PRELIMINARY OPPOSITION PROXY MATERIAL

                      ASSET VALUE FUND LIMITED PARTNERSHIP
                          376 MAIN STREET, P.O. BOX 74
                              BEDMINSTER, NJ 07921
                                 (908) 234-1881

                                                                     May__, 1998

Dear Fellow Cortech Stockholder:

     We and two other  investors  ("Asset Value") own  approximately  15% of the
ourstanding shares of Cortech, Inc. ("Cortech"), which makes us by far Cortech's
largest  stockholders.  In connection with the upcoming  Annual  Meeting,  Asset
Value is seeking your vote to elect its four nominees, who would then constitute
a majority of the Cortech  Board.1  Asset Value seeks to gain control of Cortech
because it believes that Cortech's Board has repeatedly exercised poor judgment.

     As you know,  Cortech lost over $77 million  through the end of fiscal 1996
attempting  to  exploit  its  technology.  Finally  in April of 1997,  the Board
announced that Cortech would cease operations and pursue strategic  alternatives
to use its remaining cash which as of December 31, 1997 was $15.4 million.

           Mirror, Mirror on the Wall, Who's the Fairest of Them All?

     Kenneth Lynn, CEO of Cortech, and the Board would have us believe that once
they  determined  that Cortech could not succeed as a stand-alone  entity,  they
scoured  the land for a merger  partner  and the  only  prospective  suitor  was
BioStar. BioStar, a company which lost almost ($2,000,000) in fiscal 1997 and by
the end of 1997 had a  negative  net  worth of  ($5,600,000).  After  the  Board
announced in December of 1997 that Cortech would merge with BioStar, Asset Value
warned the Board that Asset Value  believed the Merger was not in the  interests
of stockholders  who, Asset Value said,  would never approve such a transaction.
Notwithstanding this warning, the Board proceeded,  in Asset Value's opinion, to
waste a  substantial  portion of  Cortech's  remaining  resources on the Merger,
which  just as  Asset  Value  predicted,  failed,  in our  opinion,  for lack of
stockholder support.

                    We ask you. What will this Board do next?
    Don't take a chance. Vote for a change. Vote for Asset Value's nominees!

     Now it is time  for the  Annual  Meeting;  time  for  the  stockholders  to
re-evaluate  the past  leadership  of Cortech and time to consider a change.  We
believe that Asset Value has the same interests as all other  stockholders which
it believes will be a change from this management - a substantial change.

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     1    Cortech  has a staggered  board which means under the current  by-laws
that only two of the five  directors  must seek election this year.  Asset Value
seeks to amend the by-laws to increase  the size of the board from five to seven
and to elect its four  nominees  as  directors  to the four  vacancies  (the two
available  under  the  current  by-laws  and the two  vacancies  created  by the
proposed  amendment).  If successful,  Asset Value's nominees would constitute a
majority of the board.






                                  MORE RED INK!

     Cortech's  Form 10-Q  filed for the first  quarter  of 1998  reported  that
Cortech's  losses  not  only  continued  but  increased  compared  to last  year
($1,399,000  in 1998;  $897,000  in 1997).  In a quarter  with No  research  and
development  activities  and No revenues,  Cortech  still had  approximately  15
full-time2 employees and general and administrative  expenses of $1,522,000,  of
which,  according to Cortech,  merger expense only  accounted for  approximately
$673,000.  In the  aggregate,  Cortech has lost over $86 million as of March 31,
1998. In the face of these unabated losses,  Asset Value believes that the Board
still appears bent on maintaining  the status quo. In our view, it was this same
vacillating decision making that failed to staunch the hemorrhaging of Cortech's
stockholders  equity in the past and we  believe  that we should  not allow this
past to become the  future.  Vote for  Change:  Send in the White Proxy Card and
Vote for Asset Value's Nominees.

      WARNING: "Those who cannot remember the past are condemned to repeat
                                      it."3

     In our  opinion,  several  individuals  and  entities,  other then  Cortech
stockholders  would have  reaped the  benefits of the Merger  with  BioStar.  We
believe  that Mr.  Lynn stood to benefit  from the Merger  because it would have
triggered his golden  parachute  ($1,300,000  for him and others with  severance
agreements) and enabled him (and other Board members and executive  officers) to
exercise 623,535 options.  BioStar's  management would have received  additional
compensation  and options in  connection  with the Merger.  In fact, it seems to
Asset Value,  that every  participant  was to profit from the Merger  except the
public stockholders of Cortech, who would have suffered a dilution in book value
per  Cortech  share of 64% (from an  historical  $.83 to a pro forma $.30) while
BioStar  stockholders  would have enjoyed an  improvement  in book value from an
historical negative ($2.86) to a positive $.17 per share.

PLEASE  ASK  YOURSELF:

     DO YOU WANT THE BOARD MEMBERS WHO APPROVED THE BIOSTAR MERGER TO SELECT THE
NEXT MERGER CANDIDATE FOR CORTECH?

     IF THE ANSWER IS NO THEN  PLEASE  SEND THE WHITE  PROXY CARD TO ASSET VALUE
AND VOTE TO INCREASE THE BOARD AND TO ELECT ALL OF ASSET VALUE'S NOMINEES.



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     2    Cortech  does not  disclose  whether  there are  additional  part-time
employees and consultants still hanging on.

     3    The Life of Reason, (1905) George Santayana






               WOULD THE GODS GIVE US THE GIFT TO SEE OURSELVES AS
                                 OTHERS SEE US 4

     In connection with his support of the BioStar  transaction,  Lynn described
himself as a "fiduciary". Far from it in our view. Prior to the Merger proposal,
Lynn owned Cortech Shares worth less than $2,000 in the marketplace. As a result
of the Merger,  Lynn and others with severance  agreements  would have received:
(1)  payments of  $1,300,000;  (2) payment of premiums  for health  benefits for
eighteen months; and (3) the immediate vesting of 623,535 options.  Mr. Lynn was
also to continue as a director of the successor corporation after the Merger.

     Even before  approving the ill-fated  Merger with BioStar,  we believe that
the Cortech  Board and Mr. Lynn  ignored  the  growing  disparity  over the past
several  years  between the  interests  of Cortech's  management  and the public
stockholders'  interests.  The chart below reflects the  difference  between Mr.
Lynn's increasing compensation between 1993 and 1997 and the concomitant decline
of the market value of Cortech Shares.






                       GRAPH OF CORTECH'S HIGH STOCK PRICE AND LYNN'S
                                        COMPENSATION.

                                       1993        1994       1995       1996        1997
                                      ------      ------     ------     ------      ------
                                                                     
Cortech's High Stock Price            $18.25      $14.25     $3.65625    $3.8125    $2.03125
Lynn's Compensation                   $140,000    $181,744   $305,499    $330,006   $330,513


                                               NOT A PRETTY PICTURE!




     After Asset Value acquired its interest in Cortech in the fall of September
1997,  we asked the Cortech Board to elect a nominee of Asset Value to the Board
(only one on a five member Board). The Cortech Board, in effect,  refused,  then
the Cortech  Directors  approved a transaction  which,  in our view,  would have
negatively  affected all  stockholders.  They did this without  bothering to ask
for, or permit, the participation of Cortech's largest stockholder, Asset Value,
whose  interests,  clearly,  in  our  opinion,  are  more  matched  with  public
stockholders  than a Board which  collectively owns less than 2 1/2 % of Cortech
Common Stock.


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     4    An  anglicized  version of a  quotation  from the poem "To a Louse" by
Scottish poet Robert Burns.






                          THE SHAPE OF THINGS TO COME5

     Asset Value has only  considered  possible  alternatives  for the future of
Cortech in a preliminary  way and therefore it does not know with certainty that
there are  potential  acquisitions  or  Mergers  that  would be  attractive  for
Cortech.

     Asset Value has stated and  restates  here that it has no  specific  Merger
partner  in mind.  So,  what will Asset  Value do if it  obtains  control of the
Cortech Board? As we stated,  we believe that once the Cortech Board  determined
to change  control of Cortech,  it should have sought  competitive  transactions
more  aggressively,  by  advertising  in the  financial  media,  by  engaging an
investment  banker from the outset to solicit Merger  partners in the investment
community and by publicly  stating that the Board was conducting an open bidding
process for control of Cortech.  If elected  Asset  Value's  nominees  will take
these steps.  But as stated above,  there can be no assurance  that taking these
steps will  produce a  transaction  that will be  favorable  for Cortech and its
stockholders.

                               STOP THE RED INK !

     Paul  Koether of Asset  Value has  suggested  publicly  that a shutdown  of
Cortech is an  appropriate  alternative  which would leave Cortech with cash and
future tax  benefits  from past losses plus the  enticement  of publicly  traded
shares  that  could be a vehicle  for a private  company  to become  public.  He
recognizes   that  there  would  be  risks   associated  with  such  an  action,
particularly  that  Cortech  would no longer be an  "ongoing"  business  and the
possible  reduction  in the  value  of the  technology  because  of the  loss of
experienced  personnel.  In any event,  Asset  Value would  evaluate  the matter
further with  current  employees if it gained  control,  therefore,  there is no
assurance that Cortech would be shut down.

     Asset Value can only give stockholders the assurance that its nominees will
try to further reduce Cortech's expenses and will move as quickly as possible to
secure a Merger  partner,  which  they  believe  maximizes  stockholder  values.
Remember  Asset  Value  has  promised  not to seek to  merge  Cortech  with  any
affiliate or entity in which Asset Value is an investor.  Asset Value intends to
benefit from its Cortech  investment only to the same extent other  stockholders
benefit.  Asset Value's nominees have pledged not to accept any fees for serving
as directors.

                             IT'S TIME FOR A CHANGE.
                                VOTE FOR CHANGE.
                              VOTE FOR ASSET VALUE.

           "WHO CARES WHAT OWNERS THINK? Who owns American companies?
   The management, of course. Shareholders are tolerated, but managers rule.6"

                THE CORTECH BOARD ACTS LIKE ITS VOICE IS THE ONLY
                                     CHOICE.
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     5   H.G. Wells

     6   Market Watch, New York Times 3/8/98, Floyd Norris.  This quote has been
made without the permission of the New York Times or Mr. Norris.





     But we  stockholders  can  demonstrate  that they are wrong. We urge you to
read our enclosed  Proxy  Statement and vote YES to increasing the Board and FOR
Asset Value's nominees.

                                            Sincerely,
                                            Paul O. Koether
                                            Asset Value Fund Limited Partnership


                          SEND IN THE WHITE PROXY CARD
                         VOTE YES TO INCREASE THE BOARD
                     VOTE FOR ALL OF ASSET VALUE'S NOMINEES


                                    IMPORTANT

     If your shares are held in "Street  Name" only your bank or broker can vote
your shares, and only upon receipt of your specific instructions. Please contact
the person  responsible  for your account and  instruct  them to execute a white
proxy card as soon as possible.

     If you have any questions or need further assistance in voting, please call
John W. Galuchie,  Jr., of Asset Value Fund Limited Partnership collect at (908)
234-1881, or our proxy solicitor:

                           BEACON HILL PARTNERS, INC.
                                 90 BROAD STREET
                            NEW YORK, NEW YORK 10004
                                 (800) 253-3814