CORPORATE GOVERNANCE AND
                              STANDSTILL AGREEMENT


                                  by and among


                          COPLEY PHARMACEUTICAL, INC.,




                          HOECHST CELANESE CORPORATION



                                       and




                          HCCP ACQUISITION CORPORATION








                           Dated as of October 8, 1993


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                                      - i -
                                TABLE OF CONTENTS

Section                                                                    Page

1.       Effectiveness of Agreement.............................................
2.       Defined Terms..........................................................
3.       Covenants..............................................................
4.       Board of Directors.....................................................
5.       Authority of Board of Directors........................................
6.       Chief Executive Officer of the Company.................................
7.       Restrictions on Transfer...............................................
8.       Registration Rights....................................................
9.       Legends................................................................
10.      Termination............................................................
11.      Representations........................................................
12.      Entire Agreement; Assignment...........................................
13.      Validity...............................................................
14.      Notices................................................................
15.      Governing Law..........................................................
16.      Descriptive Headings...................................................
17.      Specific Performance...................................................
18.      Parties in Interest....................................................
19.      Confidentiality Agreement..............................................
20.      Counterparts...........................................................
21.      Best Efforts...........................................................



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                                                       - 8 -



                  CORPORATE GOVERNANCE AND STANDSTILL AGREEMENT



         CORPORATE GOVERNANCE AND STANDSTILL  AGREEMENT,  dated as of October 8,
1993, by and among Hoechst Celanese Corporation,  a Delaware corporation ("HC"),
HCCP  Acquisition  Corporation,  a  Delaware  corporation  and  a  wholly  owned
subsidiary  of  HC  ("Sub"),  and  Copley   Pharmaceutical,   Inc.,  a  Delaware
corporation (the "Company").
                                               W I T N E S S E T H:
         WHEREAS,  HC, Sub and the Company,  simultaneously  with the  execution
hereof, are entering into an Acquisition Agreement (the "Acquisition Agreement")
pursuant to which Sub will commence a cash tender offer (the "Offer") for shares
of common stock, par value $.01 per share, of the Company (the "Shares"); and
         WHEREAS,  simultaneously  herewith HC and Sub are entering into a Stock
Purchase Agreement (the "Stock Purchase Agreement") with the stockholders listed
therein  pursuant to which the parties  thereto are agreeing to certain  matters
with respect to certain of such stockholders' Shares; and
         WHEREAS,  the  parties  desire to  confirm  their  understandings  with
         respect to the matters set forth herein.  NOW,  THEREFORE,  the parties
         hereto, in consideration of the mutual covenants and agreements herein
contained,  and  intending  to be legally  bound  hereby,  covenant and agree as
follows:
         1........Effectiveness  of Agreement. This Agreement shall be effective
upon  acquisition by HC or Sub of at least a majority of the outstanding  Shares
(the  "Effective  Time").  In the event that the  Acquisition  Agreement and the
Stock Purchase  Agreement are terminated  without HC or Sub acquiring  Shares in
connection therewith, this Agreement shall thereupon become null and void and be
of no further force and effect.
         2........Defined Terms.  As used in this Agreement, the following terms
shall have the meanings ascribedthereto:
 .................."Acquisition Agreement" has the meaning set forth in the
"Whereas" clauses.
 .................."1933 Act" means the Securities Act of 1933, as amended
including the Rules and Regulationspromulgated thereunder).
 .................."1934 Act" means the Securities Exchange Act of 1934,
as amended (including the Rules andRegulations promulgated thereunder).
 .................."Affiliate" of any entity or Person shall mean any other
Person controlling, controlled by, or under common control with, such Person. 
"Control," when used with respect to any Person, means the power to direct the
management policies of such Person, directly, indirectly, individually or
jointly, whether through ownership of voting securities, by contract or 
otherwise; and the terms "controlling" and "controlled" having meanings 
correlative to the foregoing.
 .................."Agreement" has the meaning set forth in the introduction.
 .................."Beneficially Own" and "Beneficial Ownership" with respect to
any securities means having beneficial ownership as determined pursuant to Rule
13d-3 under the 1934 Act.
 .................."Board" or "Board of Directors" shall mean the Board of
Directors of the Company.
 .................."By-laws" means the Amended and Restated By-laws of the 
Company adopted April 9, 1992, as such may be amended from time to time.
 .................."Capital Stock" of any Person means any and all shares,
interests, participations or other equivalents (however designated) of equity
interests in such Person.
 .................."Certificate of Incorporation" means the Amended and Restated
Certificate of Incorporation of the Company, as such may be amended from time to
time.
 .................."Company" has the meaning set forth in the Introduction.
 .................."Company Directors" shall initially be Jane Hirsh and two
current directors of the Company who are not employees of the Company.
Thereafter, the Company Directors shall be the persons designated by the Company
Directors then in office.
 .................."Demand Registration" has the meaning set forth in Section
8(a).
 .................."Demand Registration Statement" has the meaning set forth in
Section 8(a).
 .................."Effective Time" has the meaning set forth in Section 1.
 .................."Extraordinary Matters" has the meaning set forth in Section
4(b).
 .................."Fully Diluted Basis" shall mean, with respect to the Capital
Stock of any Person, all shares of such Capital Stock which would be outstanding
if all shares of such Capital Stock issuable or deliverable upon the exercise of
all then outstanding rights, options and warrants (vested or unvested) issued or
granted by such Person to subscribe for or purchase shares of such Capital Stock
of such  Person,  and upon the  conversion  or exchange of all then  outstanding
securities issued by such Person or any of its Subsidiaries  convertible into or
exchangeable  for shares of such Capital  Stock of such Person,  were issued and
outstanding at the time ofdetermination.
 .................."HC" has the meaning set forth in the Introduction.
 .................."HC Directors" shall be such persons as are so designated by
HC, as such designation may change from time to time.
 .................."HC Parties" means collectively HC and Sub and any Affiliates
thereof.
 .................."Independent Directors" shall be jointly selected by the
Company Directors and the HC Directors, as such selection may change from time
to time.  Following five years from the date hereof, the Independent Directors
shall mean a person who (x) is in fact independent, (y) does not have any direct
financial interest or any material indirect financial interest in HC or the 
Company or any of their respective Affiliates (other than by reason of ownership
of not more than 1% of any class of securities thereof), and (z) is not 
connected with HC or the Company or any of their respective Affiliates as an 
officer, employee, consultant, agent, advisor, representative, trustee, partner,
director (other than of the Company) or person performing similar functions.
 .................."Offer" has the meaning set forth in the "Whereas" clauses.
 .................."Person" shall mean any individual, firm, corporation,
partnership or other entity.
 .................."SEC" means the Securities and Exchange Commission of the 
United States or any substantially similar " successor governmental entity.
 .................."Shares" has the meaning set forth in the "Whereas" clauses.
 .................."Stock Purchase Agreement" has the meaning set forth in the
"Whereas" clauses.
 .................."Sub" has the meaning set forth in the Introduction.
 .................."Subsidiary" of any Person (that Person, the "Parent") means
any other Person of which Capital Stock representing at least a majority of the
voting power under normal circumstances to elect a majority of the board of 
directors or other governing body of such Person shall be owned directly or
indirectly by the Parent and/or one or more of the Parent's Subsidiaries.
 .................."Total Voting Power" means the aggregate Voting Power of all
of the Voting Stock, if all Voting Stock were present and voted at a meeting of
the Company's stockholders.
 .................."Voting Power" of any Voting Stock means the number of votes
such Voting Stock would be entitled to cast in the election of directors of the
Company at any meeting of stockholders of the Company.
 .................."Voting Stock" means the outstanding Shares and any other
outstanding securities issued by the Company having the ordinary power to vote
in the election of directors of the Company, excluding securities issued by the
Company having such power only upon the happening of a contingency.
         3........Covenants.
 ..................(a)      From and after the Effective Time, without the 
Company's prior written consent(including the consent of at least one Company
Director) the HC Parties will not, directly or indirectly:
                           (i)      acquire, or agree to acquire, Beneficial 
         Ownership of any Voting Stock except pursuant to Section 3(d) hereof;
                           (ii) solicit proxies with respect to any Voting Stock
         or be a "participant"  in a  "solicitation"  or "election  contest" (as
         such terms are used in Regulation 14A  promulgated  under Section 14 of
         the 1934 Act) or seek to  influence  any  Person  with  respect  to the
         voting  of  any  Voting   Stock,   in  any  case  in  opposition  to  a
         recommendation  of the  Board,  except  as  contemplated  by the  Stock
         Purchase Agreement;
                           (iii)  vote its  Voting  Stock  with  respect  to any
         matter in opposition to the recommendation of the Board of Directors or
         fail to vote its Voting Stock in favor of any matter recommended by the
         Board of Directors; or
                           (iv) have any  Voting  Stock on  deposit  in a voting
         trust or subject any Voting Stock to any  arrangement or agreement with
         respect to the voting of such Voting  Stock or other  agreement  having
         similar effect.
 ..................(b)      With respect to determining the number of shares of
Voting  Stock or other  Capital  Stock of the Company  outstanding  at any time,
unless  the  Company  shall  have  provided  the HC  Parties  with  more  recent
information in writing, the HC Parties and their Affiliates shall be entitled to
rely upon the  information  filed by the Company with the SEC setting  forth the
number of shares of Voting Stock of the Company outstanding.
 ..................(c)      The HC Parties hereby agree that at any meeting of 
the  stockholders  of the  Company or in  connection  with any action by written
consent by the  stockholders of the Company,  they shall vote their Voting Stock
Beneficially  Owned by them against any action or agreement,  and the HC Parties
will not take any  other  action,  that  would  (x)  result  in a breach  of any
covenant,  representation  or warranty or any other obligation of the HC Parties
under  this   Agreement  or  (y)  impede,   interfere  with  or  discourage  the
transactions  contemplated  by this  Agreement.  The Company  shall not take any
action that would result in a breach of any covenant, representation or warranty
or any other obligation of the Company under this Agreement or impede, interfere
with or discourage the transactions contemplated by this Agreement.
 ..................(d)     If the Company shall issue any shares of Voting Stock,
including upon the exercise or conversion of options,  warrants, rights or other
securities,  the Company shall  thereupon offer to sell to HC (or any Subsidiary
designated  by HC) a number of shares of Voting  Stock of the class  issued such
that immediately  following such issuance,  HC would Beneficially Own the lesser
of:(i) 54.3% of the then outstanding  Total Voting Power and (ii) the percentage
of the Total Voting Power which HC Beneficially  Owned immediately prior to such
issuance.  The Company shall offer to sell such shares to HC at a price equal to
the  issue  price  for such  shares;  provided  that,  in the case of  issuances
pursuant to the  exercise of options  issued  pursuant to a Company  employee or
director  stock option plan,  the Company  shall offer to sell shares to HC at a
price  equal to the fair  market  value of such shares on the date of the option
exercise. In the case of cashless option exercises, the Company and HC shall use
their best efforts to enter into  arrangements  providing that HC shall have the
right to acquire a portion of the shares  being issued in  connection  with such
cashless exercise.
 ..................The Company shall notify HC promptly, and in any event within
two days of  issuance,  of the  issuance of any shares.  Such notice  shall also
include the number and class of shares to be offered to HC, the  purchase  price
thereof and, based on the most recent information available to the Company after
due inquiry,  the number of  outstanding  shares and the number and terms of any
outstanding options, warrants and rights. HC shall have 60 days from the receipt
of such notice to notify the Company as to whether it shall  purchase all or any
part of such shares.  The closing of such  purchase and sale shall take place at
the date and time specified in the HC notice,  provided such closing is not less
than two nor more than ten days from the date the Company receives such notice.
 ..................HC and the Company shall reasonably cooperate to effect the 
foregoing,  including by entering into such further  agreements,  providing such
information or execute such instruments, as either party may reasonably request.
 ..................(e)      Except as provided in Section 3(d), any purchases of
Shares by HC or its  Affiliates  prior to the  fifth  anniversary  hereof  shall
require the approval of a majority of the members of the Board of Directors  who
are Company  Directors.  Following  the fifth  anniversary  of the date  hereof,
notwithstanding  any  provisions  hereof  to the  contrary,  (i) HC may  acquire
Company securities in privately negotiated, unsolicited transactions, so long as
at least 17% of the outstanding  Shares remain freely  tradeable Shares and (ii)
without the  approval of a majority of the  Independent  Directors,  HC will not
otherwise acquire any Shares.
 ..................(f)      So long as there are Company Directors or Independent
Directors on the Board,  (i) HC will not take any actions to amend provisions of
the Certificate of Incorporation or By-Laws relating to the  indemnification  of
directors of the Company or cause the Company to breach any  existing  indemnity
agreement  with  officers  or  directors  and (ii) will not cause the Company to
terminate its directors and officers'  insurance policy and,  following the time
the HC Directors  constitute a majority of the Board,  will cause the Company to
continue such policy,  or other policy of similar scope,  as long as the Company
is not  required  to spend in any year  more  than  150% of its  current  annual
expenditures for such purpose.
 ..................(g) Each transaction or series of related transactions between
the Company and HC or an Affiliate of HC and each other corporate  action of the
Company in which there is a potential  conflict  between the  interests of HC or
any Affiliate and the interests of the Company and its other  stockholders shall
be subject to the prior approval of a majority of the  Independent  Directors of
the Company.
         4........Board of Directors.
 ..................(a)      At the Effective Time, the Company shall cause the
Board of Directors to consist of 9 persons, 3 of whom are Company  Directors,  3
of whom are HC Directors and 3 of whom are  Independent  Directors.  Each of the
Company  Directors,  HC Directors and Independent  Directors shall be divided as
equally as possible among the 3 classes of directors on the Board.
 ..................(b)      After the Effective Time, the Company will use its
best efforts to continue the  arrangements  set forth in paragraph  (a),  above,
provided, that (i) if the HC Parties shall Beneficially Own less than 35% of the
Total Voting Power, HC shall cause the  resignation of one HC Director,  so that
there are two HC  Directors  on the Board and the Board shall then  include four
Independent  Directors,  (y) if the HC Parties shall  Beneficially Own less than
25% of the Total Voting Power, HC shall cause the resignation of HC Directors so
that there is one HC Director on the Board and the Board shall then include five
Independent Directors and (z) if the HC Parties shall Beneficially Own less than
10% of the  Total  Voting  Power,  HC  shall  cause  the  resignation  of all HC
Directors on the Board of Directors.
 ..................(c)      The composition of each committee of the Board of
Directors shall reflect proportionately as closely as possible the composition 
of the Board of Directors.
         5........Authority of Board of Directors.
 ..................(a)      Except as set forth in paragraph (b) below or
otherwise  required by law, the Certificate of Incorporation or the Bylaws,  all
actions and decisions of the Board of Directors shall require a majority vote of
the directors then in office.
 ..................(b)      In addition to any stockholder vote or vote by the
Board of Directors which may be required by law, the affirmative vote of at 
least one HC Director shall be required in order to authorize the following
actions or matters (collectively, the "Extraordinary Matters"):
                           (i)  in  one  transaction  or  a  series  of  related
         transactions,   the   transfer,   lease,   license,   sale,   mortgage,
         encumbrance,  pledge or other  disposition of any assets of the Company
         or its Subsidiaries involving more than $10 million of assets;
                           (ii)  in  one  transaction  or a  series  of  related
         transactions,  the purchase or other acquisition of the assets or stock
         of, or the investment in or capital  contribution to, any other Person,
         where the consideration represents more than $10 million;
                           (iii)  in one  transaction  or a  series  of  related
         transactions,  the merger,  consolidation or other business combination
         involving   the   Company  or  any  of  its   Subsidiaries   where  the
         consideration represents more than $10 million;
                           (iv)  in  one  transaction  or a  series  of  related
         transactions,  the issuance, sale or repurchase of Voting Capital Stock
         or rights to acquire (including convertible  securities) Voting Capital
         Stock involving more than $10 million;
                           (v) amendments to the Certificate of Incorporation or
                           the By-laws;  (vi) the  termination  of employment or
                           the hiring of a Chief  Executive  Officer;  (vii) the
                           approval of an annual  budget for the Company and its
                           Subsidiaries
         (including,  but not limited to, capital expenditures,  debt incurrence
         and operating  expenses),  any amendments  thereto and any  significant
         expenditures or borrowings not contemplated thereby;
                           (viii) any increase in the annual compensation (other
         than  pursuant  to the  annual  bonus  pool or stock  options)  for the
         officers  of the  Company  subject to Section  16(a) under the 1934 Act
         aggregating  more than 15% in any one year, any change in the method of
         calculating the Company's  annual bonus pool (including the formula for
         such bonus over 10% of the  Company's  annual  pretax  profits) and any
         awards of options representing more than an aggregate of 250,000 Shares
         for all directors, officers and employees of the Company in any year;
                           (ix) the declaration, setting aside or payment of any
         dividend or distribution on its Capital Stock payable in cash, stock or
         property;
                           (x) the amendment to or waiver of this Agreement; and
                           (xi) the  initiation  of  bankruptcy,  insolvency  or
         reorganization   proceedings  involving  the  Company  or  any  of  its
         Subsidiaries.
 ..................In addition, the affirmative vote of at least one Company
Director is required in order to authorize the actions set forth in paragraphs
(b)(v) and (x) above.
 ..................(c)      The provisions set forth in paragraph (b) above
relating to the vote of the Board of Directors required to approve Extraordinary
Matters shall terminate five years from the date hereof; provided, however, that
(i) the provisions set forth in paragraphs (b)(i),  (ii), (iii), (iv), (vii) and
(viii) shall terminate if the HC Parties  Beneficially  Own less than 50% of the
Total Voting  Power and (ii) the  provisions  set forth in  paragraph  (b) above
shall  terminate if the HC Parties  Beneficially  Own less than 35% of the Total
Voting Power or if a third party shall  Beneficially  Own at least a majority of
the Total Voting Power;  and further  provided,  however,  that such  provisions
shall not terminate if the HC Parties' percentage Beneficial Ownership decreased
following  an  issuance of Voting  Stock  unless the HC Parties do not acquire a
sufficient  number  of  shares of  Voting  Stock to be in  compliance  with this
provision within 70 days of notice to HC of such issuance of Voting Stock.
         6........Chief Executive Officer of the Company.
 ..................(a)      Following the Effective Time, the Chairperson of the
Board and Chief Executive  Officer of the Company shall be Jane C.I. Hirsh,  who
shall serve in accordance  with the terms of the Employment  Agreementdated  the
date hereof, between Ms. Hirsh and the Company.
         7........Restrictions on Transfer. The HC Parties may sell, transfer or
dispose of all or a portion  of any  Voting  Stock  Beneficially  Owned.  If any
Person acquiring  Voting Stock from the HC Parties,  other than in a transaction
pursuant  to Rule 144 under the 1933 Act or in a bona fide public  offering,  in
which the  underwriters  are  instructed  to achieve as wide a  distribution  as
practicable,  would,  to the best  knowledge of the HC Parties after  reasonable
inquiry,  Beneficially  Own 5% or more of the Total Voting Power determined on a
Fully Diluted  Basis,  such person as a condition to transfer  shall agree to be
bound by the  provisions  hereof,  and shall be entitled to all benefits  hereof
(including registration rights to the extent transferred), other than Sections 4
and 5.
         8........Registration Rights.
 ..................(a)      If a HC Party requests the Company in writing to 
register  under the 1933 Act any Shares  (references to Shares in this Section 8
shall  include  references to any security of the Company) held by such HC Party
(a "Demand  Registration"),  the Company shall use its best efforts to cause the
Shares  specified in such request to be  registered  as promptly as  practicable
under the 1933 Act so as to permit the sale thereof and in connection  therewith
promptly  prepare and file, on such  appropriate MP form as HC shall  reasonably
request, a registration statement (a "Demand Registration  Statement") under the
1933 Act to  effect  such  registration  and use its best  efforts  to have such
registration statement become effective as promptly as practicable and otherwise
use its best  efforts  to make  such  filings  and take such  actions  as may be
necessary  or  desirable to allow HC lawfully to  distribute  Shares;  provided,
however,  that (i) each such  Demand  Registration  is for the  registration  of
Shares  leaving  a  market  value  on the date of such  demand  of at least  $25
million,  (ii)  the  Company  shall  not be  obligated  to  file a  registration
statement  pursuant to this Section 8 during the 180-day  period  following  the
effectiveness of any other registration  statement filed by the Company pursuant
to this  paragraph (a) and (iii)  Company's  obligations  shall cease once three
Demand Registration Statements have become effective and have remained effective
(including  not being  subject to any stop order or  injunction)  for the period
contemplated by paragraph (b) below.
 ..................(b)      Upon any registration becoming effective pursuant to
this Section 8, the Company shall use its best efforts to keep such registration
statement  current  for a period of 90 days or such  shorter  period  which will
terminate  when all Shares  covered by such Demand  Registration  Statement have
been sold.
 ..................(c)      Notwithstanding the foregoing, (i) the Company shall
not be obligated to cause any special audit to be undertaken in connection  with
any such  registration  and (ii) with respect to each Demand  Registration,  the
Company  shall be  entitled  to  postpone  for up to 90 days the  filing  of any
registration  statement otherwise required to be prepared and filed by it (A) to
the extent necessary to prepare the financial  statements of the Company for the
fiscal  period most  recently  ended prior to such written  request,  (B) if the
Company  would be  required  to  disclose  in such  registration  statement  the
existence of any fact not  otherwise  required to be  disclosed  and the Company
reasonably  determines that such disclosure would be materially  injurious to it
or (C) if the nationally  recognized investment banking firm serving as managing
underwriter  notifies the HC Parties that a registration  at the time and on the
terms  requested  would  Adversely  affect any financing by the Company that had
been  contemplated  by  the  Company  prior  to  receipt  of  notice  requesting
registration pursuant to paragraph (a).
 ..................(d)      The Company shall pay all of the expenses incurred in
connection with each Demand  Registration,  except that the HC Parties shall pay
all fees of .any  independent  counsel  retained  by them  and any  underwriting
Discounts in connection therewith.
 ..................(e)      If requested by the HC Parties, the Company shall 
enter into an  underwriting  agreementwith  a nationally  recognized  investment
banking  firm  selected  by  the  HC  Parties,   in  connection  with  a  Demand
Registration Statement, containing representations,  warranties, indemnities and
agreements then  customarily  included by an issuer in  underwriting  agreements
with    respect    to    secondary    distributions    by   such    underwriter.
 ..................(f)  If requested by the HC Parties,  the Company  shall enter
into an indemnification
agreement with the HC Parties providing for indemnification on customary terms.
         9........Legends.  The certificates  evidencing all Voting Stock at any
time Beneficially  Owned by an HC Party or any of their respective  transferees,
shall bear the  following  legends  unless and until such time as HC or any such
transferee  delivers an opinion of counsel reasonably  acceptable to the Company
and its  counsel  to the  effect  that such  legend is not  required  under this
Agreement or that this  Agreement has been  terminated  in  accordance  with its
terms, and, in the case of a transferee,  that such transfer is not in violation
of this  Agreement  and that the  transferee  is not  subject to or bound by the
provisions of this Agreement, and stating the basis therefor:
                  "THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO THE
                  TERMS AND CONDITIONS OF A CORPORATE  GOVERNANCE AND STANDSTILL
                  AGREEMENT  DATED AS OF  OCTOBER  8, 1993 BY AND AMONG  HOECHST
                  CELANESE CORPORATION,  HCCP ACQUISITION CORPORATION AND COPLEY
                  PHARMACEUTICAL,  INC.,  COPIES  OF WHICH  ARE ON FILE WITH THE
                  SECRETARY  OF  COPLEY,  AND ARE  HELD  AND  MAY  NOT BE  SOLD,
                  ASSIGNED,  TRANSFERRED,  PLEDGED,  HYPOTHECATED,   ENCUMBERED,
                  OTHERWISE GRANTED AS SECURITY, OR OTHERWISE DISPOSED OF EXCEPT
                  IN ACCORDANCE THEREWITH.

                  NO  REGISTRATION OF TRANSFER OF THE SECURITIES WILL BE MADE ON
                  THE BOOKS OF COPLEY UNLESS SUCH TRANSFER IS MADE IN CONNECTION
                  WITH AN EFFECTIVE  REGISTRATION STATEMENT UNDER THE SECURITIES
                  ACT OF  1933  OR  PURSUANT  TO AN  EXEMPTION  FROM  APPLICABLE
                  FEDERAL AND STATE REGISTRATION REQUIREMENTS."

         10.......Termination.   This  Agreement   shall  terminate  five  years
following  the date  hereof,  provided  that,  so long as the Company has equity
securities  registered  under  the 1934  Act,  there  shall  be at  least  three
Independent  Directors on the Board and that Sections 3(e) and 21 shall survive.
Upon a material breach of this Agreement by the Company,  on the one hand, or HC
or Sub, on the other hand, the  obligations  of HC (and Sub) or the Company,  as
the case may be, shall terminate. Prior to such termination,  the person wishing
to terminate  shall give the other parties  written  notice of the breach and 20
days to cure such breach.
         11.......Representations.  (a)  HC  and  Sub  severally  represent  and
warrant to the Company  that (i) such party has duly  authorized,  executed  and
delivered this Agreement and this Agreement is a valid and binding  agreement of
HC and Sub, enforceable against HC and Sub in accordance with its terms and (ii)
the execution of this Agreement by HC and Sub and the consummation by HC and Sub
of the transactions  contemplated  hereby will not constitute a violation of, or
conflict  with,  or  default  under,   any  contract,   commitment,   agreement,
understanding,  arrangement  or  restriction of any kind to which HC or Sub is a
party or by which it may be bound,  and (b) the Company  represents and warrants
to each of the HC Parties that (i) the Company has duly authorized, executed and
delivered this Agreement and this Agreement is a valid and binding  agreement of
Company,  enforceable  against the Company in accordance with its terms and (ii)
the execution of this Agreement by Company and the  consummation  by the Company
of the transactions  contemplated  hereby will not constitute a violation of, or
conflict  with,  or  default  under,   any  contract,   commitment,   agreement,
understanding,  arrangement or restriction of any kind to which the Company is a
party or by which the Company is bound.
         12.......Entire Agreement;  Assignment.  This Agreement constitutes the
entire agreement among the parties with respect to the subject matter hereof and
supersedes all other prior agreements and understandings, both written and oral,
between the parties or any of them with  respect to the subject  matter  hereof,
and except as provided  herein,  shall not be assigned  by  operation  of law or
otherwise.
         13.......Validity.  The invalidity or unenforceability of any provision
of this Agreement shall not affect the validity or  enforceability  of any other
provisions of this Agreement, which shall remain in full force and effect.
         14.......Notices.  All  notices,  requests,  claims,  demands and other
communications  hereunder  shall be in writing  and shall be given (and shall be
deemed to have been duly given upon  receipt) by  delivery in person,  by cable,
telegram, telex or telefax, or by registered or certified mail (postage prepaid,
return receipt requested) to the respective parties as follows:
                  if to the HC Parties:

                           Hoechst Celanese Corporation
                           Route 202-206
                           PO Box 2500
                           Somerville, NJ 08876
                           Attention:  David A. Jenkins

                  with a copy to:

                           Skadden, Arps, Slate, Meagher & Flom
                           919 Third Avenue
                           New York, New York 10022
                           Attention:  Alan C. Myers

                  if to the Company:

                           Copley Pharmaceutical, Inc.
                           25 John Road
                           Canton, Mass. 02021
                           Attention:  Chief Financial Officer

                  with a copy to:

                           Testa, Hurwitz and Thibeault
                           Exchange Place
                           53 State Street
                           Boston, Massachusetts 02109-2809
                           Attention:  Leslie Davis

or to such  other  address  as the  person  to whom  notice  is  given  may have
previously furnished to the others in writing in the manner set forth above.
         15.......Governing  Law.  This  Agreement  shall  be  governed  by  and
construed in  accordance  with the laws of the State of Delaware,  regardless of
the laws that might otherwise govern under applicable principles of conflicts of
laws thereof.
         16.......Descriptive  Headings.  The  descriptive  headings  herein are
inserted for convenience of reference only and are not intended to be part of or
to affect the meaning or interpretation of this Agreement.
         17.......Specific  Performance.  The parties  hereto  acknowledge  that
damages  would be an inadequate  remedy for a breach of this  agreement and that
the  obligations of the parties  hereto shall be  specifically  enforceable,  in
addition to any other remedy which may be available at law or in equity.
         18.......Parties  in  Interest.   Except  as  set  forth  herein,  this
Agreement  shall be binding  upon and inure  solely to the benefit of each party
hereto,  and nothing in this  Agreement,  express or implied,  is intended to or
shall confer upon any other  person or persons any rights,  benefits or remedies
of any nature whatsoever under or by reason of this Agreement.
         19.......Confidentiality   Agreement.  The  Confidentiality  Agreement,
dated  September  9, 1993,  between HC and the Company  shall  terminate  at the
Effective Time.
         20.......Counterparts.  This  Agreement  may be executed in two or more
counterparts,  each of which shall be deemed to be an original, but all of which
shall constitute one and the same agreement.
         21.......Best  Efforts. Each party hereto shall use its reasonable best
efforts to cause the  transactions  contemplated  hereby to be  consummated  and
effected.

                   REMAINDER OF PAGE INTENTIONALLY LEFT BLANK


<PAGE>


         IN WITNESS  WHEREOF,  the undersigned  have caused this Agreement to be
executed by their respective  officers thereunto duly authorized,  all as of the
day and year first above written.
                          COPLEY PHARMACEUTICAL, INC.


                          By: /s/ Jane C.I. Hirsh___________________
                          Name:        Jane C.I. Hirsh
                          Title:       Chairperson of the Board,
                                       Chief Executive Officer and President

                          HOECHST CELANESE CORPORATION


                          By:  /s/ Harry R. Benz___________________
                          Name:        Harry R. Benz
                          Title:       Senior, Vice President-Finance,
                                       Chief Financial Officer and Director

                          HCCP ACQUISITION CORPORATION


                          By:  /s/ Don Whitcomb___________________
                          Name:        Don Whitcomb
                          Title:       President