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                                                                    EXHIBIT 99.3


                              DEPOTECH CORPORATION
                             STOCK OPTION AGREEMENT

RECITALS

      A.    The Board has adopted the Plan for the purpose of providing
additional incentive to selected Employees, consultants and other independent
advisors to continue in the Service of the Corporation (or any Parent or
Subsidiary).

      B.    Optionee is to render valuable services to the Corporation (or a
Parent or Subsidiary), and this Agreement is executed pursuant to, and is
intended to carry out the purposes of the Plan in connection with the
Corporation's grant of an option to Optionee.

      C.    All capitalized terms in this Agreement shall have the meaning
assigned to them in the attached Appendix.

            NOW, THEREFORE, it is hereby agreed as follows:

            1.    GRANT OF OPTION. The Corporation hereby grants to Optionee, as
of the Grant Date, an option to purchase up to the number of Option Shares
specified in the Grant Notice. The Option Shares shall be purchasable from time
to time during the option term specified in Paragraph 2 at the Exercise Price.

            2.    OPTION TERM. This option shall have a term of ten (10) years
measured from the Grant Date and shall accordingly expire at the close of
business on the Expiration Date, unless sooner terminated in accordance with
Paragraph 5 or 6.

            3.    LIMITED TRANSFERABILITY. This option shall be neither
transferable nor assignable by Optionee other than by will or by the laws of
descent and distribution following Optionee's death and may be exercised, during
the Optionee's lifetime, only by the Optionee.

            4.    DATES OF EXERCISE. This option shall become exercisable for
the Option Shares in one or more installments as specified in the Grant Notice.
As the option becomes exercisable for such installments, those installments
shall accumulate, and the option shall remain exercisable for the accumulated
installments until the Expiration Date or sooner termination of the option term
under Paragraph 5 or 6.

            5.    CESSATION OF SERVICE. The option term specified in Paragraph 2
shall terminate (and this option shall cease to be outstanding) prior to the
Expiration Date should any of the following provisions become applicable:

                  (a)   Should Optionee cease to remain in Service for any
      reason (other than death, Permanent Disability or Misconduct) while this
      option is outstanding, then Optionee shall have a thirty (30)-day period
      (commencing with the date of such cessation


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      of Service) during which to exercise this option, but in no event shall
      this option be exercisable at any time after the Expiration Date.

                  (b)   Should Optionee die while this option is outstanding,
      then the personal representative of Optionee's estate or the person or
      persons to whom the option is transferred pursuant to Optionee's will or
      in accordance with the laws of inheritance shall have the right to
      exercise this option. Such right shall lapse, and this option shall cease
      to be outstanding, upon the earlier of (A) the expiration of the twelve
      (12)- month period measured from the date of Optionee's death or (B) the
      Expiration Date.

                  (c)   Should Optionee cease Service by reason of Permanent
      Disability while this option is outstanding, then Optionee shall have a
      period of six (6) months (commencing with the date of such cessation of
      Service) during which to exercise this option. In no event shall this
      option be exercisable at any time after the Expiration Date.

                  (d)   During the limited period of post-Service
      exercisability, this option may not be exercised in the aggregate for more
      than the number of Option Shares for which the option is exercisable at
      the time of Optionee's cessation of Service. Upon the expiration of such
      limited exercise period or (if earlier) upon the Expiration Date, this
      option shall terminate and cease to be outstanding for any otherwise
      exercisable Option Shares for which the option has not been exercised. To
      the extent this option is not exercisable for one or more Option Shares at
      the time of Optionee's cessation of Service, this option shall immediately
      terminate and cease to be outstanding with respect to those shares.

                  (e)   Should Optionee's Service be terminated for Misconduct,
      then this option shall terminate immediately and cease to remain
      outstanding.

            6.    SPECIAL ACCELERATION OF OPTION.

                  (a)   In the event of a Corporate Transaction, this option, to
the extent outstanding at such time but not otherwise fully exercisable, shall
automatically accelerate so that this option shall, immediately prior to the
effective date of the Corporate Transaction, become exercisable for all of the
Option Shares at the time subject to this option and may be exercised for any or
all of those Option Shares as fully-vested shares of Common Stock. However, this
option shall not become exercisable on such an accelerated basis if and to the
extent: (i) this option is, in connection with the Corporate Transaction, to be
assumed by the successor corporation (or parent thereof) or (ii) this option is
to be replaced with a cash incentive program of the successor corporation which
preserves the spread existing at the time of the Corporate


                                       2.
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Transaction on the Option Shares for which this option is not otherwise at that
time exercisable (the excess of the Fair Market Value of such Option Shares over
the aggregate Exercise Price payable for such shares) and provides for
subsequent pay-out in accordance with the same exercise/vesting schedule in
effect for those Option Shares pursuant to the option exercise schedule set
forth in the Grant Notice.

                  (b)   Immediately following the Corporate Transaction, this
option, to the extent not previously exercised, shall terminate and cease to be
outstanding, except to the extent assumed by the successor corporation (or
parent thereof) in connection with the Corporate Transaction.

                  (c)   If this option is assumed in connection with a Corporate
Transaction, then this option shall be appropriately adjusted, immediately after
such Corporate Transaction, to apply to the number and class of securities which
would have been issuable to Optionee in consummation of such Corporate
Transaction had the option been exercised immediately prior to such Corporate
Transaction, and appropriate adjustments shall also be made to the Exercise
Price, provided the aggregate Exercise Price shall remain the same.

                  (d)   This Agreement shall not in any way affect the right of
the Corporation to adjust, reclassify, reorganize or otherwise change its
capital or business structure or to merge, consolidate, dissolve, liquidate or
sell or transfer all or any part of its business or assets.

            7.    ADJUSTMENT IN OPTION SHARES. Should any change be made to the
Common Stock by reason of any stock split, stock dividend, recapitalization,
combination of shares, exchange of shares or other change affecting the
outstanding Common Stock as a class without the Corporation's receipt of
consideration, appropriate adjustments shall be made to (i) the total number
and/or class of securities subject to this option and (ii) the Exercise Price in
order to reflect such change and thereby preclude any dilution or enlargement of
benefits hereunder.

            8.    SHAREHOLDER RIGHTS. The holder of this option shall not have
any shareholder rights with respect to the Option Shares until such person shall
have exercised the option, paid the Exercise Price and become a holder of record
of the purchased shares.

            9.    MANNER OF EXERCISING OPTION.

                  (a)   In order to exercise this option with respect to all or
any part of the Option Shares for which this option is at the time exercisable,
Optionee (or any other person or persons exercising the option) must take the
following actions:

                        (i)   Execute and deliver to the Corporation a Notice of
      Exercise for the Option Shares for which the option is exercised.


                                       3.
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                        (ii)  Pay the aggregate Exercise Price for the purchased
      shares in one or more of the following forms:

                              (A)   cash or check made payable to the 
                        Corporation;

                              (B)   a promissory note payable to the 
                        Corporation, but only to the extent authorized by the
                        Plan Administrator in accordance with Paragraph 13;

                              (C)   shares of Common Stock held by Optionee (or 
                        any other person or persons exercising the option) for
                        the requisite period necessary to avoid a charge to the
                        Corporation's earnings for financial reporting purposes
                        and valued at Fair Market Value on the Exercise Date; or

                              (D)   through a special sale and remittance 
                        procedure pursuant to which Optionee (or any other
                        person or persons exercising the option) shall
                        concurrently provide irrevocable instructions (I) to a
                        Corporation-designated brokerage firm to effect the
                        immediate sale of the purchased shares and remit to the
                        Corporation, out of the sale proceeds available on the
                        settlement date, sufficient funds to cover the aggregate
                        Exercise Price payable for the purchased shares plus all
                        applicable Federal, state and local income and
                        employment taxes required to be withheld by the
                        Corporation by reason of such exercise and (II) to the
                        Corporation to deliver the certificates for the
                        purchased shares directly to such brokerage firm in
                        order to complete the sale transaction.

                              Except to the extent the sale and remittance
                        procedure is utilized in connection with the option
                        exercise, payment of the Exercise Price must accompany
                        the Notice of Exercise delivered to the Corporation in
                        connection with the option exercise.

                  (iii) Furnish to the Corporation appropriate documentation
            that the person or persons exercising the option (if other than
            Optionee) have the right to exercise this option.

                  (iv)  Make appropriate arrangements with the Corporation (or
            Parent or Subsidiary employing or retaining Optionee) for the
            satisfaction of all Federal, state and local income and employment
            tax withholding requirements applicable to the option exercise.


                                       4.
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            (b)   As soon as practical after the Exercise Date, the Corporation
shall issue to or on behalf of Optionee (or any other person or persons
exercising this option) a certificate for the purchased Option Shares, with the
appropriate legends affixed thereto.

            (c)   In no event may this option be exercised for any fractional
shares.

      10.   COMPLIANCE WITH LAWS AND REGULATIONS.

            (a)   The exercise of this option and the issuance of the Option
Shares upon such exercise shall be subject to compliance by the Corporation and
Optionee with all applicable requirements of law relating thereto and with all
applicable regulations of any stock exchange (or the Nasdaq National Market, if
applicable) on which the Common Stock may be listed for trading at the time of
such exercise and issuance.

            (b)   The inability of the Corporation to obtain approval from any
regulatory body having authority deemed by the Corporation to be necessary to
the lawful issuance and sale of any Common Stock pursuant to this option shall
relieve the Corporation of any liability with respect to the non-issuance or
sale of the Common Stock as to which such approval shall not have been obtained.
The Corporation, however, shall use its best efforts to obtain all such
approvals.

      11.   SUCCESSORS AND ASSIGNS. Except to the extent otherwise provided in
Paragraphs 3 and 6, the provisions of this Agreement shall inure to the benefit
of, and be binding upon, the Corporation and its successors and assigns and
Optionee, Optionee's assigns and the legal representatives, heirs and legatees
of Optionee's estate.

      12.   NOTICES. Any notice required to be given or delivered to the
Corporation under the terms of this Agreement shall be in writing and addressed
to the Corporation at its principal corporate offices. Any notice required to be
given or delivered to Optionee shall be in writing and addressed to Optionee at
the address indicated below Optionee's signature line on the Grant Notice. All
notices shall be deemed effective upon personal delivery or upon deposit in the
U.S. mail, postage prepaid and properly addressed to the party to be notified.

      13.   FINANCING. The Plan Administrator may, in its absolute discretion
and without any obligation to do so, permit Optionee to pay the Exercise Price
for the purchased Option Shares by delivering a promissory note. The terms of
any such promissory note (including the interest rate, the requirements for
collateral and the terms of repayment) shall be established by the Plan
Administrator in its sole discretion.


                                       5.
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      14.   CONSTRUCTION. This Agreement and the option evidenced hereby are
made and granted pursuant to the Plan and are in all respects limited by and
subject to the terms of the Plan. All decisions of the Plan Administrator with
respect to any question or issue arising under the Plan or this Agreement shall
be conclusive and binding on all persons having an interest in this option.

      15.   GOVERNING LAW. The interpretation, performance and enforcement of
this Agreement shall be governed by the laws of the State of California without
resort to that State's conflict-of-laws rules.


                                       6.
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                                    EXHIBIT I

                               NOTICE OF EXERCISE


      I hereby notify DepoTech Corporation (the "Corporation") that I elect to
purchase _________ shares of the Corporation's Common Stock (the "Purchased
Shares") at the option exercise price of $__________ per share (the "Exercise
Price") pursuant to that certain option (the "Option") granted to me under the
Corporation's 1997 Supplemental Stock Option Plan on __________________, 199__.

      Concurrently with the delivery of this Exercise Notice to the Corporation,
I shall hereby pay to the Corporation the Exercise Price for the Purchased
Shares in accordance with the provisions of my agreement with the Corporation
(or other documents) evidencing the Option and shall deliver whatever additional
documents may be required by such agreement as a condition for exercise.
Alternatively, I may utilize the special broker-dealer sale and remittance
procedure specified in my agreement to effect payment of the Exercise Price.

____________________, 199__
Date


                                       _________________________________________
                                       Optionee

                                       Address:_________________________________

                                       _________________________________________

Print name in exact manner
it is to appear on the
stock certificate:                     _________________________________________

Address to which certificate
is to be sent, if different
from address above:                    _________________________________________


                                       _________________________________________

Social Security Number:                _________________________________________

Employee Number:                       _________________________________________


                                       7.
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                                    APPENDIX


            The following definitions shall be in effect under the Agreement:

      A.    AGREEMENT shall mean this Supplemental Stock Option Agreement.

      B.    BOARD shall mean the Corporation's Board of Directors.

      C.    CODE shall mean the Internal Revenue Code of 1986, as amended.

      D.    COMMON STOCK shall mean the Corporation's common stock.

      E.    CORPORATE TRANSACTION shall mean either of the following
shareholder-approved transactions to which the Corporation is a party:

            (i)   a merger or consolidation in which securities possessing more
      than fifty percent (50%) of the total combined voting power of the
      Corporation's outstanding securities are transferred to a person or
      persons different from the persons holding those securities immediately
      prior to such transaction, or

            (ii)  the sale, transfer or other disposition of all or
      substantially all of the Corporation's assets in complete liquidation or
      dissolution of the Corporation.

      F.    CORPORATION shall mean DepoTech Corporation, a California
corporation.

      G.    EMPLOYEE shall mean an individual who is in the employ of the
Corporation (or any Parent or Subsidiary), subject to the control and direction
of the employer entity as to both the work to be performed and the manner and
method of performance.

      H.    EXERCISE DATE shall mean the date on which the option shall have
been exercised in accordance with Paragraph 9 of the Agreement.

      I.    EXERCISE PRICE shall mean the exercise price per share as specified
in the Grant Notice.

      J.    EXPIRATION DATE shall mean the date on which the option expires as
specified in the Grant Notice.

      K.    FAIR MARKET VALUE per share of Common Stock on any relevant date
shall determined in accordance with the following provisions:


                                      A-1.

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            -     If the Common Stock is at the time traded on the Nasdaq
      National Market, then the Fair Market Value shall be the closing selling
      price per share of Common Stock on the date in question, as such price is
      reported by the National Association of Securities Dealers on the Nasdaq
      National Market. If there is no closing selling price for the Common Stock
      on the date in question, then the Fair Market Value shall be the closing
      selling price on the last preceding date for which such quotation exists.

            -     If the Common Stock is at the time listed on any Stock
      Exchange, then the Fair Market Value shall be the closing selling price
      per share of Common Stock on the date in question on the Stock Exchange
      determined by the Plan Administrator to be the primary market for the
      Common Stock, as such price is officially quoted in the composite tape of
      transactions on such exchange. If there is no closing selling price for
      the Common Stock on the date in question, then the Fair Market Value shall
      be the closing selling price on the last preceding date for which such
      quotation exists.

      L.    GRANT DATE shall mean the date of grant of the option as specified
in the Grant Notice.

      M.    GRANT NOTICE shall mean the Notice of Grant of Stock Option
accompanying the Agreement, pursuant to which Optionee has been informed of the
basic terms of the option evidenced hereby.

      N.    MISCONDUCT shall mean the commission of any act of fraud,
embezzlement or dishonesty by Optionee, any unauthorized use or disclosure by
Optionee of confidential information or trade secrets of the Corporation (or any
Parent or Subsidiary), or any other intentional misconduct by Optionee adversely
affecting the business or affairs of the Corporation (or any Parent or
Subsidiary) in a material manner. The foregoing definition shall not be deemed
to be inclusive of all the acts or omissions which the Corporation (or any
Parent or Subsidiary) may consider as grounds for the dismissal or discharge of
Optionee or other person in the Service of the Corporation (or any Parent or
Subsidiary).

      O.    NON-STATUTORY OPTION shall mean an option not intended to satisfy
the requirements of Code Section 422.

      P.    NOTICE OF EXERCISE shall mean the notice of exercise in the form
attached hereto as Exhibit I.

      Q.    OPTION SHARES shall mean the number of shares of Common Stock
subject to the option as specified in the Grant Notice.

      R.    OPTIONEE shall mean the person to whom the option is granted as
specified in the Grant Notice.


                                      A-2.
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      S.    PARENT shall mean any corporation (other than the Corporation) in an
unbroken chain of corporations ending with the Corporation, provided each
corporation in the unbroken chain (other than the Corporation) owns, at the time
of the determination, stock possessing fifty percent (50%) or more of the total
combined voting power of all classes of stock in one of the other corporations
in such chain.

      T.    PERMANENT DISABILITY shall mean the inability of Optionee to engage
in any substantial gainful activity by reason of any medically determinable
physical or mental impairment which is expected to result in death or has lasted
or can be expected to last for a continuous period of twelve (12) months or
more.

      U.    PLAN shall mean the Corporation's 1997 Supplemental Stock Option
Plan.

      V.    PLAN ADMINISTRATOR shall mean either the Board or a committee of the
Board acting in its administrative capacity under the Plan.

      W.    SERVICE shall mean the Optionee's performance of services for the
Corporation (or any Parent or Subsidiary) in the capacity of an Employee or a
consultant or independent advisor.

      X.    STOCK EXCHANGE shall mean the American Stock Exchange or the New
York Stock Exchange.

      Y.    SUBSIDIARY shall mean any corporation (other than the Corporation)
in an unbroken chain of corporations beginning with the Corporation, provided
each corporation (other than the last corporation) in the unbroken chain owns,
at the time of the determination, stock possessing fifty percent (50%) or more
of the total combined voting power of all classes of stock in one of the other
corporations in such chain.


                                      A-3.