Document:

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                                   EXHIBIT 4.2

                                                                   March 2, 2000

Walter C. Herlihy, Ph.D.
Chief Executive Officer
Repligen Corporation
117 Fourth Avenue
Needham, MA 02494

                                FINDERS AGREEMENT

Dear Sirs:

         Reference is made to our recent discussions relating to a proposed
private placement under Rule 506 of Regulation D of the Securities Act of 1933,
as amended (the "Act") of securities of Repligen Corp. (the "Company") as
hereinafter described. Based upon our discussions and representations which you
have made to us describing the Company and its principals, the present and
proposed business activities of the Company and the Company's operations and
financial condition, Paramount Capital, Inc. ("Paramount") hereby confirms in
principle its interest in acting as a finder for the Company, on a "best
efforts" basis, in connection with the private placement offering of the
Company's shares of Common Stock (the "Offering"), upon the following basic
terms and conditions:

         1. Paramount will introduce the Company to "accredited investors" as
defined in Rule 501 of Regulation D promulgated under the Act for the purchase
of up to 2,650,000 shares of common stock, par value $.01 per share (the "Common
Stock"). Each share of Common Stock will be sold at a price per share price (the
"Per Share Price") equal to eighty five percent (85%) of the average closing bid
price of the Common Stock for the fifteen (15) trading days immediately
preceding the Closing Date (as defined in paragraph 2 below) of the Offering;
provided, however, that in no event will the Per Share Price be greater than
$8.625. Further, subject to the Break-up Fee (as defined in paragraph 20 below)
the Company shall not be required to sell the Common Stock at a Price Per Share
less than $6.00. For purposes hereof, "closing bid price" shall mean, for each
trading day, the price at which the Common Stock was last exchanged on the
Nasdaq National Market during such trading day, or, if there were no
transactions on such trading day, the average of the reported closing bid and
asked prices, regular way, of the Common Stock on such trading day. "Trading
day" shall mean a day on which the relevant Nasdaq National Market is open for
the transaction of business.

         2. The closing date of the Offering will occur no later than sixty (60)
days following the execution of this Agreement, subject to extension at the
option of the Company for an additional thirty (30) days (the date of any such
closing is hereinafter referred to as the

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"Closing Date"). Pending completion or termination (pursuant to paragraph 18
below) of the Offering, the Company agrees that it will not enter into any
agreement, discussion or negotiations with any other person or entity relating
to a possible private offering or placement of its securities.

         3. Following (a) execution of a Securities Purchase Agreement to be
entered into by and among the Company and each purchaser (the "Purchase
Agreement") and (b) receipt by the Company of the Offering Amount, the Company
may conduct a Closing. Paramount agrees to use its reasonable best efforts to
assist the Company in causing a Closing to occur as soon as practicable
following execution of Purchase Agreements by the parties thereto. Prior to such
Closing, all amounts shall be held in escrow for the benefit of investors by an
escrow agent reasonably acceptable to the Company and Paramount.

         4. (a) Subject to the terms herein, the Company will, as soon as
practicable, but not later than 30 days after the Closing Date (the "Outside
Filing Date") (a) file a shelf registration statement (the "Shelf Registration
Statement") with respect to (i) the resale of the shares of Common Stock sold in
the Offering and (ii) the shares of Common Stock issuable upon exercise of the
Paramount Warrants (as defined below) and (together, the "Registrable Capital
Stock") with the SEC and use its best efforts to have such Shelf Registration
Statement declared effective by the SEC prior to the date which is 90 days after
the Closing Date and (b) cause such Shelf Registration Statement to remain
effective until the earlier of (a) such date as the holders of the securities
have completed the distribution described in the Shelf Registration Statement or
at such time that such shares are no longer, by reason of Rule 144(k) under the
Securities Act, required to be registered for the sale thereof by such holders
and (b) two years from the effective date of such Shelf Registration Statement.

         (b) Subject to the terms herein, in the event that the Shelf
Registration Statement is not filed by the Outside Filing Date the Company
shall, for no additional consideration, pay to each investor as liquidated
damages and not as a penalty an amount in cash equal to one percent (1%) of the
amount invested by such investor for each 30 day period in which the Shelf
Registration Statement remains unfiled; PROVIDED, HOWEVER, that in no event
shall the amount of liquidated damages payable by the Company to any investor
exceed twelve (12%) of the amount invested by such investor.

     (c) The Outside Filing Date shall be extended by at least 5 business days
from the date that the Company has received all such information that the
Company has requested in writing for use in the Shelf Registration Statement;
provided that the Company agrees to request such information within 10 days from
the Closing Date.

     5. Prior to the effective date of the Shelf Registration Statement, the
Company will file a listing application for (a) the shares of Common Stock sold
in the Offering and (b) the Common Stock issuable upon exercise of the Paramount
Warrants (as defined below) with the Nasdaq National Market.

                                      -2-
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     6. Paramount will receive cash commissions equal to seven percent (7%) of
the aggregate gross proceeds received by the Company in the Offering (the "Cash
Commissions"). Paramount may, in its discretion, retain others, who shall be
members in good standing of the National Association of Securities Dealers, Inc.
("NASD"), to act as selected dealers in placing the Common Stock. Such other
others will be compensated by Paramount out of its commissions. The Company has
advised Paramount that no person is entitled, directly or indirectly, to
compensation from the Company for services as a finder in connection with the
proposed Offering or any other transaction contemplated by this Finders
Agreement.

     7. Pending completion of the Offering and for a 30 day period thereafter,
the Company will not issue press releases with respect to the Offering or engage
in other publicity without giving Paramount advance copies of any such releases.
Other than as a result of stock splits, during the 12 month period following the
completion of the Offering, the Company will not lower the exercise price or
conversion price of any options, warrants or convertible securities currently
outstanding without the prior written consent of Paramount. The Company shall
not use the name of Paramount or any officer, director, employee or shareholder
without the express written consent of Paramount and such person other than as
required by applicable law, the rules and regulations of the United States
Securities and Exchange Commission and the NASD.

     8. The Company shall be responsible for and shall bear all out of pocket
expenses incurred by Paramount in connection with the Offering including the
Paramount's legal fees, such fees and expenses not to exceed $75,000 (the
"Expense Allowance"). The Company shall pay to Paramount an amount equal to
$5,000 as a retainer, which shall be due and payable upon execution of this
Finder's Agreement and which shall be creditable against the Expense Allowance,
to cover the cost of the Paramount's mailing, telephone, telegraph, travel, due
diligence meetings and other similar expenses including legal fees of
Paramount's counsel (other than legal fees in connection with blue sky matters
as to which fees the Company shall be responsible). Such prepaid expense
allowance shall be non-refundable.

     9. Upon consummation of the Offering contemplated hereby, the Company will,
in consideration of the services rendered by Paramount in connection with the
Offering, issue to Paramount and/or its designees for no additional
consideration (provided that such issuances shall in all events be made in
compliance with applicable securities laws, including compliance with the rules
governing exemption from registration requirements of the Act), warrants (the
"Paramount Warrants") to acquire a number of shares of Common Stock equal to
five percent (5%) of the number of shares of Common Stock sold in the Offering,
exercisable for a period of five (5) years commencing six (6) months after the
closing of the Offering at an exercise price equal to 110% of the price per
share of Common Stock sold in the Offering. The Paramount Warrants cannot be
transferred, sold, assigned or hypothecated for six (6) months except that they
may be assigned in whole or in part during such period to any NASD member
participating in the Offering or any officer or employee of Paramount or any
such NASD member. The Paramount Warrants will contain a cashless exercise
feature, anti-dilution protection and the right to have the Common Stock
issuable upon exercise thereof (including the Warrants issuable upon exercise of
the Paramount Warrants) included on the Shelf Registration

                                      -3-
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Statement. For purposes of clarification, the Company agrees that for a period
of 12 months from the Closing Date, the Paramount Warrants shall provide for
protection against dilution as a result of issuances by the Company of common
stock, or securities convertible into or exercisable for common stock, at a
price per share less than the average closing bid price for the five (5) days
preceding any such issuance.

     10. Paramount shall be entitled to receive the Cash Commissions described
in paragraph 6 and the Paramount Warrants described in paragraph 9 in the event
that any investor (a) who is or has been introduced to the Company by Paramount
and (b) who has been identified in writing to the Company prior to making an
investment and (c) with whom Paramount has had discussions regarding an
investment in the Company makes an investment in the Company during the 12-month
period following the Closing Date. Paramount will provide the Company with a
list of such introduced investors on the Closing Date. In addition, the Company
shall in all events be responsible for Paramount's reasonable out of pocket
expenses in connection with any such investment.

     11. The Company shall not use any proceeds from the Offering to repay any
indebtedness of the Company, including, but not limited to, any indebtedness to
current executive officers or principal stockholders of the Company, but
excluding accounts payable incurred in the ordinary course.

     12. (a) Unless required by law, any services and advice rendered by
Paramount pursuant to this Agreement (and the existence of this Agreement) shall
not be disclosed publicly in any manner without Paramount's prior written
approval and shall be treated by the Company as confidential information.

         (b) Confidential Information shall mean any information disclosed by
one party to the other party hereunder (in writing or verbally, whether or not
specifically marked confidential), including, without limitation, the terms of
this Agreement, all commercially valuable, proprietary or confidential
information with respect to the Company's business, products or operations
disclosed by the Company to Paramount, which includes financial information,
marketing plans, strategies and other valuable business information.
Confidential Information shall also include any financial advice provided
hereunder by Paramount to the Company. Notwithstanding anything to the contrary
in this Section 12, Confidential Information shall not include: (i) information
that is in or enters the public domain without breach of this Agreement; (ii)
information lawfully received from a third party without restriction on
disclosure and without breach of a nondisclosure obligation; (iii) information
that is developed independently by a party which party can prove with written
evidence; and (iv) information that is required by judicial or administrative
order or by governmental authority to be disclosed, provided that the party from
whom disclosure is sought uses reasonable efforts to notify the other of such
requirement so that the other may seek to make such disclosure subject to a
protective order or confidentiality agreement.

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         (c) The Company agrees to limit disclosure of the Confidential
Information only to those of its officers, employees, agents, affiliates and
consultants as the Company considers necessary, provided that each such officer,
employee, agent, affiliate or consultant of the Company shall be similarly bound
by the confidentiality obligations contained herein. The Company shall take all
reasonable commercial steps to prevent the disclosure of the Confidential
Information as it would to protect its own confidential or proprietary
information. This obligation shall be binding upon the Company and shall
continue for a period during the term of this Agreement and for a period of five
(5) years thereafter.

         (d) Paramount agrees to limit disclosure of the Confidential
Information only to those of its officers, employees, agents, affiliates and
consultants as Paramount considers necessary to render its services under this
Agreement, provided that each such officer, employee, agent, affiliate or
consultant of Paramount shall be similarly bound by the confidentiality
obligations contained herein. Paramount shall take all reasonable steps to
prevent the disclosure of the Confidential Information as it would to protect
its own confidential or proprietary information. Paramount understands and
agrees that to the extent Paramount receives Confidential Information which is
material and non-public relating to the Company, Paramount shall be deemed to be
an "insider" for purposes of United States securities laws and shall be
prohibited from selling, purchasing or otherwise trading in the securities of
the Company until public disclosure of such material non-public information.
Paramount may rely, without independent verification, on the accuracy and
completeness of any written information furnished to Paramount by the Company,
subject to its obligations under the securities laws and herein. This obligation
shall be binding upon Paramount and shall continue for a period during the term
of this Agreement and for a period of five (5) years thereafter.

     13. Paramount shall be entitled to rely on the representations, warranties
and covenants of the Company as set forth in any Purchase Agreement or other
document used by the Company in connection with or otherwise related to the
Offering, including without limitation the legal opinion of counsel to the
Company. Further, Paramount reserves the right to conduct legal, business and
financial due diligence of the Company to the extent that Paramount, in its sole
discretion, deems it necessary and appropriate.

     14. (a) The Company agrees to indemnify and hold harmless Paramount and its
respective partners, shareholders, directors, officers, agents, advisors,
representatives, employees, counsel and controlling persons within the meaning
of the Act (a "Paramount Indemnified Party") against any and all losses,
liabilities, claims, damages and expenses whatsoever (and all actions in respect
thereof), and to promptly reimburse any such Paramount Indemnified Party for the
reasonable legal fees and related expenses as incurred (including, but not
limited to the costs of giving testimony or furnishing documents in response to
a document request, a subpoena or otherwise, the costs of investigating,
preparing, pursuing or defending any such action or claim whether or not pending
or threatened and whether or not any Paramount Indemnified Party is a party
thereto), insofar as such losses, liabilities, claims, damages or expenses arise
out of, relate to, are in incurred in connection with or are in any way a result
of or relate to this Agreement or the matters contemplated by this Agreement;
PROVIDED HOWEVER that

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the Company shall not be liable to a Paramount Indemnified Party hereunder to
the extent that any loss, claim, damage, liability or expense is found in final
judgment by a court or arbitrator to have resulted from a Paramount Indemnified
Party's malfeasance, bad faith or negligence; and PROVIDED FURTHER that in no
event shall the Company's liability under this Section 14 exceed the aggregate
amount of fees paid by the Company to Paramount hereunder.

         (b) Paramount agrees to indemnify and hold harmless the Company and its
respective partners, shareholders, directors, officers, agents, advisors,
representatives, employees, counsel and controlling persons within the meaning
of the Securities Act (a "Company Indemnified Party") against any and all
losses, liabilities, claims, damages and expenses whatsoever (and all actions in
respect thereof), and to promptly reimburse any such Company Indemnified Party
for reasonable legal fees and related expenses as incurred (including, but not
limited to the costs of giving testimony or furnishing documents in response to
a document request, a subpoena or otherwise, the costs of investigating,
preparing, pursuing or defending any such action or claim whether or not pending
or threatened and whether or not any Paramount Indemnified Party is a party
thereto), insofar as such losses, liabilities, claims, damages or expenses arise
out of, relate to, are in incurred in connection with or are in any way a result
of or relate to Paramount's gross negligence or willful misconduct in the
performance of the services pursuant to this Agreement; PROVIDED HOWEVER that
Paramount shall not be liable hereunder to the extent that any loss, claim,
damage, liability or expense is found in final judgment by a court or arbitrator
to have resulted from a Company Indemnified Party's malfeasance, bad faith or
negligence; and PROVIDED FURTHER that in no event shall Paramount's liability
under this Section 14 exceed the aggregate amount of fees paid by the Company to
Paramount hereunder.

         (c) The indemnification provisions of this Section 14 shall be the sole
and exclusive remedies of the parties hereto with respect to any claims arising
hereunder by one party against the other party hereunder, except that any claim
by one party against the other party under this Agreement for an intentional and
material breach of Section 12 hereunder or a claim based on fraud, bad faith or
gross negligence shall not be limited to the remedies and limitations of this
Section 14.

     15. This Agreement shall continue for a term of sixty (60) days from the
date hereof, subject to the right of the Company to extend the term for up to an
additional thirty (30) day period, provided that good-faith negotiations are
continuing with investors to complete the Offering. Notwithstanding the
foregoing, Paramount may terminate this Agreement at any time prior to the
closing of the Offering in its sole discretion, with or without cause, and
without liability whatsoever to the Company. Paragraphs 8, 10, 12, 13, 14, 15,
16, 18, 19 and 20of this Agreement shall remain operative and in full force and
effect regardless of any expiration or termination of this Agreement by the
Company.

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     16. This Agreement shall be governed by and construed in accordance with
the laws of the State of New York without regard to principles of conflicts of
law. The parties hereby irrevocably submit to the exclusive jurisdiction of the
Courts of the State of New York.

     17. This Agreement shall be binding upon and inure to the benefit of
Paramount and the Company and each of their successors and assigns. This
Agreement may not be assigned by either party without the prior written consent
of the other.

     18. Paramount may, in its sole judgment and discretion, determine to
terminate this Agreement. The Company may in its sole judgment and discretion,
determine at any time not to proceed with the Offering; provided, however, that
in the event of such a termination, the Company shall pay to Paramount a fee
(the "Break-up Fee") equal to $100,000 (in addition to Paramount's reasonable
out of pocket expenses (for which the Company shall in all events remain
liable)).

     19. Nothing herein shall restrict or otherwise limit Paramount from
performing similar or dissimilar services for any other party or for its own
account. The provisions of this paragraph 19 shall be enforceable to the fullest
extent permitted by law.

     20. This Agreement embodies the entire agreement and understanding between
the parties hereto and supersedes any prior agreements or understandings, oral
or written, relating to the subject matter hereof. If any provision of this
Agreement is determined to be invalid or unenforceable in any respect, such
determination will not affect such provision in any other respect or any other
provision of this Agreement, which will remain in full force and effect. This
Agreement may not be amended or otherwise modified or waived except by an
instrument in writing signed by both the Company and Paramount.

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If the foregoing conforms to your understanding, please sign, date and return to
us the enclosed copy of this letter.

                                     Very truly yours,

                                     PARAMOUNT CAPITAL, INC.

                                     By:  /S/ LINDSAY ROSENWALD
                                          ---------------------------------
                                     Name:    Lindsay A. Rosenwald, M.D.
                                     Title:   Chairman

The foregoing is in conformity with our understanding:

REPLIGEN CORP.

By:  /S/ WALTER C. HERLIHY
     -----------------------------------------
Name:    Dr. Walter C. Herlihy
Title:   President and Chief Executive Officer

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                                                                    EXHIBIT 10.1

                                  VOTING AGREEMENT

          VOTING AGREEMENT, dated as of March 20, 2000, by and among Farallon
Capital Partners, L.P., a California limited partnership ("FCP"), Farallon
Capital Institutional Partners, L.P., a California limited partnership
("FCIP"), Farallon Capital Institutional Partners II, L.P., a California
limited partnership ("FCIP II"), Farallon Capital Institutional Partners III,
L.P., a Delaware limited partnership ("FCIP III"), Tinicum Partners, L.P., a
New York limited partnership ("Tinicum"), and Farallon Capital Management,
L.L.C. ("FCM") on behalf of certain managed accounts (the "Managed Accounts"
and, together with FCP, FCIP, FCIP II, FCIP III and Tincium, the
"Stockholders" and each of them a "Stockholder"), Dura Pharmaceuticals, Inc.,
 a Delaware corporation ("Dura"), Starfish Acquisition Corp., Inc., a
Delaware corporation and a wholly owned subsidiary of Dura ("Merger Sub"),
and Spiros Development Corporation II, Inc., a Delaware corporation (the
"Company").

          WHEREAS, Dura, Merger Sub and the Company, are concurrently entering
into an Agreement and Plan of Merger, dated as of March 20, 2000 (the "Merger
Agreement"), providing for the merger of Merger Sub with and into the Company
(the "Merger"), on a date not earlier than June 18, 2000, pursuant to the terms
and subject to the conditions of the Merger Agreement, and setting forth certain
representations, warranties, covenants and agreements of the parties thereto in
connection with the Merger; and

          WHEREAS, as of the date hereof, the Stockholders collectively own an
aggregate of 1,374,400 shares of Callable Common Stock, par value $0.001 per
share, of the Company ("Company Common Stock"); and

          WHEREAS, as an inducement to Dura's execution of the Merger Agreement,
Dura has requested that the Stockholder agree, and the Stockholder hereby agrees
to vote (or consent with regard to) all shares of Company Common Stock as to
which the Stockholder has voting power in favor of the Merger as provided
herein.

          NOW, THEREFORE, in consideration of the foregoing and the
representations, warranties, covenants and agreements contained herein, the
parties hereto, intending to be legally bound hereby, agree as follows:

          1.   REPRESENTATIONS OF THE STOCKHOLDERS.  The Stockholders hereby
represent and warrant to Dura as follows:

               (a)  The Stockholders are the holders of and beneficially own an
aggregate of 1,374,400 shares of Company Common Stock (the "Shares").

               (b)  None of the Stockholders (other than the Managed Accounts)
beneficially own  as of March 20, 2000 (as such term is defined in Rule 13d-3
under the Securities Exchange Act of 1934, as amended and the rules and
regulations thereunder (the "Exchange Act")) any shares of Company Common Stock,
other than the Shares.

               (c)  Each Stockholder has the right, power and authority to
execute and deliver this Agreement and to perform its obligations under this
Agreement, and this Agreement

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has been duly executed and delivered by each Stockholder.  Assuming that this
Agreement has been duly and validly authorized, executed and delivered by
Dura, this Agreement constitutes a valid and legally binding agreement of
each Stockholder, enforceable in accordance with its terms, subject to
bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and
similar laws of general applicability relating to or affecting creditors'
rights and to general principles of equity.

               (d)  The Shares are now and will at all times during the term
of this Agreement be held by the Stockholders or by a nominee or custodian
for the account of the Stockholders, free and clear of all pledges, liens,
proxies, claims, charges, security interests, preemptive rights, voting
trusts and any other encumbrances whatsoever with respect to the ownership,
transfer or voting of the Shares, except for customary brokers' liens and
Dura's rights under the Company's organizational documents.  There are no
outstanding options, warrants or rights to purchase or acquire, or other
agreements relating to, the Shares, other than this Agreement and pursuant to
the terms of the Company's organizational documents.

The representations and warranties contained herein shall be made as of the date
hereof and as of each date from the date hereof through and including the date
that the Merger is consummated.

          2.   REPRESENTATIONS, WARRANTIES AND COVENANTS OF DURA AND THE
COMPANY.  Dura and the Company each hereby represents and warrants to each of
the Stockholders as follows:

               (a)  Dura and the Company each has the right, power and authority
to execute and deliver this Agreement and to perform its obligations under this
Agreement, and this Agreement has been duly executed and delivered by each of
Dura and the Company.  Assuming that this Agreement has been duly and validly
authorized, executed and delivered by each of the Stockholders, this Agreement
constitutes a valid and legally binding agreement of each of Dura and the
Company, enforceable in accordance with its terms, subject to bankruptcy,
insolvency, fraudulent transfer, reorganization, moratorium and similar laws of
general applicability relating to or affecting creditors' rights and to general
principles of equity.

               (b)  Dura and the Company (taken together with all of their
Affiliates (as such term is defined in Rule 12b-2 under the Exchange Act) and
all other persons acting in concert or as part of a group (as defined under Rule
13d-3 under the Exchange Act) with either of them) do not have the right to
vote, or agreements, arrangements or understandings with other persons to vote,
which together constitute a sufficient number of shares of Company Common Stock
to adopt the Merger Agreement under the General Corporation Law of the State of
Delaware and have no such rights to vote, agreements, arrangements or
understandings (other than this Agreement).  Other than revocable proxies
solicited by the board of directors of the Company to vote in favor of the
adoption of the Merger Agreement, Dura and the Company each covenant not to
solicit or obtain (directly or indirectly) any rights to vote, agreements,
arrangements or understandings with respect to voting of shares of Company
Common Stock before June 18, 2000.  A vote of a majority of the outstanding
shares of Company Common Stock is required to adopt the Merger Agreement.

                                  2
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          3.   AGREEMENT TO VOTE SHARES.  Each Stockholder agrees to:  (a)
appear, or cause the record holder of the Shares beneficially owned by it on the
applicable record date (the "Record Holder") to appear, at any annual or special
meeting of the stockholders of the Company at which adoption of the Merger
Agreement will be considered for the purpose of obtaining a quorum and (b) vote,
and cause the Record Holder to vote, the Shares beneficially owned by such
Stockholder (i) in favor of adoption of the Merger Agreement (and each other
action and transaction contemplated by the Merger Agreement and this Agreement)
at every meeting of the stockholders of the Company at which such matters are
considered and at every adjournment thereof and (ii) against any action or
proposal that would compete with or could serve to materially interfere with,
delay, discourage, adversely affect or inhibit the timely consummation of the
Merger, with the total number of such Stockholder's Shares and any New Shares
correctly indicated.

          4.   NO PROXY SOLICITATIONS.  Each Stockholder agrees that such
Stockholder will not, nor will such Stockholder permit any entity under its
control to, (a) solicit proxies or become a "participant" in a "solicitation"
(as such terms are defined in Regulation 14A under the Exchange Act) in
opposition to or competition with the consummation of the Merger or otherwise
encourage or assist any party in taking or planning any action which would
compete with or otherwise could serve to materially interfere with, delay,
discourage, adversely affect or inhibit the timely consummation of the Merger in
accordance with the terms of the Merger Agreement, (b) directly or indirectly
encourage, initiate or cooperate in a stockholders' vote or action by consent of
the Company's stockholders in opposition to or in competition with the
consummation of the Merger or (c) become a member of a "group" (as such term is
used in Section 13(d) of the Exchange Act) with respect to any voting securities
of the Company for the purpose of opposing or competing with the consummation of
the Merger.

          5.   TRANSFER AND ENCUMBRANCE.  On or after the date hereof, each
Stockholder agrees not to voluntarily transfer, sell, offer, assign, pledge or
otherwise dispose of or encumber ("Transfer") any of the Shares or New Shares
prior to the earlier of (a) the effective date of the Merger or (b) the date
this Agreement shall be terminated in accordance with its terms.  In furtherance
of this Agreement, concurrently herewith each Stockholder shall, and hereby
does, authorize the Company's transfer agent to place a stop transfer order with
respect to the Shares beneficially owned by such Stockholder and acknowledges
that this Agreement places limitations on the voting and transfer of such
shares.

                                  3
<PAGE>

          6.   PERFORMANCE OF THE MERGER AGREEMENT.  Dura and the Company each
will cause each of (a) the Special Meeting (as defined in the Merger Agreement)
and (b) the Effective Time (as defined in the Merger Agreement) to occur on or
after June 18, 2000.

          7.   SPECIFIC PERFORMANCE.  Each party hereto acknowledges that it
will be impossible to measure in money the damage to the other party if the
party hereto fails to comply with any of the obligations imposed by this
Agreement, that every such obligation is material and that, in the event of any
such failure, the other party will not have an adequate remedy at law or  by way
of damages.  Accordingly, each party hereto agrees that injunctive relief or
other equitable remedy, in addition to remedies at law or damages, is the
appropriate remedy for any such failure and will not oppose the granting of such
relief on the basis that the other party has an adequate remedy at law.  Each
party hereto agrees that it will not seek, and agrees to waive any requirement
for, the securing or posting of a bond in connection with any other party's
seeking or obtaining such equitable relief.

          8.   SUCCESSORS AND ASSIGNS.  This Agreement shall be binding upon,
inure to the benefit of, and be enforceable by the parties hereto and their
respective successors and assigns.  Nothing in this Agreement, express or
implied, is intended to confer upon any other person any rights or remedies of
any nature whatsoever under or by reason of this Agreement.  This Agreement
shall not be assignable without the written consent of the other party hereto.

          9.   TERMINATION.  This Agreement will terminate upon the earliest to
occur of (i) the Effective Time, (ii) the termination of the Merger Agreement,
(iii) September 30, 2000, (iv) a decrease in the merger consideration payable
under the Merger Agreement by way of waiver of amendment, waiver or otherwise,
(v) if any of the representations, warranties or covenants in Section 2(b) of
this Agreement become untrue or are not complied with at any time, (vi) if the
board of directors of the Company (or any committee thereof) withdraws or
modifies its approval or recommendation of the Merger Agreement as contemplated
by Section 6.4 of the Merger Agreement, (vii) if the board of directors of the
Company (or any committee thereof) approves or recommends or proposes to approve
or recommend any Superior Proposal (as defined in the Merger Agreement) as
contemplated by Section 6.4 of the Merger Agreement or (viii) if an unsolicited
third party Acquisition Proposal (as defined in the Merger Agreement) is made
with respect to at least a majority of the outstanding shares of Company Common
Stock and the Company has not, at or prior to the date the Stockholders of
Company vote on the adoption of the Merger Agreement, received a fairness
opinion, dated subsequent to the date of such Acquisition Proposal, with respect
to the transactions contemplated by the Merger Agreement.

          10.  ENTIRE AGREEMENT.  This Agreement supersedes all prior
agreements, written or oral, among the parties hereto with respect to the
subject matter hereof and contains the entire agreement among the parties with
respect to the subject matter hereof.  This Agreement may not be amended,
supplemented or modified, and no provisions hereof may be modified or waived,
except by an instrument in writing signed by the parties hereto.  No waiver of
any provisions hereof by any party shall be deemed a waiver of any other
provisions hereof by any such party, nor shall any such waiver be deemed a
continuing waiver of any provision hereof by such party.

                                  4
<PAGE>

          11.  GOVERNING LAW.  This Agreement shall be deemed a contract made
under, and for all purposes shall be 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 law.

          12.  SEVERABILITY.  If any provision of this Agreement or the
application of such provision to any person or circumstances shall be held
invalid by a court of competent jurisdiction, the remainder of the provision
held invalid and the application of such provision to persons or circumstances,
other than the party as to which it is held invalid, shall not be affected.

          13.  COUNTERPARTS.  This Agreement may be executed in one or more
counterparts, each of which shall be deemed to be an original but all of which
together shall constitute one and the same instrument.

          14.  HEADINGS.  All Section headings herein are for convenience of
reference only and are not part of this Agreement, and no construction or
reference shall be derived therefrom.

                                  5
<PAGE>

          IN WITNESS WHEREOF, the parties hereto have executed and delivered
this Agreement as of the date first written above.

                   FARALLON CAPITAL PARTNERS, L.P.
                   FARALLON CAPITAL INSTITUTIONAL PARTNERS, L.P.
                   FARALLON CAPITAL INSTITUTIONAL PARTNERS II, L.P.
                   FARALLON CAPITAL INSTITUTIONAL PARTNERS III, L.P.
                   TINICUM PARTNERS, L.P.

                   By:  FARALLON PARTNERS, L.P., their general partner

                   By: /s/ Mark C. Wehrly
                       -------------------------------------------
                       Name: Mark C. Wehrly
                       Title:   Managing Member

                   FARALLON CAPITAL MANAGEMENT, L.L.C.,
                         on behalf of the Managed Accounts

                   By:   /s/ Mark C. Wehrly
                       -------------------------------------------
                       Name: Mark C. Wehrly
                       Title:   Managing Member

                   DURA PHARMACEUTICALS, INC.

                   By:   /s/ Michael T. Borer
                       -------------------------------------------
                       Name:  Michael T. Borer
                       Title:  Senior Vice President and Chief Financial Officer

                    STARFISH ACQUISITION CORP., INC.

                   By:  /s/ Michael T. Borer
                       -------------------------------------------
                       Name:  Michael T. Borer
                       Title:    Chief Financial Officer and Treasurer

                    SPIROS DEVELOPMENT CORPORATION II, INC.

                   By:  /s/ Earle T. Mast
                       -------------------------------------------
                       Name:  Earle T. Mast
                       Title:    Vice President and Chief Financial Officer

                                        6

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