Ixion Biotechnology, Inc.

                            1994 Board Retainer Plan
                     as amended March 22, 1999 and June 27, 1997

         1. Purpose of Plan. The purpose of the Ixion  Biotechnology,  Inc. 1994
Board  Retainer  Plan  (the  "Plan")  is to  provide  a  means  by  which  Ixion
Biotechnology,  Inc. (the  "Company") may attract and retain Outside  Directors,
Members of the Scientific  Advisory  Board,  and certain key employees,  and key
consultants by providing  those  personnel with an opportunity to participate in
the  growth,  development  and  financial  success of the  Company  which  their
efforts, initiative, and skill have helped produce.

         2.  Definitions.  Wherever the following  capitalized terms are used in
the Plan, they shall have the following respective meaning:

         2.1 "Award" means a grant of fully-paid  and  non-assessable  shares of
Common Stock under the Plan.

         2.2 "Board of Directors" means the board of directors of the Company.

         2.3 "Change in Control" shall be deemed to have occurred if:

                  (a) any "person"  (as such term is used in Sections  13(d) and
14(d) of the  Exchange  Act),  other than a trustee or other  fiduciary  holding
securities  under an employee benefit plan of the Company,  a corporation  owned
directly or indirectly by the stockholders of the Company in  substantially  the
same proportions as their ownership of the Common Stock, becomes the "beneficial
owner"  (as  defined  in  Rule  13d-3  under  the  Exchange  Act),  directly  or
indirectly,  of securities of the Company  representing 50% or more of the total
voting power represented by the Company's then outstanding securities which vote
generally  in  the  election  of  Directors   (referred  to  herein  as  "Voting
Securities"); or

                  (b) during any period of two  consecutive  years,  individuals
who at the  beginning of such period  constitute  the Board of Directors and any
new  Directors  whose  election  by the Board of  Directors  or  nomination  for
election  by the  Company's  stockholders  was  approved  by a vote of at  least
two-thirds (2/3) of the Directors then still in office who either were Directors
at the beginning of the period or whose  election or nomination for election was
previously so approved,  cease for any reason to constitute a majority  thereof;
or



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                  (c) the  stockholders  of the  Company  approve  a  merger  or
consolidation  of the  Company  with any other  entity,  other  than a merger or
consolidation  which  would  result  in the  voting  securities  of the  Company
outstanding  immediately  prior  thereto  continuing  to  represent  (either  by
remaining  outstanding or by being converted into voting securities of surviving
entity)  more then 50% of the  total  voting  power  represented  by the  voting
securities of the Company or such surviving entity outstanding immediately after
such merger or consolidation; or

                  (d) the stockholders of the Company approve a plan of complete
liquidation  of the Company or an agreement for the sale or  disposition  by the
Company of (in one transaction or a series of transactions) all or substantially
all of the Company's assets.

         2.4 "Committee" means the Audit and Benefits Committee of the Company.

         2.5  "Common Stock" means the Common Stock of the Company, par value 
              $0.01 per share.

         2.6  "Company" means Ixion Biotechnology, Inc., a Delaware corporation.

         2.7  "Director"  or "Outside  Director"  means a member of the Board of
              Directors who is not an officer or employee of the Company.

         2.8 "Disability" or "disabled"  means,  with respect to a Participant a
physical or mental condition resulting from any medically  determinable physical
or mental  impairment  that  renders  such person  incapable  of engaging in any
substantial  gainful  employment  and that can be expected to result in death or
that has lasted or can be expected to last for a  continuous  period of not less
than six consecutive months.

         2.9 "Exchange  Act" means the  Securities  Exchange  Action of 1934, as
amended.

         2.10 "Fair Market  Value" means the per share value of the Common Stock
as of a given date, determined as follows:

                  (a) If the Common  Stock is listed or admitted  for trading on
any national securities  exchange,  the Fair Market Value of the Common Stock is
the closing  quotation  for such stock on the day  preceding  such date,  or, if
shares  were  not  traded  on the day  preceding  such  date,  then on the  next
preceding trading day during which a sale occurred.

                  (b)  If  the  Common  Stock  is not  traded  on  any  national
securities  exchange,  but is quoted on the National  Association  of Securities
Dealers,  Inc. Automated  Quotation System (Nasdaq System) or any similar system
of  automated  dissemination  of  quotations  of prices in common use,  the Fair
Market  Value of the Common  Stock is the last sales price (if the stock is then
listed as a national  market issue under the Nasdaq  System) or the mean between
the closing  representative  bid and asked  prices (in all other  cases) for the
stock on the day  preceding  such date as  reported  by Nasdaq  System  (or such
similar quotation system).



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                  (c) If neither  clause (a) nor clause (b) of this  Section 2.9
is  applicable,  the Fair  Market  Value of the Common  Stock is the fair market
value  per  share as of such  valuation  date,  as  determined  by the  Board of
Directors in good faith and in accordance with uniform  principles  consistently
applied. Such Fair Market Value shall be determined on a regular basis, not less
than annually.

         2.11  "Member of the Scientific Advisory Board" means a member of the 
               Company's Scientific Advisory Board.

         2.12  "Officer"  means an  officer of the  Company,  as defined in Rule
               16a-1(f) under the Exchange Act, as such rule may be amended 
               from time to time.

         2.13  "Participant"  means an  Director,  or Member  of the  Scientific
               Advisory  Board,  key  employee,  or key  consultant to whom an 
               award is granted under this Plan.

         2.14  "Plan" means the Ixion Biotechnology, Inc. 1994 Board Retainer 
               Plan, as it may be amended from time to time.

         2.15 "Rule 16b-3" means Rule 16b-3  promulgated under the Exchange Act,
              as such rule may be amended from time to time.

         2.16  "Secretary" means the Secretary of the Company.

         2.17 "Securities Act" means the Securities Act of 1933, as amended.

         2.18 "Termination of Relationship"  means with respect to any Director,
Member of the Scientific  Advisory Board, or employee,  or consultant,  the time
when such person  ceases to be a  Director,  Member of the  Scientific  Advisory
Board, or employee, or consultant of the Company for any reason, with or without
cause,  including  without  limitation,  a termination by resignation,  removal,
death,  disability,  or failure to be nominated  or  reelected by the  Company's
stockholders.  Nothing in this Plan shall confer upon any such person  Director,
Member of the Scientific Advisory Board, or employee,  any right to continue his
or her  association  with the Company or shall interfere with or restrict in any
way the rights of the Company and its  stockholders,  which are hereby expressly
reserved, to remove any such person at any time for any reason whatsoever,  with
or without cause.

         3.  Stock Subject to Plan.

         3.1 Stock  Subject  to Plan.  The stock  subject  to an Award  shall be
shares of the Company's Common Stock. The aggregate number of such shares issued
and outstanding  Directors or Members of the Scientific  Advisory Board pursuant
to Awards shall not exceed 250,000.



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         3.2  Changes  in  Company  Capitalization.  In the  event  that (i) the
outstanding shares of Common Stock are hereafter changed into or exchanged for a
different  number or kind of shares or other  securities  of the Company,  or of
another   entity,   by  reason   of   reorganization,   merger,   consolidation,
recapitalization, reclassification, or (ii) the number of shares is increased or
decreased by reason of a stock split,  stock dividend,  combination of shares or
any other  increase or  decrease  in the number of such  shares of Common  Stock
effected  without receipt of consideration  by the Company  (provided,  however,
that conversion or exchange of any convertible or exchangeable securities of the
Company  shall  not  be  deemed  to  have  been  "effected  without  receipt  of
consideration"),  then the Committee shall make  appropriate  adjustments in the
number and kind of shares  available for Awards,  including  adjustments  to the
limitations in Section 3.1 on the maximum number and kind of shares which may be
issued and outstanding pursuant to Awards.

         4.  Granting of Awards

         4.1  Eligibility.  Any  serving  Outside  Director  or,  Member  of the
Scientific  Advisory  Board,  and any or newly-hired key employee or consultant,
shall be eligible for Awards.

         4.2  Grants.  Each  person who is an Outside  Director or Member of the
Scientific  Advisory  Board of the  Company at the date of the  adoption of this
Plan  shall be  granted an Award of 5,000  shares of Common  Stock.  Thereafter,
immediately  following the Annual  Meeting of the Company,  the Committee  shall
grant a further  Award of 1,000 shares of Common Stock to each  Participant  (so
long as he or she is an Outside  Director or Member of the  Scientific  Advisory
Board on each such date).  Employees and  consultants  may be granted  Awards in
connection with employment or otherwise upon recommendation by the Committee and
approval by the Board.

         4.3  Administration of the Plan.

                  (a) The  Plan  shall be  administered  by the  Committee.  The
Committee  shall  consist of at least two Outside  Directors (if there are such)
selected by the Board of Directors.  Committee  members may resign by delivering
written notice to the Secretary.  Vacancies on the Committee  shall be filled by
the Board of Directors.



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                  (b)  Except as  otherwise  provided  in the Plan and except as
otherwise  expressly  stated to the  contrary in the  Company's  Certificate  of
Incorporation,   Bylaws,  or  elsewhere,  the  Committee  shall  have  the  sole
discretionary authority (i) to impose such conditions and restrictions on Awards
as it determines  appropriate,  (ii) to interpret the Plan,  (iii) to prescribe,
amend, and rescind rules and regulations relating to the Plan, (iv) to determine
Fair Market Value in accordance  with Section 2.9 (c), and (v) to take any other
actions in  connection  with the Plan and to make all  determinations  under the
Plan as it may deem necessary or advisable for the  administration  of the Plan.
The determinations of the Committee on the matters referred to in this Section 4
shall be binding and conclusive on all persons.

                  (c)  A  majority  of  the  members  of  the  Committee   shall
constitute a quorum.  All  determinations  of the  Committee  shall be made by a
majority of its members.  Any decision or  determination  reduced to writing and
signed by all of the members of the Committee  shall be fully effective as if it
had been made by a majority vote at a meeting duly called and held.

                  (d) The  Committee  may delegate to one or more persons any of
its powers,  or designate  one or more persons to do or perform those matters to
be done or performed by the Committee, including administration of the Plan. Any
person or persons  delegated or designated by the Committee  shall be subject to
the same obligations and  requirements  imposed on the Committee and its members
under the Plan.

                  (e) Members of the Committee  shall receive such  compensation
for their  services as members as may be  determined  by the Board of Directors.
All expenses and liabilities  incurred by members of the Committee in connection
with the administration of the Plan shall be borne by the Company. The Committee
may employ attorneys,  consultants,  accountants,  appraisers, brokers, or other
persons.  The Committee,  the Company,  and its Officers and Directors  shall be
entitled to rely upon the advice,  opinions,  or valuations of any such persons.
All  elections  taken and all  interpretations  and  determinations  made by the
Committee  in good faith shall be final and binding upon all  Participants,  the
Company,  and all other interested  persons. No member of the Committee shall be
personally liable for any action,  determination or interpretation  made in good
faith with  respect to the Plan.  Members of the  Committee  and each  person or
persons   designed  or  delegated  by  the   Committee   shall  be  entitled  to
indemnification  by  the  Company  for  any  action  or  any  failure  to act in
connection  with  services  performed by or on behalf of the  Committee  for the
benefit of the  Company to the  fullest  extent  provided  or  permitted  by the
Company's  Certificate of Incorporation,  Bylaws, any insurance policy, or other
agreement intended for the benefit of the Committee, or by any applicable law.

         5.  Terms of Grants

         5.1 Grant  Agreement.  Each Grant shall be evidenced by a written Grant
Agreement  , which  shall be  signed  by the  Participant  and by an  authorized
Officer of the Company and which shall refer to such terms and conditions as the
Committee shall determine, consistent with the Plan.

         5.2 Issuance of Shares.  Participants shall be issued a certificate for
fully-paid  and  nonassessable  shares of Common  Stock for the number of shares
covered  by the Award,  which  certificate  may  contain a legend  referring  to
restrictions  on vesting and transfer and such other terms and conditions as the
Committee shall determine, consistent with the Plan.


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         5.3 Forfeiture of Unvested  Shares.  Shares which have been awarded but
not yet vested  under this  Section 5.3 shall be  forfeited  if the  Participant
ceases to be a Director,  Member of the Scientific  Advisory Board, or employee,
or consultant of the Company for any reason,  with or without  cause,  including
without limitation, a termination by resignation, removal, death, disability, or
failure to be  nominated  or reelected  by the  Company's  stockholders,  unless
provided  to the  contrary  in any Grant  Agreement  approved  by the  Committee
between the  Participant  and the  Company,  which  Agreement  shall  govern any
further vesting of shares pursuant to Awards.

         5.4 Fair Market Value.  The Company  shall provide to each  Participant
who  receives  an  Award  information  regarding  the Fair  Market  Value of the
Company's shares on the date such Award is granted.  Such  information  shall be
provided to permit the  Participant  to determine his or her federal  income tax
liability,  if any,  for such Award,  or to permit the  Participant  to make the
election contemplated by Section 78 of the Internal Revenue Code.

         5.5  Transfer Restrictions; Vesting.

                  (a) Unless otherwise approved in writing by the Committee,  no
shares of  Common  Stock  issued  pursuant  to an Award  may be sold,  assigned,
pledged,  encumbered,  or otherwise  transferred until (i) they have vested, and
(ii)  either  the  Company  has made an  offering  of its  shares to the  public
pursuant to a registration  statement under the Securities Act or there has been
a Change of Control of the Company,  except as may be provided in Section 5.5(c)
or as may  otherwise  be  provided  for in an  Grant  Agreement  which  has been
approved by the Committee. The Committee, in its absolute discretion, may impose
such other restrictions on the transferability of the shares granted pursuant to
an Award as it deems appropriate.  Any such other restriction shall be set forth
in the  respective  Grant  Agreement and may be referred to on the  certificates
evidencing such shares.

                  (b) Shares  issued to members  of the Board of  Directors,  or
employees,  or  consultants  pursuant to Awards shall vest 20% at the end of the
first year of service  after the date of the Award and 1/12 of 20% at the end of
each month  thereafter.  Subject to the provisions of Sections 5.3, 5.5(c),  and
5.5(d),  Awards  shall  otherwise  become  vested  at  such  times  and in  such
installments  (which may be  cumulative)  as the Committee  shall provide in the
terms of each individual Grant Agreement;  provided, however, that by resolution
adopted  after an  Award  is  granted  the  Committee  may,  on such  terms  and
conditions  as it may determine to be  appropriate  and subject to Sections 5.3,
5.5(c),  and  5.5(d),  accelerate  the time at which such  Award or any  portion
thereof may be vested,  or such rights may be set forth in an agreement  between
the Participant and the Company which has been approved by the Committee. Shares
issued to members of the Scientific  Advisory Board shall vest 25% at the end of
each three months of service after the date of the award.



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                  (c) No portion of an Award which is unvested at Termination of
Relationship shall thereafter become vested;  provided,  however, that provision
may be made that such Award shall become vested in the event of a Termination of
Relationship  as may be determined by the  Committee,  or such rights may be set
forth in a Grant  Agreement  between the  Participant  and the Company which has
been approved by the Committee.

                  (d) Subject to the provisions of Section 5.5(a), the Committee
shall  provide,  in terms of each  individual  Grant  Agreement  when such Award
becomes  vested,  and (without  limiting the  generality of the  foregoing)  the
Committee may provide in the terms of individual  Grant Agreements that unvested
shares  shall be  forfeited  immediately  upon a  Termination  of  Relationship;
provided,  however,  that  provision  may be made that such shares  shall become
vested  in  the  event  of  a  Termination  of   Relationship   because  of  the
Participant's  retirement,  death, disability, or as may otherwise be determined
by the Committee.

         5.6 No Right to Continued Relationship.  Nothing in this Plan or in any
Grant Agreement issued hereunder shall confer upon any Participant, any right to
continue  his or her  association  with the Company or shall  interfere  with or
restrict in any way the rights of the Company  and its  stockholders,  which are
hereby expressly reserved,  to remove any such person at any time for any reason
whatsoever, with or without cause.

         6.  Additional Provisions.

         6.1 Nontransferability.  No unvested shares issued pursuant to an Award
or  interest  or right  therein or part  thereof  shall be liable for the debts,
contracts or  engagements  of the  Participant  or his successors in interest or
shall be subject to disposition by transfer, alienation,  anticipation,  pledge,
encumbrance,  assignment,  or  any  other  means  whether  such  disposition  be
voluntary or involuntary or by operation of law by judgment,  levy,  attachment,
garnishment or any other legal or equitable  proceedings  (including  bankruptcy
and divorce proceeding), and any attempted disposition thereof shall be null and
void and of no effect.



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         6.2 Securities Act. Upon issuance of Common Stock of the Company to the
Participant,  or his heirs, the recipient of that stock shall represent that the
shares of stock are taken for  investment  and not  resale  and shall  make such
other  representations as may be necessary to qualify the issuance of the shares
as exempt from the Securities Act and  applicable  federal and state  securities
laws and  regulations,  and shall  represent that he or she shall not dispose of
those shares in violation of the  Securities  Act or of  applicable  federal and
state securities laws and regulations. The Company reserves the right to place a
legend on any stock certificate issued pursuant to the Plan to assure compliance
with this  Section  and with the  vesting and  transferability  requirements  of
Section 5. No shares of Common  Stock of the  Company  shall be  required  to be
distributed  until the Company shall have taken such action,  if any, as is then
required to comply with the  provisions of the  Securities Act or any other then
applicable federal or state securities law or regulation.

         6.3 Withholding of Tax. The Company shall have the right to deduct from
any Award made under the Plan any federal,  state or local income or other taxes
required  by law to be  withheld  with  respect  to such  Award.  It  shall be a
condition to the obligation of the Company to deliver Common Stock upon an Award
that the  Participant  pay to the Company such amount as may be requested by the
Company for the purpose of satisfying any liability for such withholding  taxes.
Any grant  under this Plan may  provide by its terms  that the  Participant  may
elect, in accordance with any applicable regulations, to pay a portion or all of
the amount of such minimum required or additional permitted withholding taxes in
shares of Common Stock,  subject to the timing restrictions set forth in Section
6 hereof.  The  Participant  shall  authorize the Company to withhold,  or shall
agree to surrender  back to the Company,  on or about the date such  withholding
tax liability is  determinable,  shares of Common Stock previously owned by such
Participant  or a  portion  of the  shares  that  were  or  otherwise  would  be
distributed  to such  Participant  pursuant  to such award  having a Fair Market
Value equal to the amount of such required or permitted  withholding taxes to be
paid in shares.

         6.4  Termination  and Amendment of Plan.  The Committee may at any time
suspend or  terminate  the Plan,  or make such  modifications  of the Plan as it
shall deem advisable, provided that the Plan not be changed to increase the cost
of the Plan to the Company.  Notwithstanding  anything to the contrary contained
herein,  the  Committee  shall not amend or modify the Plan more than once every
six (6) months or in any other manner inconsistent with the requirements of Rule
16b-3(c)(2)(ii) except to the extent required by changes in the Internal Revenue
Code, the Employee  Retirement  Income  Security Act of 1974, or regulations and
rules issued  thereunder.  No termination or amendment of the Plan may,  without
the consent of a Participant,  adversely  affect the rights of such  Participant
notwithstanding  anything to the contrary herein. No Award may be granted during
any period of suspension of the Plan nor after  termination  of the Plan, and in
no event may any Award be granted under this Plan after August 30, 2004.

         6.5 Duties of the Company.  The Company  shall pay all  original  issue
taxes with  respect to the  issuance or delivery of shares  pursuant to an Award
and  all  other  fees  and  expenses  necessarily  incurred  by the  Company  in
connection therewith.

         6.6  Absence  of a  Committee.  Should the Board of  Directors  fail to
appoint the Committee or should there be no Committee for any other reason, then
the Plan shall be  administered  by the Board of Directors.  In the absence of a
Committee,  the  Board  of  Directors  (or that  portion  thereof  comprised  in
accordance  with this Section 6.6) shall have all the powers of the Committee as
set forth herein in administration of the Plan.

         7.  General Provisions.



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         7.1 No Rights.  Neither the adoption and  maintenance  of the Plan, the
granting of Awards  pursuant  to the Plan,  nor  issuance of shares  pursuant to
Awards  shall be deemed to  constitute  a contract  of  employment  between  the
Company  and any  Participant  or to be a  condition  of the  employment  of any
person. The Plan and any Awards granted under the Plan shall not confer upon any
Participant any right with respect to a continued relationship with the Company,
nor  shall  they  interfere  in any way with the  right  of the  Company  or its
shareholders to terminate the  relationship of any Participant  with the Company
at any time, and for any reason, with or without cause.

         7.2  Costs of  Administration.  The  Company  shall  pay all  costs and
expenses of administering the Plan.

         7.3 Controlling  Laws. The issuance of shares of Common Stock under the
Plan shall be subject to all applicable laws, rules and regulations, and to such
approvals by any governmental  agencies or national securities  exchanges as may
be required.  The  provisions of this Plan shall be  interpreted so as to comply
with the conditions and  requirements  of the Securities  Act, the Exchange Act,
and rules and regulations issued  thereunder,  including without limitation Rule
16b-3,  unless  a  contrary  interpretation  of any  such  provisions  otherwise
required by applicable law. Except to the extent  preempted by Federal law, this
Plan and all Stock  Option  Agreements  entered  into  pursuant  hereto shall be
construed  and  enforced in  accordance  with,  and governed by, the laws of the
State of Delaware, determined without regard to its conflict of laws rules.