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                              DRUGABUSE SCIENCES, INC.

                             2000 STOCK INCENTIVE PLAN

                      (AS ADOPTED EFFECTIVE _______ __, 2000)

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                                  TABLE OF CONTENTS

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ARTICLE 1.  INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

ARTICLE 2.  ADMINISTRATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
     2.1  Committee Composition. . . . . . . . . . . . . . . . . . . . . . . . . . .1
     2.2  Committee Responsibilities . . . . . . . . . . . . . . . . . . . . . . . .1
     2.3  Committee for Non-Officer Grants . . . . . . . . . . . . . . . . . . . . .1

ARTICLE 3.  SHARES AVAILABLE FOR GRANTS. . . . . . . . . . . . . . . . . . . . . . .2
     3.1  Basic Limitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
     3.2  Annual Increase in Shares. . . . . . . . . . . . . . . . . . . . . . . . .2
     3.3  Additional Shares. . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

ARTICLE 4.  ELIGIBILITY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
     4.1  Nonstatutory Stock Options and Restricted Shares . . . . . . . . . . . . .2
     4.2  Incentive Stock Options. . . . . . . . . . . . . . . . . . . . . . . . . .2

ARTICLE 5.  OPTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
     5.1  Stock Option Agreement . . . . . . . . . . . . . . . . . . . . . . . . . .3
     5.2  Number of Shares . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
     5.3  Exercise Price . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
     5.4  Exercisability and Term. . . . . . . . . . . . . . . . . . . . . . . . . .3
     5.5  Effect of Change in Control. . . . . . . . . . . . . . . . . . . . . . . .3
     5.6  Modification or Assumption of Options. . . . . . . . . . . . . . . . . . .3
     5.7  Buyout Provisions. . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

ARTICLE 6.  PAYMENT FOR OPTION SHARES. . . . . . . . . . . . . . . . . . . . . . . .4
     6.1  General Rule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
     6.2  Surrender of Stock . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
     6.3  Exercise/Sale. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
     6.4  Exercise/Pledge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
     6.5  Promissory Note. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
     6.6  Other Forms of Payment . . . . . . . . . . . . . . . . . . . . . . . . . .5

ARTICLE 7.  RESTRICTED SHARES. . . . . . . . . . . . . . . . . . . . . . . . . . . .5
     7.1  Restricted Stock Agreement . . . . . . . . . . . . . . . . . . . . . . . .5
     7.2  Payment for Awards . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
     7.3  Vesting Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
     7.4  Voting and Dividend Rights . . . . . . . . . . . . . . . . . . . . . . . .5

ARTICLE 8.  PROTECTION AGAINST DILUTION. . . . . . . . . . . . . . . . . . . . . . .5
     8.1  Adjustments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
     8.2  Dissolution or Liquidation . . . . . . . . . . . . . . . . . . . . . . . .6

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     8.3  Reorganizations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

ARTICLE 9.  DEFERRAL OF DELIVERY OF SHARES . . . . . . . . . . . . . . . . . . . . .6

ARTICLE 10.  AWARDS UNDER OTHER PLANS. . . . . . . . . . . . . . . . . . . . . . . .6

ARTICLE 11.  LIMITATION ON RIGHTS. . . . . . . . . . . . . . . . . . . . . . . . . .7
     11.1  Retention Rights. . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
     11.2  Shareholders' Rights. . . . . . . . . . . . . . . . . . . . . . . . . . .7
     11.3  Regulatory Requirements . . . . . . . . . . . . . . . . . . . . . . . . .7

ARTICLE 12.  WITHHOLDING TAXES . . . . . . . . . . . . . . . . . . . . . . . . . . .7
     12.1  General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
     12.2  Share Withholding . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

ARTICLE 13.  LIMITATION ON PAYMENTS. . . . . . . . . . . . . . . . . . . . . . . . .7
     13.1  Scope of Limitation . . . . . . . . . . . . . . . . . . . . . . . . . . .7
     13.2  Basic Rule. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
     13.3  Reduction of Payments . . . . . . . . . . . . . . . . . . . . . . . . . .8
     13.4  Overpayments and Underpayments. . . . . . . . . . . . . . . . . . . . . .8
     13.5  Related Corporations. . . . . . . . . . . . . . . . . . . . . . . . . . .9

ARTICLE 14.  FUTURE OF THE PLAN. . . . . . . . . . . . . . . . . . . . . . . . . . .9
     14.1  Term of the Plan. . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
     14.2  Amendment or Termination. . . . . . . . . . . . . . . . . . . . . . . . .9

ARTICLE 15.  DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

ARTICLE 16.  EXECUTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
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                              DRUGABUSE SCIENCES, INC.

                             2000 STOCK INCENTIVE PLAN

       ARTICLE 1.    INTRODUCTION.

              The Plan was adopted by the Board effective as of the date of
the Company's initial public offering.  The purpose of the Plan is to promote
the long-term success of the Company and the creation of shareholder value by
(a) encouraging Employees, Outside Directors and Consultants to focus on
critical long-range objectives, (b) encouraging the attraction and retention
of Employees, Outside Directors and Consultants with exceptional
qualifications and (c) linking Employees, Outside Directors and Consultants
directly to shareholder interests through increased stock ownership.  The
Plan seeks to achieve this purpose by providing for Awards in the form of
Restricted Shares or Options (which may constitute incentive stock options or
nonstatutory stock options).

              The Plan shall be governed by, and construed in accordance
with, the laws of the State of California (except their choice-of-law
provisions).

       ARTICLE 2.    ADMINISTRATION.

              2.1    COMMITTEE COMPOSITION.  The Plan shall be administered
by the Committee.  The Committee shall consist exclusively of two or more
directors of the Company, who shall be appointed by the Board.  In addition,
the composition of the Committee shall satisfy:

                     (a)    Such requirements as the Securities and
       Exchange Commission may establish for administrators acting under
       plans intended to qualify for exemption under Rule 16b-3 (or its
       successor) under the Exchange Act; and

                     (b)    Such requirements as the Internal Revenue
       Service may establish for outside directors acting under plans
       intended to qualify for exemption under section 162(m)(4)(C) of
       the Code.

              2.2    COMMITTEE RESPONSIBILITIES.  The Committee shall (a)
select the Employees, Outside Directors and Consultants who are to receive
Awards under the Plan, (b) determine the type, number, vesting requirements
and other features and conditions of such Awards, (c) interpret the Plan and
(d) make all other decisions relating to the operation of the Plan.  The
Committee may adopt such rules or guidelines as it deems appropriate to
implement the Plan.  The Committee's determinations under the Plan shall be
final and binding on all persons.

              2.3    COMMITTEE FOR NON-OFFICER GRANTS.  The Board may also
appoint a secondary committee of the Board, which shall be composed of two or
more directors of the

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Company who need not satisfy the requirements of Section 2.1.  Such secondary
committee may administer the Plan with respect to Employees and Consultants
who are not considered officers or directors of the Company under section 16
of the Exchange Act, may grant Awards under the Plan to such Employees and
Consultants and may determine all features and conditions of such Awards.
Within the limitations of this Section 2.3, any reference in the Plan to the
Committee shall include such secondary committee.

       ARTICLE 3.    SHARES AVAILABLE FOR GRANTS.

              3.1    BASIC LIMITATION.  The aggregate number of Options and
Restricted Shares awarded under the Plan shall not exceed (a) 750,000 plus
(b) the aggregate number of Common Shares remaining available for grants
under all Predecessor Plans on the date of the Company's initial public
offering plus (c) the additional Common Shares described in Sections 3.2 and
3.3.  No additional grants shall be made under the Predecessor Plans after
the date of the Company's initial public offering.  The limitations of this
Section 3.1 and Section 3.2 shall be subject to adjustment pursuant to
Article 8.

              3.2    ANNUAL INCREASE IN SHARES.  As of January 1 of each
year, commencing with the year 2001, the aggregate number of Options and
Restricted Shares that may be awarded under the Plan shall automatically
increase by a number equal to the lesser of (a) 6% of the total number of
Common Shares then outstanding or (b) 2,000,000.

              3.3    ADDITIONAL SHARES.  If Options granted under this Plan
or a Predecessor Plan are forfeited or terminate for any other reason before
being exercised, then the corresponding Common Shares shall again become
available for the grant of Options or Restricted Shares under this Plan.  If
Common Shares issued upon the exercise of Options granted under this Plan or
a Predecessor Plan are forfeited, then such Common Shares shall again become
available for the grant of NSOs and Restricted Shares under this Plan.  If
Restricted Shares issued under this Plan or a Predecessor Plan are forfeited,
then the corresponding Common Shares shall again become available for the
grant of NSOs and Restricted Shares under this Plan.  The aggregate number of
Common Shares that may be issued under the Plan upon the exercise of ISOs
shall not be increased when Restricted Shares or other Common Shares are
forfeited.

       ARTICLE 4.    ELIGIBILITY.

              4.1    NONSTATUTORY STOCK OPTIONS AND RESTRICTED SHARES.  Only
Employees, Outside Directors and Consultants shall be eligible for the grant
of NSOs and Restricted Shares.

              4.2    INCENTIVE STOCK OPTIONS.  Only Employees who are
common-law employees of the Company, a Parent or a Subsidiary shall be
eligible for the grant of ISOs.  In addition, an Employee who owns more than
10% of the total combined voting power of all classes of outstanding stock of
the Company or any of its Parents or Subsidiaries shall not be eligible for
the grant of an ISO unless the requirements set forth in section 422(c)(6) of
the Code are satisfied.

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       ARTICLE 5.    OPTIONS.

              5.1    STOCK OPTION AGREEMENT.  Each grant of an Option under
the Plan shall be evidenced by a Stock Option Agreement between the Optionee
and the Company.  Such Option shall be subject to all applicable terms of the
Plan and may be subject to any other terms that are not inconsistent with the
Plan.  The provisions of the various Stock Option Agreements entered into
under the Plan need not be identical.  Options may be granted in
consideration of a reduction in the Optionee's other compensation.  A Stock
Option Agreement may provide that a new Option will be granted automatically
to the Optionee when he or she exercises a prior Option and pays the Exercise
Price in the form described in Section 6.2.

              5.2    NUMBER OF SHARES.  Each Stock Option Agreement shall
specify the number of Common Shares subject to the Option and shall provide
for the adjustment of such number in accordance with Article 8.  Options
granted to any Optionee in a single fiscal year of the Company shall not
cover more than 1,000,000 Common Shares, except that Options granted to a new
Employee in the fiscal year of the Company in which his or her service as an
Employee first commences shall not cover more than 2,000,000 Common Shares.
The limitations set forth in the preceding sentence shall be subject to
adjustment in accordance with Article 8.

              5.3    EXERCISE PRICE.  Each Stock Option Agreement shall
specify the Exercise Price; provided that the Exercise Price under an ISO
shall in no event be less than 100% of the Fair Market Value of a Common
Share on the date of grant, and the Exercise Price under an NSO shall in no
event be less than 50% of the Fair Market Value of a Common Share on the date
of grant.  In the case of an NSO, a Stock Option Agreement may specify an
Exercise Price that varies in accordance with a predetermined formula while
the NSO is outstanding.

              5.4    EXERCISABILITY AND TERM.  Each Stock Option Agreement
shall specify the date or event when all or any installment of the Option is
to become exercisable.  The Stock Option Agreement shall also specify the
term of the Option; provided that the term of an ISO shall in no event exceed
10 years from the date of grant.  A Stock Option Agreement may provide for
accelerated exercisability in the event of the Optionee's death, disability
or retirement or other events and may provide for expiration prior to the end
of its term in the event of the termination of the Optionee's service.

              5.5    EFFECT OF CHANGE IN CONTROL.  The Committee may
determine, at the time of granting an Option or thereafter, that such Option
shall become exercisable as to all or part of the Common Shares subject to
such Option in the event that a Change in Control occurs with respect to the
Company or in the event that the Optionee is subject to an Involuntary
Termination after a Change in Control.  However, in the case of an ISO, the
acceleration of exercisability shall not occur without the Optionee's written
consent.  In addition, acceleration of exercisability may be required under
Section 8.3.

              5.6    MODIFICATION OR ASSUMPTION OF OPTIONS.  Within the
limitations of the Plan, the Committee may modify, extend or assume
outstanding options or may accept the cancellation of outstanding options
(whether granted by the Company or by another issuer) in return for the grant
of new options for the same or a different number of shares and at the same
or a different exercise price.  The foregoing notwithstanding, no
modification of an Option shall,

                                        3

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without the consent of the Optionee, alter or impair his or her rights or
obligations under such Option.

              5.7    BUYOUT PROVISIONS.  The Committee may at any time (a)
offer to buy out for a payment in cash or cash equivalents an Option
previously granted or (b) authorize an Optionee to elect to cash out an
Option previously granted, in either case at such time and based upon such
terms and conditions as the Committee shall establish.

       ARTICLE 6.    PAYMENT FOR OPTION SHARES.

              6.1    GENERAL RULE.  The entire Exercise Price of Common
Shares issued upon exercise of Options shall be payable in cash or cash
equivalents at the time when such Common Shares are purchased, except as
follows:

                     (a)    In the case of an ISO granted under the Plan,
       payment shall be made only pursuant to the express provisions of
       the applicable Stock Option Agreement.  The Stock Option Agreement
       may specify that payment may be made in any form(s) described in
       this Article 6.

                     (b)    In the case of an NSO, the Committee may at
       any time accept payment in any form(s) described in this
       Article 6.

              6.2    SURRENDER OF STOCK.  To the extent that this Section 6.2
is applicable, all or any part of the Exercise Price may be paid by
surrendering, or attesting to the ownership of, Common Shares that are
already owned by the Optionee.  Such Common Shares shall be valued at their
Fair Market Value on the date when the new Common Shares are purchased under
the Plan.  The Optionee shall not surrender, or attest to the ownership of,
Common Shares in payment of the Exercise Price if such action would cause the
Company to recognize compensation expense (or additional compensation
expense) with respect to the Option for financial reporting purposes.

              6.3    EXERCISE/SALE.  To the extent that this Section 6.3 is
applicable, all or any part of the Exercise Price and any withholding taxes
may be paid by delivering (on a form prescribed by the Company) an
irrevocable direction to a securities broker approved by the Company to sell
all or part of the Common Shares being purchased under the Plan and to
deliver all or part of the sales proceeds to the Company.

              6.4    EXERCISE/PLEDGE.  To the extent that this Section 6.4 is
applicable, all or any part of the Exercise Price and any withholding taxes
may be paid by delivering (on a form prescribed by the Company) an
irrevocable direction to pledge all or part of the Common Shares being
purchased under the Plan to a securities broker or lender approved by the
Company, as security for a loan, and to deliver all or part of the loan
proceeds to the Company.

              6.5    PROMISSORY NOTE.  To the extent that this Section 6.5 is
applicable, all or any part of the Exercise Price and any withholding taxes
may be paid by delivering (on a form prescribed by the Company) a
full-recourse promissory note.

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              6.6    OTHER FORMS OF PAYMENT.  To the extent that this Section
6.6 is applicable, all or any part of the Exercise Price and any withholding
taxes may be paid in any other form that is consistent with applicable laws,
regulations and rules.

       ARTICLE 7.    RESTRICTED SHARES.

              7.1    RESTRICTED STOCK AGREEMENT.  Each grant of Restricted
Shares under the Plan shall be evidenced by a Restricted Stock Agreement
between the recipient and the Company.  Such Restricted Shares shall be
subject to all applicable terms of the Plan and may be subject to any other
terms that are not inconsistent with the Plan.  The provisions of the various
Restricted Stock Agreements entered into under the Plan need not be identical.

              7.2    PAYMENT FOR AWARDS.  Restricted Shares may be sold or
awarded under the Plan for such consideration as the Committee may determine,
including (without limitation) cash, cash equivalents, full-recourse
promissory notes and services rendered.

              7.3    VESTING CONDITIONS.  Each Award of Restricted Shares may
or may not be subject to vesting.  Vesting shall occur, in full or in
installments, upon satisfaction of the conditions specified in the Restricted
Stock Agreement. A Restricted Stock Agreement may provide for accelerated
vesting in the event of the Participant's death, disability or retirement or
other events.  The Committee may determine, at the time of granting
Restricted Shares or thereafter, that all or part of such Restricted Shares
shall become vested in the event that a Change in Control occurs with respect
to the Company or in the event that the Participant is subject to an
Involuntary Termination after a Change in Control.

              7.4    VOTING AND DIVIDEND RIGHTS.  The holders of Restricted
Shares awarded under the Plan shall have the same voting, dividend and other
rights as the Company's other shareholders.  A Restricted Stock Agreement,
however, may require that the holders of Restricted Shares invest any cash
dividends received in additional Restricted Shares.  Such additional
Restricted Shares shall be subject to the same conditions and restrictions as
the Award with respect to which the dividends were paid.

       ARTICLE 8.    PROTECTION AGAINST DILUTION.

              8.1    ADJUSTMENTS.  In the event of a subdivision of the
outstanding Common Shares, a declaration of a dividend payable in Common
Shares or a combination or consolidation of the outstanding Common Shares (by
reclassification or otherwise) into a lesser number of Common Shares,
corresponding adjustments shall automatically be made in each of the
following:

                     (a)    The number of Options and Restricted Shares
       available for future Awards under Article 3;

                     (b)    The limitations set forth in Section 5.2;

                     (c)    The number of Common Shares covered by each
       outstanding Option; or

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                     (d)    The Exercise Price under each outstanding
       Option.

In the event of a declaration of an extraordinary dividend payable in a form
other than Common Shares in an amount that has a material effect on the price
of Common Shares, a recapitalization, a spin-off or a similar occurrence, the
Committee shall make such adjustments as it, in its sole discretion, deems
appropriate in one or more of the foregoing.  Except as provided in this
Article 8, a Participant shall have no rights by reason of any issuance by
the Company of stock of any class or securities convertible into stock of any
class, any subdivision or consolidation of shares of stock of any class, the
payment of any stock dividend or any other increase or decrease in the number
of shares of stock of any class.

              8.2    DISSOLUTION OR LIQUIDATION.  To the extent not
previously exercised, Options shall terminate immediately prior to the
dissolution or liquidation of the Company.

              8.3    REORGANIZATIONS.  In the event that the Company is a
party to a merger or other reorganization, outstanding Options and Restricted
Shares shall be subject to the agreement of merger or reorganization.  Such
agreement shall provide for (a) the continuation of the outstanding Awards by
the Company, if the Company is a surviving corporation, (b) the assumption of
the outstanding Awards by the surviving corporation or its parent or
subsidiary, (c) the substitution by the surviving corporation or its parent
or subsidiary of its own awards for the outstanding Awards, (d) full
exercisability or vesting and accelerated expiration of the outstanding
Awards or (e) settlement of the full value of the outstanding Awards in cash
or cash equivalents followed by cancellation of such Awards.

       ARTICLE 9.    DEFERRAL OF DELIVERY OF SHARES.

              The Committee (in its sole discretion) may permit or require an
Optionee to have Common Shares that otherwise would be delivered to such
Optionee as a result of the exercise of an Option converted into amounts
credited to a deferred compensation account established for such Optionee by
the Committee as an entry on the Company's books.  Such amounts shall be
determined by reference to the Fair Market Value of such Common Shares as of
the date when they otherwise would have been delivered to such Optionee.  A
deferred compensation account established under this Article 9 may be
credited with interest or other forms of investment return, as determined by
the Committee. An Optionee for whom such an account is established shall have
no rights other than those of a general creditor of the Company.  Such an
account shall represent an unfunded and unsecured obligation of the Company
and shall be subject to the terms and conditions of the applicable agreement
between such Optionee and the Company.  If the conversion of Options is
permitted or required, the Committee (in its sole discretion) may establish
rules, procedures and forms pertaining to such conversion, including (without
limitation) the settlement of deferred compensation accounts established
under this Article 9.

       ARTICLE 10.   AWARDS UNDER OTHER PLANS.

              The Company may grant awards under other plans or programs.
Such awards may be settled in the form of Common Shares issued under this
Plan.  Such Common Shares shall be treated for all purposes under the Plan
like Restricted Shares and shall, when issued, reduce the number of Common
Shares available under Article 3.

                                        6

<PAGE>

       ARTICLE 11.   LIMITATION ON RIGHTS.

              11.1   RETENTION RIGHTS.  Neither the Plan nor any Award
granted under the Plan shall be deemed to give any individual a right to
remain an Employee, Outside Director or Consultant.  The Company and its
Parents, Subsidiaries and Affiliates reserve the right to terminate the
service of any Employee, Outside Director or Consultant at any time, with or
without cause, subject to applicable laws, the Company's certificate of
incorporation and by-laws and a written employment agreement (if any).

              11.2   SHAREHOLDERS' RIGHTS.  A Participant shall have no
dividend rights, voting rights or other rights as a shareholder with respect
to any Common Shares covered by his or her Award prior to the time when a
stock certificate for such Common Shares is issued or, in the case of an
Option, the time when he or she becomes entitled to receive such Common
Shares by filing a notice of exercise and paying the Exercise Price.  No
adjustment shall be made for cash dividends or other rights for which the
record date is prior to such time, except as expressly provided in the Plan.

              11.3   REGULATORY REQUIREMENTS.  Any other provision of the
Plan notwithstanding, the obligation of the Company to issue Common Shares
under the Plan shall be subject to all applicable laws, rules and regulations
and such approval by any regulatory body as may be required.  The Company
reserves the right to restrict, in whole or in part, the delivery of Common
Shares pursuant to any Award prior to the satisfaction of all legal
requirements relating to the issuance of such Common Shares, to their
registration, qualification or listing or to an exemption from registration,
qualification or listing.

       ARTICLE 12.   WITHHOLDING TAXES.

              12.1   GENERAL.  To the extent required by applicable federal,
state, local or foreign law, a Participant or his or her successor shall make
arrangements satisfactory to the Company for the satisfaction of any
withholding tax obligations that arise in connection with the Plan.  The
Company shall not be required to issue any Common Shares or make any cash
payment under the Plan until such obligations are satisfied.

              12.2   SHARE WITHHOLDING.  To the extent that applicable law
subjects a Participant to tax withholding obligations, the Committee may
permit such Participant to satisfy all or part of such obligations by having
the Company withhold all or a portion of any Common Shares that otherwise
would be issued to him or her or by surrendering all or a portion of any
Common Shares that he or she previously acquired.  Such Common Shares shall
be valued at their Fair Market Value on the date when they are withheld or
surrendered.

       ARTICLE 13.   LIMITATION ON PAYMENTS.

              13.1   SCOPE OF LIMITATION.  This Article 13 shall apply to an
Award only if:

                     (a)    The independent auditors most recently
       selected by the Board (the "Auditors") determine that the after-
       tax value of such Award to the Participant, taking into account the
       effect of all federal, state and local income

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<PAGE>

       taxes, employment taxes and excise taxes applicable to the Participant
       (including the excise tax under section 4999 of the Code), will be
       greater after the application of this Article 13 than it was before
       the application of this Article 13; or

                     (b)    The Committee, at the time of making an Award
       under the Plan or at any time thereafter, specifies in writing
       that such Award shall be subject to this Article 13 (regardless of
       the after-tax value of such Award to the Participant).

If this Article 13 applies to an Award, it shall supersede any contrary
provision of the Plan or of any Award granted under the Plan.

              13.2   BASIC RULE.  In the event that the Auditors determine
that any payment or transfer by the Company under the Plan to or for the
benefit of a Participant (a "Payment") would be nondeductible by the Company
for federal income tax purposes because of the provisions concerning "excess
parachute payments" in section 280G of the Code, then the aggregate present
value of all Payments shall be reduced (but not below zero) to the Reduced
Amount.  For purposes of this Article 13, the "Reduced Amount" shall be the
amount, expressed as a present value, which maximizes the aggregate present
value of the Payments without causing any Payment to be nondeductible by the
Company because of section 280G of the Code.

              13.3   REDUCTION OF PAYMENTS.  If the Auditors determine that
any Payment would be nondeductible by the Company because of section 280G of
the Code, then the Company shall promptly give the Participant notice to that
effect and a copy of the detailed calculation thereof and of the Reduced
Amount, and the Participant may then elect, in his or her sole discretion,
which and how much of the Payments shall be eliminated or reduced (as long as
after such election the aggregate present value of the Payments equals the
Reduced Amount) and shall advise the Company in writing of his or her
election within 10 days of receipt of notice.  If no such election is made by
the Participant within such 10-day period, then the Company may elect which
and how much of the Payments shall be eliminated or reduced (as long as after
such election the aggregate present value of the Payments equals the Reduced
Amount) and shall notify the Participant promptly of such election.  For
purposes of this Article 13, present value shall be determined in accordance
with section 280G(d)(4) of the Code. All determinations made by the Auditors
under this Article 13 shall be binding upon the Company and the Participant
and shall be made within 60 days of the date when a Payment becomes payable
or transferable.  As promptly as practicable following such determination and
the elections hereunder, the Company shall pay or transfer to or for the
benefit of the Participant such amounts as are then due to him or her under
the Plan and shall promptly pay or transfer to or for the benefit of the
Participant in the future such amounts as become due to him or her under the
Plan.

              13.4   OVERPAYMENTS AND UNDERPAYMENTS.  As a result of
uncertainty in the application of section 280G of the Code at the time of an
initial determination by the Auditors hereunder, it is possible that Payments
will have been made by the Company which should not have been made (an
"Overpayment") or that additional Payments which will not have been made by
the Company could have been made (an "Underpayment"), consistent in each case
with the calculation of the Reduced Amount hereunder.  In the event that the
Auditors, based upon the

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assertion of a deficiency by the Internal Revenue Service against the Company
or the Participant which the Auditors believe has a high probability of
success, determine that an Overpayment has been made, such Overpayment shall
be treated for all purposes as a loan to the Participant which he or she
shall repay to the Company, together with interest at the applicable federal
rate provided in section 7872(f)(2) of the Code; provided, however, that no
amount shall be payable by the Participant to the Company if and to the
extent that such payment would not reduce the amount which is subject to
taxation under section 4999 of the Code.  In the event that the Auditors
determine that an Underpayment has occurred, such Underpayment shall promptly
be paid or transferred by the Company to or for the benefit of the
Participant, together with interest at the applicable federal rate provided
in section 7872(f)(2) of the Code.

              13.5   RELATED CORPORATIONS.  For purposes of this Article 13,
the term "Company" shall include affiliated corporations to the extent
determined by the Auditors in accordance with section 280G(d)(5) of the Code.

       ARTICLE 14.   FUTURE OF THE PLAN.

              14.1   TERM OF THE PLAN.  The Plan, as set forth herein, shall
become effective on the date of the Company's initial public offering.  The
Plan shall remain in effect until it is terminated under Section 14.2.

              14.2   AMENDMENT OR TERMINATION.  The Board may, at any time
and for any reason, amend or terminate the Plan.  An amendment of the Plan
shall be subject to the approval of the Company's shareholders only to the
extent required by applicable laws, regulations or rules.  The amendment or
termination of the Plan shall not affect any Award previously granted under
the Plan.  No Awards shall be granted under the Plan after the termination
thereof.  The Plan shall terminate automatically 10 years after its adoption
by the Board, unless (a) the Plan is extended by the Board and (b) the
extension is approved within 12 months by a vote of the shareholders of the
Company.

       ARTICLE 15.   DEFINITIONS.

              15.1   "AFFILIATE" means any entity other than a Subsidiary, if
the Company and/or one or more Subsidiaries own not less than 50% of such
entity.

              15.2   "AWARD" means any award of an Option or a Restricted
Share under the Plan.

              15.3   "BOARD" means the Company's Board of Directors, as
constituted from time to time.

              15.4   "CAUSE" shall mean (a) the unauthorized use or
disclosure of the confidential information or trade secrets of the Company,
which use or disclosure causes material harm to the Company, (b) conviction
of, or a plea of "guilty" or "no contest" to, a felony under the laws of the
United States or any State thereof, (c) gross negligence, (d) willful
misconduct or (e) a failure to perform assigned duties that continues after
the Participant has received written notice of such failure from the Board.
The foregoing, however, shall not be

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<PAGE>

deemed an exclusive list of all acts or omissions that the Company (or the
Parent, Subsidiary or Affiliate employing the Participant) may consider as
grounds for the discharge of the Participant without Cause.

              15.5   "CHANGE IN CONTROL" means:

                     (a)    The consummation of a merger or consolidation
       of the Company with or into another entity or any other corporate
       reorganization, if persons who were not shareholders of the
       Company immediately prior to such merger, consolidation or other
       reorganization own immediately after such merger, consolidation or
       other reorganization 50% or more of the voting power of the
       outstanding securities of each of (i) the continuing or surviving
       entity and (ii) any direct or indirect parent corporation of such
       continuing or surviving entity;

                     (b)    The sale, transfer or other disposition of
       all or substantially all of the Company's assets;

                     (c)    A change in the composition of the Board, as
       a result of which 50% or fewer of the incumbent directors are
       directors who either (i) had been directors of the Company on the
       date 24 months prior to the date of the event that may constitute
       a Change in Control (the "original directors") or (ii) were
       elected, or nominated for election, to the Board with the
       affirmative votes of at least a majority of the aggregate of the
       original directors who were still in office at the time of the
       election or nomination and the directors whose election or
       nomination was previously so approved; or

                     (d)    Any transaction as a result of which any
       person is the "beneficial owner" (as defined in Rule 13d-3 under
       the Exchange Act), directly or indirectly, of securities of the
       Company representing at least 50% of the total voting power
       represented by the Company's then outstanding voting securities.
       For purposes of this Subsection (d), the term "person" shall have
       the same meaning as when used in sections 13(d) and 14(d) of the
       Exchange Act but shall exclude (i) a trustee or other fiduciary
       holding securities under an employee benefit plan of the Company
       or of a Parent or Subsidiary and (ii) a corporation owned directly
       or indirectly by the shareholders of the Company in substantially
       the same proportions as their ownership of the common stock of the
       Company.

A transaction shall not constitute a Change in Control if its sole purpose is
to change the state of the Company's incorporation or to create a holding
company that will be owned in substantially the same proportions by the
persons who held the Company's securities immediately before such transaction.

              15.6   "CODE" means the Internal Revenue Code of 1986, as amended.

              15.7   "COMMITTEE" means a committee of the Board, as described in
Article 2.

              15.8   "COMMON SHARE" means one share of the common stock of the
Company.

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<PAGE>

              15.9   "COMPANY" means DrugAbuse Sciences, Inc., a California
corporation.

              15.10  "CONSULTANT" means a consultant or adviser who provides
bona fide services to the Company, a Parent, a Subsidiary or an Affiliate as
an independent contractor.  Service as a Consultant shall be considered
employment for all purposes of the Plan, except as provided in Section 4.2.

              15.11  "EMPLOYEE" means a common-law employee of the Company, a
Parent, a Subsidiary or an Affiliate.

              15.12  "EXCHANGE ACT" means the Securities Exchange Act of
1934, as amended.

              15.13  "EXERCISE PRICE" means the amount for which one Common
Share may be purchased upon exercise of an Option, as specified in the
applicable Stock Option Agreement.

              15.14  "FAIR MARKET VALUE" means the market price of Common
Shares, determined by the Committee in good faith on such basis as it deems
appropriate.  Whenever possible, the determination of Fair Market Value by
the Committee shall be based on the prices reported in THE WALL STREET
JOURNAL. Such determination shall be conclusive and binding on all persons.

              15.15  "INVOLUNTARY TERMINATION" means the termination of the
Participant's service by reason of:

                     (a)    The involuntary discharge of the Participant
       by the Company (or the Parent, Subsidiary or Affiliate employing
       him or her) for reasons other than Cause; or

                     (b)    The voluntary resignation of the Participant
       following (i) a material adverse change in his or her title,
       stature, authority or responsibilities with the Company (or the
       Parent, Subsidiary or Affiliate employing him or her), (ii) a
       material reduction in his or her base salary or (iii) receipt of
       notice that his or her principal workplace will be relocated by
       more than 30 miles.

              15.16  "ISO" means an incentive stock option described in
section 422(b) of the Code.

              15.17  "NSO" means a stock option not described in sections 422
or 423 of the Code.

              15.18  "OPTION" means an ISO or NSO granted under the Plan and
entitling the holder to purchase Common Shares.

              15.19  "OPTIONEE" means an individual or estate who holds an
Option.

              15.20  "OUTSIDE DIRECTOR" means a member of the Board who is
not an Employee.  Service as an Outside Director shall be considered
employment for all purposes of the Plan, except as provided in Section 4.2.

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<PAGE>

              15.21  "PARENT" means any corporation (other than the Company)
in an unbroken chain of corporations ending with the Company, if each of the
corporations other than the Company owns stock possessing 50% or more of the
total combined voting power of all classes of stock in one of the other
corporations in such chain.  A corporation that attains the status of a
Parent on a date after the adoption of the Plan shall be considered a Parent
commencing as of such date.

              15.22  "PARTICIPANT" means an individual or estate who holds an
Award.

              15.23  "PLAN" means this DrugAbuse Sciences, Inc. 2000 Stock
Incentive Plan, as amended from time to time.

              15.24  "PREDECESSOR PLAN" means the DrugAbuse Sciences, Inc.
1994 Stock Plan, the DrugAbuse Sciences, Inc. 1999 Stock Plan A or the
DrugAbuse Sciences, Inc. 1999 Stock Plan B.

              15.25  "RESTRICTED SHARE" means a Common Share awarded under
the Plan.

              15.26  "RESTRICTED STOCK AGREEMENT" means the agreement between
the Company and the recipient of a Restricted Share that contains the terms,
conditions and restrictions pertaining to such Restricted Share.

              15.27  "STOCK OPTION AGREEMENT" means the agreement between the
Company and an Optionee that contains the terms, conditions and restrictions
pertaining to his or her Option.

              15.28  "SUBSIDIARY" means any corporation (other than the
Company) in an unbroken chain of corporations beginning with the Company, if
each of the corporations other than the last corporation in the unbroken
chain owns stock possessing 50% or more of the total combined voting power of
all classes of stock in one of the other corporations in such chain.  A
corporation that attains the status of a Subsidiary on a date after the
adoption of the Plan shall be considered a Subsidiary commencing as of such
date.

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       ARTICLE 16.   EXECUTION.

              To record the adoption of the Plan by the Board on January 13,
2000, the Company has caused its duly authorized officer to execute this
document in the name of the Company.

                                       DRUGABUSE SCIENCES, INC.




                                       By: _________________________________

                                       Title: ______________________________


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