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                                                                     Exhibit 4.1

                         FORM OF SUBSCRIPTION AGREEMENT

                  SUBSCRIPTION AGREEMENT (this "Agreement") made as of the date
set forth on the signature page hereof between InKine Pharmaceutical Company,
Inc., a New York corporation, (the "Company") and the undersigned (the
"Subscriber").

                                   WITNESSETH:

                  WHEREAS, the Company is offering in a private placement to
accredited investors (the "Offering") a minimum of 1.5 million shares of its
Common Stock, par value $.0001 per share, (the "Common Stock") (the "Minimum
Offering") and a maximum of 2.5 million shares of Common Stock (the "Maximum
Offering"), with an option in favor of the Placement Agent to offer up to an
additional 500,000 shares to cover overallotments, all at a purchase price of
$3.80 per share. The shares of Common Stock offered hereby are sometimes
referred to as the "Shares;"

                  WHEREAS, the Subscriber desires to purchase that number of
Shares set forth on the signature page hereof on the terms and conditions
hereinafter set forth; and

                  WHEREAS, the Company has engaged Leerink Swann & Company (the
"Placement Agent") as placement agent for the Offering on a "best-efforts"
basis.

                  NOW, THEREFORE, in consideration of the premises and the
mutual representations and covenants hereinafter set forth, the parties hereto
agree as follows:

I.        SUBSCRIPTION FOR SHARES AND REPRESENTATIONS BY SUBSCRIBER

                  1.1 Subject to the terms and conditions hereinafter set forth,
the Subscriber hereby irrevocably subscribes for and agrees to purchase from the
Company such number of Shares as is set forth upon the signature page hereof at
a price equal to the calculation of the above mentioned formula per Share and
the Company agrees to sell such Shares to the Subscriber for said purchase
price. The purchase price is payable by personal or business check, wire
transfer of immediately available funds or money order made payable to U.S. Bank
National, Escrow Agent, F/B/O InKine Pharmaceutical Company, Inc."
contemporaneously with the execution and delivery of this Agreement by the
Subscriber.

                  All wires should be sent to:

                  BBK: U.S. Bank N.A.

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                  ABA #091000022

                  BNF: U.S. Bank Trust N.A./AC #180121167365
                  OBI: TFM Wire Clearing A/C #47300017
                  Ref: InKine/Leerink Escrow Attn: Chad Myers 651-244-8542

                  Certificates for the Shares will be delivered by the Company
to the Subscriber within 2 business days of the Closing of the Offering
applicable to the Subscriber as set forth in Section III hereof.

                   1.2 The Subscriber recognizes that the purchase of Shares
involves a high degree of risk in that (i) the Company remains a development
stage business with a limited operating history and requires substantial funds
in addition to the proceeds of the Offering; (ii) an investment in the Company
is highly speculative and only investors who can afford the loss of their entire
investment should consider investing in the Company; (iii) the Subscriber may
not be able to liquidate its investment; (iv) transferability of the Shares is
extremely limited; and (v) in the event of a disposition, the Subscriber could
sustain the loss of its entire investment.

                   1.3 The Subscriber represents that the Subscriber is an
"accredited investor" as such term is defined in Rule 501 of Regulation D
promulgated under the Securities Act of 1933, as amended, (the "Act") as
indicated by the responses to the questions contained in Section VII hereof, and
that the Subscriber is able to bear the economic risk and illiquidity of an
investment in the Shares.

                   1.4 The Subscriber hereby acknowledges and represents that
(i) the Subscriber has prior investment experience, including investment in
non-listed and unregistered securities, or that the Subscriber has employed the
services of an investment advisor, attorney and/or accountant to read all of the
documents furnished or made available by the Company both to the Subscriber and
to all other prospective investors to evaluate the merits and risks of such an
investment on the Subscriber's behalf; (ii) the Subscriber recognizes the highly
speculative nature of an investment in the Shares; and (iii) the Subscriber is
able to bear the economic risk and illiquidity which the Subscriber assumes by
investing in the Shares.

                   1.5 The Subscriber hereby acknowledges receipt and careful
review of the Confidential Offering Package dated March 22, 2000; hereby
represents that the Subscriber has

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been furnished by the Company during the course of this transaction with all
information regarding the Company which the Subscriber has requested or desired
to know; has been afforded the opportunity to ask questions of and receive
answers from duly authorized officers or other representatives of the Company
concerning the terms and conditions of the Offering; and has received any
additional information which the Subscriber has requested.

                   1.6 (a) In making the decision to invest in the Shares, the
Subscriber has relied solely upon the information provided by the Company in the
Offering Package. To the extent necessary, the Subscriber has retained, at its
own expense, and relied upon the advice of appropriate professionals regarding
the investment, tax and legal merits and consequences of this Agreement and its
purchase of the Shares hereunder. The Subscriber acknowledges and agrees that
the Placement Agent has not supplied any information for inclusion in the
Offering Package other than information furnished in writing to the Company by
the Placement Agent specifically for inclusion in the Offering Package relating
to the Placement Agent, that the Placement Agent has no responsibility for the
accuracy or completeness of the Offering Package and that the Subscriber has not
relied upon the independent investigation or verification, if any, which may
have been undertaken by the Placement Agent.

              (b) The Subscriber covenants that (i) the Subscriber was contacted
regarding the sale of the Shares by the Placement Agent (or an authorized agent
or representative thereof) with whom the Subscriber had a prior substantial
pre-existing relationship and (ii) no Shares were offered or sold to it by means
of any form of general solicitation or general advertising, and in connection
therewith the Subscriber did not (A) receive or review any advertisement,
article, notice or other communication published in a newspaper or magazine or
similar media or broadcast over television or radio, whether closed circuit or
generally available; or (B) attend any seminar, meeting or industry investor
conference whose attendees were invited by any general solicitation or general
advertising.

                  1.7 The Subscriber hereby acknowledges that the Offering has
not been reviewed by the United States Securities and Exchange Commission (the
"SEC") because of the Company's representations that this Offering is intended
to be exempt from the registration requirements of Section 5 of the Act pursuant
to Sections 3(b), 4(2), and 4(6) thereof and Regulation D promulgated under the
Act. The Subscriber agrees that the Subscriber will not sell or otherwise
transfer the Shares unless they are registered under the Act or unless an
exemption from such registration is available.

                  1.8 The Subscriber understands that none of the Shares have
been registered under the Act by reason of a claimed exemption under the
provisions of the Act which depends, in part, upon the Subscriber's investment
intention. In this connection, the Subscriber hereby represents that the
Subscriber is purchasing the Shares for the Subscriber's own account for
investment and not with a view toward the resale or distribution thereof to
others. The Subscriber, if an entity, was not formed for the purpose of
purchasing the Shares. The Subscriber understands that Rule 144 promulgated
under the Act requires, among other conditions, a one-year holding period prior
to the resale (in limited amounts) of securities acquired in a non-public
offering without having to satisfy the registration requirements under

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the Act.

                  1.9 The Subscriber understands and hereby acknowledges that
the Company is under no obligation to register the Shares under the Act or any
state securities or "blue sky" laws other than as set forth in Section V. The
Subscriber consents that the Company may, if it desires, permit the transfer of
the Shares out of the Subscriber's name only when the Subscriber's request for
transfer is accompanied by an opinion of counsel reasonably satisfactory to the
Company that neither the sale nor the proposed transfer results in a violation
of the Act or any applicable state "blue sky" laws (collectively, "Securities
Laws"). The Subscriber agrees to hold the Company and the Placement Agent and
their respective directors, officers, employees, agents and controlling persons
and their respective heirs, representatives, successors and assigns harmless and
to indemnify them against all losses, damages, liabilities, costs and expenses
incurred by them as a result of any breach of any representation, warranty or
acknowledgement, or any misrepresentation made by the Subscriber contained in
this Agreement (including the Confidential Investor Questionnaire contained in
Section VII herein) or any sale or distribution by the Subscriber in violation
of the Securities Laws.

                  1.10 The Subscriber consents to the placement of a legend on
any certificate or other document evidencing the Shares indicating that such
Shares have not been registered under the Act or any state securities or "blue
sky" laws and setting forth or referring to the restrictions on transferability
and sale thereof contained in this Agreement. The Subscriber is aware that the
Company will make a notation in its appropriate records and issue "stop
transfer" instructions to its transfer agent with respect to the restrictions on
the transferability of such Shares.

                  1.11 The Subscriber understands that the Company will review
this Agreement and hereby gives authority to the Company to call Subscriber's
bank or place of employment (in a call in which the Placement Agent
participates) or otherwise review the financial standing of the Subscriber; and
it is further agreed that upon their mutual agreement the Placement Agent and
the Company reserve the unrestricted right, without further documentation or
agreement on the part of the Subscriber, to reject or limit any subscription, to
accept subscriptions for Shares and to close the Offering to the Subscriber at
any time.

                  1.12 The Subscriber hereby represents that the address of the
Subscriber furnished by the Subscriber on the signature page hereof is the
Subscriber's principal residence if the Subscriber is an individual or its
principal business address if it is a corporation or other entity.

                  1.13 The Subscriber represents that the Subscriber has full
power and authority (corporate, statutory and otherwise) to execute and deliver
this Agreement and to purchase the Shares subscribed for hereby. This Agreement
constitutes the legal, valid and binding obligation of the Subscriber,
enforceable against the Subscriber in accordance with its terms.

                  1.14 If the Subscriber is a corporation, partnership, limited
liability company, trust, employee benefit plan, individual retirement account,
Keogh Plan, or other entity, then (a) it is authorized and qualified to become
an investor in the Company and the person signing this

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Agreement on behalf of such entity has been duly authorized by such entity to do
so, and (b) it is duly organized, validly existing and in good standing under
the laws of the jurisdiction of its organization.

                  1.15 The Subscriber acknowledges that if he or she is a
registered representative of a National Association of Securities Dealers, Inc.
("NASD") member firm, he or she must give such firm the notice required by the
NASD's Rules of Fair Practice, receipt of which must be acknowledged by such
firm in Section 7.4 below.

                  1.16 The Subscriber represents and warrants that it has not
engaged, consented to nor authorized any broker, finder or intermediary to act
on its behalf, directly or indirectly, as a broker, finder or intermediary in
connection with the transactions contemplated by this Agreement. The Subscriber
shall indemnify and hold harmless the Company from and against all fees,
commissions or other payments owing to any such person or firm acting on behalf
of such Subscriber hereunder.

                  1.17 The Subscriber acknowledges that (a) the Company has
engaged, consented to and authorized the Placement Agent in connection with the
transactions contemplated by this Agreement, (b) the Company shall pay the
Placement Agent a commission and reimburse the Placement Agent's expenses in
accordance with the Placement Agency Agreement (as defined in Section 5.1(c)
below), and the Company shall indemnify and hold harmless the Subscriber from
and against all fees, commissions or other payments owing by the Company to the
Placement Agent or any other person or firm acting on behalf of the Company
hereunder and (c) registered representatives of the Placement Agent and/or its
designees (including, without limitation, registered representatives of the
Placement Agent and/or its designees who participate in the Offering and sale of
the securities sold in the Offering) will be paid a portion of the commissions
paid to the Placement Agent including a portion of the Placement Warrants (as
defined in Section 5.1(c) below).

                  1.18 The Subscriber, whose name appears on the signature line
below, shall be the beneficial owner of the Shares for which such Subscriber
subscribes.

                  1.19 The Subscriber agrees that from the time the Subscriber
first received the Offering Package until a point in time equal to the earlier
of (i) the date that the Registration Statement (as defined in Section 5.2(a))
is declared effective by the SEC or (ii) one year from the date of the Offering
Package, the Subscriber has not and shall not, directly or indirectly, through
related parties, affiliates or otherwise, (A) sell "short" or "short against the
box" (as those terms are generally understood) any equity security of the
Company or (B) otherwise engage in any transaction that involves hedging of the
Subscriber's position in any equity security of the Company.

II.      REPRESENTATIONS BY THE COMPANY

         The Company hereby represents and warrants to the Subscriber that:

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                  2.1 Organization, Good Standing and Qualification. The Company
is a corporation duly organized, validly existing and in good standing under the
laws of the State of New York and has full corporate power and lawful authority
to conduct its business as described in the Offering Package. The Company is
duly qualified to do business as a foreign corporation and is in good standing
in the Commonwealth of Pennsylvania and in each jurisdiction in which the nature
of the business conducted, or as proposed to be conducted in the Offering
Package, by it or the properties owned, leased or operated by it, makes such
qualification or licensing necessary and where the failure to be so qualified or
licensed would have a material adverse effect upon the business, prospects or
financial condition of the Company other than Pennsylvania, where the Company
will be so qualified prior to the Closing (as defined in Section 3.2).

                  2.2 Capitalization and Voting Rights. The authorized, issued
and outstanding capital stock of the Company is as set forth in the Offering
Package; all issued and outstanding shares of capital stock of the Company are
validly issued, fully paid and nonassessable. Except as set forth in the
Offering Package, there are no outstanding options, warrants, agreements,
commitments, convertible securities, preemptive rights or other rights to
subscribe for or to purchase any shares of capital stock of the Company nor are
there any agreements, promises or commitments to issue any of the foregoing, or
discussions concerning same, which have not been disclosed in writing. Except as
set forth in the Offering Package, in this Agreement and as otherwise required
by law, there are no restrictions upon the voting or transfer of the Shares
pursuant to the Company's Certificate of Incorporation, as amended, (the
"Certificate of Incorporation"), By-laws or other governing documents or any
agreement or other instruments to which the Company is a party or by which the
Company is bound.

                  2.3 Authorization; Enforceability. The Company has all
corporate right, power and authority to enter into this Agreement and to
consummate the transactions contemplated hereby. All corporate action on the
part of the Company, its directors and stockholders necessary for the
authorization, execution, delivery and performance of this Agreement by the
Company, the authorization, sale, issuance and delivery of the Shares and the
performance of the Company's obligations hereunder has been taken. This
Agreement has been duly executed and delivered by the Company and constitutes a
legal, valid and binding obligation of the Company, enforceable against the
Company in accordance with its terms, subject to laws of general application
relating to bankruptcy, insolvency and the relief of debtors and rules of law
governing specific performance, injunctive relief or other equitable remedies,
and to limitations of public policy. The Shares have been duly and validly
authorized and, upon the issuance and delivery thereof and payment therefor as
contemplated by this Agreement, will be free and clear of liens, duly and
validly authorized and issued, fully paid and nonassessable. The issuance and
sale of the Shares contemplated hereby will not give rise to any preemptive
rights or rights of first refusal on behalf of any person.

2.4      No Conflict; Governmental Consents.

                  (a) The execution and delivery by the Company of this
Agreement and the consummation of the transactions contemplated hereby will not
result in the violation of any law,

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statute, rule, regulation, order, writ, injunction, judgment or decree of any
court or governmental authority to or by which the Company is bound, or of any
provision of the Certificate of Incorporation or By-laws of the Company, and
will not conflict with, or result in a breach or violation of, any of the terms
or provisions of, or constitute (with due notice or lapse of time or both) a
default under, any lease, loan agreement, mortgage, security agreement, trust
indenture or other agreement or instrument to which the Company is a party or by
which it is bound or to which any of its properties or assets is subject, nor
result in the creation or imposition of any lien upon any of the properties or
assets of the Company.

                  (b) No consent, approval, authorization or other order of any
governmental authority or other third-party is required to be obtained by the
Company in connection with the authorization, execution and delivery of this
Agreement or with the authorization, issuance and sale of the Shares, except
such filings as may be required to be made, and which shall have been made at or
prior to the required time, with the SEC, the NASD and the National Association
of Securities Dealers Automated Quotation System ("Nasdaq"), and with any state
or foreign blue sky or securities regulatory authority.

                  2.5 Licenses. Except as may be set forth in the Offering
Package, the Company has all licenses, permits and other governmental
authorizations currently required for the conduct of its business or ownership
of properties and is in all material respects complying therewith, except for
any licenses, permits or other governmental authorizations which would not
materially adversely affect the business, property, financial condition, results
of operations or prospects of the Company.

                  2.6 Litigation. The Company knows of no pending or threatened
legal or governmental proceedings against the Company which could materially
adversely affect the business, property, financial condition, results of
operations or prospects of the Company.

                  2.7 Accuracy of Reports. All material reports required to be
filed by the Company within the three years prior to the date of this Agreement
under the Securities Exchange Act of 1934, as amended, (the "Exchange Act") have
been duly filed with the SEC, complied at the time of filing in all material
respects with the requirements of their respective forms and, except to the
extent updated or superseded by the Offering Package or any subsequently filed
report, to the best of the Company's knowledge, were complete and correct in all
material respects as of the dates at which the information was furnished, and
contained (as of such dates) no untrue statement of a material fact or omitted
to state a material fact necessary in order to make the statements contained
therein, in light of the circumstances under which they were made, not
misleading.

                  2.8 Accuracy of Offering Package. No information set forth in
the Offering Package contains any untrue statement of a material fact or omits
to state a material fact necessary in order to make the statements contained
therein, in light of the circumstances under which they were made, not
misleading.

                  2.9 Investment Company. The Company is not an "investment
company"

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within the meaning of such term under the Investment Company Act of 1940, as
amended, and the rules and regulations of the SEC thereunder.

                  2.10 Listing. The Company shall promptly file an Application
for Listing of Additional Shares with the Nasdaq SmallCap Market and hereby
represents and warrants to the Placement Agent and the Subscriber that it will
take any other necessary action in accordance with the rules of the Nasdaq
SmallCap Market to enable the Shares (and the Common Stock issuable upon
exercise of the Placement Warrants as defined in Section 5.1 (c)) to trade on
the Nasdaq SmallCap Market.

III.     TERMS OF SUBSCRIPTION

                  3.1 The Offering is for a minimum of 1.5 million Shares and a
maximum of 2.5 million Shares. The Shares are offered on a "best efforts" basis.
The Placement Agent, at its option, may offer for sale by the Company up to an
additional 500,000 Shares to cover over-allotments. Subscribers must each
purchase a minimum of 75,000 Shares unless the Company and the Placement Agent
agree to a lesser number.

                  3.2 After the Minimum Offering amount has been subscribed for,
the Company and the Placement Agent shall mutually agree as to the number of
closings and the timing thereof (each, a "Closing") and they will not be
obligated to conduct the first Closing within any specific time following
receipt of subscriptions for the Minimum Offering. The foregoing
notwithstanding, the first Closing is expected to occur no later than April 27,
2000, subject to extension of this Offering for up to an additional 60 days at
the option of the Placement Agent and the Company (such date, as the same may be
extended, the "Closing Date"). The purchase price is payable by personal or
business check, wire transfer of immediately available funds or money order made
payable to "U.S. Bank National, Escrow Agent, F/B/O InKine Pharmaceutical
Company, Inc." as provided in Section 1.1.

                  3.3 Pending the sale of the Shares, all subscription funds
paid hereunder shall be deposited by the Escrow Agent in escrow with U.S. Bank
National. If the Company shall not have obtained subscriptions (including this
subscription) for the Minimum Offering on or before May 19, 2000, then this
subscription shall be void and all funds paid hereunder by the Subscriber shall
be promptly returned to the Subscriber, without deduction therefrom and with
interest thereon, in accordance with Section 3.5 hereof.

                  3.4 The Subscriber hereby authorizes and directs the Company
to deliver the Shares to be issued to the Subscriber pursuant to this Agreement
directly to the Subscriber's account maintained by the Placement Agent or, if no
such account exists, to the residential or business address indicated on the
signature page hereto.

                  3.5 The Subscriber hereby authorizes and directs the Company
to return any funds related to unaccepted subscriptions to the same account from
which the funds were drawn, including any customer account maintained with the
Placement Agent.

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IV.      CONDITIONS TO OBLIGATIONS OF THE SUBSCRIBERS AND THE COMPANY

                  4.1 The Subscribers' obligation to purchase the Shares at the
Closing is subject to the fulfillment on or prior to the date of such Closing of
the following conditions, which conditions may be waived at the option of each
Subscriber to the extent permitted by law:

                  (a) Representations and Warranties. The representations and
warranties made by the Company in Section II hereof shall be true and correct in
all material respects when made, and shall be true and correct in all material
respects on the date of such Closing with the same force and effect as if they
had been made on and as of said date. If any such representations or warranties
shall not be true and accurate in any respect prior to the Closing, the Company
shall give immediate written notice of such fact to the Placement Agent,
specifying which representations or warranties are not true and accurate and the
reason therefor.

                  (b) Covenants. All covenants, agreements and conditions
contained in this Agreement to be performed by the Company on or prior to such
purchase shall have been performed or complied with in all material respects.

                  (c) No Legal Order Pending. There shall not then be in effect
any legal or other order enjoining or restraining the transactions contemplated
by this Agreement.

                  (d) No Law Prohibiting or Restricting Such Sale. There shall
not be in effect any law, rule or regulation prohibiting or restricting such
sale or requiring any consent or approval of any person to issue the Shares
which consent or approval shall not have been obtained (except as may otherwise
be provided in this Agreement).

                  (e) Minimum Subscriptions. The Company shall have received
binding subscriptions for at least the Minimum Offering.

                  (f) Legal Opinion. Upon the Closing, counsel to the Company
shall have delivered to the Placement Agent for the benefit of the Subscribers a
legal opinion with respect to such legal matters relating to this Agreement and
the Offering Package as the Placement Agent may reasonably require.

                  4.2 The Company's obligation to sell the Shares at the Closing
is subject to the fulfillment on or prior to the date of such Closing of the
following conditions, which conditions may be waived at the option of the
Company to the extent permitted by law:

                  (a) Acknowledgements, Representations and Warranties. The
acknowledgements, representations and warranties made by the Subscriber in
Section I hereof shall be true and correct in all material respects when made,
and shall be true and correct in all material respects on the date of such
Closing with the same force and effect as if they had been made on and as of
said date. If any such representations, warranties or acknowledgements shall not
be true and accurate in any respect prior to the Closing, the undersigned shall
give immediate

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written notice of such fact to the Company, to the Placement Agent, and to his
representatives, if any, specifying which representations, warranties or
acknowledgements are not true and accurate and the reason therefor.

                  (b) Covenants. All covenants, agreements and conditions
contained in this Agreement to be performed by the Subscriber on or prior to
such purchase shall have been performed or complied with in all material
respects.

                  (c) No Legal Order Pending. There shall not then be in effect
any legal or other order enjoining or restraining the transactions contemplated
by this Agreement.

                  (d) No Law Prohibiting or Restricting Such Sale. There shall
not be in effect any law, rule or regulation prohibiting or restricting such
sale or requiring any consent or approval of any person to issue the Shares
which consent or approval shall not have been obtained (except as may otherwise
be provided in this Agreement).

                  (e) Minimum Subscriptions. The Company shall have received
binding subscriptions for a least the Minimum Offering.

V.       REGISTRATION RIGHTS

                  5.1 As used in this Agreement, the following terms shall have
the following meanings:

                           (a) "Affiliate" shall mean, with respect to any
Person (as defined below), any other Person controlling, controlled by, or under
direct or indirect common control with, such Person (for the purposes of this
definition "control," when used with respect to any specified Person, shall mean
the power to direct the management and policies of such person, directly or
indirectly, whether through ownership of voting securities, by contract or
otherwise; and the terms "controlling" and "controlled" shall have meanings
correlative to the foregoing).

                           (b) "Business Day" shall mean a day, Monday through
Friday, on which banks are generally open for business in each of New York, New
York; Boston, Massachusetts; and Philadelphia, Pennsylvania;

                           (c) "Holders" shall mean the Subscriber and any
person holding Registrable Securities as defined below (including the
Registrable Securities underlying the Placement Warrants (the "Placement
Warrants") to be granted to the Placement Agent and/or their designees pursuant
to the engagement letter between the Company and the Placement Agent dated March
1, 2000, (the "Placement Agency Agreement")), a holder of the Placement
Warrants, or any person to whom the rights under Section V have been transferred
in accordance with Section 5.9 hereof.

                           (d) "Person" shall mean any person, individual,
corporation, limited liability company, partnership, trust or other
nongovernmental entity or any governmental

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agency, court, authority or other body (whether foreign, federal, state, local
or otherwise).

                           (e) The terms "register," "registered" and
"registration" refer to the registration effected by preparing and filing with
the SEC a registration statement in compliance with the Act, and the declaration
or ordering by the SEC of the effectiveness of such registration statement.

                           (f) "Registrable Securities" shall mean (i) the
Shares and (ii) the shares of Common Stock issuable upon the exercise of the
Placement Warrants; provided, however, that securities shall only be treated as
Registrable Securities if and only for so long as they (A) have not been
disposed of pursuant to a registration statement declared effective by the SEC,
(B) have not been sold in a transaction exempt from the registration and
prospectus delivery requirements of the Act so that all transfer restrictions
and restrictive legends with respect thereto are removed upon the consummation
of such sale, and (C) are held by a Holder or a permitted transferee pursuant to
Section 5.9.

                           (g) "Registration Expenses" shall mean all expenses
incurred by the Company in complying with Section 5.2 hereof, including, without
limitation, all registration, qualification and filing fees, printing expenses,
escrow fees, fees and expenses of counsel for the Company, blue sky fees and
expenses and the expense of any special audits incident to, or required by, any
such registration (but excluding the aggregate fees of legal counsel for all
Holders).

                           (h) "Registration Statement" shall have the meaning
ascribed to such term in Section 5.2 (a).

                           (i) "Registration Period" shall have the meaning
ascribed to such term in Section 5.4 (a).

                           (j) "Selling Expenses" shall mean all underwriting
discounts and selling commissions applicable to the sale of Registrable
Securities and the aggregate fees and expenses of legal counsel for all Holders.

                  5.2 (a) The Company shall, as soon as practicable, but not
later than ten (10) business days after the first Closing Date (such tenth
business day herein referred to as the "Filing Date"), (i) use its best efforts
to file with the SEC a registration statement (the "Registration Statement")
with respect to the resale of the Registerable Securities and use its best
efforts to have such Registration Statement declared effective by the SEC as
soon thereafter as is practical and (ii) cause such Registration Statement to
remain effective until the earlier of such date as the Holders have completed
the distribution described in the Registration Statement and such time as such
Shares are no longer, by reason of Rule 144 (k) under the Act, required to be
registered for the sale thereof by such Holders. If requested by the Placement
Agent, and in accordance with applicable securities laws, the Registration
Statement shall cover the direct sale of such Registrable Securities to the
Holders of such securities.

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                           (b) If the Registration Statement is not filed on or
prior to the Filing Date, then for each successive thirty (30) day period beyond
such Date, the Company shall pay to each Subscriber, in cash, as liquidated
damages and not as a penalty, one percent (1%) of the aggregate purchase price
previously paid by such Subscriber for Shares (or a pro rata amount for any
periods less than thirty (30) days) until such time as the filing is made;
provided, however, such Subscriber shall not be entitled to such cash payment if
and to the extent that such delays are the result of the failure of such
Subscriber to provide the Company with written information necessary to complete
the Registration Statement by the Filing Date.

                  5.3 All Registration Expenses incurred in connection with any
registration, qualification, exemption or compliance pursuant to Section 5.2
shall be borne by the Company. All Selling Expenses relating to the sale of
securities registered by or on behalf of Holders shall be borne by such Holders
pro rata on the basis of the number of securities so registered.

                  5.4 In the case of the registration, qualification, exemption
or compliance effected by the Company pursuant to this Agreement, the Company
shall, upon reasonable request, inform each Holder as to the status of such
registration, qualification, exemption and compliance. At its expense the
Company shall:

                           (a) use its best efforts to keep such registration,
and any qualification, exemption or compliance under state securities laws which
the Holders reasonably request the Company to obtain, continuously effective
until the Holders have completed the distribution described in the registration
statement relating thereto. The period of time during which the Company is
required hereunder to keep the Registration Statement effective is referred to
herein as "the Registration Period." Notwithstanding the foregoing, at the
Company's election, the Company may cease to keep such registration,
qualification, exemption or compliance effective with respect to any Registrable
Securities, and the registration rights of a Holder with respect to such
Registrable Securities shall expire, at such time as the Holder may sell all
Registrable Securities then held by such Holder under Rule 144 under the Act in
a three-month period, but this sentence shall not relieve the Company of any
obligation to comply with this Section V as to any shares of Common Stock
issuable upon exercise of the Placement Warrants;

                           (b) advise the Holders:

                                    (i) when the Registration Statement or any
amendment thereto has been filed with the SEC and when the Registration
Statement or any post-effective amendment thereto has become effective;

                                    (ii) of any request by the SEC for
amendments or supplements to the Registration Statement or the prospectus
included therein or for additional information;

                                    (iii) of the issuance by the SEC of any stop
order suspending the effectiveness of the Registration Statement or the
initiation of any proceedings for such purpose;

                                    (iv) of the receipt by the Company of any
notification with

                                       12
<PAGE>   13
respect to the suspension of the qualification of the Registrable Securities
included therein for sale in any jurisdiction or the initiation or threatening
of any proceeding for such purpose; and

                                    (v) of the happening of any event that
requires the making of any changes in the Registration Statement or the
prospectus so that, as of such date, the statements therein are not misleading
and do not 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 were made) not misleading;

                           (c) make every reasonable effort to obtain the
withdrawal of any order suspending the effectiveness of any Registration
Statement at the earliest possible time;

                           (d) furnish to each Holder, without charge, at least
one copy of such Registration Statement and any post-effective amendment or
supplement thereto, including financial statements and schedules, and, if the
Holder so requests in writing, all exhibits (excluding those incorporated by
reference) in the form filed with the SEC;

                           (e) during the Registration Period, deliver to each
Holder, without charge, a reasonable number of copies of the prospectus included
in such Registration Statement and any amendment or supplement thereto as such
Holder may reasonably request; and the Company consents to the use, consistent
with the provisions hereof, of the prospectus and any amendment or supplement
thereto by each of the selling Holders of Registrable Securities in connection
with the offering and sale of the Registrable Securities covered by the
prospectus and any amendment or supplement thereto;

                           (f) during the Registration Period, deliver to each
Holder, without charge, (i) as soon as practicable (but in the case of the
annual report of the Company to its stockholders, within 120 days after the end
of each fiscal year of the Company) one copy of: (A) its annual report to its
stockholders, if any (which annual report shall contain financial statements
audited in accordance with generally accepted accounting principles in the
United States of America by a firm of certified public accountants of recognized
standing); (B) if not included in substance in its annual report to
stockholders, its annual report on Form 10-K (or similar form); (C) a copy of
the full Registration Statement (excluding exhibits); and (ii) upon reasonable
request, all exhibits excluded by the parenthetical to the immediately preceding
clause (C);

                           (g) prior to any public offering of Registrable
Securities pursuant to any Registration Statement, register or qualify or obtain
an exemption for the offer and sale under the securities or blue sky laws of
such jurisdictions as any such Holders reasonably request in writing, provided
that the Company shall not for any such purpose be required to qualify generally
to transact business as a foreign corporation in any jurisdiction where it is
not so qualified or to consent to general service of process in any such
jurisdiction, and do any and all other acts or things reasonably necessary or
advisable to enable the offer and sale in such jurisdictions of the Registrable
Securities covered by such Registration Statement;

                           (h) cooperate with the Holders to facilitate the
timely preparation and

                                       13
<PAGE>   14
delivery of certificates representing Registrable Securities to be sold pursuant
to any Registration Statement free of any restrictive legends to the extent not
required at such time and in such denominations and registered in such names as
Holders may request at least five (5) business days prior to sales of
Registrable Securities pursuant to such Registration Statement;

                           (i) upon the occurrence of any event contemplated by
Section 5.4(b)(v) above, the Company shall promptly prepare a post-effective
amendment to the Registration Statement or a supplement to the related
prospectus, or file any other required document so that, as thereafter delivered
to purchasers of the Registrable Securities included therein, the prospectus
will not include any untrue statement of a material fact or omit to state any
material fact necessary to make the statements therein, in the light of the
circumstances under which they were made, not misleading; and

                           (j) use its best efforts to comply with all
applicable rules and regulations of the SEC, and make generally available to the
Holders not later than 45 days (or 90 days if the fiscal quarter is the fourth
fiscal quarter) after the end of its fiscal quarter in which the first
anniversary date of the effective date of the Registration Statement occurs, an
earnings statement satisfying the provisions of Section 11(a) of the Act.

                  5.5 The Holders shall have no right to take any action to
restrain, enjoin or otherwise delay any registration pursuant to Section 5.2
hereof as a result of any controversy that may arise with respect to the
interpretation or implementation of this Agreement.

                  5.6 (a) To the extent permitted by law, the Company shall
indemnify each Holder, each underwriter of the Registrable Securities and each
person controlling such Holder and each such underwriter within the meaning of
Section 15 of the Act, with respect to which any registration, qualification or
compliance has been sought pursuant to this Agreement, against all claims,
losses, expenses, costs, damages and liabilities (or action in respect thereof),
including any of the foregoing incurred in settlement of any litigation,
commenced or threatened (subject to Section 5.6(c) below), arising out of or
based on (i) any untrue statement (or alleged untrue statement) of a material
fact contained in any registration statement, prospectus or offering circular,
or any amendment or supplement thereof, incident to any such registration,
qualification or compliance, or based on any omission (or alleged omission) to
state therein a material fact required to be stated therein or necessary to make
the statements therein not misleading in light of the circumstances in which
they were made, or (ii) any violation or alleged violation by the Company of the
Act, the Exchange Act, or any rule or regulation promulgated under the Act or
the Exchange Act, and shall reimburse each Holder, each underwriter of the
Registrable Securities and each person controlling such Holder and each such
underwriter, for legal and other expenses reasonably incurred in connection with
investigating or defending any such claim, loss, damage, liability or action as
incurred; provided that the Company shall not be liable in any such case to the
extent that any untrue statement or omission or allegation thereof is made in
reliance upon and in conformity with written information furnished to the
Company by or on behalf of such Holder or underwriter and stated to be
specifically for use in preparation of such registration statement, prospectus
or offering circular; provided that the Company shall not be liable in any such
case where the claim, loss, damage or liability arises out of or is related to
the failure of the

                                       14
<PAGE>   15
Holder to comply with the covenants and agreements contained in this Agreement
respecting sales of Registrable Securities, and except that the foregoing
indemnity agreement is subject to the condition that, insofar as it relates to
any such untrue statement or alleged untrue statement or omission or alleged
omission made in the preliminary prospectus but eliminated or remedied in the
amended prospectus on file with the SEC at the time the registration statement
becomes effective or in the amended prospectus filed with the SEC pursuant to
Rule 424(b) of the Act or in the prospectus subject to completion under Rule 434
of the Act, which together meet the requirements of Section 10(a) of the Act
(the "Final Prospectus"), such indemnity agreement shall not inure to the
benefit of any such Holder, any such underwriter or any such controlling person,
if a copy of the Final Prospectus furnished by the Company to the Holder for
delivery was not furnished to the person or entity asserting the loss,
liability, claim or damage at or prior to the time such furnishing is required
by the Act and the Final Prospectus would have cured the defect giving rise to
such loss, liability, claim or damage.

                           (b) Each Holder will severally, if Registrable
Securities held by such Holder are included in the securities as to which such
registration, qualification or compliance is being effected, indemnify the
Company, each of its directors and officers, each underwriter of the Registrable
Securities and each person who controls the Company and each underwriter of the
Registrable Securities within the meaning of Section 15 of the Act, against all
claims, losses, expenses, costs, damages and liabilities (or actions in respect
thereof), including any of the foregoing incurred in settlement of any
litigation, commenced or threatened (subject to Section 5.6(c) below), arising
out of or based on any untrue statement (or alleged untrue statement) of a
material fact contained in any registration statement, prospectus or offering
circular, or any amendment or supplement thereof, incident to any such
registration, qualification or compliance or based on any omission (or alleged
omission) to state therein a material fact required to be stated therein or
necessary to make the statements therein not misleading in light of the
circumstances in which they were made, and will reimburse the Company, such
directors and officers, each underwriter of the Registrable Securities and each
person controlling the Company and each underwriter of the Registrable
Securities for reasonable legal and any other expenses or costs reasonably
incurred in connection with investigating or defending any such claim, loss,
damage, liability or action as incurred, in each case to the extent, but only to
the extent, that such untrue statement or omission or allegation thereof is made
in reliance upon, and in conformity with, written information furnished to the
Company by or on behalf of the Holder and stated to be specifically for use in
preparation of such registration statement, prospectus or offering circular;
provided that the indemnity shall not apply to the extent that such claim, loss,
damage or liability results from the fact that a current copy of the prospectus
or offering circular was not made available to the Holder and such current copy
of the prospectus or offering circular would have cured the defect giving rise
to such loss, claim, expense, costs, damage or liability. Notwithstanding the
foregoing, in no event shall a Holder be liable for any such claims, losses,
expenses, costs, damages or liabilities in excess of the proceeds received by
such Holder in that offering, except in the event of fraud by such Holder.

                           (c) Each party entitled to indemnification under this
Section 5.6 (the "Indemnified Party") shall give notice to the party required to
provide indemnification (the "Indemnifying Party") promptly after such
Indemnified Party has actual knowledge of any claim

                                       15
<PAGE>   16
as to which indemnity may be sought, and shall permit the Indemnifying Party to
assume the defense of any such claim or any litigation resulting therefrom,
provided that counsel for the Indemnifying Party, who shall conduct the defense
of such claim or litigation, shall be approved by the Indemnified Party (whose
approval shall not unreasonably be withheld), and the Indemnified Party may
participate in such defense with its own counsel at such Indemnified Party's
expense unless the named parties to any proceeding covered hereby (including any
impleaded parties) include both the Company or any others the Company may
designate and one or more Indemnified Persons, and representation of the
Indemnified Persons and such other parties by the same counsel would be
inappropriate due to actual or potential differing interests between them, and
provided further that the failure of any Indemnified Party to give notice as
provided herein shall not relieve the Indemnifying Party of its obligations
under this Agreement, unless such failure is materially prejudicial to the
Indemnifying Party in defending such claim or litigation. An Indemnifying Party
shall not be liable for any settlement of an action or claim effected without
its written consent (which consent will not be unreasonably withheld).

                           (d) If the indemnification provided for in this
Section 5.6 is held by a court of competent jurisdiction to be unavailable to an
Indemnified Party with respect to any loss, liability, claim, damage, cost or
expense referred to therein, then the Indemnifying Party, in lieu of
indemnifying such Indemnified Party thereunder, shall contribute to the amount
paid or payable by such Indemnified Party as a result of such loss, liability,
claim, damage, cost or expense in such proportion as is appropriate to reflect
the relative fault of the Indemnifying Party on the one hand and of the
Indemnified Party on the other in connection with the statements or omissions
which resulted in such loss, liability, claim, damage, cost or expense as well
as any other relevant equitable considerations. The relative fault of the
Indemnifying Party and of the Indemnified Party shall be determined by reference
to, among other things, whether the untrue or alleged untrue statement of a
material fact or the omission to state a material fact relates to information
supplied or which should have been supplied by the Indemnifying Party or by the
Indemnified Party and the parties' relative intent, knowledge, access to
information and opportunity to correct or prevent such statement or omission.

                  5.7 (a) Upon receipt of any notice from the Company of the
happening of any event requiring the preparation of a supplement or amendment to
a prospectus relating to Registrable Securities so that, as thereafter delivered
to the Holders, such prospectus will not contain an untrue statement of a
material fact or omit to state any material fact required to be stated therein
or necessary to make the statements therein not misleading, each Holder shall
forthwith discontinue disposition of Registrable Securities pursuant to the
registration statement contemplated by Section 5.2 until its receipt of copies
of the supplemented or amended prospectus from the Company and, if so directed
by the Company, each Holder shall deliver to the Company all copies, other than
permanent file copies then in such Holder's possession, of the prospectus
covering such Registrable Securities current at the time of receipt of such
notice.

                           (b) Any Holder which owns five percent (5%) or more
(and with respect to 5.7(b)(ii), "any Holder") of the Company's outstanding
Common Stock shall suspend, upon request of the Company, any disposition of
Registrable Securities pursuant to the

                                       16
<PAGE>   17
Registration Statement and prospectus contemplated by Section 5.2 during (i) any
period not to exceed one 120-day period within any one 12-month period the
Company requires in connection with a primary underwritten offering of equity
securities and (ii) any period, not to exceed two 45-day periods within any
twelve month period, when the Company determines in good faith that offers and
sales pursuant thereto should not be made by reason of the presence of material
undisclosed circumstances or developments with respect to which the disclosure
that would be required in such a prospectus is premature, would have an adverse
effect on the Company or is otherwise inadvisable.

                           (c) As a condition to the inclusion of its
Registrable Securities, each Holder shall furnish to the Company such
information regarding such Holder, the securities of the Company owned
beneficially or of record by such Holder and the distribution proposed by such
Holder as the Company may request in writing or as shall be required in
connection with any registration, qualification or compliance referred to in
this Section V.

                           (d) With respect to any sale of Registrable
Securities pursuant to a Registration Statement filed pursuant to this Section
V, each Holder hereby covenants with the Company (i) not to make any sale of the
Registrable Securities without effectively causing the prospectus delivery
requirements under the Act to be satisfied, and (ii) if such Registrable
Securities are to be sold by any method or in any transaction other than on a
national securities exchange, the Nasdaq National Market, the Nasdaq SmallCap
Market or in the over-the-counter market, in privately negotiated transactions,
or in a combination of such methods, or as otherwise described in the prospectus
contemplated by Section 5.2, to notify the Company at least five (5) business
days prior to the date on which the Holder first offers to sell any such
Registrable Securities.

                           (e) Each Holder acknowledges and agrees that the
Registrable Securities sold pursuant to the Registration Statement described in
this Section are not transferable on the books of the Company unless the stock
certificate submitted to the transfer agent evidencing such Registrable
Securities is accompanied by a certificate reasonably satisfactory to the
Company to the effect that (i) the Registrable Securities have been sold in
accordance with such Registration Statement and (ii) the requirement of
delivering a current prospectus has been satisfied.

                           (f) Each Holder shall not take any action with
respect to any distribution deemed to be made pursuant to such registration
statement, which would constitute a violation of Regulation M under the Exchange
Act or any other applicable rule, regulation or law.

                           (g) At the end of the period during which the Company
is obligated to keep the Registration Statement current and effective as
described above, the Holders of Registrable Securities included in the
Registration Statement and the shares underlying the Placement Warrants shall
discontinue sales of shares pursuant to such Registration Statement upon receipt
of notice from the Company of its intention to remove from registration the
shares covered by such Registration Statement which remain unsold, and such
Holders shall notify the

                                       17
<PAGE>   18
Company of the number of shares registered which remain unsold immediately upon
receipt of such notice from the Company.

                  5.8 With a view to making available to the Holders the
benefits of certain rules and regulations of the SEC which at any time permit
the sale of the Registrable Securities to the public without registration, the
Company shall use its reasonable best efforts:

                           (a) to make and keep public information available, as
those terms are understood and defined in Rule 144 under the Act, at all times;

                           (b) to file with the SEC in a timely manner all
reports and other documents required of the Company under the Exchange Act; and

                           (c) so long as a Holder owns any Registrable
Securities, to furnish to such Holder upon any reasonable request a written
statement by the Company as to its compliance with Rule 144 under the Act, and
of the Exchange Act, and a copy of the most recent annual or quarterly report of
the Company, and such other reports and documents of the Company as such Holder
may reasonably request in availing itself of any rule or regulation of the SEC
allowing a Holder to sell any such securities without registration.

                  5.9 With the written consent of the Company and the Holders
holding at least a majority of the Registrable Securities that are then
outstanding, any provision of this Section V may be waived (either generally or
in a particular instance, either retroactively or prospectively and either for a
specified period of time or indefinitely) or amended. Upon the effectuation of
each such waiver or amendment, the Company shall promptly give written notice
thereof to the Holders, if any, who have not previously received notice thereof
or consented thereto in writing.

VI.      MISCELLANEOUS

                  6.1 Any notice or other communication given hereunder shall be
deemed sufficient in writing and sent by (a) 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 (b) registered or
certified mail, return receipt requested, or delivered by hand against written
receipt therefor, addressed to InKine Pharmaceutical Company, Inc., Sentry Park
East, 1720 Walton Road, Blue Bell, PA 19422, Facsimile: (610) 260-9354,
Attention: Robert F. Apple, with a copy to Leerink Swann & Company, 60 State
Street, Boston, MA 02019, Facsimile (617) 918-4955, Attention: Thomas A.
Fitzgerald. Notices shall be deemed to have been given or delivered on the date
of mailing, except notices of change of address, which shall be deemed to have
been given or delivered when received.

                  6.2 Except as set forth in Section 5.9, this Agreement shall
not be changed, modified or amended except by a writing signed by the parties to
be charged, and this Agreement may not be discharged except by performance in
accordance with its terms or by a writing signed by the party to be charged.


                                       18
<PAGE>   19
                  6.3 Upon the execution and delivery of this Agreement by the
Subscriber, this Agreement shall become a binding obligation of the Subscriber
with respect to the purchase of Shares as herein provided, subject to acceptance
by the Company and the Placement Agent; subject, however, to the right hereby
reserved to the Company to enter into the same agreements with other subscribers
and to add and/or delete other persons as subscribers.

                  6.4 (a) Notwithstanding the place where this Agreement may be
executed by any of the parties hereto, the parties expressly agree that all the
terms and provisions hereof shall be construed in accordance with and governed
by the laws of the State of New York without regard to principles of conflicts
of law. In the event that a judicial proceeding is necessary, the sole forum for
resolving disputes arising out of or relating to this Agreement is the Supreme
Court of the State of New York in and for the County of New York or the Federal
Courts for such state and county, and all related appellate courts
(collectively, the "New York Courts"). The parties hereby irrevocably and
unconditionally consent to the jurisdiction of such courts.

                           (b) Each of the parties hereby irrevocably and
unconditionally consents to venue in the New York Courts, and hereby irrevocably
and unconditionally waives any objection to the laying of venue of any judicial
proceeding in the New York Courts, and agrees not to plead or claim in any such
New York Court that any such judicial proceeding brought in any such court has
been brought in an inconvenient forum.

                   6.5 The holding of any provision of this Agreement to be
invalid or unenforceable by a court of competent jurisdiction shall not affect
any other provision of this Agreement, which shall remain in full force and
effect. If any provision of this Agreement shall be declared by a court of
competent jurisdiction to be invalid, illegal or incapable of being enforced in
whole or in part, such provision shall be interpreted so as to remain
enforceable to the maximum extent permissible consistent with applicable law and
the remaining conditions and provisions or portions thereof shall nevertheless
remain in full force and effect and enforceable to the extent they are valid,
legal and enforceable, and no provisions shall be deemed dependent upon any
other covenant or provision unless so expressed herein.

                   6.6 It is agreed that a waiver by either party of a breach of
any provision of this Agreement shall not operate, or be construed, as a waiver
of any subsequent breach by that same party.

                   6.7 The parties agree to execute and deliver all such further
documents, agreements and instruments and take such other and further action as
may be necessary or appropriate to carry out the purposes and intent of this
Agreement.

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

                   6.9 The Subscriber agrees not to issue any public statement
with respect to the

                                       19
<PAGE>   20
Subscriber's investment or proposed investment in the Company or the terms of
any agreement or covenant between them and the Company without the Company's
prior written consent, except such disclosures as may be required under
applicable law or under any applicable order, rule or regulation.

                  6.10 Nothing in this Agreement shall create or be deemed to
create any rights in any person or entity not a party to this Agreement, except
for the holders of Registrable Securities.

                  6.11 Any pronoun herein shall include all genders and/or the
plural or singular as appropriate from the context.

             [The remainder of this page intentionally left blank.]

                                       20
<PAGE>   21
VII.     CONFIDENTIAL INVESTOR QUESTIONNAIRE


                  7.1 The Subscriber represents and warrants that he, she or it
comes within one category marked below, and that for any category marked, he,
she or it has truthfully set forth, where applicable, the factual basis or
reason the Subscriber comes within that category. ALL INFORMATION IN RESPONSE TO
THIS SECTION VII WILL BE KEPT STRICTLY CONFIDENTIAL. The undersigned agrees to
furnish any additional information which the Company deems necessary in order to
verify the answers set forth below.

Category A _____         The undersigned is an individual (not a partnership,
                         corporation, etc.) whose individual net worth, or joint
                         net worth with his or her spouse, presently exceeds
                         $1,000,000.

                                           Explanation. In calculating net worth
                                           you may include equity in personal
                                           property and real estate, including
                                           your principal residence, cash,
                                           short-term investments, stock and
                                           securities. Equity in personal
                                           property and real estate should be
                                           based on the fair market value of
                                           such property less debt secured by
                                           such property.

Category B _____         The undersigned is an individual (not a partnership,
                         corporation, etc.) who had an individual income in
                         excess of $200,000 in each of the two most recent
                         years, or joint income with his or her spouse in excess
                         of $300,000 in each of those years (in each case
                         including foreign income, tax exempt income and full
                         amount of capital gains and losses but excluding any
                         income of other family members and any unrealized
                         capital appreciation) and has a reasonable expectation
                         of reaching the same income level in the current year.

Category C _____         The undersigned is a director or executive officer of
                         the Company.

Category D _____         The undersigned is a bank; a savings and loan
                         association; insurance company; registered investment
                         company; registered business development company;
                         licensed small business investment company or "SBIC";
                         or employee benefit plan within the meaning of Title
                         1 of Employee Retirement Income Security Act or
                         "ERISA" and (a) the investment decision is made by a
                         plan fiduciary which is either a bank, savings and
                         loan association, insurance company or registered
                         investment advisor, or (b) the plan has total assets
                         in excess of $5,000,000 or is a self-directed plan
                         with investment decisions made solely by persons that
                         are accredited investors.

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

                         -------------------------------------------------------
                                            (describe entity)

                                       21
<PAGE>   22
Category E _____           The undersigned is a private business development
                           company as defined in section 202(a)(22) of the
                           Investment Advisors Act of 1940.

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

                           -----------------------------------------------------
                                            (describe entity)

Category F _____           The undersigned is either a corporation, partnership,
                           Massachusetts business trust, or nonprofit
                           organization within the meaning of Section 501(c)(3)
                           of the Internal Revenue Code, in each case not formed
                           for the specific purpose of acquiring the Shares and
                           with total assets in excess of $5,000,000.

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

                           -----------------------------------------------------
                                            (describe entity)

Category G _____           The undersigned is a trust with total assets in
                           excess of $5,000,000, not formed for the specific
                           purpose of acquiring the Shares where the purchase is
                           directed by a "sophisticated person" as defined in
                           Regulation 506(b)(2)(ii) under the Act.

Category H _____           The undersigned hereby certifies that it is an
                           accredited investor because all of its equity owners
                           are accredited investors. The Company, in its sole
                           discretion, may request information regarding the
                           basis on which such equity owners are accredited.

Category I _____           The undersigned hereby certifies that it is an
                           accredited investor because it has total assets in
                           excess of $5,000,000 and was not formed for the
                           specific purpose of acquiring the Shares.

Category J _____           The undersigned is not within any of the categories
                           above and is therefore not an accredited investor.

The Company will notify a prospective Subscriber whether such Subscriber is
eligible to purchase Shares pursuant to this Agreement (and the Company, in its
sole discretion, retains the right to accept or reject all such purchases). The
undersigned agrees that it will notify the Company at any time on or prior to
the Closing Date in the event that the representations and warranties in this
Investor Questionnaire shall cease to be true, accurate and complete.

                                       22
<PAGE>   23
                  7.2      SUITABILITY (please answer each question)

(a) For an individual Subscriber, please describe your current employment,
including the company by which you are employed and its principal business:

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(b) For an individual Subscriber, please describe any college or graduate
degrees held by you:

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(c)  For all Subscribers, please list types of prior investments:

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(d) For all Subscribers, please state whether you have you participated in other
private placements before:

                           YES                                NO
                              -------                           -------

(e) If your answer to question (d) above was "YES", please indicate frequency of
such prior participation in private placements of:

<TABLE>
<CAPTION>
                                                                                        Biotechnology,
                                                                                        Pharmaceutical and
                                    Public                    Private                   Other Life Science
                                    Companies                 Companies                 Companies *
                                    ---------                 ---------                 ------------------
<S>                                                           <C>                       <C>
         Frequently                 ---------                 ---------                 ---------
         Occasionally               ---------                 ---------                 ---------
         Never                      ---------                 ---------                 ---------
</TABLE>

         *indicate how many companies, whether public or private, are in the
          biotechnology, pharmaceutical or other life sciences sectors.

                                       23
<PAGE>   24
(f) For an individual Subscriber, do you expect your current level of income to
significantly decrease in the foreseeable future?

                           YES_______                         NO_______

(g) For trust, corporate, partnership and other institutional Subscribers, do
you expect your total assets to significantly decrease in the foreseeable
future?

                           YES_______                         NO_______

(h) For all Subscribers, do you have any other investments or contingent
liabilities which you reasonably anticipate could cause you to need sudden cash
requirements in excess of cash readily available to you?

                           YES_______                         NO_______

(i) For all Subscribers, are you familiar with the risk aspects and the
non-liquidity of investments such as the securities for which you seek to
subscribe?

                           YES_______                         NO_______

(j) For all Subscribers, do you understand that there is no guarantee of
financial return on this investment and that you run the risk of losing your
entire investment?

                           YES_______                         NO_______


                  7.3      MANNER IN WHICH TITLE IS TO BE HELD. (circle one)

                             (a)    Individual Ownership

                             (b)    Community Property

                             (c)    Joint Tenant with Right of
                                    Survivorship (both parties
                                    must sign)

                             (d)    Partnership*

                             (e)    Tenants in Common

                             (f)    Company*

                             (g)    Trust*

                             (h)    Other

         *If Shares are being subscribed for by an entity, the attached
          Certificate of Signatory must also be completed.

                                       24
<PAGE>   25
                  7.4      NASD AFFILIATION.

Are you affiliated or associated with an NASD member firm (please check one)?

                           YES                       NO
                               ---------                ----------

If Yes, please describe:**

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

         **If Subscriber is a Registered Representative with an NASD member
           firm, have the following acknowledgment signed by the appropriate
           party:

           The undersigned NASD member firm acknowledges receipt of the
           notice required by Article 3, Sections 28(a) and (b) of the Rules
           of Fair Practice.

                                   ---------------------------------------------
                                   Name of NASD Member Firm

                                   By:
                                      ------------------------------------------
                                           Authorized Officer - Signature

                                    --------------------------------------------
                                           Authorized Officer - Printed Name

                                   Date:                             , 2000
                                        -----------------------------



                  7.5      COMPANY RELIANCE ON THIS QUESTIONNAIRE

The undersigned is informed of the significance to the Company of the foregoing
representations and answers contained in this Section VII and such answers have
been provided under the assumption that the Company and its counsel will rely on
them.

                                       25
<PAGE>   26
SIGNATURE PAGE                            DATE SIGNED: APRIL _____ , 2000


NUMBER OF SHARES:                         _______________________

MULTIPLIED BY OFFERING PRICE PER SHARE:   x               $3.80
                                                          -----

EQUALS SUBSCRIPTION AMOUNT:               =               $
                                                          =====



Signature                             Second Signature (if purchasing jointly)


Printed Name                          Printed Second Name

Entity Name                           Entity Name

Address                               Address


City, State and Zip Code              City, State and Zip Code


Telephone-Business                    Telephone--Business

Facsimile-Business                    Facsimile--Business

Tax ID # or Social Security #         Tax ID # or Social Security #

Name in which securities should be issued: ____________________________________

CHECK "YES" IF YOU WOULD LIKE THE SECURITIES TO BE DELIVERED TO YOUR ACCOUNT
WITH LEERINK SWANN & COMPANY OR "NO" IF YOU WOULD LIKE THE SECURITIES TO BE
DELIVERED TO YOUR ADDRESS AS SET FORTH ABOVE.

                               YES _____ NO _____

                                       26
<PAGE>   27
This Subscription Agreement is agreed to and accepted as of April ________,
2000.

                                            INKINE PHARMACEUTICAL COMPANY, INC.

                                            By:

                                            ____________________________________
                                            Name: Robert F. Apple
                                            Title: Chief Financial Officer

                                       27
<PAGE>   28
                            CERTIFICATE OF SIGNATORY

        (To be completed if Shares are being subscribed for by an entity)


                  I,________________________, am the____________________________

of _____________________________________________ (the "Entity").

         I certify that I am empowered and duly authorized by the Entity to
execute and carry out the terms of the Subscription Agreement and to purchase
and hold the Shares, and certify further that the Subscription Agreement has
been duly and validly executed on behalf of the Entity and constitutes a legal
and binding obligation of the Entity.

         IN WITNESS WHEREOF, I have set my hand this___ day of April, 2000.

                                         _______________________________________
                                                       (Signature)

                                       28