1
                                                                     EXHIBIT 4.1

                                    RESTATED
                          CERTIFICATE OF INCORPORATION
                                       OF
                          GELTEX PHARMACEUTICALS, INC.


         The undersigned, Mark Skaletsky and Peter Wirth, do hereby certify:

         A. They are the duly elected and acting President and Secretary,
respectively, of Geltex Pharmaceuticals, Inc., a Delaware corporation (the
"Corporation").

         B. The original Certificate of Incorporation of the Corporation was
filed with the Secretary of State on November 15, 1991, and the name under which
the Corporation was originally incorporated is Geltex, Inc.

         C. The Certificate of Incorporation, as previously amended, is further
amended and restated to read in full as follows:

         FIRST. The name of the Corporation is Geltex Pharmaceuticals, Inc.
(hereinafter sometimes referred to as the "Corporation").

         SECOND. The address of the Corporation's registered office in the State
of Delaware is 1013 Centre Road, Wilmington, County of New Castle, Delaware
19805-1297. The name of its registered agent at such address is The
Prentice-Hall Corporation System, Inc.

         THIRD. The purpose of the 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. The total number of shares of all classes of stock which the
Corporation shall have authority to issue is fifty-five million (55,000,000)
shares, of which five million (5,000,000) shares, par value $0.01 per share, are
to be of a class designated "Preferred Stock" and fifty million (50,000,000)
shares, par value $0.01 per share, are to be of a class designated "Common
Stock."

         The following is a statement of the designations, preferences, voting
powers, qualifications, special or relative rights and privileges in respect of
the authorized capital stock of the Corporation.

4.1.     Undesignated Preferred Stock

         The Board of Directors is authorized, subject to limitations prescribed
by law and the provisions of this Article FOURTH, to provide by resolution for
the issuance of the shares of Preferred Stock in one or more series, and by
filing a certificate pursuant to the applicable law of the State of Delaware, to
establish from time to time the number of shares to be included in each such
series, and to fix the designations, powers, preferences and rights of the
shares of each such series and qualifications, limitations or restrictions
thereof.

         The authority of the Board with respect to each series shall include,
but shall not be limited to, determination of the following:


                                      - 9 -
   2
         (a) The number of shares constituting that series and the distinctive
designation of that series;

         (b) The dividend rate, if any, on the shares of that series, whether
dividends shall be cumulative, and if so, from which date or dates, and the
relative rights of priority, if any, of payment of dividends on shares of the
series;

         (c) Whether that series shall have voting rights, in addition to the
voting rights provided by law, and, if so, the terms of such voting rights;

         (d) Whether that series shall have conversion privileges, and, if so,
the terms and conditions of such conversion, including provision for adjustment
of the conversion rate in such events as the Board of Directors shall determine;

         (e) Whether or not the shares of that series shall be redeemable, and
if so, the terms and conditions of such redemption, including the date or dates
upon or after which they shall be redeemable, and the amount per share payable
in case of redemption, which amount may vary under different conditions and at
different redemption dates;

         (f) Whether that series shall have a sinking fund for the redemption or
purchase of shares of that series, and if so, the terms and amount of such
sinking fund;

         (g) The rights of the shares of that series in the event of voluntary
or involuntary liquidation, dissolution or winding up of the Corporation, and
the relative rights of priority, if any, of payment of shares of that series;

         (h) Any other relative rights, preferences and limitations of that
series.

4.2.     Series A Junior Participating Preferred Stock

         4.2.1. Authorized Amount and Designation. A total of Five Hundred
Thousand (500,000) shares of the Preferred Stock shall be designated as "Series
A Junior Participating Preferred Stock" (the "Junior Preferred Stock"). Such
number of shares may be increased or decreased by resolution of the Board of
Directors; provided, that no decrease shall reduce the number of shares of
Junior Preferred Stock to a number less than the number of shares then
outstanding plus the number of shares reserved for issuance upon the exercise of
outstanding options, rights or warrants or upon the conversion of any
outstanding securities issued by the Corporation convertible into Junior
Preferred Stock.

         4.2.2.  Dividends and Distributions.

                 (A) Subject to the prior and superior rights of the holders of
any shares of any series of preferred stock (collectively, the "Preferred
Stock") ranking prior and superior to the Junior Preferred Stock with respect to
dividends, the holders of shares of Junior Preferred Stock, in preference to the
holders of Common Stock of the Corporation (the "Common Stock"), and of any
other junior stock, shall be entitled to receive, when, as and if declared by
the Board of Directors out of funds legally available for the purpose, quarterly
dividends payable in cash on the first day of March, June, September and
December in each year (each such date being referred to herein as a "Quarterly
Dividend Payment Date"), commencing on the first Quarterly Dividend Payment Date
after the first issuance of a share or fraction of a share of Junior Preferred
Stock, in an amount per share (rounded to the nearest cent) equal to the greater
of (a) $1.00 or (b) subject to the provision for adjustment hereinafter set
forth, 100 times the aggregate per share amount of all cash dividends, and 100
times the aggregate per share amount


                                     - 10 -
   3
(payable in kind) of all non-cash dividends or other distributions, other than a
dividend payable in shares of Common Stock or a subdivision of the outstanding
shares of Common Stock (by reclassification or otherwise), declared on the
Common Stock since the immediately preceding Quarterly Dividend Payment Date or,
with respect to the first Quarterly Dividend Payment Date, since the first
issuance of any share or fraction of a share of Junior Preferred Stock. In the
event the Corporation shall at any time declare or pay any dividend on the
Common Stock payable in shares of Common Stock, or effect a subdivision or
combination or consolidation of the outstanding shares of Common Stock (by
reclassification or otherwise than by payment of a dividend in shares of Common
Stock) into a greater or lesser number of shares of Common Stock, then in each
such case the amount to which holders of shares of Junior Preferred Stock were
entitled immediately prior to such event under clause (b) of the preceding
sentence shall be adjusted by multiplying such amount by a fraction, the
numerator of which is the number of shares of Common Stock outstanding
immediately after such event and the denominator of which is the number of
shares of Common Stock that were outstanding immediately prior to such event.

                 (B) The Corporation shall declare a dividend or distribution
on the Junior Preferred Stock as provided in paragraph (A) of this Section
4.2.2. immediately after it declares a dividend or distribution on the Common
Stock (other than a dividend payable in shares of Common Stock); provided that,
in the event no dividend or distribution shall have been declared on the Common
Stock during the period between any Quarterly Dividend Payment Date and the next
subsequent Quarterly Dividend Payment Date, a dividend of $1.00 per share on the
Junior Preferred Stock shall nevertheless be payable on such subsequent
Quarterly Dividend Payment Date.

                 (C) Dividends shall begin to accrue and be cumulative on
outstanding shares of Junior Preferred Stock from the Quarterly Dividend Payment
Date next preceding the date of issue of such shares, unless the date of issue
of such shares is prior to the record date for the first Quarterly Dividend
Payment Date, in which case dividends on such shares shall begin to accrue from
the date of issue of such shares, or unless the date of issue is a Quarterly
Dividend Payment Date or is a date after the record date for the determination
of holders of shares of Junior Preferred Stock entitled to receive a quarterly
dividend and before such Quarterly Dividend Payment Date, in either of which
events such dividends shall begin to accrue and be cumulative from such
Quarterly Dividend Payment Date. Accrued but unpaid dividends shall not bear
interest. Dividends paid on the shares of Junior Preferred Stock in an amount
less than the total amount of such dividends at the time accrued and payable on
such shares shall be allocated pro rata on a share-by-share basis among all such
shares at the time outstanding. The Board of Directors may fix a record date for
the determination of holders of shares of Junior Preferred Stock entitled to
receive payment of a dividend or distribution declared thereon, which record
date shall be not more than 60 days prior to the date fixed for the payment
thereof.

         4.2.3.  Voting Rights.  The holders of shares of Junior Preferred Stock
shall have the following voting rights:

                 (A) Subject to the provision for adjustment hereinafter set
forth, each share of Junior Preferred Stock shall entitle the holder thereof to
100 votes on all matters submitted to a vote of the stockholders of the
Corporation. In the event the Corporation shall at any time declare or pay any
dividend on the Common Stock payable in shares of Common Stock, or effect a
subdivision or combination or consolidation of the outstanding shares of Common
Stock (by reclassification or otherwise than by payment of a dividend in shares
of Common Stock) into a greater or lesser number of shares of Common Stock, then
in each such case the number of votes per share to which holders of shares of
Junior Preferred Stock were entitled immediately prior to such event shall be
adjusted by multiplying such number by a fraction, the numerator of which is the
number of shares of Common Stock outstanding


                                     - 11 -
   4
immediately after such event and the denominator of which is the number of
shares of Common Stock that were outstanding immediately prior to such event.

                 (B) Except as otherwise provided herein, in the Restated
Certificate of Incorporation, in any other Resolution of the Board of Directors
of the Corporation creating a series of Preferred Stock, or by law, the holders
of shares of Junior Preferred Stock and the holders of shares of Common Stock
and any other capital stock of the Corporation having general voting rights
shall vote together as one class on all matters submitted to a vote of
stockholders of the Corporation.

                 (C) Except as set forth herein or as otherwise provided by
law, holders of Junior Preferred Stock shall have no voting rights.

         4.2.4.  Certain Restrictions.

                 (A) Whenever quarterly dividends or other dividends or
distributions payable on the Junior Preferred Stock as provided in Section
4.2.2. are in arrears, thereafter and until all accrued and unpaid dividends and
distributions, whether or not declared, on shares of Junior Preferred Stock
outstanding shall have been paid in full, the Corporation shall not:

                     (i)  declare or pay dividends, or make any other 
distributions, on any shares of stock ranking junior (either as to dividends or
upon liquidation, dissolution or winding up) to the Junior Preferred Stock;

                    (ii)  declare or pay dividends, or make any other 
distributions, on any shares of stock ranking on a parity (either as to
dividends or upon liquidation, dissolution or winding up) with the Junior
Preferred Stock, except dividends paid ratably on the Junior Preferred Stock and
all such parity stock on which dividends are payable or in arrears in proportion
to the total amounts to which the holders of all such shares are then entitled;

                   (iii)  redeem or purchase or otherwise acquire for 
consideration shares of any stock ranking junior (either as to dividends or upon
liquidation, dissolution or winding up) to the Junior Preferred Stock, provided
that the Corporation may at any time redeem, purchase or otherwise acquire
shares of any such junior stock in exchange for shares of any stock of the
Corporation ranking junior (either as to dividends or upon dissolution,
liquidation or winding up) to the Junior Preferred Stock; or

                    (iv)  redeem, purchase or otherwise acquire for 
consideration any shares of Junior Preferred Stock, or any shares of stock
ranking on a parity with the Junior Preferred Stock, except in accordance with a
purchase offer made in writing or by publication (as determined by the Board of
Directors) to all holders of such shares upon such terms as the Board of
Directors, after consideration of the respective annual dividend rates and other
relative rights and preferences of the respective series and classes, shall
determine in good faith will result in fair and equitable treatment among the
respective series or classes.

                 (B) The Corporation shall not permit any subsidiary of the
Corporation to purchase or otherwise acquire for consideration any shares of
stock of the Corporation unless the Corporation could, under paragraph (A) of
this section 4 purchase or otherwise acquire such shares at such time and in
such manner.

         4.2.5.  Reacquired Shares.  Any shares of Junior Preferred Stock
purchased or otherwise acquired by the Corporation in any manner whatsoever
shall be retired and cancelled promptly after the acquisition


                                     - 12 -
   5
thereof. All such shares shall upon their cancellation become authorized but
unissued shares of Preferred Stock and may be reissued as part of a new series
of Preferred Stock, subject to the conditions and restrictions on issuance set
forth herein, in the Restated Certificate of Incorporation, in any other
Resolution of the Board of Directors of the Corporation creating a series of
Preferred Stock, or as otherwise required by law.

         4.2.6. Liquidation, Dissolution or Winding Up. Upon any liquidation,
dissolution or winding up of the Corporation, no distribution shall be made (1)
to the holders of shares of stock ranking junior (either as to dividends or upon
liquidation, dissolution or winding up) to the Junior Preferred Stock unless,
prior thereto, the holders of shares of Junior Preferred Stock shall have
received $100.00 per share, plus an amount equal to accrued and unpaid dividends
and distributions thereon, whether or not declared, to the date of such payment,
provided that the holders of shares of Junior Preferred Stock shall be entitled
to receive, to the extent greater than the foregoing, an aggregate amount per
share, subject to the provision for adjustment hereinafter set forth, equal to
100 times the aggregate amount to be distributed per share to holders of shares
of Common Stock, or (2) to the holders of shares of stock ranking on a parity
(either as to dividends or upon liquidation, dissolution or winding up) with the
Junior Preferred Stock, except distributions made ratably on the Junior
Preferred Stock and all other such parity stock in proportion to the total
amounts to which the holders of all such shares are entitled upon such
liquidation, dissolution or winding up. In the event the Corporation shall at
any time declare or pay any dividend on the Common Stock payable in shares of
Common Stock, or effect a subdivision or combination or consolidation of the
outstanding shares of Common Stock (by reclassification or otherwise than by
payment of a dividend in shares of Common Stock) into a greater or lesser number
of shares of Common Stock, then in each such case the aggregate amount to which
holders of shares of Junior Preferred Stock were entitled immediately prior to
such event under the proviso in clause (1) of the preceding sentence shall be
adjusted by multiplying such amount by a fraction, the numerator of which is the
number of shares of Common Stock outstanding immediately after such event and
the denominator of which is the number of shares of Common Stock that were
outstanding immediately prior to such event.

         4.2.7. Consolidation, Merger, etc. In case the Corporation shall enter
into any consolidation, merger, combination or other transaction in which the
shares of Common Stock are exchanged for or changed into other stock or
securities, cash and/or any other property, then in any such case each share of
Junior Preferred Stock shall at the same time be similarly exchanged or changed
into an amount per share (subject to the provision for adjustment hereinafter
set forth) equal to 100 times the aggregate amount of stock, securities, cash
and/or any other property (payable in kind), as the case may be, into which or
for which each share of Common Stock is changed or exchanged. In the event the
Corporation shall at any time declare or pay any dividend on Common Stock
payable in shares of Common Stock, or effect a subdivision or combination or
consolidation of the outstanding shares of Common Stock (by reclassification or
otherwise than by payment of a dividend in shares of Common Stock) into a
greater or lesser number of shares of Common Stock, then in each such case the
amount set forth in the preceding sentence with respect to the exchange or
change of shares of Junior Preferred Stock shall be adjusted by multiplying such
amount by a fraction, the numerator of which is the number of shares of Common
Stock outstanding immediately after such event and the denominator of which is
the number of shares of Common Stock that were outstanding immediately prior to
such event.

         4.2.8.  Redemption.  The shares of Junior Preferred Stock shall not be
redeemable.

         4.2.9.  Rank.  The Junior Preferred Stock shall rank junior with 
respect to the payment of dividends and the distribution of assets to all series
of the Corporation's Preferred Stock that specifically provide that they shall
rank prior to the Junior Preferred Stock. Nothing herein shall preclude the
Board


                                     - 13 -
   6
from creating any series of Preferred Stock ranking on a parity with or prior to
the Junior Preferred Stock as to the payment of dividends or the distribution of
assets.

         4.2.10. Amendment. The Restated Certificate of Incorporation of the
Corporation shall not be amended in any manner which would materially alter or
change the powers, preferences or special rights of the Junior Preferred Stock
so as to affect them adversely without the affirmative vote of the holders of at
least two-thirds of the outstanding Junior Preferred Stock, voting together as a
single series.

         4.2.11. Fractional Shares. The Junior Preferred Stock may be issued in
fractions of a share which shall entitle the holder, in proportion to such
holder's fractional shares, to exercise voting rights, receive dividends,
participate in distributions and to have the benefit of all other rights of
holders of the Junior Preferred Stock.

4.3.     Common Stock

         The Common Stock is subject to the rights and preferences of the
Preferred Stock as hereinbefore set forth or authorized.

         Subject to the provisions of any applicable law or of the by-laws of
the Corporation, as from time to time amended, with respect to the fixing of a
record date for the determination of stockholders entitled to vote, and except
as otherwise provided herein or by law or by the resolution or resolutions
providing for the issue of any series of Preferred Stock, the holders of
outstanding shares of Common Stock shall have exclusive voting rights for the
election of directors and for all other purposes, each holder of record of
shares of Common Stock being entitled to one vote for each share of Common Stock
standing in his name on the books of the Corporation.

         Subject to the rights of any one or more series of Preferred Stock, the
holders of Common Stock shall be entitled to receive such dividends from time to
time as may be declared by the Board of Directors out of any funds of the
Corporation legally available for the payment of such dividends.

         In the event of the liquidation, dissolution, or winding up of the
Corporation, whether voluntary or involuntary, after payment shall have been
made to the holders of the Preferred Stock of the full amount to which they are
entitled, the holders of Common Stock shall be entitled to share ratably
according to the number of shares of Common Stock held by them, in all remaining
assets of the Corporation available for distribution to its stockholders.

4.4.     Issuance

         Subject to the provisions of this Certificate of Incorporation and
except as otherwise provided by law, the shares of stock of the Corporation,
regardless of class, may be issued for such consideration and for such corporate
purposes as the Board of Directors may from time to time determine.

         FIFTH.   The Corporation is to have perpetual existence.

         SIXTH. Election of directors need not be by written ballot unless the
by-laws of the Corporation shall so provide. The Board of Directors shall
consist of not less than three nor more than fifteen directors, the exact number
to be determined from time to time by resolution adopted by the affirmative vote
of a majority of the directors then in office. The directors shall be divided
into three classes, as nearly equal in number as the then total number of
directors constituting the entire Board permits, with the term of office of one
class expiring each year. The initial directors of the first class


                                     - 14 -
   7
shall be elected to hold office for a term expiring at the next succeeding
annual meeting, the initial directors of the second class shall be elected to
hold office for a term expiring at the second succeeding annual meeting and the
initial directors of the third class shall be elected to hold office for a term
expiring at the third succeeding annual meeting. At each succeeding annual
meeting of stockholders beginning in the first year following the election of
such staggered Board of Directors, successors to the class of directors whose
term expires at that meeting shall be elected for a three year term. If the
number of directors is changed, any increase or decrease shall be apportioned
among the classes so as to maintain the number of directors in each class as
nearly equal as possible, and any additional directors of any class elected to
fill a vacancy resulting from an increase in the size of such class shall hold
office for a term that shall coincide with the remaining term of that class, but
in no event will a decrease in the number of directors shorten the term of any
incumbent director. Any vacancies in the Board of Directors for any reason, and
any directorships resulting from any increase in the number of directors, may be
filled by the Board of Directors, acting by a majority of the directors then in
office, although less than a quorum, and any directors so chosen shall hold
office until the next election of the class for which such directors shall have
been chosen. Notwithstanding the foregoing, and except as otherwise required by
law, whenever the holders of any one or more series of Preferred Stock shall
have the right, voting separately as a class, to elect one or more directors of
the Corporation, the election, terms of office and other features of such
directorships shall be governed by the terms of this Certificate of
Incorporation and certificates of designation applicable thereto, and such
directors so elected shall not be divided into classes pursuant to this Article
SIXTH unless expressly provided by such terms. Subject to the foregoing, at each
annual meeting of stockholders the successors to the class of directors whose
terms shall then expire shall be elected to hold office for a term expiring at
the annual meeting for the year in which their term expires and until their
successors shall be elected and qualified, subject to prior death, resignation,
retirement or removal.

         Except as otherwise determined by the Board of Directors in
establishing a series of Preferred Stock as to directors elected by holders of
such series, at any special meeting of the stockholders called at least in part
for the purpose, any director or directors may, by the affirmative vote of the
holders of at least a majority of the stock entitled to vote for the election of
directors, be removed from office for cause. The provisions of this subsection
shall be the exclusive method for the removal of directors.

         SEVENTH. The Board of Directors of the Corporation is expressly
authorized to adopt, amend or repeal the by-laws of the Corporation.

         EIGHTH. A director shall not be personally liable to the Corporation or
its stockholders for monetary damages for breach of fiduciary duty as a
director, except to the extent that the elimination or limitation of liability
is not permitted under the General Corporation Law of the State of Delaware as
in effect when such liability is determined. No amendment or repeal of this
provision shall deprive a director of the benefits hereof with respect to any
act or omission occurring prior to such amendment or repeal.

         NINTH. The Corporation shall, to the fullest extent permitted by
Section 145 of the General Corporation Law of the State of Delaware, as amended
from time to time, indemnify each person who was or is a party or is threatened
to be made a party to any threatened, pending or completed action, suit or
proceeding, whether civil, criminal, administrative or investigative, by reason
of the fact that he is or was, or has agreed to become, a director or officer of
the Corporation, or is or was serving, or has agreed to serve, at the request of
the Corporation, as a director, officer or trustee of, or in a similar capacity
with, another corporation, partnership, joint venture, trust or other enterprise
(including attorneys' fees), judgments, fines and amounts paid in settlement
actually and reasonably incurred by him or on his behalf in connection with such
action, suit or proceeding and any appeal therefrom.


                                     - 15 -
   8
         Indemnification may include payment by the Corporation of expenses in
defending an action or proceeding in advance of the final disposition of such
action or proceeding upon receipt of any undertaking by the person indemnified
to repay such payment if it is ultimately determined that such person is not
entitled to indemnification under this Article, which undertaking may be
accepted without reference to the financial ability of such person to make such
repayments.

         The Corporation shall not indemnify any such person seeking
indemnification in connection with a proceeding (or part thereof) initiated by
such person unless the initiation thereof was approved by the Board of Directors
of the Corporation.

         The indemnification rights provided in this Article (i) shall not be
deemed exclusive of any other rights to which those indemnified may be entitled
under any law, agreement or vote of stockholders or disinterested directors or
otherwise, and (ii) shall inure to the benefit of the heirs, executors and
administrators of such persons. The Corporation may, to the extent authorized
from time to time by its Board of Directors, grant indemnification rights to
other employees or agents of the Corporation or other persons serving the
Corporation and such rights may be equivalent to, or greater or less than, those
set forth in this Article.

         TENTH:  (i) Except as set forth in part (ii) of this Article TENTH, the
affirmative vote of the holders of 66 2/3% of the shares of all classes of stock
of the Corporation entitled to vote for the election of directors, considered
for the purposes of this Article TENTH as one class, shall be required (a) for
the adoption of any agreement for the merger or consolidation of the Corporation
or any Subsidiary (as hereinafter defined) with or into any Other Corporation
(as hereinafter defined), (b) to authorize any sale, lease, exchange, mortgage,
pledge or other disposition of all or substantially all of the assets of the
Corporation or any Subsidiary to any Other Corporation, (c) to authorize the
issuance or transfer by the Corporation of any Substantial Amount (as
hereinafter defined) of securities of the Corporation in exchange for the
securities or assets of any Other Corporation, or (d) to engage in any other
transaction the effect of which is to combine the assets and business of the
Corporation or any Subsidiary with any Other Corporation. Such affirmative vote
shall be in addition to the vote of the holders of the stock of the Corporation
otherwise required by law, the Certificate of Incorporation of the Corporation
or any agreement or contract to which the Corporation is a party.

                (ii) The provisions of part (i) of this Article TENTH shall not
be applicable to any transaction described therein if such transaction is
approved by a resolution of the Board of Directors of the Corporation, provided
that the directors voting in favor of such resolution include a majority of the
persons who were duly elected and acting members of the Board of Directors prior
to the time any such Other Corporation became a Beneficial Owner (as hereinafter
defined) of 5% or more of the shares of stock of the Corporation entitled to
vote for the election of directors. In considering such transaction, the Board
of Directors shall give due consideration to such factors as it deems relevant,
which may include without limitation the social and economic effects on the
employees, customers, suppliers and other constituents of the Corporation and
its Subsidiaries and on the communities in which the Corporation and its
Subsidiaries operate or are located.

               (iii) The Board of Directors shall have the power and duty to 
determine for the purposes of this Article TENTH, on the basis of information
known to such Board, if and when any Other Corporation is the Beneficial Owner
of 5% or more of the outstanding shares of stock of the Corporation entitled to
vote for the election of directors. Any such determination, if made in good
faith, shall be conclusive and binding for all purposes of this Article TENTH.


                                     - 16 -
   9
                (iv) As used in this Article TENTH, the following terms shall
have the meanings indicated:

                       "Other Corporation" means any person, firm, corporation
or other entity, other than a Subsidiary of the Corporation, which is the
Beneficial Owner of 5% or more of the shares of stock of the Corporation
entitled to vote in the election of directors.

                       "Subsidiary" means any corporation in which the 
Corporation owns, directly or indirectly, more than 50% of the voting
securities.

                       "Substantial Amount" means any securities of the
Corporation having a then fair market value of more than $500,000.

                       An Other Corporation (as defined above) shall be deemed
to be the "Beneficial Owner" of stock if such Other Corporation or any
"affiliate" or "associate" of such Other Corporation (as those terms are defined
in Rule 12b-2 promulgated under the Securities and Exchange Act of 1934 (15
U.S.C. 78 aaa et seq.), as amended from time to time), directly or indirectly,
controls the voting of such stock or has any options, warrants, conversion or
other rights to acquire such stock.

                 (v) This Article TENTH may not be amended, revised or revoked,
in whole or in part, except by the affirmative vote of the holders of 66 2/3% of
the shares of all classes of stock of the Corporation entitled to vote for the
election of directors, considered for the purposes of this Article TENTH as one
class of stock.

         ELEVENTH: No action required to be taken or which may be taken at any
annual or special meeting of stockholders of the Corporation may be taken by
written consent without a meeting, and the power of stockholders to consent in
writing without a meeting to the taking of any action is specifically denied.

         This Article ELEVENTH may not be amended, revised or revoked, in whole
or in part, except by the affirmative vote of the holders of 66 2/3% of the
shares of all classes of stock of the Corporation entitled to vote for the
election of directors, considered for the purposes of this Article ELEVENTH as
one class of stock.

         D. The foregoing Restated Certificate of Incorporation has been
approved by the Board of Directors of the Corporation.

         E. The foregoing Restated Certificate of Incorporation was adopted by
the holders of a majority of the outstanding shares of Common Stock in
accordance with the provisions of Sections 242 and 245 of the General
Corporation Law of the State of Delaware.


                                     - 17 -
   10
         IN WITNESS WHEREOF, the Corporation has caused this Certificate to be
signed by Mark Skaletsky, its President, and attested by Peter Wirth, its
Secretary on June 4, 1996.

                                       /s/ Mark Skaletsky
                                       -----------------------------------------
                                       Mark Skaletsky, President


Attest:

/s/ Peter Wirth
- ----------------------------------
Peter Wirth, Secretary


                                     - 18 -