  its  outstanding  shares of Common Stock into a greater
              number of shares,  (C)  combine its  outstanding  shares of Common
              Stock   into  a   smaller   number  of  shares  or  (D)  issue  by
              reclassification  of its Common Stock any shares of capital  stock
              of  the  Company,   the  Per  Unit  Price  shall  be  adjusted  by
              multiplying  the Per Unit Price by a fraction,  the  numerator  of
              which shall be the number of Common  Shares  which this Option was
              exercisable  for prior to such action and the denominator of which
              shall be the  number of Common  Shares  which a Holder  would have
              owned  immediately  following  such  action had such  Option  been
              exercised  immediately  prior  to the  record  or  effective  date
              therefor.  An adjustment made pursuant to this Subsection 3(a)(ii)
              shall become  effective  immediately  after the record date in the
              case of a dividend  or  distribution  and shall  become  effective
              immediately after the effective date in the case of a subdivision,
              combination or reclassification.

                      (iii) Except as provided in Subsections  3(a)(i) and 3(e),
              in case the  Company  shall  issue or sell any Common  Stock,  any
              securities  convertible into Common Stock, any rights,  options or
              warrants to purchase  Common Stock or any  securities  convertible
              into Common Stock, in each case for a price per share or entitling
              the holders  thereof to purchase Common Stock at a price per share
              (determined by dividing (A) the total amount,  if any, received or
              receivable by the Company in consideration of the issuance or sale
              of such securities plus the total  consideration,  if any, payable
              to the Company upon  exercise or  conversion  thereof (the "COMMON
              STOCK TOTAL CONSIDERATION") by (B) the number of additional shares
              of  Common  Stock  issued,  sold  or  issuable  upon  exercise  or
              conversion of such  securities)  which is less than either (i) the
              then  current  Market Price Per Share of Common Stock in effect on
              the  date of such  issuance  or sale or (ii)  the Per  Unit  Price
              divided by the number of shares of Common  Stock that each Unit is
              then  exercisable  for, the Per Unit Price shall be adjusted as of
              the  date of such  issuance  or sale by  multiplying  the Per Unit
              Price then in effect by a fraction,  the  numerator of which shall
              be (x)  the  sum of (1) the  number  of  shares  of  Common  Stock
              outstanding  on the record date of such  issuance or sale plus (2)
              the Total  Consideration  divided by (I) the then  current  Market
              Price of the  Common  Stock or (II) the  quotient  of the Per Unit
              Price  divided by the  number of shares of Common  Stock that each
              Unit  is then  exercisable  for,  whichever  is  greater,  and the
              denominator  of which  shall be (y) the number of shares of Common
              Stock outstanding on the record


                                       -5-


<PAGE>

              date  of  such  issuance  or  sale  plus  the  maximum  number  of
              additional  shares of Common Stock  issued,  sold or issuable upon
              exercise or conversion of such securities.

              (iv) In accordance  with Section 6 of this Unit  Purchase  Option,
              notwithstanding   the   anti-dilution   provisions  set  forth  in
              Subsections  3(a)(i)-(iii),  if an event set forth in  Subsections
              3(a)(i)-(iii)  (a "TRIGGER  EVENT") shall occur, and provided that
              the anti-dilution  provisions of the Common Stock, as set forth in
              Article  VI of the  Subscription  Agreement,  shall  apply to such
              Trigger  Event,  then any  adjustments  as a result of the Trigger
              Event  shall  occur  as  follows:  (A)  first,  the  anti-dilution
              provisions,  as set  forth  in  Article  VI shall  apply;  and (B)
              second,  the  anti-dilution  provisions  set forth in  Subsections
              3(a)(i)-(iii)  shall apply only to the extent that the application
              of such provisions shall result in the Holder receiving additional
              shares of capital stock of the Company, having the Per Option Unit
              Price reduced or otherwise  further improve the economic  position
              of the Holder.

              (b) No adjustment  in the Per Unit Price shall be required  unless
such  adjustment  would  require an  increase  or decrease of at least $0.05 per
Unit;  provided,  however,  that any adjustments which by reason of this Section
3(b) are not required to be made shall be carried forward and taken into account
in any subsequent adjustment; provided, further, however, that adjustments shall
be required and made in accordance  with the provisions of this Section 3 (other
than this Subsection  3(b)) not later than such time as may be required in order
to preserve the tax-free  nature of a distribution to the Holder of this Option.
All  calculations  under this  Section 3 shall be made to the nearest cent or to
the nearest  1/100th of a share,  as the case may be. Anything in this Section 3
to the  contrary  notwithstanding,  the  Company  shall be entitled to make such
reductions in the Per Unit Price,  in addition to those required by this Section
3, as it in its  discretion  shall deem to be  advisable in order that any stock
dividend,  subdivision of shares or  distribution of rights to purchase stock or
securities  convertible or exchangeable  for stock hereafter made by the Company
to its stockholders shall not be taxable.

              (c)  Whenever  the Per Unit Price is  adjusted as provided in this
Section 3 and upon any  modification  of the  rights of a Holder of  Options  in
accordance  with this  Section 3, the  Company  shall  promptly  prepare a brief
statement of the facts requiring such adjustment or modification  and the manner
of computing the same and cause copies of such  certificate  to be mailed to the
Holders of the  Options.  The Company  may, but shall not be obligated to unless
requested  by the Holders of more than fifty  percent  (50%) of the  outstanding
Options,  obtain, at its expense,  a certificate of a firm of independent public
accountants of recognized  standing  selected by the Board of Directors (who may
be the regular auditors of the Company) setting forth the Per Unit Price and the
number of Warrants,  Warrant Shares or Common Shares,  as the case may be, after
such  adjustment or the effect of such  modification,  a brief  statement of the
facts requiring such adjustment or modification  and the manner of computing the
same and cause  copies of such  certificate  to be mailed to the  Holders of the
Options.

              (d) If the Board of  Directors  of the Company  shall  declare any
dividend or other  distribution  with  respect to the Common  Stock other than a
cash  distribution out of earned surplus,  the Company shall mail notice thereof
to the  Holders of the  Options  not less than 10 days prior to the record  date
fixed for determining  stockholders  entitled to participate in such dividend or
other distribution.


                                       -6-


<PAGE>

              (e) No  adjustment  in the Per Unit Price shall be required in the
case of the issuance by the Company of Common Stock (i) pursuant to the exercise
of any  Option or (ii)  pursuant  to (A) the  exercise  of any stock  options or
warrants  currently  outstanding or (B) securities  issued after the date hereof
pursuant to any Company benefit plan;  provided,  however,  that with respect to
Subsection 3(e)(ii),  the issuance of such securities were approved by the Board
of Directors of the Company (or a committee  thereof) and were issued at a price
no less than the Market Price of the securities on the date of issuance.

              (f) In case of any capital reorganization or reclassification,  or
any  consolidation or merger to which the Company is a party other than a merger
or consolidation in which the Company is the continuing corporation,  or in case
of any sale or conveyance to another entity of the property of the Company as an
entirety  or  substantially  as a  entirety,  or in the  case  of any  statutory
exchange of securities with another corporation (including any exchange effected
in connection with a merger of a third corporation into the Company), the Holder
of this Option  shall have the right  thereafter  to receive on the  exercise of
this Option the kind and amount of securities,  cash or other property which the
Holder would have owned or have been entitled to receive  immediately after such
reorganization,  reclassification,  consolidation,  merger,  statutory exchange,
sale or  conveyance  had this Option  been  exercised  immediately  prior to the
effective date of such reorganization, reclassification,  consolidation, merger,
statutory  exchange,  sale or  conveyance  and in any such case,  if  necessary,
appropriate  adjustment  shall be made in the  application of the provisions set
forth in this Section 3 with respect to the rights and  interests  thereafter of
the  Holder  of this  Option  to the end that the  provisions  set forth in this
Section 3 shall thereafter corres pondingly be made applicable, as nearly as may
reasonably  be,  in  relation  to any  shares  of stock or other  securities  or
property  thereafter  deliverable  on the  exercise  of this  Option.  The above
provisions  of  this   Subsection  3(f)  shall  similarly  apply  to  successive
reorganizations,   reclassifica  tions,   consolidations,   mergers,   statutory
exchanges,  sales or  conveyances.  The Company  shall require the issuer of any
shares of stock or other  securities or property  thereafter  deliverable on the
exercise  of  this  Option  to be  responsible  for  all of the  agreements  and
obligations  of  the  Company  hereunder.  Notice  of any  such  reorganization,
reclassification,  consolidation, merger, statutory exchange, sale or conveyance
and of said provisions so proposed to be made, shall be mailed to the Holders of
the  Options  not  less  than 30 days  prior  to  such  event.  A sale of all or
substantially  all of the assets of the Company for a  consideration  consisting
primarily  of  securities  shall be deemed a  consolidation  or  merger  for the
foregoing purposes.

              (g) If, as a result of an adjustment made pursuant to this Section
3, the Holder of any Option  thereafter  surrendered  for exercise  shall become
entitled to receive  shares of two or more classes of capital stock or shares of
Common  Stock and other  capital  stock of the  Company,  the Board of Directors
(whose  determination  shall be  conclusive  and shall be described in a written
notice  to the  Holder of any  Option  promptly  after  such  adjustment)  shall
determine the  allocation of the adjusted Per Unit Price between or among shares
or such  classes of capital  stock or shares of Common  Stock and other  capital
stock.

              (h)  Upon the  expiration  of any  rights,  options,  warrants  or
conversion  privileges,  if such  shall not have been  exercised,  the number of
Units  purchasable  upon exercise of this Option,  to the extent this Option has
not then been exercised,  shall,  upon such expiration,  be readjusted and shall
thereafter be such as they would have been had they been originally adjusted (or
had the original adjustment not been required,  as the case may be) on the basis
of (i) the fact that  Common  Stock,  if any,  actually  issued or sold upon the
exercise of such rights,  options,  warrants or conversion privileges,  and (ii)
the fact that such shares of Common Stock, if any, were


                                       -7-


<PAGE>

issued or sold for the consideration  actually received by the Company upon such
exercise plus the  consideration,  if any,  actually received by the Company for
the issuance, sale or grant of all such rights, options,  warrants or conversion
privileges  whether  or  not  exercised;   provided,   however,   that  no  such
readjustment shall have the effect of decreasing the number of Units purchasable
upon  exercise  of this  Option by an  amount  in  excess  of the  amount of the
adjustment  initially  made in  respect of the  issuance,  sale or grant of such
rights, options, warrants or conversion privileges.

              (i)  Whenever  the Per Unit Price  payable  upon  exercise of each
Option is  adjusted  pursuant  to this  Section  3, (i) the  number of shares of
Common Stock included in a Unit shall  simultaneously be adjusted by multiplying
the number of shares of Common  Stock  included in a Unit  immediately  prior to
such  adjustment  by the Per Unit  Price  in  effect  immediately  prior to such
adjustment  and  dividing  the product so  obtained  by the Per Unit  Price,  as
adjusted  and (ii) the  number of shares  of  Common  Stock or other  securities
issuable  upon  exercise of the Warrants  included in the Units and the exercise
price payable for each of the Warrant Shares (initially $0.50 per Warrant Share,
subject to  adjustment)  pursuant  to the  Warrant  terms  shall be  adjusted in
accordance with the terms of the Warrant Agreement applicable to holders of such
Warrants.

              (k) In case the  Company  shall  modify the rights of  conversion,
exchange or exercise of any of the securities  referred to in Section  3(a)(iii)
or any other securities of the Company convertible,  exchangeable or exercisable
for  shares of Common  Stock,  for any  reason  other  than an event  that would
require  adjustment to prevent  dilution,  so that the  consideration  per share
received by the Company after such  modification is less than either (x) the Per
Unit Price  divided  by the  number of shares of Common  Stock that each Unit is
then exercisable for or (y) the Market Price per Share of Common Stock as of the
date  prior to such  modification,  then  such  securities,  to the  extent  not
theretofore exercised,  converted or exchanged,  shall be deemed to have expired
or terminated immediately prior to the date of such modification and the Company
shall be deemed,  for purposes of calculating any  adjustments  pursuant to this
Section 3, to have issued such new securities upon such new terms on the date of
modification.  Such adjustment  shall become effective as of the date upon which
such modification shall take effect.

                      4. FULLY PAID STOCK;  TAXES.  The Company  agrees that the
shares of the Common Stock  represented by each and every certificate for Common
Shares  delivered  on the exercise of this Option and the shares of Common Stock
delivered upon the exercise of the Warrants, shall at the time of such delivery,
be validly issued and outstanding, fully paid and nonassessable, and not subject
to preemptive  rights or rights of first refusal,  and the Company will take all
such actions as may be  necessary to assure that the par value or stated  value,
if any,  per share of the Common Stock is at all times equal to or less than the
then Per Unit Price. The Company further  covenants and agrees that it will pay,
when due and  payable,  any and all Federal and state stamp,  original  issue or
similar taxes which may be payable in respect of the issue of any Warrant Share,
Common Share or any certificate  thereof to the extent  required  because of the
issuance by the Company of such security.

                      5.       REGISTRATION UNDER SECURITIES ACT OF 1933.

                      (a) The Holder  shall,  with respect to the Common  Shares
only, have the right
to  participate  in the  registration  rights  granted to holders of Registrable
Securities   pursuant  to  Section  5  of  the   subscription   agreements  (the
"Subscription  Agreements")  between  such  holders  and the  Company  that were
entered into at the time of the initial sale of the Units. By acceptance


                                       -8-


<PAGE>

of this Option,  the Holder agrees to comply with the provisions in Section 5 of
the Subscription Agreement to same extent as if it were a party thereto.

                      (b) Until all Common  Shares and Warrant  Shares have been
sold under a
Registration  Statement or pursuant to Rule 144 under the Act, the Company shall
use its  reasonable  best  efforts  to file  with the  Securities  and  Exchange
Commission all current reports and the information as may be necessary to enable
the Holder to effect sales of its shares in reliance  upon Rule 144  promulgated
under the Act.

                      6. ARTICLE VI RIGHTS.  Upon  exercise of this Option,  the
Holder  shall be entitled to the  contractual  rights set forth in Article VI of
the  Subscription  Agreement  to the  same  extent  as if such  Units  had  been
purchased in the Offering,  it being understood and agreed that the Holder shall
receive additional shares of Common Stock upon the exercise of this Option which
would have been issued to the Holder pursuant to Article VI of the  Subscription
Agreement as if the Holder had held the shares of Common Stock  hereunder  since
the Final Closing Date.

                      7.       INVESTMENT INTENT; LIMITED TRANSFERABILITY.

                      (a) The Holder represents,  by accepting this Option, that
it understands  that this Option and any securities  obtainable upon exercise of
this Option have not been registered for sale under Federal or state  securities
laws and are  being  offered  and  sold to the  Holder  pursuant  to one or more
exemptions from the  registration  requirements of such securities  laws. In the
absence  of an  effective  registration  of  such  securities  or  an  exemption
therefrom,  any certificates for such securities shall bear the legend set forth
on the first page hereof.  The Holder understands that it must bear the economic
risk  of its  investment  in this  Option  and any  securities  obtainable  upon
exercise of this  Option for an  indefinite  period of time,  as this Option and
such securities have not been registered  under Federal or state securities laws
and therefore  cannot be sold unless  subsequently  registered  under such laws,
unless an exemption from such registration is available.

                      (b)  The  Holder,   by  his   acceptance  of  its  Option,
represents to the Company that it is acquiring  this Option and will acquire any
securities  obtainable  upon  exercise  of this  Option for its own  account for
investment  and  not  with a view  to,  or for  sale  in  connection  with,  any
distribution thereof in violation of the Act. The Holder agrees that this Option
and any such securities will not be sold or otherwise  transferred  unless (i) a
registration  statement with respect to such transfer is effective under the Act
and any applicable  state  securities laws or (ii) such sale or transfer is made
pursuant to one or more exemptions from the Act.

                      (c) This Option may not be sold, transferred,  assigned or
hypothecated  for six  months  from the date  hereof  except  (i) to any firm or
corporation  that  succeeds  to all or  substantially  all  of the  business  of
Paramount Capital, Inc., (ii) to any of the officers,  employees,  associates or
affiliated companies of Paramount Capital,  Inc., or of any such successor firm,
(iii) to any  NASD  member  participating  in the  Offering  or any  officer  or
employee of any such NASD member or (iv) in the case of an individual,  pursuant
to such  individual's  last  will  and  testament  or the  laws of  descent  and
distribution, and is so transferable only upon the books of the Company which it
shall  cause to be  maintained  for such  purpose.  The  Company  may  treat the
registered  Holder of this Option as he or it appears on the Company's  books at
any time as the Holder for all purposes.  The Company shall permit any Holder of
an Option or its duly authorized attorney,  upon written request during ordinary
business  hours, to inspect and copy or make extracts from its books showing the
registered holders of Options. All Options issued upon the transfer or


                                       -9-


<PAGE>

assignment  of this Option will be dated the same date as this  Option,  and all
rights of the holder thereof shall be identical to those of the Holder.

                      8.  LOSS,  ETC.,  OF  OPTION.  Upon  receipt  of  evidence
satisfactory  to the Company of the loss,  theft,  destruction  or mutilation of
this Option, and of indemnity  reasonably  satisfactory to the Company, if lost,
stolen or destroyed,  and upon  surrender and  cancellation  of this Option,  if
mutilated,  the Company  shall execute and deliver to the Holder a new Option of
like date, tenor and denomination.

                      9.  OPTION  HOLDER NOT  STOCKHOLDER.  This Option does not
confer upon the Holder any right to vote or to consent to or receive notice as a
stockholder of the Company,  as such, in respect of any matters  whatsoever,  or
any other rights or liabilities as a stockholder,  prior to the exercise hereof;
this Option does, however,  confer certain rights and require certain notices to
Holders as set forth herein.

                      10. COMMUNICATION.  No notice or other communication under
this Option shall be  effective  unless,  but any notice or other  communication
shall be  effective  and shall be deemed to have been  given if,  the same is in
writing and is mailed by first-class mail, postage prepaid, addressed to:

                        (a) the Company at Procept,  Inc.,  840 Memorial  Drive,
                Boston, MA 02139,  Attn:  President or such other address as the
                Company has designated in writing to the Holder, or

                        (b) the  Holder  at c/o  Paramount  Capital,  Inc.,  787
                Seventh Avenue,  New York, NY 10019 or other such address as the
                Holder has designated in writing to the Company.

                      11.  HEADINGS.  The  headings  of this  Option  have  been
inserted  as a matter  of  convenience  and shall not  affect  the  construction
hereof.

                      12.  APPLICABLE  LAW. This Option shall be governed by and
construed in  accordance  with the law of the State of New York  without  giving
effect to the principles of conflicts of law thereof.

                      13. AMENDMENT,  WAIVER,  ETC. Except as expressly provided
herein,  neither  this  Option  nor any  term  hereof  may be  amended,  waived,
discharged or terminated other than by a written  instrument signed by the party
against whom enforcement of any such amendment, waiver, discharge or termination
is sought; provided, however, that any provisions hereof may be amended, waived,
discharged  or terminated  upon the written  consent of the Company and the then
current Majority of the Holders of the Options only.


                                      -10-


<PAGE>


                      IN WITNESS WHEREOF,  the Company has caused this Option to
be signed by its President and attested by its Secretary this __th day of April,
1998.

                                                Procept, Inc.



                                                By:
                                                   ----------------------------
                                                Name:
                                                Title:


ATTEST:



- ---------------------------
        Secretary





                                      -11-


<PAGE>



                                  SUBSCRIPTION

                      The undersigned,  __________________________,  pursuant to
the  provisions  of the  foregoing  Option,  hereby  agrees to subscribe for and
purchase ________________ Units of Procept, Inc., each Unit consisting of Common
Stock, $.001 par value, and Class C Warrants to purchase ___________ share(s) of
Common Stock,  covered by said Option, and makes payment therefor in full at the
price per share provided by said Option.  The  undersigned  hereby  confirms the
representations and warranties made by it in the Option.

Dated:                            Signature:
      -----------------                     ---------------------------------

                                  Address:
                                          -----------------------------------



                                  SUBSCRIPTION
                                (promissory note)

                      The undersigned,  __________________________,  pursuant to
the  provisions  of the  foregoing  Option,  hereby  agrees to subscribe for and
purchase ________________ shares of the Common Stock, par value $.001, and Class
C Warrants to purchase  ______________ share(s) of Common Stock of Procept, Inc.
covered by said  Option,  and makes  payment  therefor  in full at the price per
share provided by said Option by delivery of the attached  Promissory  Note. The
undersigned hereby confirms the representations and warranties made by it in the
Option and in the attached Promissory Note.

Dated:                            Signature:
      -----------------                     ---------------------------------

                                  Address:
                                          -----------------------------------



                                CASHLESS EXERCISE

                      The undersigned  _______________________,  pursuant to the
provisions  of the  foregoing  Option,  hereby elects to exchange its Option for
__________  Units,  each Unit consisting of Common Stock,  $.001 par value,  and
Class C Warrants to purchase  __________  share(s) of Common Stock,  pursuant to
the cashless exercise  provisions of the Option. The undersigned hereby confirms
the representations and warranties made by it in the Option.

Dated:                            Signature:
      -----------------                     ---------------------------------

                                  Address:
                                          -----------------------------------


                                      -12-


<PAGE>

                                   ASSIGNMENT

                      FOR VALUE  RECEIVED  ______________________  hereby sells,
assigns and transfers unto ____________________________ the foregoing Option and
all rights  evidenced  thereby,  and does  irrevocably  constitute  and  appoint
_____________________,  attorney,  to  transfer  said  Option  on the  books  of
Procept, Inc.

Dated:                            Signature:
      -----------------                     ---------------------------------

                                  Address:
                                          -----------------------------------


                               PARTIAL ASSIGNMENT

                      FOR  VALUE  RECEIVED   ___________________________  hereby
assigns and transfers  unto  ____________________________  the right to purchase
________ Units of Procept Inc., each Unit consisting of Common Stock,  $.001 par
value, and Class C Warrants to purchase ______________ share(s) of Common Stock,
covered by the foregoing Option, and a proportionate part of said Option and the
rights  evidenced   thereby,   and  does  irrevocably   constitute  and  appoint
____________________,  attorney,  to  transfer  that part of said  Option on the
books of Procept, Inc.

Dated:                            Signature:
      -----------------                     ---------------------------------

                                  Address:
                                          -----------------------------------


                                      -13-


<PAGE>

                                     [FORM]

                                 PROMISSORY NOTE

$[           ]                                              NEW YORK, NEW YORK
                                                             [               ]

                      [UNITHOLDER]  ("Borrower"),  for  value  received,  hereby
promises  to pay to  the  order  of  [COMPANY  NAME]  (together  with  any  such
subsequent  holder of this Note, the "Holder" or the "Company") the sum of [ ]($
), or such lesser amount as shall then equal the  outstanding  principal  amount
hereof.  Such amount shall be due and payable on October 7, 2003 (the  "Maturity
Date"),  together with  interest  thereon at a rate per annum equal to the prime
rate as stated by Citibank,  N.A. as of the date hereof,  (the "Interest Rate"),
and which  shall be  calculated  on the basis of a 360-day  year for actual days
elapsed,  on the terms and  conditions  set forth  hereinafter.  Payment for all
amounts due hereunder  shall be made by certified  check or wire transfer to the
Holder at c/o [ ] Attn:  [President],  or other  such  address as the Holder may
designate by notice to Borrower.  If this Promissory Note is prepaid in whole or
in part by the tendering of shares pursuant to Paragraph 2 below,  the repayment
date shall be the date on which the Borrower delivers a notice to the Company in
accordance  with  Paragraph 4 irrevocably  stating the  Borrower's  intention to
repay the Promissory  Note by tendering such shares.  The Borrower is delivering
this  Promissory  Note as payment of the exercise  price for the purchase of the
shares of Common Stock (the "Stock") underlying the Unit dated [ ] (the "Unit").
The Promissory Note shall be secured by the Stock which the Holder shall hold in
safe-keeping as collateral for the  indebtedness  represented by this Promissory
Note.

                      1.  Prepayment;  Repayment.  The  Borrower may at any time
prepay in whole or in part the principal  sum, plus accrued  interest to date of
payment, of this Note, without penalty or premium. All sums paid hereon shall be
applied first to accrued,  unpaid interest on this Note and the balance, if any,
to the reduction of the principal hereof. This Note shall not be due and payable
until the Maturity Date. On the Maturity Date, the entire  principal  amount of,
and all accrued interest on, this Note shall  automatically  become  immediately
due and payable without presentment, demand, protest or other formalities of any
kind, all of which are hereby expressly waived by the Company.

                      2.  Prepayment  or Repayment  by Tendering of Shares.  Any
prepayment or repayment may be made by instructing  the Company to withhold that
number of shares of Common Stock and/or  Warrants  currently held by the Company
as collateral for this Promissory Note in accordance with Paragraph 1(a)(iii) of
the Unit  Purchase  Option  and  having a value,  based  upon the  Market  Price
(assuming the Exchange Date referenced  therein is the date such  instruction is
received by the  Company) (as  determined  in the Unit  Purchase  Option) of the
Common Stock, equal to the outstanding principal sum plus accrued interest.  The
Company will deliver the balance of the securities not withheld  pursuant to the
immediately  preceding  sentence  of this  Paragraph  2 to the  Borrower  at the
address set forth in  Paragraph 4 below within five (5) days of the date of such
prepayment or repayment, as the case may be.


                                      -14-


<PAGE>

                      3.  Events of  Default.  If any events  specified  in this
Paragraph 3 shall occur and continue  uncured for a period of 90 days  following
notice from the lender such event has occurred(herein  individually  referred to
as an "Event of Default"), the Holder of the Note may, so long as such condition
exists,  declare  the  entire  principal  and  unpaid  accrued  interest  hereon
immediately due and payable, by notice in writing to Borrower:

                               3.1.  Failure  to pay the  principal  and  unpaid
accrued interest of the Note when due and payable; or

                               3.2. The  institution  by Borrower of proceedings
to be  adjudicated  as  bankrupt  or  insolvent,  or the  consent by Borrower to
institution  of  bankruptcy or insolvency  proceedings  against  Borrower or the
filing by Borrower of a petition or answer or consent seeking  reorganization or
release under the federal  Bankruptcy  Act, or any other  applicable  federal or
state law, or the consent by Borrower to the filing of any such  petition or the
appointment  of a  receiver,  liquidator,  assignee,  trustee  or other  similar
official for all or any substantial  part of its property,  of the taking of any
action by Borrower in furtherance of any such action; or

                               3.3.  If,   within  sixty  (60)  days  after  the
commencement of an action against Borrower (and service of process in connection
therewith  on  Borrower)  seeking any  bankruptcy,  insolvency,  reorganization,
liquidation  or  similar  relief  under any  present or future  statute,  law of
regulation, such action shall not have been resolved in favor of Borrower of all
orders or proceedings  thereunder  affecting the property of Borrower stayed, or
if the stay of any such order or proceeding  shall  thereafter be set aside,  or
if,  within  sixty  (60) days  after the  appointment  without  the  consent  or
acquiescence  of Borrower of any trustee or receiver for all or any  substantial
part of the property of Borrower, such appointment shall not have been vacated.


                      4. Notices.  Any notice required,  desired or permitted to
be given hereunder shall be in writing and shall be delivered  personally,  sent
certified or registered  United States mail, return receipt requested or sent by
overnight courier service addressed to:

                      If to the Holder:

                               c/o [company name]
                               [address]
                               Attn: President

                      If to Borrower:

                               [name and address]

Such notices shall be deemed given (i) if delivered  personally,  upon delivery,
(ii) if mailed as  aforesaid,  two (2) business days after deposit in the United
States mail and (iii) if sent by overnight  courier service one (1) business day
after  deposit  with the  courier  service.  Any party may change its address by
notice to the other party given in accordance with this section.


                                      -15-


<PAGE>
                      IN WITNESS  WHEREOF,  the Borrower has caused this Note to
be issued this [ ] day of [ ] [ ].



                                              BORROWER:



                                              Name:
                                              Address:


                                              ---------------------------



                                      -16-





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