<PAGE>
                                                                     EXHIBIT 4.1

                         COMMON STOCK PURCHASE AGREEMENT




                          DATED AS OF DECEMBER 29, 2000




                                 BY AND BETWEEN



                         RIBOZYME PHARMACEUTICALS, INC.



                                       AND



                                ACQUA WELLINGTON
                       NORTH AMERICAN EQUITIES FUND, LTD.


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                                TABLE OF CONTENTS

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                                                                                                               PAGE
<S>                    <C>                                                                                     <C>
ARTICLE I                Definitions..............................................................................1

         Section 1.1       Definitions............................................................................1

ARTICLE II               Purchase and Sale of Common Stock........................................................3

         Section 2.1       Purchase and Sale of Stock.............................................................3
         Section 2.2       The Shares.............................................................................3
         Section 2.3       Purchase Price and Closing.............................................................3

ARTICLE III              Representations and Warranties...........................................................4

         Section 3.1       Representations and Warranties of the Company..........................................4
         Section 3.2       Representations and Warranties of the Purchaser.......................................11

ARTICLE IV               Covenants...............................................................................12

         Section 4.1       Securities Compliance.................................................................12
         Section 4.2       Registration and Listing..............................................................12
         Section 4.3       Registration Statement................................................................12
         Section 4.4       Compliance with Laws..................................................................12
         Section 4.5       Keeping of Records and Books of Account...............................................13
         Section 4.6       Reporting Requirements................................................................13
         Section 4.7       Non-public Information................................................................13
         Section 4.8       Effective Registration Statement......................................................13
         Section 4.9       No Stop Orders........................................................................13
         Section 4.10      Amendments to the Registration Statement..............................................14
         Section 4.11      Prospectus Delivery...................................................................14
         Section 4.12      Other Financing.......................................................................14
         Section 4.13      Notice................................................................................15

ARTICLE V                Conditions to Closing, Draw Downs and Call Options......................................15

         Section 5.1       Conditions Precedent to the Obligation of the Company to Issue a Draw
                              Down Notice or Grant a Call Option and Sell the Shares.............................15
         Section 5.2       Conditions Precedent to the Obligation of the Purchaser to Close......................16
         Section 5.3       Conditions Precedent to the Obligation of the Purchaser to Accept a
                              Draw Down or Call Option Grant and Purchase the Shares.............................17

ARTICLE VI               Draw Down Terms; Call Option............................................................18

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<S>                    <C>                                                                                     <C>
         Section 6.1       Draw Down Terms.......................................................................18
         Section 6.2       Purchaser's Call Option...............................................................20

ARTICLE VII              Termination.............................................................................21

         Section 7.1       Termination by Mutual Consent.........................................................21
         Section 7.2       Other Termination.....................................................................21
         Section 7.3       Effect of Termination.................................................................22

ARTICLE VIII             Indemnification.........................................................................22

         Section 8.1       General Indemnity.....................................................................22
         Section 8.2       Indemnification Procedures............................................................23

ARTICLE IX               Miscellaneous...........................................................................24

         Section 9.1       Fees and Expenses.....................................................................24
         Section 9.2       Specific Enforcement, Consent to Jurisdiction.........................................25
         Section 9.3       Entire Agreement; Amendment...........................................................25
         Section 9.4       Notices...............................................................................25
         Section 9.5       Waivers...............................................................................26
         Section 9.6       Headings..............................................................................26
         Section 9.7       Successors and Assigns................................................................27
         Section 9.8       Governing Law.........................................................................27
         Section 9.9       Survival..............................................................................27
         Section 9.10      Counterparts..........................................................................27
         Section 9.11      Publicity.............................................................................27
         Section 9.12      Severability..........................................................................27
         Section 9.13      Further Assurances....................................................................28

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                                      -ii-
<PAGE>

                         COMMON STOCK PURCHASE AGREEMENT



     This COMMON STOCK PURCHASE AGREEMENT (this "AGREEMENT") is dated as of
December 29, 2000 by and between Ribozyme Pharmaceuticals, Inc., a Delaware
corporation (the "COMPANY"), and Acqua Wellington North American Equities Fund,
Ltd., a limited liability company organized under the laws of the Commonwealth
of The Bahamas (the "PURCHASER").

     The parties hereto agree as follows:


                                    ARTICLE I

                                   Definitions

          SECTION 1.1 DEFINITIONS.

          (a) "ALTERNATE MARKET" shall mean the Nasdaq Small Cap Market, the
American Stock Exchange, the New York Stock Exchange or the OTC Bulletin Board,
whichever is at the time the principal trading exchange or market for the Common
Stock.

          (b) "CALL OPTION" shall have the meaning assigned to such term in
Section 6.2(a) hereof.

          (c)  "COMMISSION" shall mean the Securities and Exchange Commission.

          (d) "COMMISSION DOCUMENTS" shall have the meaning assigned to such
term in Section 3.1(f) hereof.

          (e) "COMMISSION FILINGS" means the Company's Form 10-K for the fiscal
year ended December 31, 1999, Forms 10-Q for the periods ended March 31, 2000,
June 30, 2000 and September 30, 2000, Registration Statement on Form S-3, No.
333-49400 and Form 8-K, dated December 5, 2000 and all other filings made by the
Company after the date hereof pursuant to the Securities Exchange Act of 1934.

          (f) "COMMON STOCK" shall have the meaning assigned to such term in
Section 2.1 hereof.

          (g) "DRAW DOWN" means the exercise by the Company of its right to
request the purchase of shares of Common Stock by the Purchaser.

          (h) "DRAW DOWN AMOUNT" means the actual amount of a Draw Down up to
$8,000,000 or such other amount mutually agreed upon by the Purchaser and the
Company.

          (i)  "DRAW DOWN DISCOUNT PERCENTAGE" shall mean the following: if the
Threshold Price is equal to or greater than $12.00 but less than $15.00, the
draw down discount

                                       -1-
<PAGE>


percentage shall equal 93.4%; if the Threshold Price is equal to or greater than
$15.00 but less than $18.00, the draw down discount percentage shall equal
93.6%; if the Threshold Price is equal to or greater than $18.00 but less than
$24.00, the draw down discount percentage shall equal 94%; PROVIDED, HOWEVER,
that for every $3.00 increase in the Threshold Price from $24.00 to $36.00, the
draw down discount percentage shall be increased 0.2%, incrementally, up to a
maximum draw down discount percentage of 95%; PROVIDED, FURTHER, that for every
$3.00 increase in the Threshold Price from $39.00 to $51.00, the draw down
discount percentage shall be increased by 0.1% incrementally, up to a maximum
draw down discount percentage of 95.5%.

          (j) "DRAW DOWN EXERCISE DATE" shall have the meaning assigned to such
term in Section 5.1 hereof.

          (k) "DRAW DOWN NOTICE" shall have the meaning assigned to such term in
Section 6.1(i) hereof.

          (l) "DRAW DOWN PRICING PERIOD" shall mean a period of twenty (20)
consecutive Trading Days following a Draw Down Notice, or such other period
mutually agreed upon by the Purchaser and the Company.

          (m) "EFFECTIVE DATE" shall mean November 17, 2000, the date the
Registration Statement of the Company covering the Shares being subscribed for
hereby was declared effective.

          (n) "INVESTMENT PERIOD " shall have the meaning assigned to such term
in Section 7.1 hereof.

          (o) "MATERIAL ADVERSE EFFECT" shall mean any effect on the business,
results of operations, prospects, assets or financial condition of the Company
that is material and adverse to the Company and its subsidiaries, taken as a
whole and/or any condition, circumstance, or situation that would prohibit the
Company from entering into and performing any of its obligations under this
Agreement in any material respect.

          (p) "MATERIAL CHANGE IN OWNERSHIP" shall mean that, as of any
particular measurement date, the officers and directors of the Company shall
beneficially own in the aggregate less than 5% of the outstanding Common Stock
of the Company, except that for purposes of making any such calculation, Common
Stock issued to the Purchaser pursuant to this Agreement shall not be included
in such calculation.

          (q) "PROSPECTUS" as used in this Agreement means the prospectus in the
form included in the Registration Statement, as supplemented by any prospectus
supplement filed with the Commission pursuant to Rule 424(b).

          (r) "REGISTRATION STATEMENT" shall mean the registration statement on
Form S-3, Commission File Number 333-49400 under the Securities Act, filed with
the Commission for the registration of the Shares, as such Registration
Statement may be amended from time to time.


                                       -2-
<PAGE>

          (s) "SECURITIES ACT" shall mean the Securities Act of 1933, as
amended, and the rules and regulations of the Commission thereunder.

          (t) "SETTLEMENT DATE" shall have the meaning assigned to such term in
Section 6.1(d) hereof.

          (u) "SHARES" shall mean the shares of Common Stock of the Company that
may be purchased hereunder.

          (v) "THRESHOLD PRICE" is the lowest price at which the Company may set
in the Draw Down Notice to sell Shares during a Draw Down Pricing Period (not
taking into account the Draw Down Discount Percentage during such Draw Down
Pricing Period).

          (w) "TRADING DAY" shall mean a day on which the Common Stock is traded
on the Nasdaq National Market or an Alternate Market.

          (x) "VWAP" shall mean the daily volume weighted average price (based
on a Trading Day from 9:30 a.m. to 4:00 p.m., eastern time) of the Common Stock
of the Company on the NASDAQ National Market or an Alternate Market as reported
by Bloomberg Financial LP using the AQR function.



                                   ARTICLE II

                        PURCHASE AND SALE OF COMMON STOCK

          SECTION 2.1 PURCHASE AND SALE OF STOCK. Subject to the terms and
conditions of this Agreement, the Company shall issue and sell to the Purchaser
and the Purchaser shall purchase from the Company up to $60,000,000 of the
Company's common stock, $0.01 par value per share (the "COMMON STOCK"), based on
Draw Downs, subject to Section 6.1 hereof, of up to $8,000,000 per Draw Down and
up to an additional $8,000,000 of Common Stock based on Call Options of up to
the Draw Down Amount for the applicable Draw Down Pricing Period that the
Company may grant to the Purchaser in the Company's sole discretion.

          SECTION 2.2 THE SHARES. The Company has authorized and has reserved
and covenants to continue to reserve, subject to Section 4.4(b) hereof, free of
preemptive rights and other similar contractual rights of stockholders, a
sufficient number of its authorized but unissued shares of its Common Stock to
cover the Shares to be issued in connection with all Draw Downs and Call
Options.

          SECTION 2.3 PURCHASE AND CLOSING. In consideration of and in express
reliance upon the representations, warranties, covenants, terms and conditions
of this Agreement, the Company agrees to issue and sell to the Purchaser and the
Purchaser, agrees to purchase that number of the Shares to be issued in
connection with each Draw Down and each Call Option exercised by the Purchaser.
The closing of the execution and delivery of this Agreement shall occur upon
delivery by facsimile of executed signature pages of this Agreement and all
other documents, instruments and writings required to be delivered pursuant to
this Agreement to the

                                       -3-
<PAGE>

offices of Parker Chapin LLP, The Chrysler Building, 405 Lexington Avenue, New
York, NY 10174 (the "CLOSING") at 10:00 a.m., eastern time, on (i) December 29,
2000, or (ii) such other time and place or on such date as the Purchaser and the
Company may agree upon (the "CLOSING DATE"). Each party shall deliver all
documents, instruments and writings required to be delivered by such party
pursuant to this Agreement at or prior to the Closing.


                                   ARTICLE III

                         REPRESENTATIONS AND WARRANTIES

          SECTION 3.1 REPRESENTATIONS AND WARRANTIES OF THE COMPANY. The Company
hereby makes the following representations and warranties to the Purchaser:

          (a) ORGANIZATION, GOOD STANDING AND POWER. The Company is a
corporation duly incorporated, validly existing and in good standing under the
laws of Delaware and has the requisite corporate power to own, lease and operate
its properties and assets and to conduct its business as it is now being
conducted. As of the date hereof, the Company does not have any subsidiaries (as
defined in Section 3.1(g)) except as set forth in the Registration Statement and
in the Company's most recent Form 10-K, including the accompanying financial
statements (the "FORM 10-K"), or in the Company's most recent Form 10-Q (the
"FORM 10-Q"), or on SCHEDULE 3.1(g) attached hereto. The Company and each such
subsidiary is duly qualified as a foreign corporation to do business and is in
good standing in every jurisdiction in which the nature of the business
conducted or property owned by it makes such qualification necessary except for
any jurisdiction in which the failure to be so qualified will not have a
Material Adverse Effect.

          (b) AUTHORIZATION; ENFORCEMENT. The Company has the requisite
corporate power and authority to enter into and perform this Agreement and to
issue and sell the Shares in accordance with the terms hereof. The execution,
delivery and performance of this Agreement by the Company and the consummation
by it of the transactions contemplated hereby have been duly and validly
authorized by all necessary corporate action, and, except as contemplated by
Section 4.4(b), no further consent or authorization of the Company or its Board
of Directors or stockholders is required. This Agreement has been duly executed
and delivered by the Company. This Agreement constitutes, or shall constitute
when executed and delivered, a valid and binding obligation of the Company
enforceable against the Company in accordance with its terms, except as such
enforceability may be limited by applicable bankruptcy, insolvency,
reorganization, moratorium, liquidation, conservatorship, receivership or
similar laws relating to, or affecting generally the enforcement of, creditor's
rights and remedies or by other equitable principles of general application.

          (c) CAPITALIZATION. The authorized capital stock of the Company and
the shares thereof issued and outstanding as of the date hereof are set forth on
SCHEDULE 3.1(c) attached hereto. All of the outstanding shares of the Company's
Common Stock have been duly and validly authorized, and are fully paid and
non-assessable. Except as set forth in this Agreement including SCHEDULE 3.1(c),
as of the date hereof no shares of Common Stock are entitled to preemptive
rights or registration rights and there are no outstanding options, warrants,
scrip, rights to subscribe to, call or commitments of any character whatsoever
relating to, or

                                       -4-
<PAGE>

securities or rights convertible into, any shares of capital stock of the
Company. Furthermore, except as set forth in this Agreement including SCHEDULE
3.1(c), as of the date hereof there are no contracts, commitments,
understandings, or arrangements by which the Company is or may become bound to
issue additional shares of the capital stock of the Company or options,
securities or rights convertible into shares of capital stock of the Company.
Except for customary transfer restrictions contained in agreements entered into
by the Company in order to sell restricted securities or as set forth in
SCHEDULE 3.1(c), as of the date hereof, the Company is not a party to any
agreement granting registration rights to any person with respect to any of its
equity or debt securities. The Company is not a party to, and it has no
knowledge of, any agreement restricting the voting or transfer of any shares of
the capital stock of the Company. The offer and sale of all capital stock,
convertible securities, rights, warrants, or options of the Company issued prior
to the Closing complied with all applicable federal and state securities laws,
and no stockholder has a right of rescission or damages with respect thereto
which would have a Material Adverse Effect. The Company has furnished or made
available to the Purchaser true and correct copies of the Company's Certificate
of Incorporation and in effect on the date hereof (the "CHARTER"), and the
Company's Bylaws as in effect on the date hereof (the "BYLAWS").

          (d) ISSUANCE OF SHARES. The Shares to be issued under this Agreement
have been duly authorized by all necessary corporate action and, when paid for
and issued in accordance with the terms hereof, the Shares shall be validly
issued and outstanding, fully paid and non-assessable, and the Purchaser shall
be entitled to all rights accorded to a holder of Common Stock.

          (e) NO CONFLICTS. The execution, delivery and performance of this
Agreement by the Company and the consummation by the Company of the transactions
contemplated herein do not (i) violate any provision of the Company's Charter or
Bylaws, (ii) conflict with, or constitute a default (or an event which with
notice or lapse of time or both would become a default) under, or give to others
any rights of termination, amendment, acceleration or cancellation of, any
material agreement, mortgage, deed of trust, indenture, note, bond, license,
lease agreement, instrument or obligation to which the Company is a party, (iii)
create or impose a lien, charge or encumbrance on any property of the Company
under any agreement or any commitment to which the Company is a party or by
which the Company is bound or by which any of its respective properties or
assets are bound, or (iv) result in a violation of any federal, state, local or
foreign statute, rule, regulation, order, judgment or decree (including federal
and state securities laws and regulations) applicable to the Company or any of
its subsidiaries or by which any property or asset of the Company or any of its
subsidiaries are bound or affected, except, in all cases (other than violations
pursuant to clauses (i) and (iv) (to the extent of federal securities law)), for
such conflicts, defaults, terminations, amendments, acceleration, cancellations
and violations as would not, individually or in the aggregate, have a Material
Adverse Effect. The Company is not required under federal, state or local law,
rule or regulation to obtain any consent, authorization or order of, or make any
filing or registration with, any court or governmental agency in order for it to
execute, deliver or perform any of its obligations under this Agreement, or
issue and sell the Shares in accordance with the terms hereof (other than any
filings which may be required to be made by the Company with the Commission, or
the Nasdaq National Market subsequent to the Closing, and, any registration
statement which may be filed pursuant hereto); provided that, for purpose of the
representation made in this sentence, the

                                       -5-
<PAGE>

Company is assuming and relying upon the accuracy of the relevant
representations and agreements of the Purchaser herein.

          (f) COMMISSION DOCUMENTS, FINANCIAL STATEMENTS. The Common Stock of
the Company is registered pursuant to Section 12(b) or 12(g) of the Securities
Exchange Act of 1934, as amended (the "EXCHANGE ACT"), and since December 31,
1999 the Company has timely filed all reports, schedules, forms, statements and
other documents required to be filed by it with the Commission pursuant to the
reporting requirements of the Exchange Act, including material filed pursuant to
Section 13(a) or 15(d) of the Exchange Act (all of the foregoing including
filings incorporated by reference therein being referred to herein as the
"COMMISSION DOCUMENTS"). The Company has delivered or made available to the
Purchaser true and complete copies of the Commission Documents filed with the
Commission since December 31, 1999 and prior to the Closing Date. The Company
has not provided to the Purchaser any information which, according to applicable
law, rule or regulation, should have been disclosed publicly by the Company but
which has not been so disclosed, other than with respect to the transactions
contemplated by this Agreement. The Form 10-K for the year ended December 31,
1999 complied in all material respects with the requirements of the Exchange Act
and the rules and regulations of the Commission promulgated thereunder and other
federal, state and local laws, rules and regulations applicable to such
documents, and the said Form 10-K did not contain any untrue statement of a
material fact or omit to state a material fact required to be stated therein or
necessary in order to make the statements therein, in light of the circumstances
under which they were made, not misleading. The financial statements of the
Company included in the Commission Documents comply as to form in all material
respects with applicable accounting requirements and the published rules and
regulations of the Commission or other applicable rules and regulations with
respect thereto. Such financial statements have been prepared in accordance with
generally accepted accounting principles ("GAAP") applied on a consistent basis
during the periods involved (except (i) as may be otherwise indicated in such
financial statements or the notes thereto or (ii) in the case of unaudited
interim statements, to the extent they may not include footnotes or may be
condensed or summary statements), and fairly present in all material respects
the financial position of the Company and its subsidiaries as of the dates
thereof and the results of operations and cash flows for the periods then ended
(subject, in the case of unaudited statements, to normal year-end audit
adjustments).

          (g) SUBSIDIARIES. The Commission Documents or SCHEDULE 3.1(g) attached
hereto set forth each subsidiary of the Company as of the date hereof, showing
the jurisdiction of its incorporation or organization and showing the percentage
of each person's ownership of the outstanding stock or other interests of such
subsidiary. For the purposes of this Agreement, "subsidiary" shall mean any
corporation or other entity of which at least a majority of the securities or
other ownership interest having ordinary voting power (absolutely or
contingently) for the election of directors or other persons performing similar
functions are at the time owned directly or indirectly by the Company and/or any
of its other subsidiaries. Except as set forth in the Commission Documents or
the Commission Filings, none of such subsidiaries is a "significant subsidiary"
as defined in Regulation S-X.

          (h)  NO MATERIAL ADVERSE EFFECT. Since September 30, 2000, the Company
has not experienced or suffered any Material Adverse Effect.

                                       -6-
<PAGE>

          (i) NO UNDISCLOSED LIABILITIES. The Company has no liabilities,
obligations, claims or losses (whether liquidated or unliquidated, secured or
unsecured, absolute, accrued, contingent or otherwise) that would be required to
be disclosed on a balance sheet of the Company or any subsidiary (including the
notes thereto) in conformity with GAAP not disclosed in the Commission
Documents, other than those incurred in the ordinary course of the Company's or
its subsidiaries respective businesses since September 30, 2000 and which,
individually or in the aggregate, do not or would not have a Material Adverse
Effect.

          (j) NO UNDISCLOSED EVENTS OR CIRCUMSTANCES. No event or circumstance
has occurred or exists with respect to the Company or its subsidiaries or their
respective businesses, properties, prospects, operations or financial condition,
which, under applicable law, rule or regulation, requires public disclosure or
announcement by the Company but which has not been so publicly announced or
disclosed and which, individually or in the aggregate, do not or would not have
a Material Adverse Effect.

          (k) INDEBTEDNESS. SCHEDULE 3.1(k) sets forth as of September 30, 2000
all outstanding secured and unsecured Indebtedness of the Company, or for which
the Company or any subsidiary has commitments. For the purposes of this
Agreement, "Indebtedness" shall mean (a) any liabilities for borrowed money or
amounts owed in excess of $100,000 (other than trade accounts payable incurred
in the ordinary course of business), (b) all guaranties, endorsements and other
contingent obligations in respect of Indebtedness of others, whether or not the
same are or should be reflected in the Company's balance sheet (or the notes
thereto), except guaranties by endorsement of negotiable instruments for deposit
or collection or similar transactions in the ordinary course of business; and
(c) the present value of any lease payments in excess of $100,000 due under
leases required to be capitalized in accordance with GAAP. Neither the Company
or any subsidiary is in default with respect to any Indebtedness.

          (l) TITLE TO ASSETS. Each of the Company and its subsidiary has good
and marketable title to all of its real and personal property reflected in the
Commission Documents, free of any mortgages, pledges, charges, liens, security
interests or other encumbrances, except for those indicated in the Commission
Documents or the Commission Filings or such that could not reasonably be
expected to cause a Material Adverse Effect. All said leases of the Company and
each of its subsidiaries are valid and subsisting and in full force and effect
in all material respects.

          (m) ACTIONS PENDING. There is no action, suit, claim, investigation or
proceeding pending or, to the knowledge of the Company, threatened against the
Company which questions the validity of this Agreement or the transactions
contemplated hereby or any action taken or to be taken pursuant hereto or
thereto. There is no action, suit, claim, investigation or proceeding pending
or, to the knowledge of the Company, threatened, against or involving the
Company or any subsidiary, or any of their respective properties or assets
which, if adversely determined, is reasonably likely to result in a Material
Adverse Effect.

          (n) COMPLIANCE WITH LAW. The business of the Company has been and is
presently being conducted in accordance with all applicable federal, state and
local governmental laws, rules, regulations and ordinances, except as such that
do not cause a Material Adverse Effect. Each of the Company and its subsidiary
has all franchises, permits, licenses, consents

                                       -7-
<PAGE>

and other governmental or regulatory authorizations and approvals necessary for
the conduct of its business as now being conducted unless the failure to possess
such franchises, permits, licenses, consents and other governmental or
regulatory authorizations and approvals, individually or in the aggregate, could
not reasonably be expected to have a Material Adverse Effect.

          (o)  CERTAIN FEES. No brokers, finders or financial advisory fees or
commissions will be payable by the Company with respect to the transactions
contemplated by this Agreement.

          (p) DISCLOSURE. To the Company's knowledge, neither this Agreement or
the Schedules hereto nor any other documents, certificates or instruments
furnished to the Purchaser by or on behalf of the Company in connection with the
transactions contemplated by this Agreement contain any untrue statement of a
material fact or omits to state a material fact necessary in order to make the
statements made herein or therein, in the light of the circumstances under which
they were made herein or therein, not misleading.

          (q) OPERATION OF BUSINESS. The Company or its subsidiary owns or has a
valid right to use all patents, trademarks, service marks, trade names,
copyrights, licenses and authorizations as set forth in the Commission Documents
or the Commission Filings and all rights with respect to the foregoing, which
are necessary for the conduct of its business as now conducted without any
conflict with the rights of others, except to the extent set forth in the
Commission Documents or the Commission Filings that a Material Adverse Effect
could not reasonably be expected to result from such conflict.

          (r) ENVIRONMENTAL COMPLIANCE. Except as disclosed in the Commission
Filings, the Company has obtained all approvals, authorization, certificates,
consents, licenses, orders and permits or other similar authorizations of all
governmental authorities, or from any other person, that are required under any
Environmental Laws except where the failure to do so would not have a Material
Adverse Effect. "Environmental Laws" shall mean all applicable laws relating to
the protection of the environment including, without limitation, all
requirements pertaining to reporting, licensing, permitting, controlling,
investigating or remediating emissions, discharges, releases or threatened
releases of hazardous substances, chemical substances, pollutants, contaminants
or toxic substances, materials or wastes, whether solid, liquid or gaseous in
nature, into the air, surface water, groundwater or land, or relating to the
manufacture, processing, distribution, use, treatment, storage, disposal,
transport or handling of hazardous substances, chemical substances, pollutants,
contaminants or toxic substances, material or wastes, whether solid, liquid or
gaseous in nature. Except for such instances as would not individually or in the
aggregate have a Material Adverse Effect, to the best of the Company's
knowledge, there are no past or present events, conditions, circumstances,
incidents, actions or omissions relating to or in any way affecting the Company
that violate or could reasonably be expected to violate any Environmental Law
after the Closing or that could reasonably be expected to give rise to any
environmental liability, or otherwise form the basis of any claim, action,
demand, suit, proceeding, hearing, study or investigation (i) under any
Environmental Law, or (ii) based on or related to the manufacture, processing,
distribution, use, treatment, storage (including without limitation underground
storage tanks), disposal, transport or handling, or the emission, discharge,
release or threatened release of any hazardous substance.

                                       -8-
<PAGE>

          (s) MATERIAL AGREEMENTS. Except as set forth in the Commission
Documents and this Agreement, the Company is not a party to any written or oral
contract, instrument, agreement, commitment, obligation, plan or arrangement, a
copy of which would be required to be filed with the Commission as an exhibit to
a registration statement on Form S-3 or applicable form (collectively, "MATERIAL
AGREEMENTS") if the Company was registering securities under the Securities Act.
The Company has in all material respects performed all the obligations required
to be performed by it to date under the foregoing agreements, has received no
notice of default and, to the best of the Company's knowledge is not in default
under any Material Agreement now in effect, the result of which could reasonably
be expected to cause a Material Adverse Effect.

          (t) TRANSACTIONS WITH AFFILIATES. There are no loans, leases,
agreements, contracts, royalty agreements, management contracts or arrangements
or other continuing transactions exceeding $100,000 between (a) the Company, or
any of its customers (excluding agreements related to the purchase or lease of
the Company's products) or suppliers on the one hand, and (b) on the other hand,
any officer, employee, consultant or director of the Company, or any person who
would be covered by Item 404(a) of Regulation S-K or any corporation or other
entity controlled by such officer, employee, consultant, director or person.

          (u) SECURITIES ACT OF 1933. The Company has complied in all material
respects with all applicable federal and state securities laws in connection
with the offer, issuance and sale of the Shares hereunder.

               (i) Each Prospectus included as part of the Registration
Statement as originally filed or as part of any amendment or supplement thereto,
or filed pursuant to Rule 424 under the Securities Act, complied when so filed
in all material respects with the provisions of the Securities Act. The
Commission has not issued any order preventing or suspending the use of any
Prospectus.

               (ii) The Company meets the requirements for the use of Form S-3
under the Securities Act. The Registration Statement in the form in which it
became effective and also in such form as it may be when any post-effective
amendment thereto became effective and the Prospectus and any supplement or
amendment thereto when filed with the Commission under Rule 424(b) under the
Securities Act, complied in all material respects with the provisions of the
Securities Act and did not at any such times contain an untrue statement of a
material fact or omit to state a material fact required to be stated therein or
necessary to make the statements therein (in the case of the Prospectus, in the
light of the circumstances under which they made) not misleading, except that
this representation and warranty does not apply to statements in or omissions
from the Registration Statement or the Prospectus made in reliance upon and in
conformity with information relating to the Purchaser furnished to the Company
in writing by or on behalf of the Purchaser expressly for use therein.

               (iii) The Company has not distributed and, prior to the
completion of the sale of the Shares to the Purchaser, will not distribute any
offering material in connection with the offering and sale of the Shares other
than the Registration Statement, the Prospectus or other materials, if any,
permitted by the Securities Act.

                                       -9-
<PAGE>

          (v) EMPLOYEES. As of the date hereof, the Company has no collective
bargaining arrangements or agreements covering any of its employees. Except as
set forth on SCHEDULE 3.1(v) attached hereto, as of the date hereof the Company
has no employment contract or any other similar contract or restrictive
covenant, relating to the right of any officer, employee or consultant to be
employed or engaged by the Company. Each of the Company and its subsidiary
requires its officers, technical employees and certain consultants to enter into
agreements regarding proprietary information and assignment of inventions, or
other similar agreements containing restrictive covenants. As of the date
hereof, since December 31, 1999, no officer, consultant or key employee of the
Company whose termination, either individually or in the aggregate, could
reasonably be expected to have a Material Adverse Effect, has terminated or, to
the knowledge of the Company, has any present intention of terminating his or
her employment or engagement with the Company.

          (w)  USE OF PROCEEDS. The proceeds from the sale of the Shares will be
used by the Company and its subsidiary for general corporate purposes.

          (x) PUBLIC UTILITY HOLDING COMPANY ACT AND INVESTMENT COMPANY ACT
STATUS. The Company is not a "holding company" or a "public utility company" as
such terms are defined in the Public Utility Holding Company Act of 1935, as
amended. The Company is not, and as a result of and immediately upon Closing
will not be, an "investment company" or a company "controlled" by an "investment
company," within the meaning of the Investment Company Act of 1940, as amended.

          (y) ERISA. No liability to the Pension Benefit Guaranty Corporation
has been incurred with respect to any Plan (as defined below) by the Company
which is or would have a Material Adverse Effect. The execution and delivery of
this Agreement and the issue and sale of the Shares will not involve any
transaction which is subject to the prohibitions of Section 406 of ERISA or in
connection with which a tax could be imposed pursuant to Section 4975 of the
Internal Revenue Code of 1986, as amended, provided that, if any of the
Purchaser, or any person or entity that owns a beneficial interest in any of the
Purchaser, is an "employee pension benefit plan" (within the meaning of Section
3(2) of ERISA) with respect to which the Company is a "party in interest"
(within the meaning of Section 3(14) of ERISA), the requirements of Sections
407(d)(5) and 408(e) of ERISA, if applicable, are met. As used in this Section
3.1(y), the term "Plan" shall mean an "employee pension benefit plan" (as
defined in Section 3 of ERISA) which is or has been established or maintained,
or to which contributions are or have been made, by the Company or by any trade
or business, whether or not incorporated, which, together with the Company, is
under common control, as described in Section 414(b) or (c) of the Code.

          (z) ACKNOWLEDGMENT REGARDING PURCHASER'S PURCHASE OF SHARES. The
Company acknowledges and agrees that the Purchaser is acting solely in the
capacity of arm's length purchaser with respect to this Agreement and the
transactions contemplated hereunder. The Company further acknowledges that the
Purchaser is not acting as a financial advisor or fiduciary of the Company (or
in any similar capacity) with respect to this Agreement and the transactions
contemplated hereunder and any advice given by the Purchaser or any of its
representatives or agents in connection with this Agreement and the transactions
contemplated hereunder is merely incidental to the Purchaser's purchase of the
Shares.

                                      -10-
<PAGE>

          SECTION 3.2 REPRESENTATIONS AND WARRANTIES OF THE PURCHASER. The
Purchaser hereby makes the following representations and warranties to the
Company:

          (a)  ORGANIZATION AND STANDING OF THE PURCHASER. The Purchaser is a
limited liability company duly organized, validly existing and in good standing
under the laws of the Commonwealth of the Bahamas.

          (b) AUTHORIZATION AND POWER. The Purchaser has the requisite corporate
power and authority to enter into and perform this Agreement and to purchase the
Shares in accordance with the terms hereof. The execution, delivery and
performance of this Agreement by Purchaser and the consummation by it of the
transactions contemplated hereby have been duly authorized by all necessary
corporate action, and no further consent or authorization of the Purchaser, its
Board of Directors or stockholders is required. This Agreement constitutes, or
shall constitute when executed and delivered, a valid and binding obligation of
the Purchaser enforceable against the Purchaser in accordance with its terms,
except as such enforceability may be limited by applicable bankruptcy,
insolvency, reorganization, moratorium, liquidation, conservatorship,
receivership, or similar laws relating to, or affecting generally the
enforcement of, creditor's rights and remedies or by other equitable principles
of general application.

          (c) NO CONFLICTS. The execution, delivery and performance of this
Agreement and the consummation by the Purchaser of the transactions contemplated
hereby and thereby or relating hereto do not and will not (i) result in a
violation of such Purchaser's charter documents or bylaws or (ii) conflict with,
or constitute a default (or an event which with notice or lapse of time or both
would become a default) under, or give to others any rights of termination,
amendment, acceleration or cancellation of any material agreement, mortgage,
deed of trust, indenture, note, bond, license, lease agreement, instrument or
obligation to which the Purchaser is a party, (iii) create or impose or lien,
charge or encumbrance on any property of the Purchaser under any agreement or
any commitment to which the Purchaser is party or by which the Purchaser is on
or by which any of its respective properties or assets are bound or (iv) result
in a violation of any law, rule, or regulation, or any order, judgment or decree
of any court or governmental agency applicable to the Purchaser or its
properties, except for such conflicts, defaults and violations as would not,
individually or in the aggregate, prohibit or otherwise interfere with the
ability of the Purchaser to enter into and perform its obligations under this
Agreement in any material respect. The Purchaser is not required to obtain any
consent, authorization or order of, or make any filing or registration with, any
court or governmental agency in order for it to execute, deliver or perform any
of its obligations under this Agreement or to purchase the Shares in accordance
with the terms hereof, provided that for purposes of the representation made in
this sentence, the Purchaser is assuming and relying upon the accuracy of the
relevant representations and agreements of the Company herein.

          (d) INFORMATION. The Purchaser and its advisors, if any, have been
furnished with all materials relating to the business, finances and operations
of the Company and materials relating to the offer and sale of the Shares which
have been requested by the Purchaser. The Purchaser and its advisors, if any,
have been afforded the opportunity to ask questions of the Company. The
Purchaser has sought such accounting, legal and tax advice as it has considered
necessary to make an informed investment decision with respect to its
acquisition of the Shares. Purchaser understands that it (and not the Company)
shall be responsible for its own tax

                                      -11-
<PAGE>

liabilities that may arise as a result of this investment or the transactions
contemplated by this Agreement.

          (e) SELLING RESTRICTION. The Purchaser has the right to sell shares of
the Company's Common Stock during the Investment Period. The Purchaser
covenants, however, that prior to and during the Investment Period, neither the
Purchaser nor any of its affiliates nor any entity managed by the Purchaser will
ever sell shares of Common Stock of the Company other than what the Purchaser
has accumulated to purchase under the terms of this Agreement or in any accounts
directly or indirectly managed by the Purchaser or any affiliate of the
Purchaser or any entity managed by the Purchaser.


                                   ARTICLE IV

                                    COVENANTS

     The Company covenants with the Purchaser as follows, which covenants are
for the benefit of the Purchaser and its permitted assignees, that during the
term of this Agreement:

          SECTION 4.1 SECURITIES COMPLIANCE. The Company shall notify the
Commission and the Nasdaq National Market or an Alternate Market, if applicable,
in accordance with their rules and regulations, of the transactions contemplated
by this Agreement, and shall take all other necessary action and proceedings as
may be required and permitted by applicable law, rule and regulation, for the
legal and valid issuance of the Shares to the Purchaser or subsequent holders.

          SECTION 4.2 REGISTRATION AND LISTING. The Company will take all action
necessary to cause its Common Stock to continue to be registered under Sections
12(b) or 12(g) of the Exchange Act, will comply in all respects with its
reporting and filing obligations under the Exchange Act, and will not take any
action or file any document (whether or not permitted by the Securities Act or
the rules promulgated thereunder) to terminate or suspend such registration or
to terminate or suspend its reporting and filing obligations under the Exchange
Act or Securities Act, except as permitted herein. The Company will take all
action necessary to continue the listing or trading of its Common Stock and the
listing of the Shares purchased by Purchaser hereunder on the Nasdaq National
Market or an Alternate Market and will comply in all respects with the Company's
reporting, filing and other obligations under the bylaws or rules of the Nasdaq
National Market or an Alternate Market.

          SECTION 4.3 REGISTRATION STATEMENT. Before the Company shall issue a
Draw Down Notice, the Company shall have caused a sufficient number of shares of
Common Stock to be authorized and registered to cover the Shares to be issued in
connection with this Agreement.

          SECTION 4.4 COMPLIANCE WITH LAWS.

          (a) The Company shall comply with all applicable laws, rules,
regulations and orders, noncompliance with which could have a Material Adverse
Effect.

                                      -12-
<PAGE>

          (b) The Company will not be obligated to issue and the Purchaser will
not be obligated to purchase any shares of the Company's Common Stock which
would result in the issuance under this Agreement of more than nineteen and
nine-tenths percent (19.9%) of the issued and outstanding shares of the
Company's Common Stock.

          SECTION 4.5 KEEPING OF RECORDS AND BOOKS OF ACCOUNT. The Company shall
keep adequate records and books of account, in which complete entries will be
made in accordance with GAAP consistently applied, reflecting all financial
transactions of the Company and its subsidiaries, and in which, for each fiscal
year, all proper reserves for depreciation, depletion, obsolescence,
amortization, taxes, bad debts and other purposes in connection with its
business shall be made.

          SECTION 4.6 REPORTING REQUIREMENTS. Upon request, the Company shall
furnish or make available the following to the Purchaser so long as such
Purchaser shall be obligated hereunder to purchase Shares:

          (a) Quarterly Reports filed with the Commission on Form 10-Q as soon
as available, and in any event within forty-five (45) days after the end of each
of the first three fiscal quarters of the Company; and

          (b) Annual Reports filed with the Commission on Form 10-K as soon as
available, and in any event within ninety (90) days after the end of each fiscal
year of the Company.

          SECTION 4.7 NON-PUBLIC INFORMATION. Neither the Company nor any of its
officers or agents shall disclose any material non-public information about the
Company to the Purchaser and neither the Purchaser nor any of its affiliates,
officers or agents will solicit any material non-public information from the
Company.

          SECTION 4.8 EFFECTIVE REGISTRATION STATEMENT. If it is necessary for
the Registration Statement or a post-effective amendment thereto to be declared
effective before the offering of the Shares may commence, the Company will
endeavor to cause the Registration Statement or such post-effective amendment to
become effective as soon as reasonably practicable and will advise the Purchaser
promptly and, if requested by the Purchaser, will confirm such advice in
writing, when it receives notice that the Registration Statement or such
post-effective amendment has become effective.

          SECTION 4.9 NO STOP ORDERS. The Company will advise the Purchaser
promptly and, if requested by the Purchaser, will confirm such advice in
writing: (i) of its receipt of notice of any request by the Commission for
amendment of or a supplement to the Registration Statement, any Prospectus or
for additional information; (ii) of its receipt of notice of the issuance by the
Commission of any stop order suspending the effectiveness of the Registration
Statement or of the suspension of qualification of the Shares for offering or
sale in any jurisdiction or the initiation of any proceeding for such purpose;
and (iii) of its becoming aware of the happening of any event, which makes any
statement of a material fact made in the Registration Statement or the
Prospectus (as then amended or supplemented) untrue or which requires the making
of any additions to or changes in the Registration Statement or the

                                      -13-
<PAGE>

Prospectus (as then amended or supplemented) in order to state a material fact
required by the Securities Act or the regulations thereunder to be stated
therein or necessary in order to make the statements therein not misleading, or
of the necessity to amend or supplement the Prospectus (as then amended or
supplemented) to comply with the Securities Act or any other law. If at any time
the Commission shall issue any stop order suspending the effectiveness of the
Registration Statement, the Company will make all reasonable efforts to obtain
the withdrawal of such order at the earliest possible time.

          SECTION 4.10 AMENDMENTS TO THE REGISTRATION STATEMENT. The Company
will not (i) file any amendment to the Registration Statement or make any
amendment or supplement to the Prospectus of which the Purchaser shall not
previously have been advised or to which the Purchaser shall reasonably object
after being so advised or (ii) so long as, in the reasonable opinion of counsel
for the Purchaser, a Prospectus is required to be delivered in connection with
sales by any Purchaser or dealer, file any information, documents or reports
pursuant to the Exchange Act without delivering a copy of such information,
documents or reports to the Purchaser, promptly following such filing.

          SECTION 4.11 PROSPECTUS DELIVERY. The Company shall file a prospectus
supplement to its Registration Statement on the first business day immediately
following the end of each Draw Down Pricing Period, and will deliver to the
Purchaser, without charge, in such quantities as reasonably requested by the
Purchaser, copies of each form of Prospectus and prospectus supplement on each
Settlement Date. The Company consents to the use of the Prospectus (and of any
amendment or supplement thereto) in accordance with the provisions of the
Securities Act and with the securities or Blue Sky laws of the jurisdictions in
which the Shares may be sold by the Purchaser, in connection with the offering
and sale of the Shares and for such period of time thereafter as the Prospectus
is required by the Securities Act to be delivered in connection with sales of
the Shares. If during such period of time any event shall occur that in the
judgment of the Company or in the opinion of counsel for the Purchaser is
required to be set forth in the Prospectus (as then amended or supplemented) or
should be set forth therein in order to make the statements therein, in the
light of the circumstances under which they were made, not misleading, or if it
is necessary to supplement or amend the Prospectus to comply with the Securities
Act or any other law, the Company will forthwith prepare and, subject to the
provisions of Section 4.10 above, file with the Commission an appropriate
supplement or amendment thereto, and will expeditiously furnish to the Purchaser
a reasonable number of copies thereof.

          SECTION 4.12 OTHER FINANCING. If the Company enters into any other
financing agreement, the primary purpose of which would be to obtain equity
financing for the Company (an "OTHER FINANCING"), during a Draw Down Pricing
Period, the Company shall promptly notify the Purchaser of such Other Financing
and the Purchaser shall have the options set forth in Section 6.1(k) hereof. As
used herein, "Other Financing" shall not include the Company (i) entering into a
loan, credit or lease facility with a bank or financing institution (including
any equity component thereof), (ii) establishing an employee stock option plan
or agreement or finance the acquisition of other companies, equipment,
technologies or lines of business, (iii) issuing shares of Common Stock in
connection with the Company's current option plans (as the same may be amended
from time to time), stock purchase plans, rights plans,

                                      -14-
<PAGE>

currently outstanding warrants or options, or increase the number of shares
available under any such plans (the primary purpose of which is not to raise
equity), and (iv) issuing shares of Common Stock and/or preferred stock in
connection with the formation and maintenance of strategic partnerships,
alliances or joint ventures and the acquisition of products, licenses or other
assets (each a "PERMITTED TRANSACTION").

          SECTION 4.13 NOTICES. The Company shall immediately notify the
Purchaser that (i) a Material Adverse Effect or Material Change in Ownership has
occurred or (ii) the Company has entered into an Other Financing (as defined in
Section 4.12 hereof).


                                    ARTICLE V

               CONDITIONS TO CLOSING, DRAW DOWNS AND CALL OPTIONS

          SECTION 5.1 CONDITIONS PRECEDENT TO THE OBLIGATION OF THE COMPANY TO
ISSUE A DRAW DOWN NOTICE OR GRANT A CALL OPTION AND SELL THE SHARES. The
obligation hereunder of the Company to issue a Draw Down Notice or grant a Call
Option and sell the Shares to the Purchaser is subject to the satisfaction or
waiver, at or before each Draw Down or Call Option request (the "DRAW DOWN
EXERCISE DATE"), of each of the conditions set forth below. These conditions are
for the Company's sole benefit and may be waived by the Company at any time in
its sole discretion.

          (a) ACCURACY OF THE PURCHASER'S REPRESENTATIONS AND WARRANTIES. The
representations and warranties of the Purchaser in this Agreement shall be true
and correct in all material respects as of the date when made and as of each
Draw Down Exercise Date and each Settlement Date as though made at that time,
except for representations and warranties that are expressly made as of a
particular date.

          (b) REGISTRATION STATEMENT. The Company shall have Shares registered
under the Registration Statement which are valued at an amount equal to or in
excess of the number of Shares issuable pursuant to such Draw Down Notice or
Call Option. The Registration Statement registering the offer and sale of the
Shares shall have been declared effective by the Commission and shall have been
amended or supplemented, as required, to disclose the sale of the Shares prior
to each Settlement Date, as applicable, and there shall be no stop order
suspending the effectiveness of the Registration Statement.

          (c) PERFORMANCE BY THE PURCHASER. The Purchaser shall have performed,
satisfied and complied in all material respects with all covenants, agreements
and conditions required by this Agreement to be performed, satisfied or complied
with by the Purchaser at or prior to each Settlement Date.

          (d) NO INJUNCTION. No statute, regulation, executive order, decree,
ruling or injunction shall have been enacted, entered, promulgated or endorsed
by any court or governmental authority of competent jurisdiction which prohibits
the consummation of any of the transactions contemplated by this Agreement.

                                      -15-
<PAGE>

          (e) NO SUSPENSION, ETC. Trading in the Company's Common Stock shall
not have been suspended by the Commission or the Nasdaq National Market or an
Alternate Market (except for any suspension of trading of limited duration
agreed to by the Company, which suspension shall be terminated prior to such
Draw Down Exercise Date and applicable Settlement Date), and, at any time prior
to each Draw Down Exercise Date, trading in securities generally as reported on
the Nasdaq National Market or an Alternate Market shall not have been suspended
or limited, or minimum prices shall not have been established on securities
whose trades are reported by the Nasdaq National Market or an Alternate Market,
nor shall a banking moratorium have been declared either by the United States or
New York State authorities, nor shall there have occurred any material outbreak
or escalation of hostilities or other national or international calamity or
crisis of such magnitude in its effect on, or any material adverse change in any
financial market which, in each case, in the judgment of the Company, makes it
impracticable or inadvisable to issue the Shares.

          (f) NO PROCEEDINGS OR LITIGATION. No action, suit or proceeding before
any arbitrator or any governmental authority shall have been commenced, and no
investigation by any governmental authority shall have been threatened, against
the Company, or any of the officers, directors or affiliates of the Company
seeking to restrain, prevent or change the transactions contemplated by this
Agreement, or seeking damages in connection with such transactions.

          SECTION 5.2 CONDITIONS PRECEDENT TO THE OBLIGATION OF THE PURCHASER TO
CLOSE. The obligation hereunder of the Purchaser to enter this Agreement is
subject to the satisfaction or waiver, at or before the Closing, of each of the
conditions set forth below. These conditions are for the Purchaser's sole
benefit and may be waived by the Purchaser at any time in its sole discretion.

          (a) ACCURACY OF THE COMPANY'S REPRESENTATIONS AND WARRANTIES. Each of
the representations and warranties of the Company shall be true and correct in
all material respects as of the date when made and as of the Closing Date, as
though made at that time, except for representations and warranties that speak
as of a particular date.

          (b) PERFORMANCE BY THE COMPANY. The Company shall have performed,
satisfied and complied in all material respects with all covenants, agreements
and conditions required by this Agreement to be performed, satisfied or complied
with by the Company at or prior to the Closing.

          (c) EFFECTIVE REGISTRATION STATEMENT. The Registration Statement
registering the offer and sale of the Shares shall have been declared effective
by the Commission and shall have been amended or supplemented, as required, to
disclose the sale of the Shares prior to each Settlement Date, as applicable,
and there shall be no stop order suspending the effectiveness of the
Registration Statement.

          (d) NO INJUNCTION. No statute, rule, regulation, executive order,
decree, ruling or injunction shall have been enacted, entered, promulgated or
endorsed by any court or governmental authority of competent jurisdiction which
prohibits the consummation of any of the transactions contemplated by this
Agreement.

                                      -16-
<PAGE>

          (e) NO PROCEEDINGS OR LITIGATION. No action, suit or proceeding before
any arbitrator or any governmental authority shall have been commenced, and no
investigation by any governmental authority shall have been threatened, against
the Company, or any of the officers, directors or affiliates of the Company
seeking to restrain, prevent or change the transactions contemplated by this
Agreement, or seeking damages in connection with such transactions.

          (f) OPINION OF COUNSEL, ETC. At the Closing, the Purchaser shall have
received an opinion of counsel to the Company, dated the date of Closing, in the
form of Exhibit A hereto, a secretary's certificate, dated the date of Closing,
in the form of Exhibit B hereto, and such other certificates and documents as
the Purchaser or its counsel shall reasonably require incident to the Closing.

          SECTION 5.3 CONDITIONS PRECEDENT TO THE OBLIGATION OF THE PURCHASER TO
ACCEPT A DRAW DOWN OR CALL OPTION GRANT AND PURCHASE THE SHARES. The obligation
hereunder of the Purchaser to accept a Draw Down or Call Option grant and to
acquire and pay for the Shares on the Settlement Date is subject to the
satisfaction or waiver, at or before each Draw Down Exercise Date and each
Settlement Date, as applicable, of each of the conditions set forth below. The
conditions are for the Purchaser's sole benefit and may be waived by the
Purchaser at any time in its sole discretion.

          (a) ACCURACY OF THE COMPANY'S REPRESENTATIONS AND WARRANTIES. Each of
the representations and warranties of the Company shall be true and correct in
all material respects as of the date when made and as of the Draw Down Exercise
Date and Settlement Date, as applicable, as though made at that time, except for
representations and warranties that speak as of a particular date.

          (b) REGISTRATION STATEMENT. The Company shall have Shares registered
under the Registration Statement which are valued at an amount equal to or in
excess of the number of Shares issuable pursuant to such Draw Down Notice or
Call Option. The Registration Statement registering the offer and sale of the
Shares shall have been declared effective by the Commission and shall have been
amended or supplemented, as required, to disclose the sale of the Shares prior
to each Draw Down Exercise Date or each Settlement Date, as applicable, and
there shall be no stop order suspending the effectiveness of the Registration
Statement.

          (c) NO SUSPENSION, ETC. Trading in the Company's Common Stock shall
not have been suspended by the Commission or the Nasdaq National Market or an
Alternate Market (except for any suspension of trading of limited duration
agreed to by the Company, which suspension shall be terminated prior to each
Draw Down Exercise Date), and, at any time prior to such Draw Down Exercise Date
or such Settlement Date, trading in securities generally as reported by the
Nasdaq National Market or an Alternate Market shall not have been suspended or
limited, or minimum prices shall not have been established on securities whose
trades are reported by the Nasdaq National Market or an Alternate Market, nor
shall a banking moratorium have been declared either by the United States or New
York State authorities, nor shall there have occurred any material outbreak or
escalation of hostilities or other national or international calamity or crisis
of such magnitude in its effect on, or any material adverse change in any
financial market which, in each case, in the judgment of the Purchaser, makes it
impracticable or

                                      -17-
<PAGE>

inadvisable to purchase the Shares. The Common Stock shall be listed on Nasdaq
or an Alternate Market.

          (d)  PERFORMANCE BY THE COMPANY. The Company shall have performed,
satisfied and complied in all material respects with all covenants, agreements
and conditions required by this Agreement to be performed, satisfied or complied
with by the Company at or prior to the Draw Down Exercise Date and the
Settlement Date and shall have delivered the Compliance Certificate
substantially in the form attached hereto as Exhibit C.

          (e)  NO INJUNCTION. No statute, rule, regulation, executive order,
decree, ruling or injunction shall have been enacted, entered, promulgated or
endorsed by any court or governmental authority of competent jurisdiction which
prohibits the consummation of any of the transactions contemplated by this
Agreement.

          (f)  NO PROCEEDINGS OR LITIGATION. No action, suit or proceeding
before any arbitrator or any governmental authority shall have been commenced,
and no investigation by any governmental authority shall have been threatened,
against the Company, or any of the officers, directors or affiliates of the
Company seeking to restrain, prevent or change the transactions contemplated by
this Agreement, or seeking damages in connection with such transactions.

          (g)  NO MATERIAL ADVERSE EFFECT; NO MATERIAL CHANGE IN OWNERSHIP. No
Material Adverse Effect or Material Change in Ownership shall have occurred.


                                   ARTICLE VI

                          DRAW DOWN TERMS; CALL OPTION

          SECTION 6.1 DRAW DOWN TERMS. Subject to the satisfaction of the
conditions set forth in this Agreement, the parties agree as follows:

          (a)  The Company may, in its sole discretion, issue a Draw Down Notice
with respect to a Draw Down during each Draw Down Pricing Period of up to (i)
$1,500,000 if the Threshold Price is equal to or greater than $12.00 but less
than $15.00 and (ii) up to an additional $500,000 for every $3.00 increase in
the Threshold Price above $12.00 up to and including $51.00, for a maximum Draw
Down Amount during each Draw Down Pricing Period of up to $8,000,000; PROVIDED,
that the Company may, in its sole discretion, issue a Draw Down Notice with
respect to any Draw Down Amount at any Threshold Price or any Draw Down Discount
Percentage pursuant to terms mutually agreed upon by the Purchaser and the
Company, which Draw Down the Purchaser will be obligated to accept. Prior to
issuing any Draw Down Notice, the Company shall have Shares registered under the
Registration Statement which are valued at an amount equal to or in excess of
the Draw Down Amount.

          (b)  The number of Shares to be issued in connection with each Draw
Down shall be equal to the sum of the quotients (for each Trading Day of the
Draw Down Pricing Period for which the VWAP equals or exceeds the Threshold
Price) of (x) 1/20th (or such other fraction based on the length of the Draw
Down Pricing Period) of the Draw Down Amount

                                      -18-
<PAGE>

divided by (y) the applicable Draw Down Discount Percentage multiplied by the
VWAP of the Common Stock for such Trading Day.

          (c)  Only one Draw Down shall be allowed in each Draw Down Pricing
Period.

          (d)  The number of Shares purchased by the Purchaser with respect to
each Draw Down shall be determined on a daily basis during each Draw Down
Pricing Period and settled on the second business day following the end of each
Draw Down Pricing Period (the "SETTLEMENT DATE").

          (e)  There shall be a minimum of five (5) Trading Days between Draw
Downs, unless otherwise mutually agreed upon between the Purchaser and the
Company.

          (f)  There shall be a maximum of twenty-four (24) monthly Draw Downs
during the term of this Agreement.

          (g)  Each Draw Down will expire on the end of the last Trading Day of
each Draw Down Pricing Period.

          (h)  If the VWAP on a given Trading Day is less than the Threshold
Price, then the total amount of the Draw Down for the relevant Draw Down Pricing
Period will be reduced by 1/20th (or such other fraction based on the length of
the Draw Down Pricing Period). At no time shall the Threshold Price be set below
$12.00, unless mutually agreed upon by the Company and the Purchaser. If trading
in the Company's Common Stock is suspended for any reason for more than three
(3) hours in any Trading Day, at the Purchaser's option, the price of the Common
Stock shall be deemed to be below the Threshold Price for that Trading Day and
the Draw Down for the relevant Draw Down Pricing Period shall be reduced by
1/20th (or such other fraction based on the length of the Draw Down Pricing
Period). Notwithstanding anything in the foregoing to the contrary, for each
Trading Day during the Draw Down Pricing Period that the VWAP is less than the
Threshold Price or is deemed to be below the Threshold Price pursuant to the
immediately preceding sentence, the Purchaser may elect in its sole discretion
to purchase Shares at a price equal to the Threshold Price multiplied by the
Draw Down Discount Percentage at the end of such Draw Down Pricing Period. The
Purchaser will inform the Company via facsimile transmission no later than 8:00
p.m. (eastern time) on the last Trading Day of such Draw Down Pricing Period as
to the number of Shares, if any, the Purchaser chooses to purchase under such
circumstances set forth in this Section 6.1(h).

          (i)  The Company must inform the Purchaser via facsimile transmission
as to the Draw Down Amount the Company wishes to exercise before commencement of
trading on the first Trading Day of the Draw Down Pricing Period (the "DRAW DOWN
NOTICE"), substantially in the form attached hereto as Exhibit D. In addition to
the Draw Down Amount, the Company shall set the Threshold Price with each Draw
Down Notice and shall designate the first Trading Day of the Draw Down Pricing
Period. Notwithstanding anything in the foregoing to the contrary, if the
Company wishes the date of the Draw Down Notice to be the first day of the Draw
Down Pricing Period, the Draw Down Notice must be delivered to the Purchaser and

                                      -19-
<PAGE>

receipt of such Draw Down Notice confirmed by the Purchaser prior to the
commencement of trading on the date of such Draw Down Notice.

          (j)  On each Settlement Date, the Company shall deliver the Shares
purchased by the Purchaser to the Purchaser or to The Depositary Trust Company
("DTC") on the Purchaser's behalf via the Deposit Withdrawal Agent Commission
system ("DWAC"), and upon receipt of the Shares, the Purchaser shall cause
payment therefor to be made to the account designated by the Company by wire
transfer of immediately available funds provided that the Shares are received no
later than 1:00 p.m., eastern time, or next day available funds if the Shares
are received thereafter.

          (k)  If during any Draw Down Pricing Period the Company shall enter
into an Other Financing (other than shares of Common Stock issued under this
Agreement or pursuant to a Permitted Transaction), the Purchaser may in its sole
discretion (i) purchase the Draw Down Amount of shares of Common Stock and/or
exercise Call Options granted during such Draw Down Pricing Period on the terms
at which the Company issued shares of Common Stock in the Other Financing during
such Draw Down Pricing Period, net of any third party's discount and fees, (ii)
purchase the Draw Down Amount of shares of Common Stock and/or exercise Call
Options granted during such Draw Down Pricing Period at the applicable Draw Down
Discount Percentage times the VWAP for such Draw Down Pricing Period, or (iii)
elect not to purchase any Shares during such Draw Down Pricing Period. The
Purchaser shall notify the Company of its election on the business day preceding
the Settlement Date.

          (l)  If on the Settlement Date, the Company fails to deliver the
Shares to be purchased by the Purchaser, and such failure continues for ten (10)
Trading Days, the Company shall pay, in cash or restricted shares of Common
Stock, at the option of the Purchaser, as liquidated damages and not as a
penalty to the Purchaser an amount equal to two percent (2%) of the Draw Down
Amount for the initial thirty (30) days and each additional thirty (30) day
period thereafter until such failure has been cured, which shall be pro rated
for such periods less than thirty (30) days (the "PERIODIC AMOUNT"). Cash
payments to be made pursuant to this clause (1) shall be due and payable
immediately upon demand in immediately available cash funds. Certificates
evidencing the restricted shares of Common Stock shall be delivered immediately
upon demand. The parties agree that the Periodic Amount represents a reasonable
estimate on the part of the parties, as of the date of this Agreement, of the
amount of damages that may be incurred by the Purchaser if the Company fails to
deliver the Shares on the Settlement Date. If the Purchaser elects to receive
shares of Common Stock instead of cash, the Purchaser shall have the right to
demand registration once within twelve (12) months of the date of issuance of
such shares of Common Stock and piggyback registration rights if the Company
files a separate registration statement.

          SECTION 6.2 PURCHASER'S CALL OPTION.

          (a)  During each Draw Down Pricing Period, the Company at its sole
discretion may grant to the Purchaser the right to exercise multiple call
options of up to the applicable Draw Down Amount (a "CALL OPTION"). The amount
of the Call Option shall be set forth in the Draw Down Notice. For each Trading
Day during a Draw Down Pricing Period, the

                                      -20-
<PAGE>

Purchaser may exercise a Call Option by providing notice to the Company of the
exercise of a Call Option (the "CALL OPTION NOTICE"), substantially in the form
attached hereto as Exhibit E.

          (b)  The number of shares of Common Stock to be issued in connection
with each Call Option shall equal the quotient of (i) the amount of the Call
Option exercised and (ii) the product of the applicable Draw Down Discount
Percentage and the greater of (A) the VWAP for the Common Stock on the day the
Purchaser issues its Call Option Notice and (B) the Threshold Price.

          (c)  Each Call Option exercised shall be settled on the applicable
Settlement Date.

          (d)  The Threshold Price designated by the Company in its Draw Down
Notice shall apply to each Call Option.

          (e)  For each Call Option that the Purchaser exercises pursuant to
this Section 6.2, the Purchaser must issue via facsimile a Call Option Notice to
the Company no later than 8:00 p.m. (eastern time) on the day such Call Option
is exercised. If the Purchaser does not exercise a Call Option by 8:00 p.m.
(eastern time) on the last day of the applicable Draw Down Pricing Period, the
Purchaser's Call Options with respect to that Draw Down Pricing Period shall
terminate.


                                   ARTICLE VII

                                   TERMINATION

          SECTION 7.1 TERMINATION BY MUTUAL CONSENT. The term of this Agreement
shall be the earlier of (i) twenty-eight (28) consecutive months from the date
of execution of this Agreement (the "INVESTMENT PERIOD"), (ii) the date that the
value of all of the shares of Common Stock registered under the Registration
Statement have been issued and sold and (iii) the date that the Purchaser has
purchased in the aggregate $60,000,000 pursuant to all Draw Downs issued and
Call Options granted and exercised. This Agreement may be terminated at any time
by mutual consent of the parties.

          SECTION 7.2 OTHER TERMINATION. The Company shall inform the Purchaser,
and the Purchaser shall have the right to terminate this Agreement within the
subsequent thirty (30) days (the "EVENT PERIOD"), if (x) the Company enters into
an Other Financing without the prior consent of the Purchaser, which consent
will not be unreasonably delayed, conditioned or withheld, which provides for
(i) the issuance of Common Stock or securities convertible, exercisable or
exchangeable into Common Stock at a discount to the then current market price of
the Common Stock, except for such issuance in a public underwritten offering,
(ii) a mechanism for the reset of the purchase price of the Common Stock to
below the then current market price of the Common Stock, or (iii) the issuance
of Common Stock with warrants, which have an exercise price such that together
with the price of the Common Stock would result in the issuance of shares of
Common Stock at a per share price below the then current market price of the
Common Stock, or (y) an event resulting in a Material Adverse Effect or Material
Change in

                                      -21-
<PAGE>

Ownership has occurred. The Purchaser may terminate this Agreement upon one (1)
day's notice during the Event Period.

          SECTION 7.3 EFFECT OF TERMINATION. In the event of termination by the
Company or the Purchaser, written notice thereof shall forthwith be given to the
other party and the transactions contemplated by this Agreement shall be
terminated without further action by either party. If this Agreement is
terminated as provided in Section 7.1 or 7.2 herein, this Agreement shall become
void and of no further force and effect, except as provided in Section 9.9
hereof. Nothing in this Section 7.3 shall be deemed to release the Company or
the Purchaser from any liability for any breach under this Agreement, or to
impair the rights of the Company and the Purchaser to compel specific
performance by the other party of its obligations under this Agreement.


                                  ARTICLE VIII

                                 INDEMNIFICATION

          SECTION 8.1 GENERAL INDEMNITY.

          (a)  INDEMNIFICATION BY THE COMPANY. The Company will indemnify and
hold harmless the Purchaser, each of its directors, fund managers and officers,
and each person, if any, who controls the Purchaser within the meaning of
Section 15 of the Securities Act or Section 20(a) of the Exchange Act from and
against any losses, claims, damages, liabilities and expenses (including
reasonable costs of defense and investigation and all reasonable attorneys'
fees) to which the Purchaser, each of its directors, fund managers and officers,
and each person, if any, who controls the Purchaser may become subject, under
the Securities Act or otherwise, insofar as such losses, claims, damages,
liabilities and expenses (or actions in respect thereof) arise out of or are
based upon, (i) any untrue statement or alleged untrue statement of a material
fact contained, or incorporated by reference, in the Registration Statement
relating to Common Stock being sold to the Purchaser (including the any
prospectus supplement filed in connection with the transactions contemplated
hereunder (the "PROSPECTUS SUPPLEMENT") which are a part of it), or any
amendment or supplement to it, or (ii) the omission or alleged omission to state
in that Registration Statement or any document incorporated by reference in the
Registration Statement, a material fact required to be stated therein or
necessary to make the statements therein not misleading, PROVIDED that the
Company shall not be liable under this Section 8.1(a) to the extent that a court
of competent jurisdiction shall have determined by a final judgment (with no
appeals available) that such loss, claim, damage, liability or action resulted
directly from any such acts or failures to act, undertaken or omitted to be
taken by the Purchaser or such person through its bad faith or willful
misconduct; PROVIDED, however, that the foregoing indemnity shall not apply to
any loss, claim, damage, liability or expense to the extent, but only to the
extent, arising out of or based upon any untrue statement or alleged untrue
statement or omission or alleged omission made in reliance upon and in
conformity with written information furnished to the Company by the Purchaser
expressly for use in the Registration Statement, any preliminary prospectus or
the Prospectus (or any amendment or supplement thereto); and PROVIDED, further,
that with respect to the Prospectus, the foregoing indemnity shall not inure to
the benefit of the Purchaser or any such person from whom the person asserting
any loss, claim, damage, liability or expense

                                      -22-
<PAGE>

purchased Common Stock, if copies of the Prospectus were timely delivered to the
Purchaser pursuant hereto and a copy of the Prospectus (as then amended or
supplemented if the Company shall have furnished any amendments or supplements
thereto) was not sent or given by or on behalf of the Purchaser or any such
person to such person, if required by law so to have been delivered, at or prior
to the written confirmation of the sale of the Common Stock to such person, and
if the Prospectus (as so amended or supplemented) would have cured the defect
giving rise to such loss, claim, damage, liability or expense.

     The Company will reimburse the Purchaser and each such controlling person
promptly upon demand for any legal or other costs or expenses reasonably
incurred by the Purchaser or any controlling person in investigating, defending
against, or preparing to defend against any such claim, action, suit or
proceeding, except that the Company will not be liable to the extent a claim or
action which results in a loss, claim, damage, liability or expense arises out
of, or is based upon, an untrue statement, alleged untrue statement, omission or
alleged omission, included in any Registration Statement, Prospectus or
Prospectus Supplement or any amendment or supplement to the thereto in reliance
upon, and in conformity with, written information furnished by the Purchaser to
the Company for inclusion in the Registration Statement, Prospectus or
Prospectus Supplement.

          (b)  INDEMNIFICATION BY THE PURCHASER. The Purchaser will indemnify
and hold harmless the Company, each of its directors and officers, and each
person, if any, who controls the Company within the meaning of Section 15 of the
Securities Act or Section 20(a) of the Exchange Act from and against any
expenses (including reasonable costs of defense and investigation and all
attorneys' fees) to which the Company and each director, officer and person, if
any, who controls the Company may become subject, under the Securities Act or
otherwise, insofar as such losses, claims, damages, liabilities and expenses (or
actions in respect thereof) arise out of or are based upon, (i) any untrue
statement or alleged untrue statement of a material fact contained in the
Registration Statement or any Prospectus or Prospectus Supplement or any
amendment or supplement to it or (ii) the omission or alleged omission to state
in the Registration Statement or any Prospectus or Prospectus Supplement or any
amendment or supplement to it a material fact required to be stated therein or
necessary to make the statements therein not misleading, to the extent, but only
to the extent, the untrue statement, alleged untrue statement, omission or
alleged omission was made in reliance upon, and in conformity with, written
information furnished by the Purchaser to the Company for inclusion in the
Registration Statement, the Prospectus or Prospectus Supplement or an amendment
or supplement thereto, and the Purchaser will reimburse the Company and each
such director, officer or controlling person promptly upon demand for any legal
or other costs or expenses reasonably incurred by the Company or the other
person in investigating, defending against, or preparing to defend against any
such claim, action, suit or proceeding.

          SECTION 8.2 INDEMNIFICATION PROCEDURES. Promptly after a person
receives notice of a claim or the commencement of an action for which the person
intends to seek indemnification under paragraph (a) or (b) of Section 8.1, the
person will notify the indemnifying party in writing of the claim or
commencement of the action, suit or proceeding, but failure to notify the
indemnifying party will not relieve the indemnifying party from liability under
paragraph (a) or (b) of Section 8.1, except to the extent it has been materially
prejudiced by the failure to give notice. The indemnifying party will be
entitled to participate in the defense of any

                                      -23-
<PAGE>

claim, action, suit or proceeding as to which indemnification is being sought,
and if the indemnifying party acknowledges in writing the obligation to
indemnify the party against whom the claim or action is brought, the
indemnifying party may (but will not be required to) assume the defense against
the claim, action, suit or proceeding with counsel satisfactory to it. After an
indemnifying party notifies an indemnified party that the indemnifying party
wishes to assume the defense of a claim, action, suit or proceeding the
indemnifying party will not be liable for any legal or other expenses incurred
by the indemnified party in connection with the defense against the claim,
action, suit or proceeding except that if, in the opinion of counsel to the
indemnifying party, one or more of the indemnified parties should be separately
represented in connection with a claim, action, suit or proceeding the
indemnifying party will pay the reasonable fees and expenses of one separate
counsel for the indemnified parties. Each indemnified party, as a condition to
receiving indemnification as provided in Paragraph (a) or (b) or Section 8.1,
will cooperate in all reasonable respects with the indemnifying party in the
defense of any action or claim as to which indemnification is sought. No
indemnifying party will be liable for any settlement of any action effected
without its prior written consent. No indemnifying party will, without the prior
written consent of the indemnified party, effect any settlement of a pending or
threatened action with respect to which an indemnified party is, or is informed
that it may be, made a party and for which it would be entitled to
indemnification, unless the settlement includes an unconditional release of the
indemnified party from all liability and claims which are the subject matter of
the pending or threatened action.

     If for any reason the indemnification provided for in this Agreement is not
available to, or is not sufficient to hold harmless, an indemnified party in
respect of any loss or liability referred to in paragraph (a) or (b) of Section
8.1, each indemnifying party will, in lieu of indemnifying the indemnified
party, contribute to the amount paid or payable by the indemnified party as a
result of the loss or liability, (i) in the proportion which is appropriate to
reflect the relative benefits received by the indemnifying party on the one hand
and by the indemnified party on the other from the sale of stock which is the
subject of the claim, action, suit or proceeding which resulted in the loss or
liability or (ii) if that allocation is not permitted by applicable law, in such
proportion as is appropriate to reflect not only the relative benefits of the
sale of stock, but also the relative fault of the indemnifying party and the
indemnified party with respect to the statements or omissions which are the
subject of the claim, action, suit or proceeding that resulted in the loss or
liability, as well as any other relevant equitable considerations.


                                   ARTICLE IX

                                  MISCELLANEOUS

          SECTION 9.1 FEES AND EXPENSES.

          (a)  The Company shall pay all reasonable fees and expenses related to
the transactions contemplated by this Agreement; PROVIDED, that the Company
shall pay, at the Closing, all reasonable attorneys fees and expenses (exclusive
of disbursements and out-of-pocket expenses) incurred by the Purchaser of up to
$50,000 in connection with the preparation, negotiation, execution and delivery
of this Agreement. In addition, the Company shall pay all reasonable fees and
expenses incurred by the Purchaser in connection with any

                                      -24-
<PAGE>

amendments, modifications or waivers of this Agreement or incurred in connection
with the enforcement of this Agreement, including, without limitation, all
reasonable attorneys' fees and expenses.

          (b)  If on the fourteen (14) month anniversary of this Agreement, the
Company has not requested Draw Downs in an aggregate amount of $9,000,000, the
Company shall pay the Purchaser a fee equal to $300,000 in cash.

          SECTION 9.2 SPECIFIC ENFORCEMENT, CONSENT TO JURISDICTION.

          (a)  The Company and the Purchaser acknowledge and agree that
irreparable damage would occur in the event that any of the provisions of this
Agreement were not performed in accordance with their specific terms or were
otherwise breached. It is accordingly agreed that the parties shall be entitled
to an injunction or injunctions to prevent or cure breaches of the provisions of
this Agreement and to enforce specifically the terms and provisions hereof or
thereof, this being in addition to any other remedy to which any of them may be
entitled by law or equity.

          (b)  Each of the Company and the Purchaser (i) hereby irrevocably
submits to the jurisdiction of the United States District Court and other courts
of the United States sitting in the State of New York for the purposes of any
suit, action or proceeding arising out of or relating to this Agreement and (ii)
hereby waives, and agrees not to assert in any such suit, action or proceeding,
any claim that it is not personally subject to the jurisdiction of such court,
that the suit, action or proceeding is brought in an inconvenient forum or that
the venue of the suit, action or proceeding is improper. Each of the Company and
the Purchaser consents to process being served in any such suit, action or
proceeding by mailing a copy thereof to such party at the address in effect for
notices to it under this Agreement and agrees that such service shall constitute
good and sufficient service of process and notice thereof. Nothing in this
Section shall affect or limit any right to serve process in any other manner
permitted by law.

          SECTION 9.3 ENTIRE AGREEMENT; AMENDMENT. This Agreement contains the
entire understanding of the parties with respect to the matters covered hereby
and, except as specifically set forth herein, neither the Company nor the
Purchaser makes any representations, warranty, covenant or undertaking with
respect to such matters. No provision of this Agreement may be waived or amended
other than by a written instrument signed by the party against whom enforcement
of any such amendment or waiver is sought.

          SECTION 9.4 NOTICES. Any notice, demand, request, waiver or other
communication required or permitted to be given hereunder shall be in writing
and shall be effective (a) upon hand delivery, by telecopy or facsimile at the
address or number designated below (if delivered on a business day during normal
business hours where such notice is to be received), or the first business day
following such delivery (if delivered other than on a business day during normal
business hours where such notice is to be received) or (b) on the second
business day following the date of mailing by express courier service, fully
prepaid, addressed to such address, or upon actual receipt of such mailing,
whichever shall first occur. The addresses for such communications shall be:

                                      -25-
<PAGE>


If to the Company:                     Ribozyme Pharmaceuticals, Inc.
                                       2950 Wilderness Place
                                       Boulder, CO 80301
                                       Tel. No.: (303) 449-6500
                                       Fax No.:  (303) 449-6995
                                       Attention: Chief Executive Officer

With copies to:                        Gibson, Dunn & Crutcher LLP
                                       2029 Century Park East
                                       Suite 4000
                                       Los Angeles, California 90067
                                       Tel. No.: (310) 552-8500
                                       Fax No.:  (310) 551-8741
                                       Attention: Robert K. Montgomery, Esq.

If to the Purchaser:                   Acqua Wellington North American
                                       Equities Fund, Ltd.
                                       c/o Fortis Fund Services (Bahamas) Ltd.
                                       Montague Sterling Centre
                                       East Bay Street, P. O. Box SS-6238
                                       Nassau, Bahamas
                                       Tel. No:  (242) 394-2700
                                       Fax No.:  (242) 394-9667
                                       Attention:  Anthony L.M. Inder Rieden

With copies to:                        Parker Chapin LLP
                                       The Chrysler Building
                                       405 Lexington Avenue
                                       New York, NY  10174
                                       Tel. No: (212) 704-6000
                                       Fax No:  (212)704-6288
                                       Attention:  Christopher S. Auguste

     Any party hereto may from time to time change its address for notices by
giving at least ten (10) days written notice of such changed address to the
other party hereto.

          SECTION 9.5 WAIVERS. No waiver by either party of any default with
respect to any provision, condition or requirement of this Agreement shall be
deemed to be a continuing waiver in the future or a waiver of any other
provisions, condition or requirement hereof, nor shall any delay or omission of
any party to exercise any right hereunder in any manner impair the exercise of
any such right accruing to it thereafter.

          SECTION 9.6 HEADINGS. The article, section and subsection headings in
this Agreement are for convenience only and shall not constitute a part of this
Agreement for any other purpose and shall not be deemed to limit or affect any
of the provisions hereof.

                                      -26-
<PAGE>

          SECTION 9.7 SUCCESSORS AND ASSIGNS. The Purchaser may not assign this
Agreement to any person without the prior consent of the Company, which consent
will not be unreasonably withheld. This Agreement shall be binding upon and
inure to the benefit of the parties and their successors and assigns. The
parties hereto may not amend this Agreement or any rights or obligations
hereunder without the prior written consent of the Company and each Purchaser to
be affected by the amendment. After Closing, the assignment by a party to this
Agreement of any rights hereunder shall not affect the obligations of such party
under this Agreement.

          SECTION 9.8 GOVERNING LAW. This Agreement shall be governed by and
construed in accordance with the internal laws of the State of New York, without
giving effect to the choice of law provisions.

          SECTION 9.9 SURVIVAL. The representations and warranties of the
Company and the Purchaser contained in Article III and the covenants contained
in Article IV shall survive the execution and delivery hereof and the Closing
until the termination of this Agreement, and the agreements and covenants set
forth in Article VIII of this Agreement shall survive the execution and delivery
hereof and the Closing hereunder.

          SECTION 9.10 COUNTERPARTS. This Agreement may be executed in any
number of counterparts, all of which taken together shall constitute one and the
same instrument and shall become effective when counterparts have been signed by
each party and delivered to the other parties hereto, it being understood that
all parties need not sign the same counterpart. In the event any signature is
delivered by facsimile transmission, the party using such means of delivery
shall cause four additional executed signature pages to be physically delivered
to the other parties within five days of the execution and delivery hereof.

          SECTION 9.11 PUBLICITY. The Company shall not issue any press release
or otherwise make any public statement or announcement with respect to this
Agreement or the transactions contemplated hereby or the existence of this
Agreement without the prior written consent of the Purchaser. In the event the
Company is required by law or regulation to issue a press release or otherwise
make a public statement or announcement with respect to this Agreement or the
transaction contemplated hereby prior to or after the Closing, the Company shall
consult with the Purchaser on the form and substance of such press release or
other disclosure.

          SECTION 9.12 SEVERABILITY. The provisions of this Agreement are
severable and, in the event that any court of competent jurisdiction shall
determine that any one or more of the provisions or part of the provisions
contained in this Agreement shall, for any reason, be held to be invalid,
illegal or unenforceable in any respect, such invalidity, illegality or
unenforceability shall not affect any other provision or part of a provision of
this Agreement, and this Agreement shall be reformed and construed as if such
invalid or illegal or unenforceable provision, or part of such provision, had
never been contained herein, so that such provisions would be valid, legal and
enforceable to the maximum extent possible.

                                      -27-
<PAGE>

          SECTION 9.13 FURTHER ASSURANCES. From and after the date of this
Agreement, upon the request of the Purchaser or the Company, each of the Company
and the Purchaser shall execute and deliver such instrument, documents and other
writings as may be reasonably necessary or desirable to confirm and carry out
and to effectuate fully the intent and purposes of this Agreement.




                                  [END OF PAGE]

<PAGE>



     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed by their respective authorized officer as of the date first above
written.


                                       RIBOZYME PHARMACEUTICALS, INC.



                                       By: /s/   LAWRENCE E. BULLOCK
                                          --------------------------------------
                                          Name:  Lawrence E. Bullock
                                          Title: Vice President of
                                                 Administration and
                                                 Finance, Chief Financial
                                                 Officer and Secretary


                                       ACQUA WELLINGTON NORTH
                                       AMERICAN EQUITIES FUND, LTD.



                                       By: /s/   ANTHONY L.M. INDER RIEDEN
                                          --------------------------------------
                                          Name:  Anthony L.M. Inder Rieden
                                          Title: Director


<PAGE>


                                EXHIBIT A TO THE
                         COMMON STOCK PURCHASE AGREEMENT



                               OPINION OF COUNSEL

                     [LETTERHEAD OF _______________________]

                       [FORM OF COMPANY'S COUNSEL OPINION]



          1.   The Company is a corporation duly incorporated, validly existing
and in good standing under the laws of the State of Delaware. The Company has
the requisite corporate power to own and operate its properties and assets, and
to carry on its business as presently conducted. Each of the Company and its
subsidiaries is duly qualified to do business as a foreign corporation and is in
good standing in every jurisdiction in which the nature of the business
conducted or property owned by it makes such qualification necessary except for
any jurisdiction in which the failure to be so qualified will not have Material
Adverse Effect.

          2.   The Company has the requisite corporate power and authority to
enter into and perform its obligations under the Purchase Agreement and to issue
and sell the Common Shares. The execution, delivery and performance of the
Purchase Agreement by the Company and the consummation by it of the transactions
contemplated thereby have been duly and validly authorized by all necessary
corporate action and no further consent or authorization of the Company or its
Board of Directors or stockholders is required. The Purchase Agreement has been
duly executed and delivered by the Company and the Purchase Agreement
constitutes a legal, valid and binding obligation of the Company enforceable
against the Company in accordance with its terms. The Common Stock is not
subject to preemptive rights under the Company's Charter or By-Laws.

          3.   The Shares have been duly authorized and, when delivered against
payment in full as provided in the Purchase Agreement, will be validly issued,
fully paid and nonassessable. Assuming the Shares are issued pursuant to an
effective registration statement and any required prospectus supplement is filed
and delivered as required by the Securities Act, the issuance and sale of the
Shares to the Purchaser will not violate Section 5 of the Securities Act.

          4.   The execution, delivery and performance of and compliance with
the terms of the Purchase Agreement and the consummation by the Company of the
transactions contemplated thereby (i) do not violate any provision of the
Company's Charter or By-Laws, (ii) conflict with, or constitute a default (or an
event which with notice or lapse of time or both would become a default) under,
or give to others any rights of termination, amendment, acceleration or
cancellation of, any material agreement, mortgage, deed of trust, indenture,


<PAGE>


note, bond, license, lease agreement, instrument or obligation to which the
Company is a party, (iii) create or impose a lien, charge or encumbrance on any
property of the Company under any agreement or any commitment to which the
Company is a party or by which the Company is bound or by which any of its
respective properties or assets are bound, or (iv) result in a violation of any
federal, state or local statute, rule, regulation, order, judgment or decree
(including federal securities laws and regulations) applicable to the Company or
any of its subsidiaries or by which any property or asset of the Company or any
of its subsidiaries are bound or affected, except, (in all cases other than
violations pursuant to clause (i) above and clause (iv) to the extent of federal
securities laws and regulations) for such conflicts, defaults, terminations,
amendments, acceleration, cancellations and violations as would not,
individually or in the aggregate, have a Material Adverse Effect.

          5.   There is no action, suit, claim, investigation or proceeding
pending or threatened against the Company or any subsidiary which questions the
validity of this Agreement or the transactions contemplated hereby or any action
taken or to be taken pursuant hereto or thereto. There is no action, suit,
claim, investigation or proceeding pending or, threatened, against or involving
the Company, any subsidiary or any of their respective properties or assets and
which, if adversely determined, is reasonably likely to result in a Material
Adverse Effect.

          6.   No consent, approval or authorization of or designation,
declaration or filing with any governmental authority on the part of the Company
is required in connection with the valid execution and delivery of the Purchase
Agreement, or the offer, sale or issuance of the Shares or the consummation of
any other transaction contemplated by the Purchase Agreement (other than any
filings which may be required to be made by the Company with the Commission, the
Nasdaq Stock Market subsequent to the Closing, and, any registration statement
which may be filed pursuant to the Purchase Agreement).

          7.   The Registration Statement has been declared effective under the
Securities Act and, to our knowledge, no stop order suspending its effectiveness
has been issued and no proceedings for that purpose have been, to our knowledge,
instituted or are pending or threatened before or contemplated by the
Commission.


<PAGE>


                                    EXHIBIT B
                     TO THE COMMON STOCK PURCHASE AGREEMENT

                             SECRETARY'S CERTIFICATE

                                ___________, 2000

     The undersigned, ______________________, Secretary of Ribozyme
Pharmaceuticals, Inc., a Delaware corporation (the "Company"), delivers this
certificate in connection with the issuance and sale of shares of common stock
of the Company in an aggregate amount of up to $60,000,000 to Acqua Wellington
North American Equities Fund, Ltd. (the "Purchaser") pursuant to the Common
Stock Purchase Agreement, dated as of December 29, 2000 (the "Agreement"), by
and among the Company and the Purchaser, and hereby certifies on the date
hereof, that (capitalized terms used herein without definition have the meanings
assigned to them in the Agreement):


     1.   Attached hereto as EXHIBIT A is a true, complete and correct copy of
the Certificate of Incorporation of the Company as filed with the Secretary of
State of the State of Delaware. The Certificate of Incorporation of the Company
has not been further amended or restated, and no document with respect to any
amendment to the Certificate of Incorporation of the Company has been filed in
the office of the Secretary of State of the State of Delaware since ______ __,
2000, the date shown on the face of the state certification relating to the
Company's Certificate of Incorporation, which is in full force and effect on the
date hereof, and no action has been taken by the Company in contemplation of any
such amendment or the dissolution, merger or consolidation of the Company.

     2.   Attached hereto as EXHIBIT B is a true and complete copy of the
By-laws of the Company, as amended and restated through, and as in full force
and effect on, the date hereof, and no proposal for any amendment, repeal or
other modification to the By-laws of the Company has taken or is currently
pending before the Board of Directors or stockholders of the Company.

     3.   Attached hereto as EXHIBIT C is a true and correct copy of all written
actions and resolutions of the Board of Directors (including any committees
thereof) of the Company relating to the transactions contemplated by the
Agreement; said actions and resolutions have not been amended, rescinded or
modified since their adoption and remain in full force and effect as of the date
hereof; said actions and resolutions are the only resolutions adopted by the
Board of Directors of the Company, or any committee thereof, pertaining to (A)
the offering of the Common Stock to be sold by the Company pursuant to the
Agreement, (B) the execution and delivery of the Agreement and (C) all other
transactions in connection with the foregoing.

     4.   Each person who, as an officer of the Company, or as attorney-in-fact
of an officer of the Company, signed (A) the Agreement, (B) the Registration
Statement and (C) any other document delivered prior hereto or on the date
hereof in connection with the transactions contemplated by the Agreement, was
duly elected, qualified and acting as such officer or duly appointed and acting
as such attorney-in-fact, and the signature of each such person appearing on any
such document is his genuine signature.

<PAGE>


     5.   The Agreement as executed and delivered on behalf of the Company has
been approved by the Company.

     6.   The actions, resolutions and other records of the Company relating to
all of the proceedings of the Stockholders of the Company, the Board of
Directors of the Company and any committees thereof made available to the
Purchasers and their counsel are the true, correct and complete copies thereof,
with respect to all proceedings of said Stockholders, Board of Directors and
committees thereof. Such records and other documents of the Company made
available to the Purchasers and their counsel were true and complete in all
respects. There have been no material changes, additions or alterations in said
records and other documents that have not been disclosed to the Purchasers.

     IN WITNESS WHEREOF, I have signed my name as of the date first above
written.



                                            By:
                                               ---------------------------------
                                               Name:
                                               Title:   Secretary



     I, __________________, Chief Executive Officer of ___________________., do
hereby certify that ______________________ is the duly elected, qualified and
acting Secretary of the above mentioned company, and that the signature set
forth above is her true and genuine signature.


     IN WITNESS WHEREOF, I have hereunto signed my name as of the date first
above written.



                                             By:
                                               ---------------------------------
                                               Name:
                                               Title:  Chief Executive Officer

<PAGE>


                                    EXHIBIT C
                     TO THE COMMON STOCK PURCHASE AGREEMENT

                             COMPLIANCE CERTIFICATE

     In connection with the issuance of shares of common stock of Ribozyme
Pharmaceuticals, Inc. (the "Company") pursuant to the Draw Down Notice, dated
___________ delivered by the Company to Acqua Wellington North American Equities
Fund, Ltd. (the "Purchaser") pursuant to Article VI of the Common Stock Purchase
Agreement dated as of December 29, 2000 by and between the Company and Acqua
Wellington North American Equities Fund, Ltd. (the "Agreement"), the undersigned
hereby certifies as follows:

     1.   The undersigned is the duly elected Chief [Executive/Financial]
Officer of the Company.

     2.   The representations and warranties of the Company set forth in Section
3.1 of the Agreement are true and correct in all material respects as though
made on and as of the date hereof, except for representations and warranties
that speak as of a particular date.

     3.   The Company has performed in all material respects all covenants and
agreements to be performed by the Company on or prior to the Draw Down Exercise
Date and the Settlement Date related to the Draw Down Notice and has complied in
all material respects with all obligations and conditions contained in Section
5.3 of the Agreement.

     Capitalized terms used but not otherwise defined herein shall have the
meanings assigned to them in the Agreement.

     The undersigned has executed this Certificate this _____ day of _________,
2000.



                                            By:
                                               ---------------------------------

                                            Name:
                                                 -------------------------------

                                            Title:
                                                 -------------------------------

<PAGE>


                                    EXHIBIT D
                     TO THE COMMON STOCK PURCHASE AGREEMENT

                            FORM OF DRAW DOWN NOTICE

     Reference is made to the Common Stock Purchase Agreement dated as of
December 29, 2000 (the "Purchase Agreement") between Ribozyme Pharmaceuticals,
Inc., a Delaware corporation (the "Company"), and Acqua Wellington North
American Equities Fund, Ltd. Capitalized terms used and not otherwise defined
herein shall have the meanings given such terms in the Purchase Agreement.

     In accordance with and pursuant to Section 6.1 of the Purchase Agreement,
the Company hereby issues this Draw Down Notice to exercise a Draw Down request
for the Draw Down Amount indicated below.

         Draw Down Amount:
                           -----------------------------------------------------

         Call Option Amount:
                              --------------------------------------------------

         Draw Down Pricing Period start date:
                                             -----------------------------------

         Draw Down Pricing Period end date:
                                           -------------------------------------

         Settlement Date:
                         -------------------------------------------------------

         Threshold Price:
                         -------------------------------------------------------

         Minimum Threshold Price:
                                 -----------------------------------------------

         Dollar Amount and/or Number of Shares
         of Common Stock Currently Unissued
         under the Registration Statement:
                                          --------------------------------------


Dated:
       -----------------------------

                                                --------------------------------

                                                By:
                                                  ------------------------------
                                                  Name:
                                                  Title:

                                                Address:
                                                Facsimile No.:
                                                Wire Instructions:
                                                                 ---------------
                                                Contact Name:
                                                             -------------------

Receipt Acknowledged:

Acqua Wellington North American Equities Fund, Ltd.

By:
   -------------------------------
   Name:
   Title:


<PAGE>



                                    EXHIBIT E
                     TO THE COMMON STOCK PURCHASE AGREEMENT

                           FORM OF CALL OPTION NOTICE

To: ______________
Fax #:

     Reference is made to the Common Stock Purchase Agreement dated as of
December 29, 2000 (the "Purchase Agreement") between Ribozyme Pharmaceuticals,
Inc., a Delaware corporation (the "Company"), and Acqua Wellington North
American Equities Fund, Ltd. Capitalized terms used and not otherwise defined
herein shall have the meanings given such terms in the Purchase Agreement.

     In accordance with and pursuant to Section 6.2 of the Purchase Agreement,
the Purchaser hereby issues this Call Option Notice to exercise a Call Option
for the Call Option Amount indicated below.

         Call Option Amount Exercised:
                                      ------------------------------------------

         Number of Shares to be purchased:
                                          --------------------------------------

         VWAP on the date hereof:
                                 -----------------------------------------------

         Draw Down Discount Percentage:
                                       -----------------------------------------

         Settlement Date:
                         -------------------------------------------------------

         Threshold Price:
                         -------------------------------------------------------

         Minimum Threshold Price:
                                 -----------------------------------------------


Dated:
       --------------------


                             Acqua Wellington North American Equities Fund, Ltd.


                             By:
                                ---------------------------------
                                Name:
                                Title:
<PAGE>

                              DISCLOSURE SCHEDULES
                          RELATING TO THE COMMON STOCK
                PURCHASE AGREEMENT, DATED AS OF DECEMBER 29, 2000
                   BETWEEN RIBOZYME PHARMACEUTICALS, INC. AND
               ACQUA WELLINGTON NORTH AMERICAN EQUITIES FUND, LTD.


     ALL SECTION AND SUBSECTION NUMBERS AND LETTERS RELATE AND COINCIDE TO SUCH
NUMBERS AND LETTERS AS SET FORTH IN THE COMMON STOCK PURCHASE AGREEMENT (THE
"AGREEMENT"). ANY TERMS REQUIRING DEFINITION HEREIN ARE DEFINED IN THE
AGREEMENT.

     ALL REPRESENTATIONS AND WARRANTIES SET FORTH IN THE AGREEMENT ARE MODIFIED
IN THEIR ENTIRETY BY THESE DISCLOSURE SCHEDULES. THE DISCLOSURES CONTAINED IN
THESE DISCLOSURE SCHEDULES SHALL BE READ IN THEIR ENTIRETY, AND ALL THE
DISCLOSURES SHALL BE READ TOGETHER.





<PAGE>



                                 SCHEDULE 3.1(g)