EXHIBIT 3.5



                            CERTIFICATE OF AMENDMENT

                                     OF THE

              AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF

                        INTERNEURON PHARMACEUTICALS, INC.

 Pursuant to Section 242 of the General Corporation Law of the State of Delaware
                        --------------------------------


It is hereby certified that:

FIRST:     The name of the Corporation is Interneuron Pharmaceuticals, Inc.

SECOND:    The Corporation hereby amends its Amended and Restated Certificate of
           Incorporation as follows:

           Paragraph  (A)(1) of  Article  FOURTH  of the  Amended  and  Restated
           Certificate of Incorporation relating to the authorized capital stock
           of the Corporation,  is hereby deleted in its entirety and amended to
           read as follows:

           The  aggregate  number of shares  which the  Corporation  shall  have
           authority to issue is eighty-five million (85,000,000), of which five
           million  (5,000,000) shares of the par value of $.001 per share shall
           be  designated  "Preferred  Stock"  and eighty  million  (80,000,000)
           shares of the par value of $.001 shall be designated "Common Stock".

THIRD:     This  Certificate  of Amendment  has been duly adopted in  accordance
           with the provisions of Section 242 of the General  Corporation Law of
           the State of Delaware.

         IN  WITNESS  WHEREOF,  the  undersigned,  being  the  President  of the
Corporation, hereunto signs his name and affirms that the statements made herein
are true under the penalties of perjury, this 5th day of March, 1997.

                                                  /s/ Glenn L. Cooper
                                                 -------------------------
                                                 Glenn L. Cooper, M.D.
                                                 President

                                                              





                     CERTIFICATE OF DESIGNATION ESTABLISHING
                            SERIES C PREFERRED STOCK

                                       OF

                        INTERNEURON PHARMACEUTICALS, INC.

                  INTERNEURON PHARMACEUTICALS, INC., a corporation organized and
existing under the General Corporation Law of the State of Delaware,

                  DOES HEREBY CERTIFY:

                  That,  pursuant  to  authority  conferred  upon  the  Board of
Directors by the Certificate of Incorporation,  as amended, of said corporation,
and pursuant to the provisions of Section 151 of the General  Corporation Law of
the State of Delaware,  said Board of Directors,  by unanimous  written  consent
dated May 27, 1993, adopted a resolution providing for the number,  designation,
powers and  preferences,  and the  qualifications,  limitations and restrictions
thereof, of a series of Preferred Stock, which resolution is as follows:

                  "RESOLVED,  that pursuant to the authority vested in the Board
                  of  Directors  in  accordance   with  the  provisions  of  its
                  Certificate  of  Incorporation,   as  amended,   a  series  of
                  Preferred  Stock  of  this   corporation   (hereinafter,   the
                  "Company")   be  and  it  hereby  is   created.   The  number,
                  designation,   powers  and   preferences,   and  the   rights,
                  qualifications,  limitations and restrictions of the shares of
                  such series of Preferred Stock are as follows:

                            Series C Preferred Stock.
                            -------------------------

                  1. Designation. The number of shares to constitute such series
of Preferred  Stock shall be 5,000 and the  designation  of such series shall be
Series C Preferred Stock (hereinafter called the "Series C Stock").

                  2.  Voting  Rights.  On all  matters  submitted  to a vote  of
stockholders  generally,  other than the  election of  Directors,  each share of
Series C Stock  will be  entitled  to a number of votes  equal to the  number of
shares  of  Common  Stock  into  which  such  share  of  Series  C Stock is then
convertible,  and rounding  the result to the nearest  whole  number.  Except as
otherwise  required by law or by any provision hereof,  the Common Stock and the
Series C Stock  will vote  together  as a single  class on all  matters on which
stockholders shall be entitled to vote.


                                       -2-




               3. Conversion.

                  (a) Conversion Ratio. Each outstanding share of Series C Stock
will be  convertible  at any time at the option of the  holder  into a number of
shares of Common Stock computed by dividing $100.00 by the Conversion Price then
in effect.

                  (b) Conversion Price; Adjustment. The initial Conversion Price
will be $13.0125.  Each time after the effective date hereof, the Company issues
or agrees to issue any  additional  shares of Common  Stock for a  consideration
which is less than  two-thirds  of the then  Conversion  Price  per share  (such
consideration being hereinafter  collectively referred to as the "Issue Price"),
the then Conversion Price shall be reduced to 150% of the Issue Price.

                  (c) Excluded Issuances.  The reduction in the Conversion Price
required  by  paragraph  3 (b) shall  not be made in the  event (i) the  Company
issues  shares of Common Stock or options,  warrants or other rights to purchase
Common  Stock  to any of its  officers,  directors,  employees,  consultants  or
scientific  advisers;  (ii) of any issuance of up to 10,000  shares (as adjusted
from time to time pursuant to the  provisions of paragraph 3(e) below) of Common
Stock or Options or  warrants  to purchase up to said number of shares of Common
Stock to any person at any one time,  provided that no more than an aggregate of
100,000  shares (as adjusted  from time to time  pursuant to the  provisions  of
paragraph  3(e) below) and options or warrants to purchase said number of shares
may be issued  pursuant to this clause (ii);  or (iii) of any issuance of Common
Stock,  Options or  Convertible  Securities  (as  defined in  paragraph  3(d)(i)
hereof)  in  respect  of an  obligation  incurred  by the  Company  prior to the
effective date hereof.

                  (d) Effect on Conversion Price of Certain Events. For purposes
of  determining  the Issue Price and the Conversion  Price under  paragraph 3(b)
above, the following will apply:

                        (i)  Issuance of Rights or Options.  Each time after the
effective  date  hereof,  the  Company in any  manner  (other  than an  excluded
issuance under  paragraph 3(c)) grants any rights or options to subscribe for or
to purchase Common stock or any stock or other  securities  convertible  into or
exchangeable  for Common  Stock  (such  rights or options  being  herein  called
"Options" and such convertible or exchangeable  stock or securities being herein
called "Convertible  Securities") and the price per share for which Common Stock
is issuable upon the exercise of such Options or upon  conversion or exchange of
such  Convertible  Securities  is less than both (x) 150% of the  average of the
last sale prices for the Common  Stock for the ten trading  days  preceding  the
date on which the Company  issues or agrees to issue such Options or Convertible
Securities and (y) the then Conversion Price, then the Conversion Price shall be
reduced to the greater of (x) 100% of the price per share for which Common Stock
is issuable upon the exercise of such Options or upon  conversion or exchange of
such  Convertible  Securities and (y) 56.67% of the initial  Conversion Price as
adjusted from time to time pursuant to the  provisions of paragraph  3(e) below.
For purposes of this  paragraph , the "price per share for 


                                       -3-





which  Common  Stock is  issuable  upon the  exercise  of such  Options  or upon
conversion  or exchange of such  Convertible  Securities"  will be determined by
dividing (A) the total amount,  if any, received or receivable by the Company as
consideration for the granting of such Option or upon the conversion or exchange
of all such  Convertible  issuable upon the exercise of such  Options,  plus the
minimum aggregate amount of additional consideration payable to the Company upon
exercise of all such Options,  plus, in the case of such Options which relate to
Convertible   Securities,   the   minimum   aggregate   amount   of   additional
consideration,  if any, payable to the Company upon the issuance or sale of such
Convertible  Securities and the conversion or exchange thereof, by (B) the total
maximum  number of shares of Common  Stock  issuable  upon the  exercise of such
Options.   Except  as  otherwise  provided  in  paragraph  3(d)(iii)  below,  no
adjustment of the Conversion Price will be made when Convertible  Securities are
actually  issued  upon the  exercise  of such  Options or when  Common  Stock is
actually  issued upon the exercise of such Options or the conversion or exchange
of such Convertible Securities.

                        (ii) Issuance of Convertible Securities. Each time after
the  effective  date hereof,  the Company in any manner  (other than an excluded
issuance under paragraph 3(c) issues or sells any Convertible Securities and the
price per share for which  Common  Stock is  issuable  upon such  conversion  or
exchange  is less than both (x) 150% of the  average of the last sale prices for
the  Common  Stock  for the ten  trading  days  preceding  the date on which the
Company issues or agrees to issue such Options or Convertible Securities and (y)
the then  Conversion  Price,  then the Conversion  Price shall be reduced to the
greater of (x) 100% of the price per share for which  Common  Stock is  issuable
upon such conversion or exchange and (y) 56.67% of the initial  Conversion Price
as adjusted  from time to time  pursuant to the  provisions  of  paragraph  3(e)
below. For the purposes of this paragraph, the "price per share for which Common
Stock is issuable  upon such  conversion  or  exchange"  will be  determined  by
dividing  (A)  the  total  amount  received  or  receivable  by the  Company  as
consideration for the issuance or sale of such Convertible Securities,  plus the
minimum  aggregate  amount of additional  consideration,  if any, payable to the
Company upon the conversion or exchange thereof, by (B) the total maximum number
of shares of Common Stock  issuable upon the  conversion or exchange of all such
Convertible  Securities.  Except as otherwise  provided in  paragraph  3(d)(iii)
below,  no adjustment of the Conversion  Price will be made when Common Stock is
actually issued upon the conversion or exchange of such Convertible  Securities,
and if any  such  issue  or sale of such  Convertible  Securities  is made  upon
exercise of any Options for which  adjustments of the Conversion  Price had been
or are to be made pursuant to other  provisions of this  paragraph 3, no further
adjustment of the Conversion Price will be made by reason of such issue or sale.

                        (iii) Change in Option Price or Conversion  Rate. If the
purchase price provided for in any Option, the additional consideration, if any,
payable upon the conversion or exchange of Convertible  Securities,  or the rate
at which any  Convertible  Securities are convertible  into or exchangeable  for
Common  Stock,  change at any time (other than under or by reason of  provisions
designed to protect  against  dilution of the type set forth in this paragraph 3
or any other  mandatory  anti-dilution  provisions  contained in such Options or
Convertible

                                       -4-




Securities)  the  Conversion  Price in effect at the time of such change will be
readjusted to the Conversion  Price which would have been in effect at such time
had such Options or Convertible  Securities still outstanding  provided for such
changed purchase price, additional consideration or changed conversion rates, as
the case may be, at the time initially granted,  issued or sold; provided,  that
such adjustment of the Conversion Price then in effect would be reduced.  If the
purchase price provided for in any Option, the additional consideration, if any,
payable upon the conversion or exchange of any  Convertible  Securities,  or the
rate at which any Convertible  Securities are  convertible  into or exchangeable
for Common Stock,  is reduced at any time under or by reason of provisions  with
respect  thereto  designed  to protect  against  dilution  of the type set forth
herein or any other mandatory  anti-dilution provision contained in such Options
or Convertible Securities, then in the case of the delivery of Common Stock upon
the exercise of any such Option or upon the  conversion  or exchange of any such
Convertible  Security,  the  Conversion  Price  then in  effect  hereunder  will
forthwith be adjusted to such respective  amount as would have been obtained had
such Option or  Convertible  Security  never been issued as to such Common Stock
and had adjustments  been made to the Conversion  Price upon the issuance of the
shares of Common Stock  delivered,  but only if as a result of such  adjustment,
the Conversion Price then in effect hereunder would be reduced.

                        (iv) Calculation of Consideration  Received. In case any
Common Stock, Options or Convertible  Securities are issued or sold or deemed to
have been issued or sold for  consideration,  part or all of which is cash,  the
amount of cash  consideration  received  therefor will be deemed to be the gross
amount received by the Company  therefor.  In case any Common Stock,  Options or
Convertible  Securities are issued or sold or deemed to have been issued or sold
for a consideration,  part or all of which is other than cash, the amount of the
consideration  other than cash received by the Company will be the fair value of
such  consideration,  except  where such  consideration  consists of  securities
publicly  traded,  in which case the  amount of  consideration  received  by the
Company will be the market price thereof as of the date of receipt.  In case any
Common Stock,  Options or Convertible  Securities are issued in connection  with
any merger in which the  Company  is the  surviving  corporation,  the amount of
consideration  therefor  will be deemed to be the fair value of such  portion of
the net assets and business of the non-surviving  corporation as is attributable
to such Common Stock, Options or Convertible Securities, as the case may be.

                        (v) Integration of  Transactions.  In case any Option or
Convertible  Security  is issued in  connection  with the issue or sale of other
securities of the Company,  together  comprising one  integrated  transaction in
which no specific  consideration  is  allocated  to such  Option or  Convertible
Security by the parties  thereto,  the Option or  Convertible  Security  will be
deemed to have been issued without consideration.

                    (e)  Subdivision  or  Combination  of Common  Stock.  If the
Company at any time subdivides (by any stock split, stock dividend or otherwise)
its  outstanding  shares of Common  Stock into a greater  number of shares,  the
Conversion  Price  in  effect  immediately  prior  to such  subdivision  will be
proportionately reduced, and if the Company at any time


                                       -5-




combines (by reverse stock split or otherwise) its outstanding  shares of Common
Stock  into  a  smaller  number  of  shares,   the  Conversion   Price  will  be
proportionately increased.

                    (f) Reorganization, Reclassification, Merger, Consolidation,
or Sale.  If any  capital  reorganization,  reclassification,  consolidation  or
merger  or any  sale  of  all or  substantially  all  of  the  Company's  assets
(collectively  any "Major  Change") is  effected  in such a way that  holders of
Common  Stock are  entitled  to  receive  (either  directly  or upon  subsequent
liquidation)  stock,  other  securities or assets with respect to or in exchange
for Common Stock, then, as a condition to such Major Change, lawful and adequate
provision  will be made,  whereby  each of the  holders  of Series C Stock  will
thereafter  have the right to  acquire  and  receive,  in lieu of the  shares of
Common  Stock  immediately   theretofore  acquirable  and  receivable  upon  the
conversion  of such  holder's  Series C  Stock,  such  shares  of  stock,  other
securities  or  assets as may be  issuable  or  payable  with  respect  to or in
exchange  for the  number  of shares of  Common  stock  immediately  theretofore
acquirable and receivable  upon  conversion of such holder's  Series C Stock had
such Major Change not taken place. In any such case,  appropriate provision will
be made with respect to such  holder's  rights and interests to the end that the
provisions  of this  paragraph  3 and  paragraph  4  below  will  thereafter  be
applicable in relation to any shares of stock,  securities or assets  thereafter
deliverable upon the conversion of Series C Stock including,  in the case of any
such  consolidation,  merger  or sale in  which  the  successor  corporation  or
purchasing corporation is other than the Company, an immediate adjustment of the
Conversion  Price to the value for the Common  Stock  reflected  by the terms of
such consolidation,  merger or sale and a corresponding  immediate adjustment in
the number of shares of Common Stock  acquirable and receivable  upon conversion
of Series C Stock,  if the value so reflected is less than the Conversion  Price
in effect immediately prior to such  consolidation,  merger or sale. The Company
will not  effect any such  consolidation,  merger or sale  unless,  prior to the
consummation  thereof,  the  successor  corporation  (if other than the Company)
resulting from such consolidation or merger, or the corporation  purchasing such
assets,  assumes, by written instrument,  the obligation to deliver to each such
holder such shares of stock,  securities  or assets as, in  accordance  with the
foregoing provisions, such holder may be entitled to acquire.

                    (g)  Certain  Events.  If  any  event  occurs  of  the  type
contemplated  by the provisions of this paragraph 3, but not expressly  provided
for by such  provisions,  then the Board of Directors  will make an  appropriate
adjustment in the Conversion Price so as to protect the rights of the holders of
Series C Stock.

                    (h)  No  Circumvention.  The  Company  will  not  issue  any
additional  shares of Series C Stock or, in  circumvention  of the provisions of
this  paragraph  3, issue any shares of preferred  stock which,  notwithstanding
such designation,  primarily possess the attributes  customarily associated with
common stock,  and do not possess  special voting rights,  scheduled or optional
redemption  features (with redemption  prices specified as to amount and limited
to such amount),  special liquidation rights fixed and limited as to amount, and
dividends  fixed in amount  and  limited  to the  amount so  fixed,  other  than
pursuant  to an  obligation  to  issue  preferred  stock  existing  prior to the
effective date hereof.


                                       -6-




                    (i) Notices.

                        (i) As soon as  practicable  after any adjustment of the
Conversion Price, the Company will send written notice thereof to all holders of
Series C Stock.

                        (ii) The  Company  will give to the  holders of Series C
Stock at least 20 days'  prior  written  notice  of the date on which  any Major
Change, dissolution or liquidation will take place.

                    (j) Mechanics of Conversion. So long as any shares of Series
C Stock remain  outstanding,  at the election of the respective holders thereof,
any and all  shares of the  Series C Stock may be  converted  at any time on and
subsequent to the second  anniversary of initial  issuance and from time to time
into the number of fully paid and  non-assessable  shares of Common Stock of the
Company  calculated  as set forth  herein.  In order to exercise the  conversion
privilege, the holder of Series C Stock shall surrender the certificates for the
Series C Stock to be converted at the offices of the Company in the Commonwealth
of  Massachusetts,  together with written  notice to the Company that the holder
elects to convert  such Series C Stock or a portion  thereof.  Such notice shall
also state the name or names (with address) in which the certificates for shares
of Common  Stock  issuable on such  conversion  shall be issued.  Series C Stock
surrendered for conversion shall be accompanied by proper assignments thereof to
the company or in blank for  transfer  and the  signature of the holder shall be
guaranteed by a firm having  membership  on the New York Stock  Exchange or by a
commercial  bank or trust company  located in or having a  correspondent  in the
City of New York, and such conversion shall be deemed effective upon the date of
delivery  of  such  certificates  in  accordance  with  the  provisions  of this
subdivision (j).

                        (k)  Fractional  Shares;  Dividends  on  Conversion.  No
fractional  shares of Common Stock will be issuable upon  conversion of Series C
Stock.  The Company in lieu thereof,  will make a payment in cash in lieu of any
fractional  share of  Common  Stock  to which  the  converting  holder  would be
entitled if such fractional share was issuable, based upon the market price of a
share of Common  Stock as of the  Conversion  Date.  Upon such  conversion,  the
Company  will pay all accrued but unpaid  dividends  with  respect to each share
converted which have not been paid theretofore.

                  4.    Dividends.

                        (a) The  annual  dividend  rate at which the  holders of
shares shall be entitled to receive  dividends is $1.00 per share per annum. The
holders  of the  shares  shall be  entitled  to  receive,  out of funds  legally
available  therefor  under  Section  170  (or  its  successor)  of the  Delaware
Corporation Law,  mandatory  preferential  dividends at such annual rate payable
annually on the first day of April in each year. Such dividends shall be accrued
on a daily basis and shall be cumulative.


                                       -7-




                        (b) The Board of Directors shall pay dividends,  in cash
or, at the  election  of the  Board of  Directors,  in  shares of Common  Stock,
including  dividends  accrued  under  paragraph  (a) but  unpaid on any share of
Series C Stock  as of the date on which  such  share is  converted  into  Common
Stock. If paid in Common Stock, the dividend shall be paid by delivering  shares
of Common Stock to, and  registered  on the books of the Company in the name of,
the  registered  holder of the share of Series C Stock on the record date or the
date of  conversion,  as the case may be.  The  number of such  shares of Common
Stock so deliverable shall be that number of whole shares which, when multiplied
by the "per-share value"  determined below,  shall equal the total amount of the
dividend then due.  "Per-share  value" shall be equal to the average of the last
sale prices of Common Stock on the National  Association  of Securities  Dealers
Automated Quotation System for the ten days immediately  preceding such dividend
payment date or, if during which the Common Stock is then listed on any national
securities  exchange,  the average of the closing prices on the primary exchange
during  such ten days.  No  fractional  shares  will be issued in payment of any
dividend  contemplated by this paragraph  4(b). In lieu thereof,  there shall be
paid,  simultaneously with the distribution of the whole shares of Common Stock,
cash in the amount of the "per share value" of any fractional share.

                        (c) If the  Company  declares  a  distribution  upon the
Common  Stock,  other than a  distribution  payable  entirely  in Common  Stock,
payable  otherwise  than  out  of  earnings  or  earned  surplus  determined  in
accordance with generally accepted accounting  principles,  consistently applied
(a "Liquidating Dividend"), then the Company will pay to each holder of Series C
Stock at the time of payment of a  Liquidating  Dividend an amount  equal to the
aggregate value of all  Liquidating  Dividends which would have been paid on the
Common Stock issuable upon conversion of such holder's Series C Stock,  had such
Common Stock been converted  immediately prior to the date on which a record was
taken for such Liquidating Dividend,  or, if no record was taken, the date as of
which the  record  holders  of Common  Stock  entitled  to such  dividends  were
determined.  For purposes of this  paragraph  4, a dividend  other than in cash,
notes,  debentures  or  capital  stock  will not be  considered  payable  out of
earnings  or earned  surplus,  regardless  of whether or not  earnings or earned
surplus  are  charged  an amount  equal to the fair value of such  dividend.  No
distribution  in respect of Series C Stock  contemplated  by this paragraph 4(c)
shall be deemed to reduce  the amount of  dividends  then  cumulated  but unpaid
under paragraph 4(a).

                        (d)  Except  as   contemplated  by  paragraph  4(c),  no
dividend or  distribution  will be declared or paid on the Common Stock when any
dividends contemplated by paragraph 4(a) are cumulated but unpaid.

         5.  Preference  on  Liquidation.  The  preference  per share  which the
holders of Series C  Preferred  Stock  shall be  entitled  to  receive  over the
holders of each share of Common Stock and each share of  Preferred  Stock (other
than the shares of any other series of Preferred Stock  initially  issued in its
entirety to American Cyanamid  Company,  which series shall rank pari passu with
Series C  Stock),  in case of the  liquidation,  distribution  or sale of all or
substantially  all of the  Company's  assets,  dissolution  or winding up of the
Company,

                                       -8-




whether  voluntary or involuntary,  shall be $100.00 per share plus, in any such
case, an amount equal to any and all dividends cumulated but unpaid.

         6. Protective  Provisions.  Until the date American Cyanamid Company or
its  affiliates  ceases to be the  registered  holder of all of the  issued  and
outstanding  Preferred  Stock of at least  one  series,  the  Company  will not,
without the  approval  by the vote or written  consent of at least a majority of
the outstanding  shares of all series of Preferred Stock initially issued in its
entirety to American Cyanamid Company, voting as a single class:

                  (a) authorize or issue shares of any class of stock having any
preference or priority,  or ranking,  unless issued to American Cyanamid Company
or its designee or to Elan Pharmaceuticals,  plc pursuant to an Option Agreement
dated as of April 22,  1991 as in  effect on June 3,  1993,  pari  passu,  as to
dividends or assets superior to any such series;

                  (b)  reclassify  any shares of any class of stock into  shares
having any preference or priority as to dividends or assets superior to any such
series;

                  (c) make any amendment to its Certificate of  Incorporation or
by-laws adversely affecting the rights of holders of any such series;

                  (d)  merge  or  consolidate  with  any  entity  (other  than a
wholly-owned  subsidiary of the Company),  or sell, lease, mortgage or otherwise
dispose  of  all  of  its  assets,  or  liquidate,  dissolve,   recapitalize  or
reorganize;

                  (e) repurchase or redeem any shares of its Common Stock;

                  (f) pay dividends or make any other distribution on any shares
of Common Stock,  other than a  distribution  payable  entirely in Common Stock,
unless,  simultaneous  with such  payment or  distribution,  the Company pays or
distributes  to each  holder  of Series C Stock at the time of such  payment  or
distribution,  a payment  or  distribution  equal in amount and paid in the same
form as the payment or  distribution  such holder  would have  received had such
holder  converted  its shares of Series C Stock into  Common  Stock  immediately
prior to the record  date for the payment or  distribution  to holders of Common
Stock.  Any  payment or  distribution  pursuant  to this  paragraph  shall be in
addition  to and shall not be deemed to  reduce  the  amount of  dividends  then
cumulated but unpaid under paragraph 4(a); or

                  (g)  guarantee  any  indebtedness  of any third party except a
subsidiary for borrowed money.

                  7.  Amendment.  No amendment of any term of the Series C Stock
may be made  without  the  affirmative  vote of  holders  of at least 2/3 of the
outstanding shares of Series C Stock.


                                       -9-




        This Certificate has been executed on this 3rd day of June 1993.

                                            INTERNEURON PHARMACEUTICALS, INC.



                                            By  /s/ Glenn L. Cooper
                                              --------------------------
                                                      President

Attest:


  /s/ Jill Cohen
--------------------
  Secretary

                                      -10-




                      RESTATED CERTIFICATE OF INCORPORATION

                                       OF

                        INTERNEURON PHARMACEUTICALS, INC.



                  INTERNEURON  PHARMACEUTICALS,   INC.  (the  "Corporation"),  a
Corporation   organized  and  existing  under  and  by  virtue  of  the  General
Corporation Law of the State of Delaware, hereby certifies as follows:

1.  The  name of the  corporation  is  Interneuron  Pharmaceuticals,  Inc..  The
Corporation  was  originally  incorporated  under  the name  Interneuron  Merger
Corporation  and the original  Certificate of  Incorporation  was filed with the
Secretary of State of the State of Delaware on February 21, 1990.

2. This Restated  Certificate of Incorporation  restates and integrates and does
not further amend the  provisions of the  Certificate  of  Incorporation  of the
Corporation.  This Restated Certificate of Incorporation was adopted pursuant to
Section 245 of the General Corporation Law of the State of Delaware.

3.  Pursuant  to  Section  245 of the  General  Corporation  Law of the State of
Delaware,  the text of the Restated  Certificate of  Incorporation as heretofore
amended or supplemented is hereby restated to read in its entirety as follows:

FIRST:     The name of the Corporation is Interneuron Pharmaceuticals, Inc.

SECOND:    The Corporation is formed to engage in any lawful act or activity for
           which corporations may be organized under the General Corporation Law
           of the State of Delaware.

THIRD:     The  registered  office of the  Corporation  is to be  located  at 32
           Loockerman  Square,  Suite L-100, in the City of Dover, in the County
           of Kent, in the State of Delaware.  The name of its registered  agent
           at that address is The Prentice-Hall Corporation System, Inc.

FOURTH:   (A) (1) The aggregate  number of shares which the  Corporation  shall
           have authority to issue is fifty-five million (55,000,000),  of which
           five million  (5,000,000)  shares of the par value of $.001 per share
           shall be designated  "Preferred Stock" and fifty million (50,000,000)
           shares  of the par  value  of $.001  per  share  shall be  designated
           "Common Stock."


                                      -11-




                           (2)  Authority  is hereby  expressly  granted  to the
                  Board of  Directors  from time to time to issue the  Preferred
                  Stock as Preferred Stock of any series and, in connection with
                  the creation of each such series,  to fix by the resolution or
                  resolutions  providing  for the issue of shares  thereof,  the
                  number of shares of such series and the designations,  powers,
                  preferences,    rights,   qualifications,    limitations   and
                  restrictions  of  such  series,  to  the  full  extent  now or
                  hereafter permitted by the laws of the State of Delaware.

                  (B)      Series B Preferred Stock.

                           (1)  Designation.  The number of shares to constitute
                  such  series  of  Preferred  Stock  shall be  239,425  and the
                  designation  of such series shall be Series B Preferred  Stock
                  (hereinafter called the "Series B Stock").

                           (2) Voting Rights. On all matters submitted to a vote
                  of  stockholders   generally,   other  than  the  election  of
                  Directors,  each share of Series B Stock will be entitled to a
                  number of votes equal to the number of shares of Common  Stock
                  into which  such share of Series B Stock is then  convertible,
                  and rounding the result to the nearest whole number. Except as
                  otherwise  required  by law or by any  provision  hereof,  the
                  Common  Stock and the Series B Stock will vote  together  as a
                  single  class on all  matters on which  stockholders  shall be
                  entitled to vote.

                           (3)      Conversion.

                                    (a) Conversion Ratio. Each outstanding share
                  of  Series  B Stock  will be  convertible  at any  time at the
                  option of the holder  into a number of shares of Common  Stock
                  computed by dividing  $12.53 by the  Conversion  Price then in
                  effect.

                                    (b)  Conversion   Price;   Adjustment.   The
                  initial  Conversion Price will be $12.53.  Each time after the
                  effective  date hereof,  the Company issues or agrees to issue
                  any additional  shares of Common Stock for a consideration per
                  share  which is less than  two-thirds  of the then  Conversion
                  Price  (such  consideration  being  hereinafter   collectively
                  referred to as the "Issue Price"),  the then Conversion  Price
                  shall be reduced to 150% of the Issue Price.

                                    (c) Excluded Issuances. The reduction in the
                  Conversion  Price required by paragraph 3(b) shall not be made
                  in the event (i) the Company  issues shares of Common Stock or
                  options,  warrants or other rights to purchase Common Stock to
                  any of its  officers,  directors,  employees,  consultants  or
                  scientific  advisers;  (ii) of any  issuance  of up to  10,000
                  shares  (as  adjusted  from  time  to  time  pursuant  to  the
                  provisions of paragraph 3(e) below) of Common Stock or options
                  or warrants to purchase up to said number of


                                      -12-




                  shares of Common Stock to any person at any one time, provided
                  that no more than an aggregate of 100,000  shares (as adjusted
                  from time to time pursuant to the provisions of paragraph 3(e)
                  below) and  options or  warrants  to  purchase  said number of
                  shares may be issued pursuant to this clause (ii); or (iii) of
                  any  issuance  of  Common   Stock,   Options  or   Convertible
                  Securities (as defined in paragraph 3(d)(i) hereof) in respect
                  of  an  obligation  incurred  by  the  Company  prior  to  the
                  effective date hereof.

                             (d) Effect on Conversion  Price of Certain  Events.
                  For purposes of determining the Issue Price and the Conversion
                  Price under paragraph 3(b) above, the following will apply:

                                    (i) Issuance of Rights or Options. Each time
                  after the effective date hereof,  the Company,  in any manner,
                  (other than an excluded  issuance under paragraph 3(c)) grants
                  any rights or options to subscribe  for or to purchase  Common
                  Stock or any  stock or other  securities  convertible  into or
                  exchangeable  for Common Stock (such  rights or options  being
                  herein called  "Options" and such  convertible or exchangeable
                  stock  or   securities   being  herein   called   "Convertible
                  Securities") and the price per share for which Common Stock is
                  issuable upon the exercise of such Options or upon  conversion
                  or exchange of such  Convertible  Securities is less than both
                  (x) 150% of the average of the last sale prices for the Common
                  Stock for the ten trading days preceding the date on which the
                  Company  issues or agrees to issue such Options or Convertible
                  Securities  and  (y)  the  then  Conversion  Price,  then  the
                  Conversion  Price  shall be reduced to the greater of (x) 100%
                  of the price per share for which Common Stock is issuable upon
                  the exercise of such Options or upon conversion or exchange of
                  such  Convertible  Securities  and (y)  56.67% of the  initial
                  Conversion Price as adjusted from time to time pursuant to the
                  provisions  of  paragraph  3(e)  below.  For  purposes of this
                  paragraph,  the  "price  per share for which  Common  Stock is
                  issuable upon the exercise of such Options or upon  conversion
                  or exchange of such Convertible Securities" will be determined
                  by  dividing  (A)  the  total  amount,  if  any,  received  or
                  receivable by the Company as consideration for the granting of
                  such Options,  plus the minimum aggregate amount of additional
                  consideration payable to the Company upon exercise of all such
                  Options,  plus,  in the case of such  Options  which relate to
                  Convertible  Securities,   the  minimum  aggregate  amount  of
                  additional consideration,  if any, payable to the Company upon
                  the issuance or sale of such  Convertible  Securities  and the
                  conversion  or  exchange  thereof,  by (B) the  total  maximum
                  number of shares of Common Stock issuable upon the exercise of
                  such  Options or upon the  conversion  or exchange of all such
                  Convertible  Securities  issuable  upon the  exercise  of such
                  Options.  Except as otherwise provided in paragraph  3(d)(iii)
                  below, no adjustment of the Conversion Price will be made when
                  Convertible Securities are actually issued upon the exercise


                                      -13-




                  of such Options or when Common  Stock is actually  issued upon
                  the exercise of such Options or the  conversion or exchange of
                  such Convertible Securities.

                                    (ii)  Issuance  of  Convertible  Securities.
                  Each time after the effective date hereof, the Company, in any
                  manner (other than an excluded issuance under paragraph 3(c)),
                  issues or sells any  Convertible  Securities and the price per
                  share for which Common Stock is issuable upon such  conversion
                  or  exchange  is less than both (x) 150% of the average of the
                  last sale prices for the Common Stock for the ten trading days
                  preceding  the date on which the  Company  issues or agrees to
                  issue such Options or Convertible  Securities and (y) the then
                  Conversion  Price,  then the Conversion Price shall be reduced
                  to the  greater  of (x) 100% of the  price per share for which
                  Common Stock is issuable upon such  conversion or exchange and
                  (y) 56.67% of the initial  Conversion  Price as adjusted  from
                  time to time  pursuant to the  provisions  of  paragraph  3(e)
                  below.  For the  purposes  of this  paragraph,  the "price per
                  share for which Common Stock is issuable upon such  conversion
                  or  exchange"  will be  determined  by dividing  (A) the total
                  amount received or receivable by the Company as  consideration
                  for the issuance or sale of such Convertible Securities,  plus
                  the minimum aggregate amount of additional  consideration,  if
                  any,  payable to the Company upon the  conversion  or exchange
                  thereof,  by (B) the total maximum  number of shares of Common
                  Stock  issuable  upon the  conversion  or exchange of all such
                  Convertible  Securities.   Except  as  otherwise  provided  in
                  paragraph  3(d)(iii)  below,  no adjustment of the  Conversion
                  Price will be made when Common  Stock is actually  issued upon
                  the conversion or exchange of such Convertible Securities, and
                  if any such issue or sale of such  Convertible  Securities  is
                  made upon exercise of any Options for which adjustments of the
                  Conversion  Price had been or are to be made pursuant to other
                  provisions of this  paragraph 3, no further  adjustment of the
                  Conversion Price will be made by reason of such issue or sale.

                                    (iii) Change in Option  Price or  Conversion
                  Rate. If the purchase  price  provided for in any Option,  the
                  additional consideration,  if any, payable upon the conversion
                  or  exchange  of any  Convertible  Securities,  or the rate at
                  which  any  Convertible  Securities  are  convertible  into or
                  exchangeable  for Common  Stock change at any time (other than
                  under or by reason of provisions  designed to protect  against
                  dilution  of the type set  forth in this  paragraph  3, or any
                  other mandatory anti-dilution provision otherwise contained in
                  such Options or Convertible Securities),  the Conversion Price
                  in effect at the time of such change will be readjusted to the
                  Conversion  Price which would have been in effect at such time
                  had such Options or Convertible  Securities still  outstanding
                  provided  for  such   changed   purchase   price,   additional
                  consideration or changed conversion rates, as the case may be,
                  at the time initially granted,  issued or sold; provided, that
                  such  adjustment of the Conversion  Price then in effect would
                  be reduced.  If the purchase price provided for in any Option,
                  the

                                      -14-




                  additional consideration,  if any, payable upon the conversion
                  or  exchange  of any  Convertible  Securities,  or the rate at
                  which  any  Convertible  Securities  are  convertible  into or
                  exchangeable  for Common Stock, is reduced at any time,  under
                  or by reason of,  provisions with respect thereto  designed to
                  protect  against  dilution of the type set forth herein or any
                  other  mandatory  anti-dilution  provision  contained  in such
                  Options  or  Convertible  Securities,  then in the case of the
                  delivery of Common  Stock upon the exercise of any such Option
                  or upon the  Conversion  or exchange  of any such  Convertible
                  Security,  the Conversion  Price then in effect hereunder will
                  forthwith be adjusted to such respective  amount as would have
                  been obtained had such Option or  Convertible  Security  never
                  been issued as to such Common Stock and had  adjustments  been
                  made to the  Conversion  Price upon the issuance of the shares
                  of  Common  Stock  delivered,  but only if as a result of such
                  adjustment,  the  Conversion  Price  then in effect  hereunder
                  would be reduced.

                                    (iv) Calculation of Consideration  Received.
                  In case any Common Stock,  Options or  Convertible  Securities
                  are  issued or sold or deemed to have been  issued or sold for
                  consideration,  part or all of which is cash,  the  amount  of
                  cash consideration  received therefor will be deemed to be the
                  gross  amount  received by the Company  therefor.  In case any
                  Common Stock, Options or Convertible  Securities are issued or
                  sold  or   deemed   to  have   been   issued  or  sold  for  a
                  consideration,  part or all of which is other than  cash,  the
                  amount of the consideration,  other than cash, received by the
                  Company will be the fair value of such  consideration,  except
                  where  such  consideration  consists  of  securities  publicly
                  traded, in which case the amount of consideration  received by
                  the Company,  will be the market price  thereof as of the date
                  of receipt.  In case any Common Stock,  Options or Convertible
                  Securities  are issued in connection  with any merger in which
                  the  Company  is the  surviving  corporation,  the  amount  of
                  consideration  therefor will be deemed to be the fair value of
                  such   portion  of  the  net  assets  and   business   of  the
                  non-surviving  corporation as is  attributable  to such Common
                  Stock, Options or Convertible Securities, as the case may be.

                                    (v) Integration of Transactions. In case any
                  Option or  Convertible  Security is issued in connection  with
                  the issue or sale of other securities of the Company, together
                  comprising  one  integrated  transaction  in which no specific
                  consideration  is  allocated  to such  Option  or  Convertible
                  Security by the  parties  thereto,  the Option or  Convertible
                  Security   will  be  deemed  to  have  been   issued   without
                  consideration.

                            (e)  Subdivision or Combination of Common Stock.  If
                  the Company at any time subdivides (by any stock split,  stock
                  dividend or otherwise) its outstanding  shares of Common Stock
                  into a  greater  number of  shares,  the  Conversion  Price in
                  effect immediately prior to such subdivision

                            
                                      -15-




                  will be  proportionately  reduced,  and if the  Company at any
                  time  combines  (by  reverse  stock  split or  otherwise)  its
                  outstanding  shares of Common  Stock into a smaller  number of
                  shares,   the   Conversion   Price  will  be   proportionately
                  increased.

                                    (f)    Reorganization,     Reclassification,
                  Merger,  Consolidation or Sale. If any capital reorganization,
                  reclassification,  consolidation  or merger or any sale of all
                  or substantially all of the Company's assets (collectively any
                  "Major  Change")  is  effected  in such a way that  holders of
                  Common Stock are entitled to receive (either  directly or upon
                  subsequent liquidation) stock, other securities or assets with
                  respect  to  or in  exchange  for  Common  Stock,  then,  as a
                  condition to such Major Change,  lawful and adequate provision
                  will be made  whereby  each of the  holders  of Series B Stock
                  will  thereafter have the right to acquire and receive in lieu
                  of  the  shares  of  Common  Stock   immediately   theretofore
                  acquirable and receivable upon the conversion of such holder's
                  Series B Stock,  such  shares of stock,  other  securities  or
                  assets as may be  issuable  or payable  with  respect to or in
                  exchange for the number of shares of Common Stock  immediately
                  theretofore  acquirable and receivable upon conversion of such
                  holder's Series B Stock had such Major Change not taken place.
                  In any such  case,  appropriate  provision  will be made  with
                  respect to such holder's  rights and interests to the end that
                  the  provisions of this paragraph 3 and paragraph 4 below will
                  thereafter  be  applicable in relation to any shares of stock,
                  securities   or  assets   thereafter   deliverable   upon  the
                  conversion  of  Series B Stock  including,  in the case of any
                  such  consolidation,  merger  or sale in which  the  successor
                  corporation  or  purchasing  corporation  is  other  than  the
                  Company,  an immediate  adjustment of the Conversion  Price to
                  the value for the Common Stock  reflected by the terms of such
                  consolidation,  merger or sale and a  corresponding  immediate
                  adjustment in the number of shares of Common Stock  acquirable
                  and receivable upon conversion of Series B Stock, if the value
                  so  reflected  is less  than the  Conversion  Price in  effect
                  immediately prior to such  consolidation,  merger or sale. The
                  Company will not effect any such consolidation, merger or sale
                  unless,  prior  to the  consummation  thereof,  the  successor
                  corporation  (if other than the Company)  resulting  from such
                  consolidation  or merger,  or the corporation  purchasing such
                  assets,  assumes  by  written  instrument  the  obligation  to
                  deliver to each such holder  such shares of stock,  securities
                  or assets as, in  accordance  with the  foregoing  provisions,
                  such holder may be entitled to acquire.

                                    (g) Certain  Events.  If any event occurs of
                  the type  contemplated  by the provisions of this paragraph 3,
                  but not expressly  provided for by such  provisions,  then the
                  Board of Directors will make an appropriate  adjustment in the
                  Conversion Price so as to protect the rights of the holders of
                  Series B Stock.


                                      -16-




                                    (h) No  Circumvention.  The Company will not
                  issue  any  additional   shares  of  Series  B  Stock  or,  in
                  circumvention of the provisions of this paragraph 3, issue any
                  shares  of  preferred   stock  which,   notwithstanding   such
                  designation,  primarily  possess  the  attributes  customarily
                  associated  with  common  stock,  and do not  possess  special
                  voting rights, scheduled or optional redemption features (with
                  redemption  prices  specified as to amount and limited to such
                  amount),  special  liquidation  rights fixed and limited as to
                  amount,  and  dividends  fixed in amount  and  limited  to the
                  amount so fixed; other than pursuant to an obligation to issue
                  preferred stock existing prior to the effective date hereof.

                                    (i)     Notices.

                                            (i) As soon as practicable after any
                  adjustment  of the  Conversion  Price,  the Company  will send
                  written notice thereof to all holders of Series B Stock.

                                            (ii) The  Company  will  give to the
                  holders  of  Series B Stock at  least 20 days'  prior  written
                  notice of the date on which any Major Change,  dissolution  or
                  liquidation will take place.

                                     (j) Mechanics of Conversion. So long as any
                  shares of Series B Stock remain  outstanding,  at the election
                  of the respective  holders thereof,  any and all shares of the
                  Series B Stock may be converted at any time on and  subsequent
                  to the second  anniversary  of the initial  issuance  and from
                  time to time into the number of fully paid and  non-assessable
                  shares of Common Stock of the Company  calculated as set forth
                  herein.  In order to exercise the  conversion  privilege,  the
                  holder of Series B Stock shall surrender the  certificates for
                  the  Series  B Stock to be  converted  at the  offices  of the
                  Company in the  Commonwealth of  Massachusetts,  together with
                  written  notice  to the  Company  that the  holder  elects  to
                  convert such Series B Stock or a portion thereof.  Such notice
                  shall also state the name or names (with address) in which the
                  certificates  for  shares of  Common  Stock  issuable  on such
                  conversion  shall be issued.  Series B Stock  surrendered  for
                  conversion shall be accompanied by proper assignments  thereof
                  to the Company or in blank for transfer  and the  signature of
                  the holder shall be guaranteed by a firm having  membership on
                  the New York Stock  Exchange or by a commercial  bank or trust
                  company  located in or having a  correspondent  in the City of
                  New York, and such conversion  shall be deemed  effective upon
                  the date of delivery of such  certificates  in accordance with
                  the provisions of this subdivision (j).

                                     (k)   Fractional   Shares;   Dividends   on
                  Conversion.  No  fractional  shares  of Common  Stock  will be
                  issuable  upon  conversion  of Series B Stock.  The Company in
                  lieu thereof, will make a payment in cash in lieu of


                                      -17-




                  any  fractional  share of Common Stock to which the converting
                  holder  would  be  entitled  if  such  fractional   share  was
                  issuable,  based  upon the  market  price of a share of Common
                  Stock as of the Conversion  Date.  Upon such  conversion,  the
                  Company will pay all then accrued, but unpaid,  dividends with
                  respect  to each  share  converted  which  have not been  paid
                  theretofore.

                           (4)      Dividends.

                                    (a) The  annual  dividend  rate at which the
                  holders of shares  shall be entitled to received  dividends is
                  $.1253 per share per annum. The holders of the shares shall be
                  entitled to receive,  out of funds legally available  therefor
                  under   Section  170  (or  its   successor)  of  the  Delaware
                  Corporation  Law,  mandatory  preferential  dividends  at such
                  annual rate payable annually on the first day of April in each
                  year.  Such dividends  shall accrue on a daily basis and shall
                  be cumulative.

                                    (b)  The  Board  of   Directors   shall  pay
                  dividends in cash or, at the Board of Directors' election,  in
                  shares of Common  Stock,  including  dividends  accrued  under
                  paragraph  (a) but unpaid on any share of Series B Stock as of
                  the date on which such share is converted  into Common  Stock.
                  If  paid  in  Common  Stock,  the  dividend  shall  be paid by
                  delivering  shares of Common Stock to, and  registered  on the
                  books of the Company in the name of, the registered  holder of
                  the share of Series B Stock on the record  date or the date of
                  conversion,  as the case may be. The number of such  shares of
                  Common  Stock so  deliverable  shall be that  number  of whole
                  shares  which,   when  multiplied  by  the  "per-share  value"
                  determined below, shall equal the total amount of the dividend
                  then due.  "Per-share  value" shall be equal to the average of
                  the last  sale  prices  of the  Common  Stock on the  National
                  Association of Securities  Dealers Automated  Quotation System
                  for the ten days  immediately  preceding such dividend payment
                  date,  or if the Common  Stock is then listed on any  national
                  securities exchange, the average of the closing prices on such
                  stock exchange during such ten days. No fractional shares will
                  be issued in  payment  of any  dividend  contemplated  by this
                  paragraph   (b).   In  lieu   thereof   there  shall  be  paid
                  simultaneously  with the  distribution  of the whole shares of
                  Common  Stock,  cash in the amount of the "per share value" of
                  any fractional share.

                                    (c) If the Company  declares a  distribution
                  upon the Common Stock, other than a distribution paid entirely
                  in Common  Stock,  payable  otherwise  than out of earnings or
                  earned  surplus   determined  in  accordance   with  generally
                  accepted  accounting   principles,   consistently  applied  (a
                  "Liquidating  Dividend"),  then the  Company  will pay to each
                  holder  of  Series  B  Stock,  at the  time  of  payment  of a
                  Liquidating  Dividend,  an amount equal to the aggregate value
                  of all Liquidating Dividends which would have been paid on the


                                      -18-




                  Common Stock issuable upon  conversion of such holder's Series
                  B Stock had such Common Stock been converted immediately prior
                  to the date on which a record  was taken for such  Liquidating
                  Dividend, or, if no record was taken, the date as of which the
                  record holders of Common Stock entitled to such dividends were
                  determined.  For  purposes  of this  paragraph  4, a dividend,
                  other than in cash,  notes,  debentures or capital stock, will
                  not be  considered  payable out of earnings or earned  surplus
                  regardless  of whether or not  earnings or earned  surplus are
                  charged an amount equal to the fair value of such dividend. No
                  distribution in respect of Series B Stock contemplated by this
                  paragraph  4(c)  shall be  deemed  to  reduce  the  amount  of
                  dividends then cumulated but unpaid under paragraph 4(a).

                                    (d)  Except  as  contemplated  by  paragraph
                  4(c), no dividend or distribution  will be declared or paid on
                  the Common Stock when any dividends  contemplated by paragraph
                  4(a) are cumulated but unpaid.

                           (5)  Preference on  Liquidation.  The  preference per
                  share which the  holders of Series B Preferred  Stock shall be
                  entitled  to receive  over the holders of each share of Common
                  Stock,  and each  share of  Preferred  Stock  (other  than the
                  shares of any other series of Preferred Stock initially issued
                  in its  entirety to American  Cyanamid  Company,  which series
                  shall rank pari passu with Series B Stock), in the case of the
                  liquidation,  distribution or sale of all or substantially all
                  of the  Company's  assets,  dissolution  or  winding up of the
                  Company, whether voluntary or involuntary, shall be $12.53 per
                  share,  plus in any such case,  an amount equal to any and all
                  dividends cumulated but unpaid.

                           (6)  Protective  Provisions.  Until the date American
                  Cyanamid Company ceases to be the registered  holder of all of
                  the issued  and  outstanding  Preferred  Stock of at least one
                  series, the Company will not, without the approval by the vote
                  or written  consent of at least a majority of the  outstanding
                  shares of all series of Preferred  Stock  initially  issued in
                  its entirety to American Cyanamid Company,  voting as a single
                  class:

                                    (a)  authorize  or issue shares of any class
                  of stock having any preference or priority,  or, unless issued
                  to American  Cyanamid  Company or its  designee,  ranking pari
                  passu, as to dividends or assets superior to any such series;

                                    (b)  reclassify  any  shares of any class of
                  stock into  shares  having any  preference  or  priority as to
                  dividends or assets, superior to any such series;

                                    (c) make any amendment to its Certificate of
                  Incorporation  or by-laws  adversely  affecting  the rights of
                  holders of any such series;

                                    
                                      -19-




                                    (d)  merge or  consolidate  with any  entity
                  (other than a  wholly-owned  subsidiary  of the  Company),  or
                  sell,   lease,   mortgage  or  otherwise  dispose  of  all  or
                  substantially  all  of its  assets,  or  liquidate,  dissolve,
                  recapitalize or reorganize;

                                    (e)  repurchase  or redeem any shares of its
                  Common Stock;

                                    (f)  pay   dividends   or  make  any   other
                  distribution  on any  shares of  Common  Stock,  other  than a
                  distribution  payable  entirely  in shares  of  Common  Stock,
                  unless,  simultaneous  with such payment or distribution,  the
                  Company pays or  distributes to each holder of Series B Stock,
                  at the time of such  payment  or  distribution,  a payment  or
                  distribution  equal in amount and paid in the same form as the
                  payment or  distribution  such holder would have  received had
                  such holder converted its shares of Series B Stock into Common
                  Stock  immediately prior to the record date for the payment or
                  distribution  to  holders  of Common  Stock.  Any  payment  or
                  distribution  pursuant to this paragraph  shall be in addition
                  to and shall not be deemed to reduce the  amount of  dividends
                  then cumulated but unpaid under paragraph 4(a); or

                                    (g) guarantee any  indebtedness of any third
                  party, except a subsidiary for borrowed money.

                           (7) Amendment. No amendment of any term of the Series
                  B Stock may be made without the affirmative vote of holders of
                  at least 2/3 of the outstanding shares of Series B Stock.

FIFTH             The Stockholders, or the Board of Directors of the Corporation
                  without the assent or vote of the stockholders, shall have the
                  power to adopt,  alter,  amend or repeal  the  By-Laws  of the
                  Corporation.

SIXTH:            No  director  of  the  Corporation  shall  be  liable  to  the
                  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 the
                  Corporation or its stockholders,  (ii) for acts or commissions
                  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.

SEVENTH:          The Corporation  shall indemnify any person to the full extent
                  permitted  by the  Business  Corporation  Law of the  State of
                  Delaware, as the same now exists or may hereafter be amended.


                                      -20-





                  IN  WITNESS  WHEREOF,   this  Restated  Certificate  has  been
subscribed to this 11th day of February,  1993 by the  undersigned,  who affirms
that the statements made herein are true under the penalty of perjury.

                                             INTERNEURON PHARMACEUTICALS, INC.


                                             By:  /s/ Lindsay Rosenwald
                                                --------------------------
                                                 Lindsay Rosenwald, M.D.
                                                 Chairman of the Board


ATTEST:



By:  /s/ Jill Cohen
   ------------------------
   Jill Cohen, Secretary


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