<PAGE>

                        RESTATED CERTIFICATE OF INCORPORATION
                                        OF
                          THERAPEUTIC DISCOVERY CORPORATION
                    (ORIGINALLY INCORPORATED ON NOVEMBER 12, 1992)


          FIRST:    NAME. The name of this corporation is Therapeutic
Discovery Corporation (the "corporation").

          SECOND:   REGISTERED OFFICE; REGISTERED AGENT. The address of the
registered office of this corporation in the State of Delaware is 1013 Centre
Road, in the City of Wilmington, County of New Castle.  The name of the
registered agent of this corporation at such address is Corporation Service
Company.

          THIRD:    PURPOSE. The purpose of this corporation is to engage in
any lawful act or activity for which corporations may be organized under the
General Corporation Law of the State of Delaware.

          FOURTH:   AUTHORIZED CAPITAL STOCK.

          (A)  This corporation is authorized to issue two classes of shares,
which shall be known as Class A Common Stock and Class B Common Stock.  The
total number of shares of stock of all classes that this corporation is
authorized to issue is 12,000,100.  The total number of shares of Class A
Common Stock which this corporation is authorized to issue is 12,000,000.
The total number of shares of Class B Common Stock which this corporation is
authorized to issue is 100. Each share of Class A Common Stock and Class B
Common Stock shall have a par value of $0.01.

          Effective immediately upon the filing of this Restated Certificate
of Incorporation, each share of Common Stock, par value $1.00 per share, of
this corporation outstanding immediately prior to such filing shall be
converted into and reclassified as one share of Class B Common Stock.

          (B)  The powers, designations, preferences, and relative,
participating, optional or other special rights granted to, and the
qualifications, limitations and restrictions imposed upon, the Class A Common
Stock and Class B Common Stock and the respective holders thereof are as
follows:

               (1)  REDEMPTION. The shares of Class A Common Stock are
     redeemable and may be redeemed as provided in (but only as provided in)
     ARTICLE FIFTH, Section (F).

               (2)  DIVIDENDS.  The holders of shares of Class A Common Stock
     and Class B Common Stock shall be entitled to receive per share and
     without preference such dividends as may be declared by the Board of
     Directors from time to time


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     out of funds legally available therefor. No dividend may be declared on
     the Class A Common Stock unless the same per share dividend is declared
     on the Class B Common Stock, and no dividend may be declared on the
     Class B Common Stock unless the same per share dividend is declared on
     the Class A Common Stock. Dividends may not be declared, nor may shares
     of Class A Common Stock or Class B Common Stock be repurchased or
     redeemed (other than pursuant to Section (F) of Article FIFTH) if, after
     payment of such dividend, or after effecting such repurchase or
     redemption, the amount of this corporation's cash, cash equivalents,
     short and long term investments would be less than the amount of
     Available Funds as of the date of such dividend, repurchase or
     redemption.

               (3)  LIQUIDATION.  In the event of voluntary or involuntary
     liquidation of this corporation, the holders of the Class A Common Stock
     and Class B Common Stock of the corporation shall be entitled to
     receive, on a pro rata per share basis and without preference, all of
     the remaining assets of this corporation available for distribution to
     its stockholders.

               (4)  VOTING RIGHTS. Except as otherwise required by law or
     provided herein, the holders of Class A Common Stock and Class B Common
     Stock shall vote together as a single class.  Each holder of Class A
     Common Stock and Class B Common Stock shall have one vote for each share
     standing in his or her name on all matters submitted to a vote of
     holders of the common shares. At any meeting of the stockholders of this
     corporation, the determination of a quorum shall be based upon the
     presence of shares of Class A Common Stock and Class B Common Stock
     representing a majority of the voting power of all of the shares of
     Class A Common Stock and Class B Common Stock.  This corporation shall
     not, without the affirmative vote of the holders of a majority of the
     issued and outstanding shares of Class B Common Stock, voting separately
     and as a class, (a) alter or change the powers, designations,
     preferences and relative, participating, optional or other special
     rights granted to, or the qualifications, limitations and restrictions
     imposed upon, the Class A Common Stock or the Class B Common Stock, (b)
     alter or change Articles FOURTH, FIFTH, SIXTH, SEVENTH or EIGHTH of this
     Restated Certificate of Incorporation, (c) authorize the creation or
     issuance of any additional class or series of stock, or otherwise make
     any amendment to this Certificate of Incorporation that would alter the
     rights of the holders of the Class B Common Stock, (d) undertake the
     voluntary dissolution, liquidation or winding up of this corporation,
     (e) merge or consolidate this corporation with or into any other
     corporation or entity, (f) sell, lease, exchange, transfer or otherwise
     dispose of any substantial asset of this corporation or (g) alter the
     bylaws of this corporation in a manner


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<PAGE>

     described in the last sentence of ARTICLE EIGHTH. Furthermore, from and
     after the Purchase Option Exercise Date, as defined in Article FIFTH,
     (i) the board of directors of this corporation shall cease to be
     classified; (ii) the number of directors of this corporation shall be
     increased to a number equal to (a) two times the maximum number of
     authorized directors (counting for this purpose both directors in office
     and vacant directorships), PLUS (b) one; and (iii) the holders of the
     Class B Common Stock shall have the sole right to elect the directors of
     this corporation, including directors to fill the new directorships
     created pursuant to clause (ii).  No vacancy created as a result of the
     increase in the size of the board of directors pursuant to the preceding
     sentence shall be filled other than by the holders of the Class B Common
     Stock.

              (5)  CONVERSION.  The Class B Common Stock shall automatically
     convert into fully paid and non-assessable shares of Class A Common
     Stock of this corporation at 12:01 a.m. New York time on the day
     immediately following the expiration of the Purchase Option granted in
     Article FIFTH.  The Class B Common Stock shall convert into Class A
     Common Stock at the rate of one share of Class A Common Stock for each
     share of Class B Common Stock.

               (6)  TRANSFER OF CLASS A COMMON STOCK. Until the first to
     occur of (i) the third anniversary of the date (the "Distribution Date")
     upon which certificates representing Units comprised in part of shares
     of Class A Common Stock are distributed by ALZA Corporation (together
     with its successors and assigns, "ALZA") to the holders of ALZA's Class
     A Common Stock or (ii) the Purchase Option Exercise Date, the Class A
     Common Stock may be transferred only as part of Units. Each "Unit"
     consists of one share of Class A Common Stock and one warrant to acquire
     one-eighth of one share of ALZA Common Stock.

          FIFTH.    PURCHASE OPTION.

          (A)  DEFINITIONS.  For purposes of this Restated Certificate of
Incorporation, the following terms shall have the following definitions:

          (1)  ALZA COMMON STOCK means the Class A Common Stock of ALZA or,
if such Class A Common Stock is converted into or exchanged for another class
or series of stock of ALZA or any other corporation, such other class or
series of stock.

          (2)  AVAILABLE FUNDS means, as of any date of determination, the
sum of (a) $250 million (contributed by ALZA in or about March 1993), PLUS
(b) interest and other income earned through investment of such funds until
their expenditure pursuant to the Development Contract through the date of


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determination, LESS (c) reasonable ongoing administrative expenses of this
corporation, including legal and accounting expenses, incurred through the
date of determination, LESS (d) the costs associated with the distribution to
ALZA's stockholders of the Units.

          (3)  DEVELOPMENT CONTRACT means the Development Agreement dated as
of March 10, 1993 between ALZA and this corporation, as such contract may be
amended or modified from time to time by amendments approved by ALZA and the
board of directors of this corporation.

          (4)  FAIR MARKET VALUE means, with reference to ALZA Common Stock,
(a) if ALZA Common Stock is listed on the New York Stock Exchange or any
other securities exchange reporting closing sales prices (including without
limitation the NASDAQ National Market System), the average of the closing
sales price of ALZA Common Stock on such exchange (which shall be the New
York Stock Exchange or, if ALZA Common Stock is not then traded on such
exchange, on the principal exchange on which ALZA Common Stock is then
traded), for the five trading days ending with the trading day that is two
trading days prior to the date of determination, (b) if ALZA Common Stock is
not listed on any securities exchange described in clause (a) but is quoted
on NASDAQ or another quotation system providing bid prices, the average (over
the five day period described in clause (a)) of the bid prices for each day
in such period on NASDAQ (or, if ALZA Common Stock is not then quoted on
NASDAQ, the largest quotation system on which ALZA Common Stock is then
quoted), and (c) if ALZA Common Stock is not listed on any exchange or quoted
on any quotation system, the value thereof as determined in good faith by
ALZA's board of directors.

          (5)  FINAL PURCHASE OPTION EXERCISE PRICE means the Purchase Option
Exercise Price MINUS (a) the amount by which this corporation's Liabilities
existing at the Purchase Option Exercise Date (other than liabilities
pursuant to the Development Contract) exceed the aggregate of this
corporation's then existing cash, cash equivalents and short-term and
long-term investments (but excluding from such cash, cash equivalents and
short-term and long-term investments the amount of Available Funds determined
as of the Purchase Option Exercise Date which had not, as of such date, been
paid by this corporation in accordance with the Development Contract); and
MINUS (b), if the Purchase Option Exercise Price was determined based upon the
provisions of clause (c) of Section (A)(10) of this Article FIFTH, any
additional amounts paid by this corporation pursuant to the Development
Contract from the date of the last report of such expenditures provided by
this corporation to ALZA pursuant to the Development Contract to the Purchase
Option Exercise Date.

          (6)  LIABILITIES means, with respect to this corporation, (a) all
liabilities required to be reflected or


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reserved against in this corporation's financial statements under generally
accepted accounting principles consistently applied ("GAAP"), (b) any
guaranty of any indebtedness of another person and (c) any reimbursement or
similar obligation with respect to any letter of credit issued for the
account of this corporation or as to which this corporation is otherwise
liable.  Liabilities of the type described in (b) and (c) shall be valued at
the full amount of the potential liability of the corporation thereon.

          (7)  LICENSE AGREEMENT means any License Agreement between ALZA and
this corporation entered into upon the exercise by ALZA of the license option
granted to it pursuant to the License Option Agreement.

          (8)  LICENSE OPTION AGREEMENT means the License Option Agreement
between ALZA and this corporation dated as of March 10, 1993, as such
agreement may be amended or modified from time to time by amendments approved
by ALZA and the board of directors of this corporation.

          (9)  PURCHASE OPTION EXERCISE DATE means the date upon which ALZA
notifies this corporation in writing of its exercise of the Purchase option
as provided in Section (C) of this Article FIFTH.

          (10) PURCHASE OPTION EXERCISE PRICE means the greatest of the
following:

               (a)  the greater of (i) 25 times the Royalties paid by or due
     from ALZA to this corporation, PLUS 25 times any Royalties that would
     have been paid by or due from ALZA to this corporation if ALZA had not
     exercised its right to buy out its obligation to pay any such Royalties
     as provided in Section 7.5 of the Development Contract or Section 3.4 of
     any License Agreement, in each case determined with reference to the
     most recent four complete calendar quarters preceding the Purchase
     Option Exercise Date for which such Royalties were paid by or due from
     ALZA or would have been paid by or due from ALZA, or (ii) 100 times such
     Royalties paid by or due from ALZA to this corporation during the most
     recent complete calendar quarter for which such Royalties were paid or
     due; PROVIDED, that in the case of either (i) or (ii) the amount so
     determined shall be reduced by any amounts previously paid by ALZA to
     this corporation to buy out any obligation to pay Royalties as provided
     in the Development Contract or any License Agreement;

               (b)  the Fair Market Value of one million shares of ALZA
     Common Stock (which number of shares shall be proportionately adjusted
     for any stock dividend, split-up, combination or reclassification of the
     ALZA Common Stock) determined as of the Purchase Option Exercise Date;


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               (c)  $325 million LESS the total amount paid by this
     corporation under the Development Contract as last reported by this
     corporation to ALZA through the Purchase Option Exercise Date; and

               (d)  $100 million.

          (11) PURCHASE OPTION EXPIRATION TIME means 11:59 p.m. New York time
on December 31, 1999; provided that such date will be extended for successive
one year periods if, as of any June 30 beginning with June 30, 1999, this
corporation has not paid at least 90% of all Available Funds pursuant to the
Development Contract.  Notwithstanding the foregoing sentence, the Purchase
Option Expiration Time will in no event occur later than 11:59 p.m. New York
time on the 60th day after the later of (a) the date of filing with the
Securities and Exchange Commission or (b) the due date of this corporation's
Annual Report on Form 10-K or Quarterly Report on Form 10-Q containing a
balance sheet showing that this corporation has less than an aggregate of $5
million in cash, cash equivalents, and short-term and long-term investments.

          (12) ROYALTIES means (a) royalties paid or other payments made by
ALZA to this corporation under a License Agreement in respect of any product
licensed by ALZA from this corporation pursuant to the License Option
Agreement and (b) payments made by ALZA under Section 7.4 of the Development
Contract. In determining the amount of Royalties for purposes of Article
FIFTH, Section (A)(10)(a), all Special Royalty Payments are to be amortized
equally over a period of 28 calendar quarters beginning with the calendar
quarter in which such Special Royalty Payment is made, regardless of the
treatment of such Special Royalty Payments in determining Royalties actually
paid under any License Agreement or the Development Contract.

          (13) SPECIAL ROYALTY PAYMENT means front-end distribution fees,
prepaid royalties and similar one-time, infrequent or special payments.

          (14) STATUS STATEMENT means, as of any date, a balance sheet dated
as of such date, together with (a) a statement and brief description of all
other liabilities of this corporation constituting Total Liabilities as of
such date not reflected on such balance sheet, (b) a statement of the amount
of Available Funds remaining as of such date, and (c) a statement of the
total amounts paid by this corporation pursuant to the Development Contract
through such date.

          (15) TOTAL LIABILITIES means, with respect to this corporation, (a)
all Liabilities and (b) any other debts, liabilities or obligations, absolute
or contingent, matured or unmatured, liquidated or unliquidated, accrued or
unaccrued, known or unknown, whenever arising, including all costs and
expenses relating thereto, and including those debts, liabilities


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and obligations arising under law, rule or regulation, or under any pending
or threatened action, suit or proceeding, or any order or consent decree of
any governmental entity or any award of any arbitrator of any kind, and those
arising under any contract, commitment or undertaking.

          (B)  GRANT OF OPTION.  ALZA is hereby granted an exclusive
irrevocable purchase option to purchase all issued and outstanding shares of
Class A Common Stock of this corporation for the Final Purchase Option
Exercise Price (the "Purchase Option").  The Purchase Option, if exercised,
must be exercised as to all, but not less than all, issued and outstanding
shares of Class A Common Stock and may be exercised at any time at or prior
to the Purchase Option Expiration Time.  ALZA shall elect, at the time of
exercise of the Purchase Option, to pay all or any portion of the Final
Purchase Option Exercise Price in cash, ALZA Common Stock (valued at its Fair
Market Value determined as of the Purchase Option Exercise Date), or any
combination thereof.  The Purchase Option may, at ALZA's option, be assigned
or otherwise transferred to any person or entity, including this corporation.

          (C)  MANNER OF EXERCISE.  The Purchase Option shall be exercised at
or before the Purchase Option Expiration Time by written notice (the
"Exercise Notice") from ALZA to this corporation stating that the Purchase
Option is being exercised and setting forth (1) the Purchase Option Exercise
Price; (2) the portion, if any, of the Purchase Option Exercise Price to be
paid in cash and the portion, if any, of the Purchase Option Exercise Price
to be paid in ALZA Common Stock, and if any portion of the Purchase Option
Exercise Price is to be paid in ALZA Common Stock, stating the Fair Market
Value of such ALZA Common Stock determined as of the Purchase Option Exercise
Date, and (3) a closing date (the "Closing Date") on which all of the issued
and outstanding shares of Class A Common Stock will be purchased.  The
Purchase Option shall be deemed to be exercised as of the date of mailing by
first class mail of the Exercise Notice to this corporation.

          (D)  CLOSING.

          (1)  CLOSING DATE; COOPERATION. Except as set forth below, the
Closing Date shall be the date specified as such in the Exercise Notice,
which date specified shall be no later than 90 days after the Purchase Option
Exercise Date. The Closing Date may be extended by ALZA if, in the judgment
of ALZA, an extension of the Closing Date is necessary to obtain any
governmental or third party consent to the purchase of the Class A Common
Stock, to permit any necessary registration statement or similar filing to be
declared effective, or to permit the expiration prior to the Closing Date of
any statutory or regulatory waiting period. ALZA may extend the Closing Date
for the reasons set forth in the preceding sentence by delivering written
notice of such extension to this corporation on or prior


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to the previously scheduled Closing Date.  This corporation shall cooperate
with ALZA to effect the closing of the Purchase Option, including without
limitation seeking any required third-party or governmental consents, and
filing any applications, notifications, registration statements or the like
which may be necessary to effect the closing.

          (2)  CERTAIN RESTRICTIONS FOLLOWING PURCHASE OPTION EXERCISE DATE.
From the Purchase Option Exercise Date until the Closing Date, this
corporation will not take any of the following actions (or permit any such
actions to be taken on its behalf) except with the prior written consent of
ALZA:

               (a)  borrow money, or mortgage, remortgage, pledge,
     hypothecate or otherwise encumber any of its assets;

               (b)  sell, lease, lend, exchange or otherwise dispose of any
     of its assets, other than sales of inventory in the ordinary course of
     business;

               (c)  pay or declare any dividends or make any distributions on
     or in respect of any shares of its capital stock;

               (d)  default in its obligations under any material contract,
     agreement, commitment or undertaking of any kind or enter into any
     material contract, agreement, purchase order or other commitment; or

               (e)  enter into any other transaction or agreement or
     arrangement, or incur any liabilities, not in the ordinary course of
     this corporation's business.

          (3)  DETERMINATION OF FINAL PURCHASE OPTION EXERCISE PRICE.  Not
later than 15 business days following the Purchase Option Exercise Date, this
corporation shall deliver a final Status Statement to ALZA prepared as of the
Purchase Option Exercise Date. Following receipt of such Status Statement and
completion of any other investigation as ALZA shall deem necessary or
appropriate, and prior to the Closing Date, ALZA shall determine the Final
Purchase Option Exercise Price by making the adjustments to the Purchase
Option Exercise Price contemplated by Section (A)(5) of this Article FIFTH
and shall notify this corporation of such determination.

          (4)  PAYMENT OF FINAL PURCHASE OPTION EXERCISE PRICE.  On or before
the Closing Date, ALZA shall deposit the full amount of the Final Purchase
Option Exercise Price with a bank or banks or similar entities designated by
ALZA (which may include ALZA's transfer agent if shares of ALZA Common Stock
are being delivered) to pay, on ALZA's behalf, the Final Purchase Option
Exercise Price (the "Payment Agent").  Funds, if any, and ALZA Common Stock,
if any, deposited with the Payment Agent shall be delivered in trust for the
benefit of the holders of Class A


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Common Stock, and ALZA shall provide the Payment Agent with irrevocable
instructions to pay, on or after the Closing Date, the Final Purchase Option
Exercise Price for the shares of Class A Common Stock to the holders of
record thereof determined as of the Closing Date.  Payment for shares of
Class A Common Stock shall be mailed to each holder at the address set forth
in this corporation's records or at the address provided by each holder or,
if no address is set forth in this corporation's records for a holder or
provided by such holder, to such holder at the address of this corporation.
At ALZA's request, this corporation shall provide, or shall cause its
transfer agent to provide, to ALZA or to the Payment Agent, free of charge, a
complete list of the record holders of shares of Class A Common Stock,
including the number of shares of Class A Common Stock held of record and the
address of each record holder.

          (E)  TRANSFER OF TITLE. Transfer of title to all of the issued and
outstanding shares of Class A Common Stock shall be deemed to occur
automatically on the Closing Date and thereafter this corporation shall be
entitled to treat ALZA as the sole holder of all of the issued and
outstanding shares of its Class A Common Stock, notwithstanding the failure
of any holder of Class A Common Stock to tender the certificates representing
such shares to the Payment Agent. This corporation shall instruct its
transfer agent not to accept any shares of Class A Common Stock for transfer
on and after the Closing Date, except for the shares of Class A Common Stock
transferred to ALZA. This corporation shall take all actions reasonably
requested by ALZA to assist in effectuating the transfer of shares of Class A
Common Stock in accordance with this Article FIFTH.

          (F)  REDEMPTION OF CLASS A COMMON STOCK. At ALZA's election (which
election may be made at any time, provided it is made, by delivery of written
notice thereof to this corporation, not less than five days prior to the
Closing Date), this corporation shall, subject to applicable restrictions in
the Delaware General Corporation Law, redeem on the Closing Date all issued
and outstanding shares of Class A Common Stock for an aggregate redemption
price equal to the Final Purchase Option Exercise Price.

          SIXTH.    PROTECTIVE PROVISIONS.

          (A)  LEGEND. Certificates evidencing shares of Class A Common Stock
issued by or on behalf of this corporation shall bear a legend in
substantially the following form:

          "The shares of Therapeutic Discovery Corporation evidenced hereby
are subject to an option in favor of ALZA Corporation, its successors and
assigns, as described in the Restated Certificate of Incorporation of
Therapeutic Discovery Corporation to purchase such shares at a purchase price
determined in accordance with Article FIFTH thereof exercisable


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by notice delivered to this Corporation at or prior to the Purchase Option
Expiration Time (as defined in the Restated Certificate of Incorporation of
Therapeutic Discovery Corporation). Copies of the Restated Certificate of
Incorporation of Therapeutic Discovery Corporation are available at the
principal place of business of Therapeutic Discovery Corporation at 1290 Page
Mill Road, P.0. Box 10950, Palo Alto, California 94303-0860 and will be
furnished to any stockholder on request and without cost."

          (B)  NO CONFLICTING ACTION. This corporation shall not take, nor
permit any other person or entity within its control to take, any action
inconsistent with ALZA's rights under Article FIFTH.  This corporation shall
not enter into any arrangement, agreement or understanding, whether oral or
in writing, that is inconsistent with or limits or impairs the rights of ALZA
and the obligations of this corporation hereunder, including without
limitation any arrangement, agreement or understanding which imposes any
obligation upon this corporation, or deprives this corporation of any
material rights, as a consequence of the exercise of the Purchase Option or
the acquisition of the outstanding Class A Common Stock pursuant thereto.

          (C)  INSPECTION AND VISITATION RIGHTS; STATUS STATEMENTS.  ALZA
shall have the right to inspect and copy, on reasonable notice and during
regular business hours, the books and records of this corporation. ALZA shall
also have the right to request from time to time (but not more frequently
than monthly) a Status Statement as of such date as ALZA may request. Each
Status Statement shall be sent within seven days of request by ALZA. ALZA
shall also have the right to send a non-voting representative to attend all
meetings of this corporation's board of directors and any committees thereof.
Such representative shall receive notice of all meetings of this
corporation's board of directors and each committee thereof, as well as
copies of all documents and other materials provided to any directors of this
corporation in connection with any such meeting not later than the time such
materials are provided to other directors. Such representative shall also be
provided with copies of all resolutions adopted or proposed to be adopted by
unanimous written consent not later than the time such resolutions are
provided to other directors.

          SEVENTH:  BOARD OF DIRECTORS.

          (A)  The number of directors which shall constitute the whole Board
of Directors of this corporation shall initially be three, but may be
increased or decreased from time to time by a resolution duly adopted by the
Board of Directors.

          (B)  Nomination of candidates for election to the Board of
Directors shall be made as provided in the bylaws of this corporation.
Election of directors need not be by written ballot.


                                      -10-
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          (C)  The Board of Directors shall be and is divided into three
classes: Class I, Class II and Class III, which shall be as nearly equal in
number as possible. Each director shall serve for a term ending on the date
of the third annual meeting of stockholders following the annual meeting at
which the director was elected; provided, however, that each initial director
in Class I shall hold office until the annual meeting of stockholders in
1994; each initial director in Class II shall hold office until the annual
meeting of stockholders in 1995; and each initial director in Class III shall
hold office until the annual meeting of stockholders in 1996. Notwithstanding
the foregoing provisions of this Article, each director shall serve until his
successor is duly elected and qualified or until his death, resignation or
removal.

          (D)  In the event of any increase or decrease in the authorized
number of directors, the newly created or eliminated directorships resulting
from such increase or decrease shall be apportioned by the Board of Directors
among the three classes of directors so as to maintain such classes as nearly
equal as possible.  No decrease in the number of directors constituting the
Board of Directors shall shorten the term of any incumbent director.

          (E)  Except as otherwise provided in Article FOURTH, Section
(B)(4), newly created directorships resulting from any increase in the number
of directors and any vacancies on the Board of Directors resulting from
death, resignation, disqualification, removal or other cause shall be filled
by the affirmative vote of a majority of the remaining directors then in
office (and not by stockholders), even though less than a quorum of the Board
of Directors. Any director elected in accordance with the preceding sentence
shall hold office for the remainder of the full term of the class of
directors in which the new directorship was created or the vacancy occurred
and until such director's successor shall have been elected and qualified.

          (F)  The name and mailing address of each person who is to serve as
a director until the annual meeting of the stockholders entitled to vote for
the class or until a successor is elected and qualified are as follows:


    NAME                       MAILING ADDRESS              CLASS

    Dr. Pieter P. Bonsen      950 Page Mill Road,             I
                              Palo Alto, CA 94303

    Adrian M. Gerber          950 Page Mill Road,             II
                              Palo Alto, CA 94303

    Dr. Felix Theeuwes        950 Page Mill Road,             III
                              Palo Alto, CA 94303

          (G)  The board of directors of this corporation shall cease to be
classified as provided in this Article SEVENTH from


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<PAGE>

and after the Purchase Option Exercise Date.  From and after such date all
directors shall be elected to one year terms; provided the term of any
director then in office shall not be reduced.

          EIGHTH:   BYLAWS.  In furtherance and not in limitation of the
powers conferred by statute, and subject to the next sentence, the Board of
Directors and the stockholders of this corporation are each expressly
authorized to adopt, amend or repeal the bylaws of this corporation subject
to any particular provisions concerning amendments set forth in this
Certificate of Incorporation or the bylaws of this corporation.  No amendment
to the bylaws may be adopted by the stockholders without the approval of
holders of a majority of the Class B Common Stock voting separately as a
class if such amendment would affect the classification of the Board of
Directors, or would otherwise regulate the conduct of the Board's affairs or
the manner in which it may act.

          NINTH:    STOCKHOLDER MEETINGS.

          (A)  SPECIAL MEETINGS. Special meetings of the stockholders for any
purpose or purposes whatsoever may be called at any time only by the Board of
Directors, the Chairman of the Board or the President of this corporation.

          (B)  NO ACTION WITHOUT MEETING.  At any time when this corporation
has more than one stockholder of any class of capital stock, no action
required to be taken or which may be taken at any annual or special meeting
of the stockholders may be taken without a meeting, and the power of
stockholders to consent in writing, without a meeting, to the taking of any
action is specifically denied. Notwithstanding the foregoing, the holder or
holders of the Class B Common Stock may take any action permitted to be taken
by such holders as a class by written consent without a meeting.

          TENTH:    LIMITATION OF LIABILITY AND INDEMNIFICATION OF DIRECTORS.

          (A)  ELIMINATION OF CERTAIN LIABILITY OF DIRECTORS.  No director of
this corporation shall be personally liable to this corporation or its
stockholders for monetary damages for breach of fiduciary duty as a director,
except for liability (i) for any breach of the director's duty of loyalty to
this corporation or its stockholders, (ii) for acts or omissions not in good
faith or which involve intentional misconduct or a knowing violation of law,
(iii) under section 174 of the Delaware General Corporation Law or (iv) for
any transaction from which the director derived an improper, personal benefit.

          (B)  INDEMNIFICATION AND INSURANCE.

          1.   RIGHT TO INDEMNIFICATION.  Each person who was or is made a
party or is threatened to be made a party to or is


                                      -12-
<PAGE>

involved in any action, suit or proceeding, whether civil, criminal,
administrative or investigative (a "proceeding"), because he or she, or a
person of whom he or she is the legal representative, is or was a director or
officer of this corporation or is or was serving at the request of this
corporation as a director, officer, employee or agent of another corporation
or of a partnership, joint venture, trust or other enterprise (including
service with respect to employee benefit plans), whether the basis of the
proceeding is alleged action in an official capacity as a director, officer,
employee or agent or in any other capacity while serving as a director,
officer, employee or agent, shall be indemnified and held harmless by this
corporation to the fullest extent authorized by the Delaware General
Corporation Law, as the same exists or may hereafter be amended (but, in the
case of any such amendment, only to the extent that such amendment permits
this corporation to provide broader indemnification rights than that law
permitted this corporation to provide before such amendment), against all
expense, liability and loss (including attorney's fees, judgments, penalties,
fines, Employee Retirement Income Security Act of 1974 excise taxes or
penalties, and amounts paid or to be paid in settlement) reasonably incurred
or suffered by such person in connection therewith; provided, however, that
this corporation shall indemnify any such person seeking indemnification in
connection with a proceeding (or part thereof) initiated by such person only
if the proceeding (or part thereof) was authorized by the Board of Directors
of this corporation. Such indemnification shall continue as to a person who
has ceased to be a director, officer, employee or agent and shall inure to
the benefit of his or her heirs, executors and administrators. The right to
indemnification conferred by this Section shall be a contract right which may
not be retroactively amended and shall include the right to be paid by this
corporation the expenses incurred in defending any such proceeding in advance
of its final disposition; provided, however, that, if the Delaware General
Corporation Law requires the payment of such expenses incurred by a director
or officer in his or her capacity as a director or officer (and not in any
other capacity in which service was or is rendered by such person while a
director or officer, including, without limitation, service with respect to
an employee benefit plan) in advance of the final disposition of the
proceeding, such payment shall be made only upon delivery to this corporation
of an undertaking, by or on behalf of such director or officer, to repay all
amounts so advanced if ultimately it shall be determined that such director
or officer is not entitled to be indemnified under this section or otherwise.
This corporation may, by action of its Board of Directors, provide
indemnification to employees and agents of this corporation with the same
scope and effect as the indemnification of directors and officer

          2.   NONEXCLUSIVITY OF RIGHTS. The right to indemnification and the
payment of expenses incurred in defending a proceeding in advance of its
final disposition conferred in this Section shall not be exclusive of any
other right which any


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<PAGE>

person may have or hereafter acquire under any statute, provision of this
Certificate of Incorporation, bylaw, agreement, vote of stockholders or
disinterested directors, or otherwise.

          3.   INSURANCE.  This corporation may maintain insurance, at its
expense, to protect itself and any director, officer, employee or agent of
this corporation or another corporation, partnership, joint venture, trust or
other enterprise against any such expenses, liability or loss, whether or not
this corporation would have the power to indemnify such person against such
expense, liability or loss under the Delaware General Corporation Law.



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<PAGE>

          IN WITNESS WHEREOF, the undersigned officers have executed this
Restated Certificate of Incorporation on March 30, 1993 and do hereby certify
that this Restated Certificate of Incorporation, which restates and integrates,
and also further amends, the provisions of this Corporation's Certificate of
Incorporation, was duly adopted by the stockholders of this Corporation in
accordance with Sections 242 and 245 of the Delaware General Corporation Law.


                                      THERAPEUTIC DISCOVERY CORPORATION


                                      By: /s/ Pieter P. Bonsen
                                         ----------------------------------
                                          Dr. Pieter P. Bonsen,
                                          President, Therapeutic Discovery
                                          Corporation


ATTEST:


 /s/ Mary M. Roensch
-----------------------------------
Mary M. Roensch, Secretary,
Therapeutic Discovery Corporation



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