Exhibit 3.1
                     RESTATED CERTIFICATE OF INCORPORATION

                                      OF

                          ARGUS PHARMACEUTICALS, INC.


      ARGUS PHARMACEUTICALS,  INC. (the "Corporation"),  a corporation organized
and existing under the General  Corporation  Law of the State of Delaware,  does
hereby  certify  that it was  incorporated  on June 13,  1986 as THE  MACROPHAGE
COMPANY.

                                  ARTICLE ONE

      This  Restated  Certificate  of  Incorporation  has been duly  adopted  in
accordance with the applicable provisions of Sections 242 and 245 of the General
Corporation  Law of the State of Delaware (the "DGCL") by the Board of Directors
of the Corporation.

                                  ARTICLE TWO

      This Restated Certificate of Incorporation was approved by written consent
of the stockholders pursuant to Section 228 of the DGCL.

                                 ARTICLE THREE

      The outstanding shares of the Corporation's  common stock, par value $.001
per share ("Old Common  Stock"),  are hereby  reclassified  and  converted  into
shares of the  Corporation's  Common Stock,  par value $.001 per share  ("Common
Stock"),  on the basis of one share of Common  Stock for each 3.3  shares of Old
Common Stock.  The Corporation  shall not issue any fractional  shares of Common
Stock in connection with any of the foregoing reclassification and conversion of
Old Common Stock;  instead,  any fractional  interest in Common Stock  resulting
from application of the specified  reclassification  and conversion ratios shall
be rounded up or down to the  nearest  whole share of Common  Stock,  and in the
event that any fractional  interest is rounded down, there shall be no cash paid
by or to the Corporation in respect of any such fractional interest.

                                 ARTICLE FOUR

      The Certificate of  Incorporation  of this  Corporation and all amendments
thereto  are  hereby  superseded  by  the  following  Restated   Certificate  of
Incorporation  which accurately sets forth the entire text of the Certificate of
Incorporation:

                                   ARTICLE I

                                     NAME

      The name of the Corporation is Argus Pharmaceuticals, Inc.

                                  ARTICLE II

                            REGISTERED OFFICE/AGENT

      The  registered  office of the  Corporation  in the State of  Delaware  is
Corporation Trust Center, 1209 Orange Street, in the City of Wilmington,  County
of New Castle,  Delaware 19801. The name of its registered agent at such address
is The Corporation Trust Company.


                                     -1-

<PAGE>



                                  ARTICLE III

                                   PURPOSES

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

                                  ARTICLE IV

                                 CAPITAL STOCK

      A.    Classes of Stock

      The total  number  of shares of all  classes  of  capital  stock  that the
Corporation shall be authorized to issue is 35,000,000 shares,  divided into the
following:  (i) 10,000,000  shares of preferred stock, par value $.001 per share
("Preferred Stock"), and (ii) 25,000,000 shares of common stock, par value $.001
per share ("Common Stock").

      B.    Preferred Stock

      Shares of  Preferred  Stock may be issued from time to time in one or more
series.  The Board of  Directors is hereby  vested with the  authority to fix by
resolution the powers,  designations,  preferences and relative,  participating,
optional and other special rights of each series of Preferred Stock,  including,
without  limitation,  the  dividend  rate,  conversion  rights,  voting  rights,
redemption price and liquidation preference, and the qualifications, limitations
or  restrictions  on such  preferences  and/or  rights  and to fix the number of
shares   constituting  any  such  series.   Unless  otherwise  provided  by  the
resolution(s)  adopted by the Board of Directors  providing for the issue of any
series of Preferred  Stock,  the number of shares  comprising such series may be
increased  or  decreased  (but not below the number of shares then  outstanding)
from time to time by duly adopted resolution(s) of the Board of Directors.

      C.    Common Stock

      Except as otherwise provided in this Restated Certificate of Incorporation
or by law or by the  resolution(s)  of the Board of Directors  providing for the
issue of any series of the Preferred Stock, each holder of Common Stock shall be
entitled  to one vote for each share  held.  Subject to all of the rights of the
Preferred Stock or any series thereof,  the holders of the Common Stock shall be
entitled to receive,  when and as  declared  by the Board of  Directors,  out of
funds legally available therefor, dividends payable in cash, stock or otherwise.
Upon any  liquidation,  dissolution  or winding up of the  Corporation,  whether
voluntary or  involuntary,  and after the holders of the Preferred Stock of each
series shall have been paid in full the amounts to which they respectively shall
be entitled,  or a sum  sufficient for such payments in full shall have been set
aside, the remaining net assets of the Corporation shall he distributed pro rata
to the holders of the Common Stock in accordance  with their  respective  rights
and interest.

                                   ARTICLE V

                              BOARD OF DIRECTORS

      Except as  otherwise  provided  by law,  the  business  and affairs of the
Corporation  shall be  managed  by,  or under  the  direction  of,  its Board of
Directors.  The number of directors of the Corporation shall be fixed by, and in
the manner provided in, the  Corporation's  Bylaws,  but shall not be fewer than
three  nor more  than  15.  None of the  directors  need be a  stockholder  or a
resident of the State of Delaware. Elections of directors need not be by written
ballot unless the Corporation's Bylaws provide otherwise. In furtherance and not
in limitation of the rights,  powers,  privileges  and  discretionary  authority
conferred  by the DGCL or other  applicable  law,  the  Board  of  Directors  is
expressly authorized to adopt, amend or repeal the Bylaws of the Corporation.


                                     -2-

<PAGE>



                                  ARTICLE VI

                                 STOCKHOLDERS

      Stockholder  action may only be taken at an annual or special meeting with
prior notice and a vote. No stockholder  action may be taken by written consent.
Meetings of stockholders  may be held within or without the State of Delaware as
the Bylaws may provide.  In addition to such special meetings as are provided by
law or this  Restated  Certificate  of  Incorporation,  special  meetings of the
stockholders  may be called  only by (a) the Board of  Directors  pursuant  to a
resolution  adopted by a majority of the Board of Directors then in office,  (b)
the  Chairman of the Board,  (c) the  President  of the  Corporation  or (d) the
holders of not less than 30% of the total voting power of all shares of stock of
the Corporation entitled to vote in the election of directors.  The books of the
Corporation  may be kept  (subject to any  provision  contained in the statutes)
outside the State of Delaware at such place(s) as may be designated from time to
time by the Board of Directors or in the Bylaws of the Corporation.

                                  ARTICLE VII

                          LIMITED DIRECTOR LIABILITY

      A  director  of the  corporation  shall  not be  personally  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
omissions  not in good  faith  or which  involved  intentional  misconduct  or a
knowing  violation  of law,  (iii) under  Section  174 of the DGCL for  unlawful
payment  of  dividends  or  improper  redemption  of  stock,  or  (iv)  for  any
transaction from which the director derived an improper personal benefit. If the
DGCL is hereafter amended to authorize the further  elimination or limitation of
the liability of directors, then the liability of a director of the Corporation,
in addition to the limitation on personal  liability  provided herein,  shall be
limited to the fullest extent  permitted by the DGCL, as amended.  Any repeal or
modification of this paragraph by the  stockholders of the Corporation  shall be
prospective  only, and shall not adversely affect any limitation on the personal
liability of a director of the  Corporation  existing at the time of such repeal
or modification.

                                 ARTICLE VIII

                                INDEMNIFICATION

      A.    Mandatory Indemnification

      Each person who at any time is or was a director of the  Corporation,  and
is threatened to be or is made a party to any  threatened,  pending or completed
action, suit or proceeding, whether civil, criminal, administrative, arbitrative
or investigative (a "Proceeding"),  by reason of the fact that such person is or
was a director  of the  Corporation,  or is or was serving at the request of the
Corporation  as a director,  officer,  partner,  venturer,  proprietor,  member,
employee,  trustee,  agent or similar functionary of another domestic or foreign
corporation,  partnership,  joint venture, sole proprietorship,  trust, employee
benefit plan or other for-profit or non-profit enterprise,  whether the basis of
a Proceeding is alleged action in such person's  official capacity or in another
capacity while holding such office,  shall be  indemnified  and held harmless by
the  Corporation  to the fullest  extent  authorized  by the DGCL,  or any other
applicable  law as may from time to time be in effect  (but,  in the case of any
such  amendment  or  enactment,  only to the extent that such  amendment  or law
permits the Corporation to provide broader  indemnification rights than such law
prior to such  amendment or enactment  permitted  the  Corporation  to provide),
against all expense,  liability and loss (including,  without limitation,  court
costs and attorneys'  fees,  judgments,  fines,  excise taxes or penalties,  and
amounts paid or to be paid in settlement)  actually and  reasonably  incurred or
suffered   by  such  person  in   connection   with  a   Proceeding,   and  such
indemnification shall continue as to a person who has ceased to be a director of
the Corporation or a director, officer, partner, venturer,  proprietor,  member,
employee,  trustee,  agent or similar functionary of another domestic or foreign
corporation,  partnership,  joint venture, sole proprietorship,  trust, employee
benefit plan or other  for-profit or non-profit  enterprise,  and shall inure to
the  benefit  of  such  person's  heirs,   executors  and  administrators.   The
Corporation's

                                     -3-

<PAGE>



obligations under this Section A include,  but are not limited to, the convening
of any meeting, and the consideration of any matter thereby, required by statute
in order to determine the eligibility of any person for indemnification.

      B.    Prepayment of Expenses

      Expenses  incurred  by a  director  of  the  Corporation  in  defending  a
Proceeding shall be paid by the Corporation in advance of the final  disposition
of such  Proceeding to the fullest  extent  permitted by, and only in compliance
with,  the DGCL or any  other  applicable  laws as may  from  time to time be in
effect, including, without limitation, any provision of the DGCL which requires,
as a  condition  precedent  to such  expense  advancement,  the  delivery to the
Corporation of an  undertaking,  by or on behalf of such director,  to repay all
amounts so advanced if it shall  ultimately be determined  that such director is
not  entitled  to be  indemnified  under  Section  A of  this  Article  VIII  or
otherwise.  Repayments  of all amounts so advanced  shall be upon such terms and
conditions, if any, as the Corporation's Board of Directors deems appropriate.

      C.    Vesting

      The  Corporation's  obligation to indemnify and to prepay  expenses  under
Sections A and B of this Article VIII shall arise, and all rights granted to the
Corporation's  directors  hereunder shall vest, at the time of the occurrence of
the transaction or event to which a Proceeding  relates, or at the time that the
action or conduct to which such Proceeding relates was first taken or engaged in
(or omitted to be taken or engaged in),  regardless  of when such  Proceeding is
first threatened, commenced or completed. Notwithstanding any other provision of
this Certificate of  Incorporation  or the Bylaws of the Corporation,  no action
taken  by  the   Corporation,   either  by  amendment  of  this  Certificate  of
Incorporation  or the Bylaws of the Corporation or otherwise,  shall diminish or
adversely affect any rights to indemnification or prepayment of expenses granted
under  Sections A and B of this Article  VIII which shall have become  vested as
aforesaid  prior to the date that such  amendment or other  corporate  action is
effective or taken, whichever is later.

      D.    Enforcement

      If a claim under  Section A or Section B or both  Sections A and B of this
Article  VIII is not  paid in full by the  Corporation  within  30 days  after a
written claim has been received by the Corporation, the claimant may at any time
thereafter  bring  suit  in  a  court  of  competent  jurisdiction  against  the
Corporation  to recover  the unpaid  amount of the claim and, if  successful  in
whole or in part,  the claimant shall also be entitled to be paid the expense of
prosecuting  such  claim.  It shall be a defense to any such suit  (other than a
suit  brought  to  enforce  a claim  for  expenses  incurred  in  defending  any
Proceeding in advance of its final disposition  where the required  undertaking,
if any is required,  has been tendered to the Corporation) that the claimant has
not met the  standards of conduct  which make it  permissible  under the DGCL or
other  applicable law to indemnify the claimant for the amount claimed,  but the
burden of proving such defense shall be on the  Corporation.  The failure of the
Corporation  (including its Board of Directors,  independent  legal counsel,  or
stockholders)  to have made a  determination  prior to the  commencement of such
suit as to whether indemnification is proper in the circumstances based upon the
applicable  standard  of conduct set forth in the DGCL or other  applicable  law
shall  neither be a defense to the  action  nor  create a  presumption  that the
claimant has not met the applicable standard of conduct.  The termination of any
Proceeding by judgment,  order, settlement,  conviction,  or upon a plea of nolo
contendere or its equivalent,  shall not, of itself,  create a presumption  that
the  person  did  not  act in good  faith  and in a  manner  which  such  person
reasonably  believed  to be in or not  opposed  to  the  best  interests  of the
Corporation,  and, with respect to any criminal Proceeding, had reasonable cause
to believe that his conduct was unlawful.

      E.    Nonexclusive

      The  indemnification  provided  by this  Article  VIII shall not be deemed
exclusive of any other rights to which a person seeking  indemnification  may be
entitled  under any statute,  bylaw,  other  provisions of this  Certificate  of
Incorporation,  agreement,  vote of stockholders or  disinterested  directors or
otherwise, both as to action in such person's official capacity and as to action
in another capacity while holding such office.

                                     -4-

<PAGE>



      F.    Permissive Indemnification

      The  rights  to  indemnification  and  prepayment  of  expenses  which are
conferred  to the  Corporation's  directors  by Sections A and B of this Article
VIII may be conferred upon any officer, employee or agent of the Corporation if,
and to the extent, authorized by the Board of Directors.

      G.    Insurance

      The Corporation  shall have power to purchase and maintain  insurance,  at
its expense, on behalf of any person who is or was a director, officer, employee
or  agent  of the  Corporation,  or is or was  serving  at  the  request  of the
Corporation  as a director,  officer,  partner,  venturer,  proprietor,  member,
employee,  trustee,  agent or similar functionary of another domestic or foreign
corporation,  partnership,  joint venture, sole proprietorship,  trust, employee
benefit plan or other for-profit or non-profit  enterprise  against any expense,
liability  or loss  asserted  against such person and incurred by such person in
any such capacity,  or arising out of such person's  status as such,  whether or
not the  Corporation  would have the power to indemnify such person against such
expense,  liability or loss under the  Corporation's  Bylaws,  the provisions of
this Article VIII, the DGCL or other applicable law.

                                  ARTICLE IX

                                  COMPROMISE

      Whenever a compromise or arrangement is proposed  between this Corporation
and its creditors or any class of them and/or between this  Corporation  and its
stockholders  or any class of them, any court of equitable  jurisdiction  within
the  State  of  Delaware  may,  on the  application  in a  summary  way of  this
Corporation or of any creditor or stockholder  thereof or on the  application of
any receiver or receivers appointed for this Corporation under the provisions of
section 291 of Title 8 of the Delaware Code or on the application of trustees in
dissolution or of any receiver or receivers appointed for this Corporation under
the provisions of section 279 of Title 8 of the Delaware Code order a meeting of
the  creditors or class of  creditors,  and/or of the  stockholders  or class of
stockholders  of this  Corporation,  as the case may be, to be  summoned in such
manner  as  the  said  court  directs.  If a  majority  in  number  representing
three-fourths  in value of the  creditors or class of  creditors,  and/or of the
stockholders or class of stockholders of this  Corporation,  as the case may be,
agree  to any  compromise  or  arrangement  and to any  reorganization  of  this
Corporation  as  consequence  of  such  compromise  or  arrangement,   the  said
compromise or arrangement  and the said  reorganization  shall, if sanctioned by
the court to which the said  application  has been  made,  be binding on all the
creditors  or  class  of  creditors,  and/or  on all  stockholders  or  class of
stockholders,  of  this  Corporation,  as the  case  may  be,  and  also on this
Corporation.


                                     -5-

<PAGE>



      IN WITNESS WHEREOF, Argus  Pharmaceuticals,  Inc. has caused this Restated
Certificate of  Incorporation to be signed by its Vice President and attested to
by its Secretary and Controller this 24th day of June, 1992.



                                          /s/ Kenneth M. Cohen
                                              ----------------
                                          Kenneth M. Cohen,

                                          Vice President


Acknowledged this 24th day of June, 1992.


/s/ Terance A. Murnane
Terance A. Murnane,
Secretary and Controller



STATE OF TEXAS          ss.
                        ss.
COUNTY OF HARRIS        ss.

      I, Rosa L. Williams, a notary public, in and for Harris County,  Texas, do
hereby  certify  that on this the 24th day of June,  1992,  personally  appeared
before me, Kenneth M. Cohen, who being by me duly sworn, declared that he is the
person who signed the foregoing  Restated  Certificate of Incorporation of Argus
Pharmaceuticals,  Inc. as Vice President of Argus Pharmaceuticals,  Inc., as the
act and deed of such corporation,  and that the statements contained therein are
true.

      GIVEN UNDER MY HAND AND SEAL OF OFFICE, this the 24th day of June, 1992.



                                          /s/ Rosa L. Williams
                                              ----------------
                                          Notary Public in and for the
                                          State of Texas

                                     -6-

<PAGE>



                           CERTIFICATE OF AMENDMENT
                                      TO
               AMENDED AND RESTATED CERTIFICATE OF INCORPORATION
                                      OF
                          ARGUS PHARMACEUTICALS, INC.


      Argus  Pharmaceuticals,  Inc., a corporation  organized and existing under
and by virtue of the  General  Corporation  Law of the  State of  Delaware  (the
"Corporation"),

DOES HEREBY CERTIFY:

      FIRST:  That a  meeting  of the  Board of  Directors  of the  Corporation,
resolutions were duly adopted setting forth a proposed  amendment of the Amended
and Restated  Certificate of Incorporation  of the  Corporation,  declaring said
amendment  to be  advisable  and  calling a meeting of the  stockholders  of the
Corporation for consideration thereof.
The resolution setting forth the proposed amendment is as follows:

      RESOLVED,  that the Amended and Restated  Certificate of  Incorporation of
      the  Corporation  be amended to change  each of Article I,  Article IV and
      Article V thereto, so that as amended,

      Article I shall be and read as follows:

                                   ARTICLE I
                                     NAME

      The name of the Corporation is Aronex Pharmaceuticals, Inc.

      Article IV shall be and read as follows:

                                  ARTICLE IV
                                 CAPITAL STOCK

      A.    Classes of Stock

            The total number of shares of all classes of capital  stock that the
      Corporation  shall be authorized to issue is  85,000,000  shares,  divided
      into the following:  (i) 10,000,000  shares of preferred  stock, par value
      $.001 per share ("Preferred  Stock"), and (ii) 75,000,000 shares of common
      stock, par value $.001 per share ("Common Stock").

      B.    Preferred Stock

            Shares of Preferred  Stock may be issued from time to time in one or
      more series. The Board of Directors is hereby vested with the authority to
      fix by  resolution  the powers,  designations,  preferences  and relative,
      participating,  optional  and  other  special  rights  of each  series  of
      Preferred  Stock,  including,   without  limitation,  the  dividend  rate,
      conversion  rights,  voting  rights,   redemption  price  and  liquidation
      preference,  and the  qualifications,  limitations or restrictions on such
      preferences and/or rights and to fix the number of shares constituting any
      such series. Unless otherwise provided by the resolution(s) adopted by the
      Board of  Directors  providing  for the issue of any  series of  Preferred
      Stock,  the number of shares  comprising  such series may be  increased or
      decreased (but not below the number of shares then  outstanding) from time
      to time by duly adopted resolution(s) of the Board of Directors.


                                     -1-

<PAGE>



      C.    Common Stock

            Except  as   otherwise   provided  in  this   Amended  and  Restated
      Certificate  of  Incorporation  or by law or by the  resolution(s)  of the
      Board of Directors  providing for the issue of any series of the Preferred
      Stock,  each holder of Common Stock shall be entitled to one vote for each
      share  held.  Subject to all of the rights of the  Preferred  Stock or any
      series  thereof,  the  holders of the Common  Stock  shall be  entitled to
      receive,  when and as  declared  by the Board of  Directors,  out of funds
      legally available therefor, dividends payable in cash, stock or otherwise.
      Upon  any  liquidation,  dissolution  or  winding  up of the  Corporation,
      whether  voluntary or involuntary,  and after the holders of the Preferred
      Stock of each  series  shall  have been paid in full the  amounts to which
      they respectively shall be entitled, or a sum sufficient for such payments
      in full  shall  have  been set  aside,  the  remaining  net  assets of the
      Corporation  shall be  distributed  pro rata to the  holders of the Common
      Stock in accordance with their respective rights and interest.

      Article V shall be and read as follows:

                                   ARTICLE V
                              BOARD OF DIRECTORS

      A.    Classification

            Except as otherwise provided by law, the business and affairs of the
      Corporation  shall be managed by, or under the  direction of, its Board of
      Directors.  The Board of Directors  shall be divided  into three  classes,
      Class I, Class II and Class III,  which shall be as nearly equal in number
      as possible.  At the annual meeting of stockholders to be held in 1995, or
      any special  meeting  held in lieu  thereof,  Class I  Directors  shall be
      elected for a term expiring at the annual  meeting of  stockholders  to be
      held in 1998,  Class II Directors  shall be elected for a term expiring at
      the  annual  meeting  of  stockholders  to be held in 1997,  and Class III
      Directors  shall be elected for a term  expiring at the annual  meeting of
      stockholders  to be held in 1996,  with each director to hold office until
      his or her successor is elected and  qualified.  At each annual meeting of
      stockholders  subsequent  to  1995,  the  successor(s)  of  the  class  of
      directors  whose term expires at that annual  meeting  shall be elected to
      hold office for a term expiring at the annual meeting of  stockholders  to
      be held in the third year following the year of such director's  election.
      None of the directors  need be a stockholder or a resident of the State of
      Delaware.  The election of directors  need not be by written ballot unless
      so  provided  in the  Corporation's  Bylaws.  No decrease in the number of
      directors  constituting  the Board of Directors  shall shorten the term of
      any  incumbent  director.  Any newly  created or  eliminated  directorship
      resulting from an increase or decrease in the Board of Directors  shall be
      appointed by the Board of Directors  among the three  classes of directors
      so as to maintain such classes as nearly equal as possible. In furtherance
      and not in limitation of the rights, powers,  privileges and discretionary
      authority  conferred by the DGCL,  or other  applicable  law, the Board of
      Directors is expressly  authorized to adopt, amend or repeal the Bylaws of
      the Corporation.

      B.    Vacancies

            Except  as  otherwise  provided  for in this  Amended  and  Restated
      Certificate  of  Incorporation,  vacancies  resulting  from  newly-created
      directorships,  death, resignation, removal or other cause shall be filled
      only by the affirmative vote of a majority of the remaining directors then
      in office, even though less than a quorum of the Board of Directors, or by
      a sole remaining  director.  Any director  elected in accordance  with the
      preceding  sentence of this Article V shall hold office for the  remainder
      of the full term of the class of directors  in which the new  directorship
      was created or the vacancy occurred until such director's  successor shall
      have been elected and qualified.


                                     -2-

<PAGE>



      C.    Removal

            Any  director  may be removed from office only for cause and only by
      either the  affirmative  vote of a majority  of the  continuing  directors
      other than such director, or by the affirmative vote of the holders of 80%
      of the then  outstanding  shares of each class of stock of the Corporation
      having voting power for the election of directors.

      SECOND: That thereafter, pursuant to resolution of its Board of Directors,
a special  meeting of the  stockholders  of the  Corporation was duly called and
held, upon notice in accordance with Section 222 of the General  Corporation law
of the State of Delaware  at which  meeting  the  necessary  number of shares as
required by statute were voted in favor of the amendment.

     THIRD:  That  said  amendment  was  duly  adopted  in  accordance  with the
provisions  of  Section  242 of the  General  Corporation  Law of the  State  of
Delaware.

      IN WITNESS  WHEREOF,  the  Corporation  has caused this  certificate to be
signed by David M. Leech, its President and Chief Executive  Officer and Terance
A. Murnane, its Controller and Secretary, this 11th day of September, 1995.


                                          /s/ David M. Leech
                                              --------------
                                          David M. Leech, President
                                            and Chief Executive Officer


ATTEST:/s/ Terance A. Murnane
           ------------------
         Terance A. Murnane,
         Controller and Secretary


                                     -3-

<PAGE>



                           CERTIFICATE OF AMENDMENT
                                      OF
              AMENDED AND RESTATED CERTIFICATE OF INCORPORATION
                                      OF
                         ARONEX PHARMACEUTICALS, INC.


     Aronex  Pharmaceuticals,  Inc. (the "Corporation"),  organized and existing
under and by virtue of the General Corporation Law of the State of Delaware (the
"DGCL") does hereby certify:

      FIRST:  That the  Board  of  Directors  of the  Corporation  duly  adopted
resolutions  setting forth the  following  amendment to the Amended and Restated
Certificate of Incorporation of the Corporation (the "Amendment"), declaring the
Amendment  to be  advisable  and  calling  for the  submission  of the  proposed
Amendment to the stockholders of the Corporation for consideration  thereof. The
resolution setting forth the proposed Amendment is as follows:

      ARTICLE IV of the Amended and Restated  Certificate  of  Incorporation  of
Aronex  Pharmaceuticals,  Inc.,  a Delaware  corporation,  is hereby  amended by
adding thereto new Section D to read as follows:

      D. Reverse Split

      (i)Effective  immediately upon the filing of this Amendment to the Amended
and Restated  Certificate  of  Incorporation  in the office of the  Secretary of
State of the State of Delaware,  each outstanding  share of previously  existing
Common Stock shall be and hereby is converted into and  reclassified as one-half
of a share of Common Stock; provided,  however, that fractional shares of Common
Stock will not be issued and each holder of a  fractional  share of Common Stock
shall receive in lieu thereof a cash payment from the Corporation  determined by
multiplying  such  fractional  share of Common  Stock by two  times the  average
closing  price of a share of  previously  existing  Common  Stock on the  Nasdaq
National  Market for the five trading days  immediately  preceding the effective
date,  and upon such other terms as the  officers of the  Corporation,  in their
sole  discretion,  deem  to be  advisable  and  in  the  best  interests  of the
Corporation.

      (ii) Certificates representing reclassified shares are hereby canceled and
upon presentation of the canceled  certificates to the Corporation,  the holders
thereof shall be entitled to receive certificate(s)  representing the new shares
into which such canceled shares have been converted.

      SECOND:  That  thereafter  pursuant  to  a  resolution  of  the  Board  of
Directors,  a special  meeting of the  stockholders  of the Corporation was duly
called and held, upon notice in accordance with Section 222 of the DGCL at which
meeting the  necessary  number of shares as  required  by statute  were voted in
favor of the Amendment.

     THIRD:  That  the  Amendment  was  duly  adopted  in  accordance  with  the
provisions of Section 242 of the DGCL.

     FOURTH:  That the Amendment shall be effective on the date this Certificate
of  Amendment  is filed and  accepted by the  Secretary of State of the State of
Delaware.



                                     -1-

<PAGE>



      IN WITNESS  WHEREOF,  the  Corporation  has caused this  certificate to be
signed by James M. Chubb, its President, and attested by Terance A. Murnane, its
Secretary, this 28th day of June, 1996.


                                    ARONEX PHARMACEUTICALS, INC.



                                    By:   /s/ James M. Chubb
                                              --------------
                                          James M. Chubb
                                          President


Attest:/s/ Terance A. Murnane
           ------------------
      Terance A. Murnane
      Secretary

                                     -2-

<PAGE>




                           CERTIFICATE OF AMENDMENT
                                      OF
              AMENDED AND RESTATED CERTIFICATE OF INCORPORATION
                                      OF
                         ARONEX PHARMACEUTICALS, INC.


     Aronex  Pharmaceuticals,  Inc. (the "Corporation"),  organized and existing
under and by virtue of the General Corporation Law of the State of Delaware (the
"DGCL") does hereby certify:

      FIRST:  That the  Board  of  Directors  of the  Corporation  duly  adopted
resolutions  setting forth the  following  amendment to the Amended and Restated
Certificate of Incorporation of the Corporation (the "Amendment"), declaring the
Amendment  to be  advisable  and  calling  for the  submission  of the  proposed
Amendment to the stockholders of the Corporation for consideration  thereof. The
resolution setting forth the proposed Amendment is as follows:

      ARTICLE IV of the Amended and Restated  Certificate  of  Incorporation  of
Aronex  Pharmaceuticals,  Inc.,  a Delaware  corporation,  is hereby  amended by
deleting Section A, and inserting the following as Section A:

      A. Classes of Stock

         The  number  of  shares  of all  classes  of  capital  stock  that  the
Corporation shall be authorized to issue is 35,000,000 shares,  divided into the
following:  (i) 5,000,000  shares of preferred  stock, par value $.001 per share
("Preferred Stock"), and (ii) 30,000,000 shares of common stock, par value $.001
per share ("Common Stock")

      SECOND:  That  thereafter  pursuant  to  a  resolution  of  the  Board  of
Directors,  a special  meeting of the  stockholders  of the Corporation was duly
called and held, upon notice in accordance with Section 222 of the DGCL at which
meeting the  necessary  number of shares as  required  by statute  were voted in
favor of the Amendment.

     THIRD:  That  the  Amendment  was  duly  adopted  in  accordance  with  the
provisions of Section 242 of the DGCL.

     FOURTH:  That the Amendment shall be effective on the date this Certificate
of  Amendment  is filed and  accepted by the  Secretary of State of the State of
Delaware.

      IN WITNESS  WHEREOF,  the  Corporation  has caused this  certificate to be
signed by James M. Chubb, its President, and attested by Terance A. Murnane, its
Secretary, this 14th day of May, 1997.


                              ARONEX PHARMACEUTICALS, INC.



                              By:   /s/ James M. Chubb
                                        --------------
                                    James M. Chubb
                                    President

ATTEST:/s/ Terance A. Murnane
           ------------------
          Terance A. Murnane
          Secretary