Document:

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                                                                   EXHIBIT 10.22

                            IMARX THERAPEUTICS, INC.

                 AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT

     THIS AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT (the "AGREEMENT") is
entered into as of October 10, 2002, by and among IMARX THERAPEUTICS, INC., a
Delaware corporation (the "COMPANY"), and the investors listed on Exhibit A
hereto, referred to hereinafter as the "INVESTORS" and each individually as an
"INVESTOR."

                                    RECITALS

     WHEREAS, certain of the Investors and the Company have entered into that
certain Investor Rights Agreement dated August 9, 2000 (the "PRIOR RIGHTS
AGREEMENT") and, in accordance with Section 5.6 of the Prior Rights Agreement,
the Company and certain of the signatories to the Prior Rights Agreement whose
signatures appear below and who hold, in the aggregate, the percentage of
capital stock of the Company required to amend and restate the Prior Rights
Agreement desire to amend and restate the Prior Rights Agreement as set forth
herein.

     WHEREAS, the Investors have purchased shares of the Company's Series A
Convertible Preferred Stock and/or Series D Convertible Preferred Stock (the
"PREFERRED STOCK") pursuant to various stock purchase agreements, most recently
pursuant to that certain Series D Preferred Stock Purchase Agreement, dated as
of the date hereof (the "PURCHASE AGREEMENT");

     WHEREAS, the obligations in the Purchase Agreement are conditioned upon the
execution and delivery of this Agreement; and

     WHEREAS, in connection with the consummation of the transactions
contemplated by the Purchase Agreement, the parties desire to enter into this
Agreement to grant registration, information and other rights to the Investors
as set forth below.

     NOW, THEREFORE, in consideration of the premises and for other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree that the Prior Rights Agreement shall be
amended and restated in its entirety as follows:

SECTION 1. GENERAL.

     1.1 DEFINITIONS. As used in this Agreement the following terms shall have
the following respective meanings:

          "EXCHANGE ACT" means the Securities Exchange Act of 1934, as amended.

          "FORM S-3" means such form under the Securities Act as in effect on
the date hereof or any successor or similar registration form under the
Securities Act subsequently adopted by the SEC which permits inclusion or
incorporation of substantial information by reference to other documents filed
by the Company with the SEC.

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          "HOLDER" means any person owning of record Registrable Securities that
have not been sold to the public or any assignee of record of such Registrable
Securities in accordance with Section 2.10 hereof.

          "INITIAL OFFERING" means the Company's first firm commitment
underwritten public offering of its Common Stock registered under the Securities
Act.

          "REGISTER," "REGISTERED," and "REGISTRATION" refer to a registration
effected by preparing and filing a registration statement in compliance with the
Securities Act, and the declaration or ordering of effectiveness of such
registration statement or document.

          "REGISTRABLE SECURITIES" means (a) Common Stock of the Company issued
or issuable upon conversion of the Shares, (b) any shares of Common Stock issued
to the Investors on or prior to the date hereof, and (c) any shares of Common
Stock of the Company issued as (or issuable upon the conversion or exercise of
any warrant, right or other security which is issued as) a dividend or other
distribution with respect to, or in exchange for or in replacement of, such
above-described securities. Notwithstanding the foregoing, Registrable
Securities shall not include any securities sold by a person to the public
either pursuant to a registration statement or Rule 144 or sold in a private
transaction in which the transferor's rights under Section 2 of this Agreement
are not assigned, or as to which all registration rights of such Holder have
terminated under Section 2.7.

          "REGISTRABLE SECURITIES THEN OUTSTANDING" shall be the number of
shares determined by calculating the total number of shares of the Company's
Common Stock that are Registrable Securities and either (a) are then issued and
outstanding or (b) are issuable pursuant to then exercisable or convertible
securities.

          "REGISTRATION EXPENSES" shall mean all expenses incurred by the
Company in complying with Sections 2.2, 2.3 and 2.4 hereof, including, without
limitation, all registration and filing fees, printing expenses, fees and
disbursements of counsel for the Company, reasonable fees and disbursements of a
single special counsel for the Holders (up to a maximum of $10,000 for the
Initial Offering and $5,000 for any registration thereafter), blue sky fees and
expenses and the expense of any special audits incident to or required by any
such registration (but excluding the compensation of regular employees of the
Company which shall be paid in any event by the Company).

          "SEC" or "COMMISSION" means the Securities and Exchange Commission.

          "SECURITIES ACT" shall mean the Securities Act of 1933, as amended.

          "SELLING EXPENSES" shall mean all underwriting discounts and selling
commissions applicable to the sale.

          "SHARES" shall mean shares of the Company's Preferred Stock held by
the Investors.

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          "SPECIAL REGISTRATION STATEMENT" shall mean a registration statement
relating to any employee benefit plan or with respect to any corporate
reorganization or other transaction under Rule 145 of the Securities Act.

SECTION 2. REGISTRATION; RESTRICTIONS ON TRANSFER.

     2.1 RESTRICTIONS ON TRANSFER.

          (A) Each Holder agrees not to make any disposition of all or any
portion of the Shares or Registrable Securities unless and until:

               (I) There is then in effect a registration statement under the
Securities Act covering such proposed disposition and such disposition is made
in accordance with such registration statement; or

               (II) (A) The transferee has agreed in writing to be bound by the
terms of this Agreement, (B) such Holder shall have notified the Company of the
proposed disposition and shall have furnished the Company with a detailed
statement of the circumstances surrounding the proposed disposition, and (C) if
reasonably requested by the Company, such Holder shall have furnished the
Company with an opinion of counsel, reasonably satisfactory to the Company, that
such disposition will not require registration of such shares under the
Securities Act. It is agreed that the Company will not require opinions of
counsel for transactions made pursuant to Rule 144 except in unusual
circumstances.

               (III) Notwithstanding the provisions of subsections (i) and (ii)
above, no such registration statement or opinion of counsel shall be necessary
for a transfer (A) by a Holder which is a partnership to its partners or former
partners in accordance with their respective partnership interests, (B) by a
Holder which is a limited liability company to its members or former members in
accordance with their respective interest in the limited liability company, (C)
by a Holder to his or her family members or trusts, family limited partnerships
or family limited liability companies, for the benefit of an individual Holder
or his or her family member(s), (D) by a Holder which is a corporation to its
shareholders in accordance with their respective interest in the corporation, or
to its subsidiaries or other entities in which it holds a controlling interest,
or (E) by a Holder to any affiliate of such Holder or any entity or vehicle
including a partnership in which such Holder and/or its affiliates has a
majority economic interest and which is managed by such Holder and/or its
affiliates; provided that in each case the transferee will be subject to the
terms of this Agreement to the same extent as if he were an original Holder
hereunder.

          (B) Each certificate representing Shares or Registrable Securities
shall (unless otherwise permitted by the provisions of the Agreement) be stamped
or otherwise imprinted with a legend substantially similar to the following (in
addition to any legend required under applicable state securities laws):

          THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE
          SECURITIES ACT OF 1933 (THE "ACT") AND MAY NOT BE OFFERED, SOLD OR
          OTHERWISE TRANSFERRED, ASSIGNED, PLEDGED OR HYPOTHECATED

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          UNLESS AND UNTIL REGISTERED UNDER THE ACT OR UNLESS THE COMPANY HAS
          RECEIVED AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY AND ITS
          COUNSEL THAT SUCH REGISTRATION IS NOT REQUIRED.

          (C) The Company shall be obligated to reissue promptly unlegended
certificates at the request of any Holder thereof if the Holder shall have
obtained an opinion of counsel (which counsel may be counsel to the Company)
reasonably acceptable to the Company to the effect that the securities proposed
to be disposed of may lawfully be so disposed of without registration,
qualification or legend.

          (D) Any legend endorsed on an instrument pursuant to applicable state
securities laws and the stop-transfer instructions with respect to such
securities shall be removed upon receipt by the Company of an order of the
appropriate blue sky authority authorizing such removal.

     2.2 DEMAND REGISTRATION. The Company covenants and agrees that at such time
as it grants any holder of its capital stock or options, warrants or other
rights to acquire its capital stock the right to demand that the Company file a
registration statement under the Securities Act (other than pursuant to Form S-3
or successor form), this Agreement shall automatically be amended without
further action by the Company or any Holder of Registrable Securities to include
such demand registration rights in this Section 2.2.

     2.3 PIGGYBACK REGISTRATIONS. The Company shall notify all Holders of
Registrable Securities in writing at least thirty (30) days prior to the filing
of any registration statement under the Securities Act for purposes of a public
offering of securities of the Company (including, but not limited to,
registration statements relating to secondary offerings of securities of the
Company, but excluding Special Registration Statements) and will afford each
such Holder an opportunity to include in such registration statement all or part
of such Registrable Securities held by such Holder. Each Holder desiring to
include in any such registration statement all or any part of the Registrable
Securities held by it shall, within twenty (20) days after the above-described
notice from the Company, so notify the Company in writing. Such notice shall
state the intended method of disposition of the Registrable Securities by such
Holder. If a Holder decides not to include all of its Registrable Securities in
any registration statement thereafter filed by the Company, such Holder shall
nevertheless continue to have the right to include any Registrable Securities in
any subsequent registration statement or registration statements as may be filed
by the Company with respect to offerings of its securities (but excluding
Special Registration Statement(s)), all upon the terms and conditions set forth
herein.

          (A) UNDERWRITING. If the registration statement under which the
Company gives notice under this Section 2.3 is for an underwritten offering, the
Company shall so advise the Holders of Registrable Securities. In such event,
the right of any such Holder to be included in a registration pursuant to this
Section 2.3 shall be conditioned upon such Holder's participation in such
underwriting and the inclusion of such Holder's Registrable Securities in the
underwriting to the extent provided herein. All Holders proposing to distribute
their Registrable Securities through such underwriting shall enter into an
underwriting agreement in customary form with the underwriter or underwriters
selected for such underwriting by the Company.

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Notwithstanding any other provision of the Agreement, if the underwriter
determines in good faith that marketing factors require a limitation of the
number of shares to be underwritten, the number of shares that may be included
in the underwriting shall be allocated, first, to the Company; second, to the
Holders on a pro rata basis based on the total number of Registrable Securities
held by the Holders; and third, to any stockholder of the Company (other than a
Holder) on a pro rata basis based on the total number of shares of Common Stock
owned by those stockholders who are not Holders desiring to participate in the
underwriting. No such reduction shall (i) reduce the securities being offered by
the Company for its own account to be included in the registration and
underwriting, or (ii) reduce the amount of securities of the selling Holders
included in the registration below twenty-five percent (25%) of the total amount
of securities included in such registration, unless such offering is the Initial
Offering and such registration does not include shares of any other selling
stockholders, in which event any or all of the Registrable Securities of the
Holders may be excluded in accordance with the immediately preceding sentence.
In no event will shares of any other selling stockholder be included in such
registration which would reduce the number of shares which may be included by
Holders without the written consent of Holders of not less than two-thirds (2/3)
of the Registrable Securities proposed to be sold in the offering. If any Holder
disapproves of the terms of any such underwriting, such Holder may elect to
withdraw therefrom by written notice to the Company and the underwriter,
delivered at least ten (10) business days prior to the effective date of the
registration statement. Any Registrable Securities excluded or withdrawn from
such underwriting shall be excluded and withdrawn from the registration. For any
Holder which is a partnership or corporation, the partners, retired partners and
stockholders of such Holder, or the estates and family members of any such
partners and retired partners and any trusts for the benefit of any of the
foregoing person shall be deemed to be a single "HOLDER," and any pro rata
reduction with respect to such "HOLDER" shall be based upon the aggregate amount
of shares carrying registration rights owned by all entities and individuals
included in such "HOLDER," as defined in this sentence.

          (B) RIGHT TO TERMINATE REGISTRATION. The Company shall have the right
to terminate or withdraw any registration initiated by it under this Section 2.3
prior to the effectiveness of such registration whether or not any Holder has
elected to include securities in such registration. The Registration Expenses of
such withdrawn registration shall be borne by the Company in accordance with
Section 2.5 hereof.

     2.4 FORM S-3 REGISTRATION. In case the Company shall receive from any
Holder or Holders a written request or requests that the Company effect a
registration on Form S-3 (or any successor to Form S-3) or any similar
short-form registration statement and any related qualification or compliance
with respect to all or a part of the Registrable Securities owned by such Holder
or Holders, the Company will:

          (A) promptly give written notice of the proposed registration, and any
related qualification or compliance, to all other Holders; and

          (B) as soon as practicable, effect such registration and all such
qualifications and compliances as may be so requested and as would permit or
facilitate the sale and distribution of all or such portion of such Holder's or
Holders' Registrable Securities as are specified in such request, together with
all or such portion of the Registrable Securities of any

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other Holder or Holders joining in such request as are specified in a written
request given within fifteen (15) days after receipt of such written notice from
the Company; provided, however, that the Company shall not be obligated to
effect any such registration, qualification or compliance pursuant to this
Section 2.4:

               (I) if Form S-3 is not available for such offering by the
Holders;

               (II) if the Company has, within the twelve (12) month period
preceding the date of such request, already effected one (1) registration on
Form S-3 for any Holders pursuant to this Section 2.4;

               (III) if the Holders, together with the holders of any other
securities of the Company entitled to inclusion in such registration, propose to
sell Registrable Securities and such other securities (if any) at an aggregate
price to the public of less than Five Hundred Thousand Dollars ($500,000);

               (IV) if within thirty (30) days of receipt of a written request
from any Holder or Holders pursuant to this Section 2.4, the Company gives
notice to such Holder or Holders of the Company's intention to make a public
offering, other than pursuant to a Special Registration Statement, within sixty
(60) days;

               (V) if the Company shall furnish to the Holders a certificate
signed by the Chairman of the Board of Directors of the Company, or if there be
none, by the Chief Executive Officer, stating that in the good faith judgment of
the Board of Directors of the Company, it would be seriously detrimental to the
Company and its stockholders for such Form S-3 registration to be effected at
such time, in which event the Company shall have the right to defer the filing
of the Form S-3 registration statement for a period of not more than ninety (90)
days after receipt of the request of the Holder or Holders under this Section
2.4; provided, that such right to delay a request shall be exercised by the
Company not more than once in any twelve (12) month period; or

               (VI) in any particular jurisdiction in which the Company would be
required to qualify to do business or to execute a general consent to service of
process in effecting such registration, qualification or compliance.

          (C) Subject to the foregoing, the Company shall file a Form S-3
registration statement covering the Registrable Securities and other securities
so requested to be registered as soon as practicable after receipt of the
request or requests of the Holders. Registrations effected pursuant to this
Section 2.4 shall not be counted as demands for registration or registrations
effected pursuant to Sections 2.2 or 2.3, respectively.

     2.5 EXPENSES OF REGISTRATION. Except as specifically provided herein, all
Registration Expenses incurred in connection with any registration,
qualification or compliance pursuant to Section 2.2 or any registration under
Section 2.3 or Section 2.4 herein shall be borne by the Company. All Selling
Expenses incurred in connection with any registrations hereunder, shall be borne
by the Holders of the securities so registered pro rata on the basis of the
number of shares so registered. The Company shall not, however, be required to
pay for expenses of any registration proceeding begun pursuant to Section 2.2 or
2.4, the request of which has been

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subsequently withdrawn by the initiating Holders unless (a) the withdrawal is
based upon material adverse information concerning the Company of which the
initiating Holders were not aware at the time of such request or (b) the Holders
of a majority of Registrable Securities agree to forfeit their right to one
requested registration pursuant to Section 2.2 or Section 2.4, as applicable, in
which event such right shall be forfeited by all Holders). If the Holders are
required to pay the Registration Expenses, such expenses shall be borne by the
Holders of securities (including Registrable Securities) requesting such
registration in proportion to the number of shares for which registration was
requested. If the Company is required to pay the Registration Expenses of a
withdrawn offering pursuant to clause (a) above, then the Holders shall not
forfeit their rights pursuant to Section 2.2 or Section 2.4 to a demand
registration.

     2.6 OBLIGATIONS OF THE COMPANY. Whenever required to effect the
registration of any Registrable Securities, the Company shall, as expeditiously
as reasonably possible:

          (A) Prepare and file with the SEC a registration statement with
respect to such Registrable Securities and use all reasonable efforts to cause
such registration statement to become effective, and, upon the request of the
Holders of a majority of the Registrable Securities registered thereunder, keep
such registration statement effective for up to one hundred eighty (180) days
or, if earlier, until the Holder or Holders have completed the distribution
related thereto.

          (B) Prepare and file with the SEC such amendments and supplements to
such registration statement and the prospectus used in connection with such
registration statement as may be necessary to comply with the provisions of the
Securities Act with respect to the disposition of all securities covered by such
registration statement for the period set forth in paragraph (a) above.

          (C) Furnish to the Holders such number of copies of a prospectus,
including a preliminary prospectus, in conformity with the requirements of the
Securities Act, and such other documents as the Holders may reasonably request
to facilitate the disposition of Registrable Securities owned by them.

          (D) Use its reasonable efforts to register and qualify the securities
covered by such registration statement under such other securities or blue sky
laws of such jurisdictions as shall be reasonably requested by the Holders;
provided that the Company shall not be required in connection therewith or as a
condition thereto to qualify to do business or to file a general consent to
service of process in any such states or jurisdictions.

          (E) In the event of any underwritten public offering, enter into and
perform its obligations under an underwriting agreement, in usual and customary
form, with the managing underwriter(s) of such offering. Each Holder
participating in such underwriting shall also enter into and perform its
obligations under such an agreement.

          (F) Notify each Holder of Registrable Securities covered by such
registration statement at any time when a prospectus relating thereto is
required to be delivered under the Securities Act of the happening of any event
as a result of which the prospectus included in such registration statement, as
then in effect, includes an untrue statement of a material fact or omits

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to state a material fact required to be stated therein or necessary to make the
statements therein not misleading in the light of the circumstances then
existing. The Company will use reasonable efforts to amend or supplement such
prospectus in order to cause such prospectus not to include any 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 not misleading in the light
of the circumstances then existing.

          (G) Use its reasonable efforts to furnish, on the date that such
Registrable Securities are delivered to the underwriters for sale, if such
securities are being sold through underwriters, (i) an opinion, dated as of such
date, of the counsel representing the Company for the purposes of such
registration, in form and substance as is customarily given to underwriters in
an underwritten public offering, addressed to the underwriters, if any, and (ii)
a letter dated as of such date, from the independent certified public
accountants of the Company, in form and substance as is customarily given by
independent certified public accountants to underwriters in an underwritten
public offering addressed to the underwriters.

     2.7 TERMINATION OF REGISTRATION RIGHTS. All registration rights granted
under this Section 2 shall terminate and be of no further force and effect five
(5) years after the date of the Company's Initial Offering. In addition, a
Holder's registration rights shall expire with respect to all Registrable
Securities proposed to be sold by such Holder (and its affiliates, partners,
former partners, members and former members) if (a) all such Registrable
Securities may be sold under Rule 144 during any ninety (90) day period and (b)
the Company has completed its Initial Offering and is subject to the provisions
of the Exchange Act.

     2.8 DELAY OF REGISTRATION; FURNISHING INFORMATION.

          (A) No Holder shall have any right to obtain or seek an injunction
restraining or otherwise delaying any such registration as the result of any
controversy that might arise with respect to the interpretation or
implementation of this Section 2.

          (B) It shall be a condition precedent to the obligations of the
Company to take any action pursuant to Section 2.2, 2.3 or 2.4 that the selling
Holders shall furnish to the Company such information regarding themselves, the
Registrable Securities held by them and the intended method of disposition of
such securities as shall be required to effect the registration of their
Registrable Securities.

     2.9 INDEMNIFICATION. In the event any Registrable Securities are included
in a registration statement under Sections 2.2, 2.3 or 2.4:

          (A) To the extent permitted by law, the Company will indemnify and
hold harmless each Holder, the partners, officers and directors of each Holder,
any underwriter (as defined in the Securities Act) for such Holder and each
person, if any, who controls such Holder or underwriter within the meaning of
the Securities Act or the Exchange Act, against any losses, claims, damages, or
liabilities (joint or several) to which they may become subject under the
Securities Act, the Exchange Act or other federal or state law, insofar as such
losses, claims, damages or liabilities (or actions in respect thereof) arise out
of or are based upon any of the following statements, omissions or violations
(collectively a "VIOLATION") by the Company:

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(i) any untrue statement or alleged untrue statement of a material fact
contained in such registration statement, including any preliminary prospectus
or final prospectus contained therein or any amendments or supplements thereto,
(ii) the omission or alleged omission to state therein a material fact required
to be stated therein, or necessary to make the statements therein not
misleading, or (iii) any violation or alleged violation by the Company of the
Securities Act, the Exchange Act, any state securities law or any rule or
regulation promulgated under the Securities Act, the Exchange Act or any state
securities law in connection with the offering covered by such registration
statement; and the Company will pay as incurred to each such Holder, partner,
officer, director, underwriter or controlling person for any legal or other
expenses reasonably incurred by them in connection with investigating or
defending any such loss, claim, damage, liability or action; provided however,
that the indemnity agreement contained in this Section 2.9(a) shall not apply to
amounts paid in settlement of any such loss, claim, damage, liability or action
if such settlement is effected without the consent of the Company, which consent
shall not be unreasonably withheld, nor shall the Company be liable in any such
case for any such loss, claim, damage, liability or action to the extent that it
arises out of or is based upon (i) a Violation which occurs in reliance upon and
in conformity with written information furnished expressly for use in connection
with such registration by such Holder, partner, officer, director, underwriter
or controlling person of such Holder, or (ii) a Violation which occurs as a
result of use by a Holder of a registration statement that the Holder was
advised to discontinue use of pursuant to Section 2.15.

          (B) To the extent permitted by law, each Holder will, if Registrable
Securities held by such Holder are included in the securities as to which such
registration qualification or compliance is being effected, indemnify and hold
harmless the Company, each of its directors, its officers and each person, if
any, who controls the Company within the meaning of the Securities Act, any
underwriter and each person who controls such underwriter and any other Holder
selling securities under such registration statement or any of such other
Holder's partners, directors or officers or any person who controls such Holder,
against any losses, claims, damages or liabilities (joint or several) to which
the Company or any such director, officer, controlling person, underwriter or
other such Holder, or partner, director, officer or controlling person of such
other Holder may become subject under the Securities Act, the Exchange Act or
other federal or state law, insofar as such losses, claims, damages or
liabilities (or actions in respect thereto) arise out of or are based upon any
Violation, in each case to the extent (and only to the extent) that such (i)
Violation occurs in reliance upon and in conformity with written information
furnished by such Holder under an instrument duly executed by such Holder and
stated to be specifically for use in connection with such registration, or (ii)
such Violation occurs as a result of use by the Holder of a registration
statement that the Holder was advised to discontinue pursuant to Section 2.15;
and each such Holder will pay as incurred any legal or other expenses reasonably
incurred by the Company or any such director, officer, controlling person,
underwriter or other Holder, or partner, officer, director or controlling person
of such other Holder in connection with investigating or defending any such
loss, claim, damage, liability or action if it is judicially determined that
there was such a Violation; provided, however, that the indemnity agreement
contained in this Section 2.9(b) shall not apply to amounts paid in settlement
of any such loss, claim, damage, liability or action if such settlement is
effected without the consent of the Holder, which consent shall not be
unreasonably withheld; provided further, that in no event shall any indemnity
under this Section 2.9 exceed the net proceeds from the offering received by
such Holder.

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          (C) Promptly after receipt by an indemnified party under this Section
2.9 of notice of the commencement of any action (including any governmental
action), such indemnified party will, if a claim in respect thereof is to be
made against any indemnifying party under this Section 2.9, deliver to the
indemnifying party a written notice of the commencement thereof and the
indemnifying party shall have the right to participate in, and, to the extent
the indemnifying party so desires, jointly with any other indemnifying party
similarly noticed, to assume the defense thereof with counsel mutually
satisfactory to the parties; provided, however, that an indemnified party shall
have the right to retain its own counsel, with the fees and expenses to be paid
by the indemnifying party, if based on the advice of counsel, representation of
such indemnified party by the counsel retained by the indemnifying party would
be inappropriate due to actual or potential differing interests between such
indemnified party and any other party represented by such counsel in such
proceeding. The failure to deliver written notice to the indemnifying party
within a reasonable time of the commencement of any such action, if materially
prejudicial to its ability to defend such action, shall relieve such
indemnifying party of any liability to the indemnified party under this Section
2.9, but the omission so to deliver written notice to the indemnifying party
will not relieve it of any liability that it may have to any indemnified party
otherwise than under this Section 2.9. Notwithstanding the above, in the event
more than one Holder is an indemnified party, the indemnifying party shall be
obligated to pay the reasonable fees and expenses of only one counsel for all
indemnified parties in each relevant jurisdiction (except to the extent that
representation of all indemnified parties in any such jurisdiction would be
inappropriate under applicable standards of professional conduct), and such
single counsel shall be selected by the indemnified party or parties who
registered the largest number of Registrable Securities in the offering at
issue.

          (D) If the indemnification provided for in this Section 2.9 is held by
a court of competent jurisdiction to be unavailable to an indemnified party with
respect to any losses, claims, damages or liabilities referred to herein, the
indemnifying party, in lieu of indemnifying such indemnified party thereunder,
shall to the extent permitted by applicable law contribute to the amount paid or
payable by such indemnified party as a result of such loss, claim, damage or
liability 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 Violation(s) that resulted in such loss, claim, damage or
liability, as well as any other relevant equitable considerations. The relative
fault of the indemnifying party and of the indemnified party shall be determined
by a court of law 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 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;
provided, that in no event shall any contribution by a Holder hereunder exceed
the net proceeds from the offering received by such Holder. No person guilty of
fraudulent misrepresentation (within the meaning of Section 11 of the Securities
Act) shall be entitled to contribution under this Section 2.9(d).

          (E) The obligations of the Company and Holders under this Section 2.9
shall survive completion of any offering of Registrable Securities in a
registration statement and the termination of this Agreement. No indemnifying
party shall be liable for any settlement entered into without its written
consent, which consent shall not be unreasonably withheld. No

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indemnifying party, in the defense of any such claim or litigation, shall,
except with the consent of each Indemnified Party, consent to entry of any
judgment or enter into any settlement which does not include as an unconditional
term thereof the giving by the claimant or plaintiff to such Indemnified Party
of a release from all liability in respect to such claim or litigation.

     2.10 ASSIGNMENT OF REGISTRATION RIGHTS. The rights to cause the Company to
register Registrable Securities pursuant to this Section 2 may be assigned (a)
by a Holder to a transferee or assignee which is a subsidiary, parent,
affiliate, general partner, limited partner, retired partner, member, retired
member or stockholder of a Holder, (b) by a Holder to a transferee or assignee
which is a Holder's family member or trust for the benefit of an individual
Holder or his family member(s), (c) by a Holder to a transferee or assignee
which acquires at least five percent (5%) of the then outstanding Registrable
Securities, or (d) by a Holder to a transferee or assignee in which all of
Holder's Registrable Securities are transferred; provided, however, (i) the
transfer of Registrable Securities complies with Section 2.1 hereof; (ii) the
transferor shall, within ten (10) days after such transfer, furnish to the
Company written notice of the name and address of such transferee or assignee
and the securities with respect to which such registration rights are being
assigned and (iii) such transferee shall agree in writing to be subject to all
restrictions set forth in this Agreement.

     2.11 AMENDMENT OF REGISTRATION RIGHTS. Any provision of this Section 2 may
be amended and the observance thereof may be waived (either generally or in a
particular instance and either retroactively or prospectively), only with the
written consent of the Company and the Holders holding at least seventy-five
percent (75%) of the Registrable Securities then outstanding. Any amendment or
waiver effected in accordance with this Section 2.11 shall be binding upon each
Holder and the Company. By acceptance of any benefits under this Section 2,
Holders of Registrable Securities hereby agree to be bound by the provisions
hereunder.

     2.12 LIMITATION ON SUBSEQUENT REGISTRATION RIGHTS. Other than as provided
in Section 5.11, after the date of this Agreement, the Company shall not,
without the prior written consent of the Holders holding at least a majority of
the Registrable Securities then outstanding, enter into any agreement with any
holder or prospective holder of any securities of the Company that would grant
such holder registration rights senior to those granted to the Holders hereunder
unless such rights are granted to the Holders hereunder.

     2.13 "MARKET STAND-OFF" AGREEMENT; AGREEMENT TO FURNISH INFORMATION. Each
Investor hereby agrees that such Investor shall not sell, transfer, make any
short sale of, grant any option for the purchase of, or enter into any hedging
or similar transaction with the same economic effect as a sale, any Common Stock
(or other securities) of the Company held by such Investor (other than those
included in the registration) for a period specified by the representative of
the underwriters of Common Stock (or other securities) of the Company not to
exceed one hundred eighty (180) days following the effective date of a
registration statement of the Company filed under the Securities Act; provided
that:

               (I) such agreement shall apply only to the Company's Initial
Offering; and

                                       11

<PAGE>

               (II) all officers and directors of the Company and holders of at
least two percent (2%) of the Company's voting securities enter into similar
agreements.

     Each Holder agrees to execute and deliver such other agreements as may be
reasonably requested by the Company or the underwriter which are consistent with
the foregoing or which are necessary to give further effect thereto. In
addition, if requested by the Company or the representative of the underwriters
of Common Stock (or other securities) of the Company, each Holder shall provide,
within ten (10) days of such request, such information as may be required by the
Company or such representative in connection with the completion of any public
offering of the Company's securities pursuant to a registration statement filed
under the Securities Act so long as the Company and such representative agree
that if the Holder supplying such information is not participating in the
Offering and so requests, the Company and such representative shall treat such
information as confidential, shall seek (with the cooperation and reasonable
efforts of the Holder) a protective order, confidential treatment or other
appropriate remedy, shall furnish only that portion of the information which is
legally required and shall exercise reasonable efforts to obtain reliable
assurance that confidential treatment will be accorded such information to the
extent reasonably requested by Holder, provided, however, that no Holder who is
not participating in the Offering and who is not a director or officer of the
Company shall be required to provide such information unless such Holder is a
holder of five percent (5%) of the outstanding shares of the Company as
determined by the rules and regulations of the Exchange Act. Notwithstanding the
foregoing, the Holders shall not be required to execute and deliver NASD
Questionnaires to the Company or the representatives of the underwriters. The
obligations described in this Section 2.13 shall not apply to a registration
pursuant to a Special Registration Statement. The Company may impose
stop-transfer instructions with respect to the shares of Common Stock (or other
securities) subject to the foregoing restriction until the end of said one
hundred eighty (180) day period. Each Investor agrees that any transferee of any
shares of Registrable Securities shall be bound by this Section 2.13.

     2.14 RULE 144 REPORTING. With a view to making available to the Holders the
benefits of certain rules and regulations of the SEC which may permit the sale
of the Registrable Securities to the public without registration, the Company
agrees to use its best efforts to:

          (A) Make and keep public information available, as those terms are
understood and defined in SEC Rule 144 or any similar or analogous rule
promulgated under the Securities Act, at all times after the effective date of
the Initial Offering;

          (B) 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, furnish to
such Holder forthwith upon request: a written statement by the Company as to its
compliance with the reporting requirements of said Rule 144 of the Securities
Act, and of the Exchange Act (at any time after it has become subject to such
reporting requirements); a copy of the most recent annual or quarterly report of
the Company; and such other reports and documents as a Holder may reasonably
request in availing itself of any rule or regulation of the SEC allowing it to
sell any such securities without registration.

                                       12

<PAGE>

     2.15 NOTICE TO DISCONTINUE. Each Holder agrees that, upon receipt of any
notice from the Company of the happening of any event of the kind described in
Section 2.6(f), such Holder shall forthwith discontinue disposition of
Registrable Securities pursuant to the registration statement covering such
Registrable Securities until such Holder's receipt of the copies of the
supplemented or amended prospectus contemplated by Section 2.6(f) and, if so
directed by the Company, such 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 which is current at the time of
receipt of such notice.

SECTION 3. COVENANTS.

     3.1 BASIC FINANCIAL INFORMATION AND REPORTING.

          (A) The Company will maintain in all material respects true books and
records of account in which full and correct entries will be made of all its
business transactions pursuant to a system of accounting established and
administered in accordance with generally accepted accounting principles
consistently applied ("GAAP"), and will set aside on its books all such proper
accruals and reserves as shall be required under GAAP.

          (B) As soon as practicable after the end of each fiscal year of the
Company, and in any event within one hundred and twenty (120) days thereafter,
the Company will furnish each Investor a balance sheet of the Company, as at the
end of such fiscal year, and a statement of income and a statement of cash flows
of the Company, for such year, all prepared in accordance with GAAP and setting
forth in each case in comparative form the figures for the previous fiscal year,
all in reasonable detail. Such financial statements shall be accompanied by a
report and opinion thereon by independent public accountants of national
standing selected by the Company's Board of Directors.

          (C) The Company will furnish each Investor, as soon as practicable
after the end of the first, second and third quarterly accounting periods in
each fiscal year of the Company, and in any event within forty-five (45) days
thereafter, a balance sheet of the Company as of the end of each such quarterly
period, and a statement of income and a statement of cash flows of the Company
for such period and for the current fiscal year to date, prepared in accordance
with GAAP, with the exception that no notes need be attached to such statements
and year-end audit adjustments may not have been made.

          (D) The Company will furnish each Investor as soon as practicable
after the end of each month, and in any event within thirty (30) days
thereafter, a balance sheet of the Company as of the end of each such month, and
a statement of income and a statement of cash flows of the Company for such
month and for the current fiscal year to date, including a comparison to plan
figures for such period, prepared in accordance with generally accepted
accounting principles consistently applied, with the exception that no notes
need be attached to such statements and year-end audit adjustments may not have
been made.

     3.2 INSPECTION RIGHTS. Each Investor that holds at least 100,000 shares of
Preferred Stock (and/or Common Stock issued upon conversion thereof) (as
adjusted for stock splits, combinations, recapitalizations and the like) shall
have the right to visit and inspect any of the

                                       13

<PAGE>

properties of the Company or any of its subsidiaries, and to discuss the
affairs, finances and accounts of the Company or any of its subsidiaries with
its officers, and to review such information as is reasonably requested all at
such reasonable times and as often as may be reasonably requested; provided,
however, that the Company shall not be obligated to comply with this Section 3.2
with respect to a competitor of the Company or with respect to information which
the Board of Directors determines in good faith is confidential and should not,
therefore, be disclosed.

     3.3 CONFIDENTIALITY OF RECORDS. Each Investor agrees to use, and to use its
best efforts to insure that its authorized representatives use, the same degree
of care as such Investor uses to protect its own confidential information (but
not less than reasonable care) to keep confidential any information furnished to
it which the Company identifies as being confidential or proprietary (so long as
such information is not in the public domain), except that such Investor may
disclose such proprietary or confidential information to any partner, member,
subsidiary or parent of such Investor for the purpose of evaluating its
investment in the Company as long as such partner, member, subsidiary or parent
is advised of the confidentiality provisions of this Section 3.3; provided, that
any financial information provided to the Investors pursuant to this Section 3
shall be deemed confidential, regardless of whether the Company identifies it as
confidential.

     3.4 RESERVATION OF COMMON STOCK. The Company will at all times reserve and
keep available, solely for issuance and delivery upon the conversion of the
Preferred Stock, all Common Stock issuable from time to time upon such
conversion.

     3.5 KEY MAN INSURANCE. Subject to the approval of the Board of Directors,
the Company will use its best efforts to obtain and maintain in full force and
effect term life insurance (with annual premiums which are reasonably acceptable
to the Board of Directors) in the amount of Three Million Dollars ($3,000,000)
on the life of Dr. Evan Unger; naming the Company as beneficiary.

     3.6 DIRECTORS' EXPENSES. The Company shall reimburse each of the members of
its Board of Directors for all reasonable out-of-pocket expenses incurred by
him/her in connection with attendance at Board meetings (including any meetings
of committees of the Board) and any other activities as are required or
requested by the Company (i.e., meetings, trade shows, etc.). Other than such
reimbursement, the Company shall not pay any compensation to any of its
directors for their services as directors, except that the Company may elect to
compensate any independent director.

     3.7 DIRECTORS AND OFFICERS INSURANCE. The Company shall promptly, and in
any event within ninety (90) days after the date hereof, obtain and maintain in
full force and effect directors and officers insurance in an amount to be
determined by the Company's Board of Directors in good faith.

     3.8 STOCK-BASED GRANTS AND AWARDS. All shares of Common Stock and/or
options, warrants or other Common Stock purchase rights, and the Common Stock
issued pursuant to such options, warrants or other rights, issued to employees,
officers or directors of, or consultants or advisors, strategic partners,
lenders and other creditors to the Company or any subsidiary,

                                       14

<PAGE>

shall be issued pursuant to stock purchase or stock option plans or other
arrangements approved by the Board of Directors (or a duly authorized committee
of the Board) that contain a provision giving the Company or its designee a
right of first refusal or right of first offer to purchase such shares of Common
Stock prior to any transfer thereof, except transfers for estate planning
purposes where the transferee agrees in writing to remain bound to such right of
first refusal or right of first offer.

     3.9 TERMINATION OF COVENANTS. All covenants of the Company contained in
Section 3 of this Agreement shall expire and terminate as to each Investor upon
the effective date of the registration statement pertaining to the Initial
Offering which results in the Preferred Stock being converted into Common Stock.

SECTION 4. RIGHTS OF FIRST REFUSAL.

     4.1 SUBSEQUENT OFFERINGS. Each Investor shall have a right of first refusal
to purchase its pro rata share of all Equity Securities, as defined below, that
the Company may, from time to time, propose to sell and issue after the date of
this Agreement, other than the Equity Securities excluded by Section 4.6 hereof.
Each Investor's pro rata share is equal to the ratio of (a) the number of shares
of the Company's Common Stock (including all shares of Common Stock issued or
issuable upon conversion of the Shares) which such Investor is deemed to be a
holder immediately prior to the issuance of such Equity Securities to (b) the
total number of shares of the Company's outstanding Common Stock (including all
shares of Common Stock issued or issuable upon conversion of the Shares or upon
the exercise of any outstanding warrants or options) immediately prior to the
issuance of the Equity Securities. The term "EQUITY SECURITIES" shall mean (i)
any Common Stock, Preferred Stock or other security of the Company, (ii) any
security convertible, with or without consideration, into any Common Stock,
Preferred Stock or other security (including any option to purchase such a
convertible security), (iii) any security carrying any warrant or right to
subscribe to or purchase any Common Stock, Preferred Stock or other security or
(iv) any such warrant or right.

     4.2 EXERCISE OF RIGHTS. If the Company proposes to issue any Equity
Securities, it shall give each Investor written notice of its intention,
describing the Equity Securities, the price and the terms and conditions upon
which the Company proposes to issue the same. Each Investor shall have thirty
(30) days from the giving of such notice to agree to purchase its pro rata share
of the Equity Securities for the price and upon the terms and conditions
specified in the notice by giving written notice to the Company and stating
therein the quantity of Equity Securities to be purchased. Notwithstanding the
foregoing, the Company shall not be required to offer or sell such Equity
Securities to any Investor who would cause the Company to be in violation of
applicable federal securities laws by virtue of such offer or sale.

     4.3 ISSUANCE OF EQUITY SECURITIES TO OTHER PERSONS. If not all of the
Investors elect to purchase their pro rata share of the Equity Securities, then
the Company shall promptly notify in writing the Investors who do so elect and
shall offer such Investors the right to acquire such unsubscribed shares. The
Investors shall have five (5) days after receipt of such notice to notify the
Company of their election to purchase all or a portion thereof of the
unsubscribed shares. If the Investors fail to exercise in full the rights of
first refusal, the Company shall have ninety (90) days thereafter to sell the
Equity Securities in respect of which the Investor's rights were not

                                       15

<PAGE>

exercised, at a price and upon general terms and conditions materially no more
favorable to the purchasers thereof than specified in the Company's notice to
the Investors pursuant to Section 4.2 hereof. If the Company has not sold such
Equity Securities within ninety (90) days of the notice provided pursuant to
Section 4.2, the Company shall not thereafter issue or sell any Equity
Securities, without first offering such securities to the Investors in the
manner provided above.

     4.4 TERMINATION AND WAIVER OF RIGHTS OF FIRST REFUSAL. The rights of first
refusal established by this Section 4 shall not apply to, and shall terminate
upon the effective date of the registration statement pertaining to the
Company's Initial Offering which results in the Preferred Stock being converted
into Common Stock. The rights of first refusal established by this Section 4 may
be amended, or any provision waived, with the written consent of Investors
holding at least seventy-five percent (75%) of the Common Stock issued or
issuable upon conversion of the Shares held by all Investors.

     4.5 TRANSFER OF RIGHTS OF FIRST REFUSAL. The rights of first refusal of
each Investor under this Section 4 may be transferred to the same parties,
subject to the same restrictions as any transfer of registration rights pursuant
to Section 2.10.

     4.6 EXCLUDED SECURITIES. The rights of first refusal established by this
Section 4 shall not apply to any of the following Equity Securities:

          (A) up to an aggregate amount of 3,000,000 shares (as adjusted for
stock splits, combinations, recapitalizations and the like, and net of any
repurchases of such shares or cancellations or expiration of such options,
warrants or other rights) of Common Stock and/or options, warrants or other
Common Stock purchase rights, and the Common Stock issued pursuant to such
options, warrants or other rights issued or to be issued to employees, officers
or directors of, or consultants or advisors, strategic partners, lenders and
other creditors to the Company or any subsidiary, pursuant to stock purchase or
stock option plans or other arrangements that are approved by the Board of
Directors;

          (B) any Equity Securities issued for consideration other than cash
pursuant to a merger, consolidation, acquisition or similar business combination
approved by the Board of Directors;

          (C) shares of Common Stock issued in connection with any stock split,
stock dividend or recapitalization by the Company;

          (D) shares of Common Stock issued upon conversion of the Shares; and

          (E) any Equity Securities that are issued by the Company pursuant to a
registration statement filed under the Securities Act.

SECTION 5. MISCELLANEOUS.

     5.1 GOVERNING LAW. This Agreement shall be governed by and construed under
the laws of the State of DELAWARE as applied to agreements among Delaware
residents entered into and to be performed entirely in Delaware.

                                       16

<PAGE>

     5.2 SURVIVAL. The representations, warranties, covenants, and agreements
made herein shall survive any investigation made by any Investor and the closing
of the transactions contemplated hereby. All statements as to factual matters
contained in any certificate or other instrument delivered by or on behalf of
the Company pursuant hereto in connection with the transactions contemplated
hereby shall be deemed to be representations and warranties by the Company
hereunder solely as of the date of such certificate or instrument.

     5.3 SUCCESSORS AND ASSIGNS. Except as otherwise expressly provided herein,
the provisions hereof shall inure to the benefit of, and be binding upon, the
successors, assigns, heirs, executors, and administrators of the parties hereto
and shall inure to the benefit of and be enforceable by each person who shall be
a holder of Registrable Securities from time to time; provided, however, that
prior to the receipt by the Company of adequate written notice of the transfer
of any Registrable Securities in compliance with Section 2.1 hereof specifying
the full name and address of the transferee, the Company may deem and treat the
person listed as the holder of such shares in its records as the absolute owner
and holder of such shares for all purposes, including the payment of dividends
or any redemption price.

     5.4 ENTIRE AGREEMENT. This Agreement, the Exhibits and Schedules hereto,
the Purchase Agreement and the other documents delivered pursuant thereto
constitute the full and entire understanding and agreement among the parties
with regard to the subjects hereof and no party shall be liable or bound to any
other in any manner by any representations, warranties, covenants and agreements
except as specifically set forth herein and therein.

     5.5 SEVERABILITY. In case any provisions of this Agreement shall be
invalid, illegal or unenforceable in any respect, the validity, legality and
enforceability of the remaining provisions shall not in any way be affected or
impaired thereby.

     5.6 AMENDMENT AND WAIVER.

          (A) Except as otherwise expressly provided, this Agreement may be
amended or modified only upon the written consent of the Company and the holders
of at least seventy-five percent (75%) of the Registrable Securities.

          (B) Except as otherwise expressly provided, the obligations of the
Company and the rights of the Holders under this Agreement may be waived only
with the written consent of the holders of at least seventy-five percent (75%)
of the Registrable Securities.

          (C) Notwithstanding the foregoing, this Agreement may be amended with
only the written consent of the Company to include additional purchasers of
Preferred Stock as "INVESTORS," "HOLDERS" and parties hereto.

          (D) Any amendment or waiver effected in accordance with this Section
shall be binding upon the Company and each Holder and each transferee of a
Holder.

          (E) For the purposes of determining the number of Holders or Investors
entitled to vote or exercise any rights hereunder, the Company shall be entitled
to rely solely on the list of record holders of its stock as maintained by or on
behalf of the Company.

                                       17

<PAGE>

     5.7 DELAYS OR OMISSIONS. Subject to Section 5.6, it is agreed that no delay
or omission to exercise any right, power, or remedy accruing to any party, upon
any breach, default or noncompliance of another party under this Agreement shall
impair any such right, power, or remedy, nor shall it be construed to be a
waiver of any such breach, default or noncompliance, or any acquiescence
therein, or of any similar breach, default or noncompliance thereafter
occurring. Subject to Section 5.6, it is further agreed that any waiver, permit,
consent, or approval of any kind or character on any Holder's part of any
breach, default or noncompliance under the Agreement or any waiver on such
Holder's part of any provisions or conditions of this Agreement must be in
writing and shall be effective only to the extent specifically set forth in such
writing. All remedies, either under this Agreement, by law, or otherwise
afforded to Holders, shall be cumulative and not alternative.

     5.8 NOTICES. All notices required or permitted hereunder shall be in
writing and shall be deemed effectively given: (a) upon personal delivery to the
party to be notified, (b) when sent by confirmed electronic mail or facsimile if
sent during normal business hours of the recipient; if not, then on the next
business day, (c) five (5) days after having been sent by registered or
certified mail, return receipt requested, postage prepaid, or (d) one (1) day
after deposit with a nationally recognized overnight courier, specifying next
day delivery, with written verification of receipt. All communications shall be
sent to the party to be notified at the address as set forth on the signature
pages hereof or Exhibit A hereto or at such other address as such party may
designate by ten (10) days advance written notice to the other parties hereto.

     5.9 ATTORNEYS' FEES. In the event that any suit or action is instituted to
enforce any provision in this Agreement, the prevailing party in such dispute
shall be entitled to recover from the losing party all fees, costs and expenses
of enforcing any right of such prevailing party under or with respect to this
Agreement, including without limitation, such reasonable fees and expenses of
attorneys and accountants, which shall include, without limitation, all fees,
costs and expenses of appeals.

     5.10 TITLES AND SUBTITLES. The titles of the sections and subsections of
this Agreement are for convenience of reference only and are not to be
considered in construing this Agreement.

     5.11 ADDITIONAL INVESTORS. Notwithstanding anything to the contrary
contained herein, if the Company shall issue additional shares of its Preferred
Stock pursuant to the Purchase Agreement, any purchaser of such shares of
Preferred Stock may become a party to this Agreement without the consent of any
other party hereto except the Company by executing and delivering an additional
counterpart signature page to this Agreement and shall be deemed an "INVESTOR"
hereunder.

     5.12 COUNTERPARTS. This Agreement may be executed in any number of
counterparts, each of which shall be an original, but all of which together
shall constitute one instrument.

                      [THIS SPACE INTENTIONALLY LEFT BLANK]

                                       18

<PAGE>

     IN WITNESS WHEREOF, the parties hereto have executed this AMENDED AND
RESTATED INVESTOR RIGHTS AGREEMENT as of the date set forth in the first
paragraph hereof.

                                        COMPANY:

                                        IMARX THERAPEUTICS, INC.

                                        By: /s/ Evan Unger
                                            ------------------------------------
                                            Evan C. Unger, M.D.
                                        Its: Chief Executive Officer

                                        1635 East 18th Street
                                        Tucson, Arizona 85719
                                        Telephone: (520) 770-1259
                                        Fax: (520) 791-2437
                                        Email: jcarlyle@imarx.com
                                        Attn: Jean Carlyle, CFO

INVESTORS:

-------------------------------------
Name of Entity (if applicable):

By:
    ---------------------------------
Print Individual Name:
                       --------------
Print Title (if applicable):
                             --------
Address:
         ----------------------------

         ----------------------------
Telephone:
           --------------------------
Fax:
     --------------------------------
Email:
       ------------------------------
Attn:
      -------------------------------

        [Amended nad restated investor Rights Agreement Signature Page]<PAGE>
                                                                   EXHIBIT 10.23

______________________                                                  150
Name of Subscriber                                                Memorandum No.

                SUBSCRIPTION AGREEMENT AND INVESTOR QUESTIONNAIRE

                            IMARX THERAPEUTICS, INC.

                          Common Stock Private Offering
                         OFFERING PRICE $2.00 PER SHARE

     THE SHARES OFFERED HEREBY ARE HIGHLY SPECULATIVE AND INVOLVE A HIGH DEGREE
OF RISK AND IMMEDIATE DILUTION AND MAY BE PURCHASED ONLY BY PERSONS WHO QUALIFY
AS "ACCREDITED INVESTORS" UNDER RULE 501 (a) OF REGULATION D UNDER THE
SECURITIES ACT.

     THIS DOCUMENT HAS NOT BEEN FILED WITH OR REVIEWED BY THE UNITED STATES
SECURITIES AND EXCHANGE COMMISSION OR ANY OTHER COMMISSION OR REGULATORY
AUTHORITY, AND HAS NOT BEEN FILED WITH OR REVIEWED BY THE ATTORNEY GENERAL OF
THE STATES OF NEW YORK, FLORIDA OR NEW JERSEY OR ANY OTHER STATE NOR HAS ANY
SUCH COMMISSION, AUTHORITY OR ATTORNEY GENERAL DETERMINED WHETHER IT IS ACCURATE
OR COMPLETE OR PASSED UPON OR ENDORSED THE MERITS OF THIS OFFERING. ANY
REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

                                   ----------

                                PLACEMENT AGENT:
                         FIRST MONTAUK SECURITIES CORP.

<PAGE>

CONFIDENTIAL SUBSCRIPTION AGREEMENT AND QUESTIONNAIRE

     THIS SUBSCRIPTION AGREEMENT AND INVESTOR QUESTIONNAIRE IS TO BE COMPLETED
BY EACH PERSON WHO DESIRES TO PURCHASE SECURITIES OF IMARX THERAPEUTICS, INC.
(THE "COMPANY") IN CONNECTION WITH THE PROPOSED PRIVATE PLACEMENT OF SHARES OF
COMMON STOCK OF THE COMPANY AS DESCRIBED IN THE OFFERING MEMORANDUM DATED AS OF
FEBRUARY 18, 2004.

     THIS MATERIAL DOES NOT CONSTITUTE AN OFFER TO SELL OR A SOLICITATION OF AN
OFFER TO BUY ANY SECURITIES. THIS OFFERING WILL BE MADE SOLELY PURSUANT TO THE
TERMS AND CONDITIONS OF THE CONFIDENTIAL PRIVATE MEMORANDUM DATED FEBRUARY 18,
2004 (THE "MEMORANDUM") WHICH CONTAINS MATERIAL INFORMATION REQUIRED TO BE
REVIEWED IN CONNECTION WITH ANY INVESTMENT DECISION. ALL TERMS NOT DEFINED
HEREIN SHALL HAVE THE MEANING ASCRIBED TO THEM IN THE MEMORANDUM.

INSTRUCTIONS:

Items to be delivered by all Investors:

     a.   One (1) completed and executed Subscription Agreement and Investor
          Questionnaire.

     b.   Payment in the amount of subscription, by wire transfer of funds or
          check. All checks should be made payable to "SIGNATURE BANK AS ESCROW
          AGENT FOR IMARX."

For Information and Wire Transfer Instructions:

                                        PLACEMENT AGENT:
                                        FIRST MONTAUK SECURITIES CORP.
                                        Parkway 109 Office Center
                                        328 Newman Springs Road
                                        Red Bank, New Jersey 07701
                                        Tel.: (732) 842-4700
                                        Attention: Ernest Pellegrino

THE SUBSCRIBER IS RESPONSIBLE FOR ALL WIRE TRANSFER FEES IMPOSED BY THE
SUBSCRIBER'S BANK.

     The Shares of Common Stock ("Shares" or "Securities") of the Company, as
well as the terms of the Offering, which are described in the Offering
Memorandum dated February 18, 2004, are being offered without registration under
the Securities Act of 1933, as amended (the "Act"), or the securities laws of
any state or any other jurisdiction, in reliance on the exemption

                                        2

<PAGE>

contained in Section 4(2) of the Act and Regulation D promulgated thereunder and
on similar exemptions under applicable state laws. Under Regulation D of the Act
and/or certain state laws, the Company is required to determine that an
individual, or an individual together with a "purchaser representative" or each
individual equity owner of an "investing entity" meets certain suitability
requirements before selling Securities to such individual or entity. You
understand that the Company will rely upon the following information to
determine whether you meet such suitability requirements.

     THE COMPANY WILL NOT SELL SECURITIES TO ANY SUBSCRIBER WHO HAS NOT FILLED
OUT, AS THOROUGHLY AS POSSIBLE, EXECUTED AND HAND DELIVERED THIS QUESTIONNAIRE.
IN THE CASE OF AN SUBSCRIBER THAT IS A PARTNERSHIP, TRUST, CORPORATION OR OTHER
ENTITY, AN AUTHORIZED OFFICER, OR GENERAL PARTNER OR EACH EQUITY OWNER OR
BENEFICIARY, AS APPLICABLE, MUST COMPLETE THIS QUESTIONNAIRE. This questionnaire
is merely a request for information and does not constitute an offer to sell or
a solicitation of an offer to buy the Shares. No sale will occur prior to the
acceptance of any subscription by the Company and the Placement Agent. The
Company and First Montauk Securities Corp., as Placement Agent, reserve the
right to reject any subscription for any reason or to accept subscriptions for
less than the minimum subscription of $100,000 (50,000 shares). The Company and
First Montauk Securities Corp. will promptly return any money without interest
to a subscriber whose subscription is rejected in whole or in part as the case
may be. Subscribers should also understand that they may be required to furnish
additional information to the Company.

     The Shares are being offered by the Company through First Montauk
Securities Corp., as Placement Agent. The purpose of this Questionnaire is to
determine whether you meet certain standards, because the Shares will not be
registered under the Act and will be sold only to persons who are "Accredited
Investors," as that term is defined in Rule 501(a) of Regulation D, promulgated
under the Act. The Shares are sometimes referred to as the "Securities."

     Your answers will be kept confidential. At all times, however, you hereby
agree that the Company may present this Questionnaire to such parties as it
deems appropriate in order to assure itself that the offer and the sale of the
Shares to you will not result in violations of federal or state securities laws
which are being relied upon by the Company in connection with the offer and sale
thereof and as otherwise required by law or any regulatory authority.

     Please type or clearly print your answers, and state "none" or
"not-applicable" when appropriate. Please complete Section A and each other
section you are requested to complete in Question A3. If there is insufficient
space for any of your answers, please attach additional pages if the Shares are
to be owned by more than one individual or by a corporation or partnership, you
may need extra copies of this Questionnaire. You may use photocopies or request
extra copies from the Company or the Placement Agent.

SECTION A: SUBSCRIBER INFORMATION

A1.   Name(s) of SUBSCRIBER(s):         ________________________________________

                                        ________________________________________

                                        ________________________________________

                                        3

<PAGE>

A2.   Principal Amount of Shares
      Subscribed for:                   $____________
      (Minimum Subscription
      is 50,000 Shares ($100,000)

A3.   Manner of Ownership of Securities.

_____ One Individual                    Please complete Section A, B and C.

_____ Husband and Wife
      Tenants by the Entirety           Please have one spouse complete Sections
                                        A, B and C. Please have both spouses
                                        complete Section C.

_____ Tenants in Common                 Please have each individual separately
                                        complete Sections A, B and C.

_____ Joint Tenants with Right of       Please have each individual separately
      Survivorship - Two or more        complete Section A, B and C.
      Individuals (but not husband
      and wife)

_____ Corporate Ownership               Please complete Section A, B, D and, if
                                        applicable, E and F for the corporation.
                                        If the corporation does not qualify as
                                        an "accredited investor" on its own,
                                        please have each person who owns an
                                        equity interest in the corporation
                                        separately complete Sections B and, if
                                        applicable, C, D, E and F.

_____ Partnership Ownership             Please complete Sections A, B and D, and
                                        have each general partner and limited
                                        partner separately complete Sections B,
                                        C, D, E and F, if applicable.

_____ Trust Ownership                   Please complete Sections A, B and F, if
                                        applicable, and have each beneficiary
                                        and trustee of the trust separately
                                        complete Sections B, C, D, E and F, if
                                        applicable.

                                        4

<PAGE>

     NASD AFFILIATION. Please state whether you or any of your associates or
affiliates (which includes your spouse, in-laws and children or parents): (i)
are a member or a person associated (including as an employee, officer,
director, partner) with a member of the National Association of Securities
Dealers, Inc. (the "NASD"), (ii) are an owner of stock or other securities of an
NASD member, (iii) has made a subordinated loan to any NASD member, or (iv) a
relative or member of the same household of any person meeting the description
set forth in clauses (i) through (iii) above.

               _____                              _____
               Yes                                No

If you marked yes above, please briefly describe the NASD relationship below:

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

SECTION B: ACCREDITED INVESTOR STATUS

B1.  Please check one or more of the following definitions of "accredited
     investor," if any, which applies to you. If none of the following applies
     to you, please leave blank.

_____ (a)   A Bank as defined in Section 3 (a) (2) of the Act, or any savings
            and loan association or other institution as defined in Section 3
            (a) (5) (A) of the Act whether acting in its individual or fiduciary
            capacity;

_____ (b)   Any broker or dealer registered pursuant to Section 15 of the
            Securities Exchange Act of 1934 (the "Exchange Act");

_____ (c)   An insurance company as defined in Section 2(13) of the Act;

_____ (d)   An investment company registered under the Investment Company Act of
            1940 or a business development company as defined in Section
            2(a)(48) of that Act;

_____ (e)   A Small Business Investment Company licensed by the U.S. Small
            Business Administration under Section 301(c) or (d) of the Small
            Business Investment Act of 1958;

_____ (f)   A plan established and maintained by a state, or its political
            subdivisions, or any agency or instrumentality of a state or its
            political subdivisions for the benefit of its employees, if such
            plan has total assets in excess of $5,000,000;

_____ (g)   Any employee benefit plan within the meaning of the Employee
            Retirement Income Security Act of 1974, as amended, if the
            investment decision is made by a plan fiduciary, as defined in
            Section 3(21) of such Act, which is either a bank, savings and loan
            association, insurance company, or registered investment

                                        5

<PAGE>

            advisor, or if the employee benefit plan has total assets in excess
            of $5,000,000 or, if a self-directed plan, with investment decisions
            made solely by persons that are Accredited Investors;

_____ (h)   A Private Business Development Company as defined in Section
            202(a)(22) of the Investment Advisers Act of 1940.

_____ (i)   An organization described in Section 501(c) (3) of the Internal
            Revenue Code, Massachusetts or similar business trust, or
            partnership, not formed for the specific purpose of acquiring the
            securities offered, with total assets in excess of $5,000,000.

_____ (j)   A natural person whose individual net worth,* or joint net worth
            with that person's spouse, at the time of purchase exceeds
            $1,000,000.

_____ (k)   A natural person who had an individual income** in excess of
            $200,000 in each of the two most recent years or joint income with
            that person's spouse in excess of $300,000 in each of those years
            and has a reasonable expectation of reaching the same income level
            in the current year.

_____ (l)   A trust, with total assets in excess of $5,000,000, not formed for
            the specific purpose of acquiring the Shares, whose purchase is
            directed by a sophisticated person as described in Rule 506(b) (2)
            (ii) of Regulation D.

_____ (m)   Any entity in which all of the equity owners are Accredited
            Investors. ***

----------
*    For purposes hereof net worth shall be deemed to include ALL of your
     assets, liquid or illiquid (including such items as home, furnishings,
     automobile and restricted securities) MINUS any liabilities (including such
     items as home mortgages and other debts and liabilities).

**   For purposes hereof the term "income" is not limited to "adjusted gross
     income" as that term is defined for federal income tax purposes, but rather
     includes certain items of income which are deducted in computing "adjusted
     gross income." For Subscribers who are salaried employees, the gross salary
     of such Subscribers, minus any significant expenses personally incurred by
     such Subscriber in connection with earning the salary, plus any income from
     any other source including unearned income, is a fair measure of "income"
     for purposes hereof. For Subscribers who are self-employed, "income" is
     generally construed to mean total revenues received during the calendar
     year minus significant expenses incurred in connection with earning such
     revenues.

***  If the Subscriber intends to qualify under (m), then all owners of the
     entity must complete a Subscription Agreement as an individual.

                                        6

<PAGE>

SECTION C: INDIVIDUAL INFORMATION

C1.  General Information

     Name: _____________________________________________________________________

     Age: _________________________   Social Security Number ___________________

     Marital Status: _______________   Spouse's Name: __________________________

If the Securities are to be owned by two or more individuals (not husband and
wife), are you related to any other co-owner(s)?

               _____                              _____
               Yes                                No

      If Yes, please explain the relationship(s):
________________________________________________________________________________

________________________________________________________________________________

C2.  Principal Residence

     Address: __________________________________________________________________
              Number                   Street

              __________________________________________________________________
              City                        State                         Zip Code

              __________________________________________________________________
              Country

Mailing Address (if other than Principal Residence above):

              __________________________________________________________________
              Number                   Street

              __________________________________________________________________
              City                        State                         Zip Code

              __________________________________________________________________
              Country

Telephone Number: ___________________

Facsimile Number: ___________________

                                        7

<PAGE>

C3.  Current Employment or Business Activity:

     Company Name: _____________________________________________________________

     Address: __________________________________________________________________
              Number                   Street

              __________________________________________________________________
              City                        State                         Zip Code

     Principal Business: _______________________________________________________

     Position and Title: _______________________________________________________

     Years Employed at Current Position: _______________________________________

C4.  Education: Please describe your business or professional education or
     training, listing any schools you have attended and degrees you have
     received.

<TABLE>
<CAPTION>
                                                DEGREES
DATES        SCHOOL                             MAJOR (IF ANY)
-----        ------                             --------------
<S>          <C>                                <C>

__________   ________________________________   ____________________

__________   ________________________________   ____________________

__________   ________________________________   ____________________
</TABLE>

C5.  Net worth, inclusive of the net worth of your spouse and the value of your
     principal residence, furnishings therein and personal automobile and other
     assets (IT IS IMPORTANT THAT YOU CHECK THE HIGHEST APPLICABLE AMOUNT)
     exclusive of any liabilities:

     [ ] below $249,999
     [ ] $250,000 to $349,999       [ ] $350,000 to $699,999
     [ ] $700,000 to $799,999       [ ] $800,000 to $1,000,000
     [ ] $1,000,000 to $1,249,999   [ ] over $1,250,000

C6.  Net worth: Your net worth, inclusive of the net worth of your spouse and
     excluding the value of your principal residence, furnishings therein and
     personal automobiles and exclusive of any liabilities:

     [ ] below $249,999
     [ ] $250,000 to $349,999       [ ] $350,000 to $699,999
     [ ] $700,000 to $799,999       [ ] $800,000 to $1,000,000
     [ ] $1,000,000 to $1,249,999   [ ] over $1,250,000

                                        8

<PAGE>

C7.  Indicate (a) your individual income from all sources for the calendar years
     2002 and 2003 and estimated income for 2004 or (b) your joint income with
     your spouse from all sources for the calendar years 2002 and 2003 and
     estimated income for 2004 (it is important that you check the highest
     applicable amount):

     (a)  individual income:

<TABLE>
<CAPTION>
        $200,000   $300,000   $400,000   $500,000
           to         to         to         and
        $299,000   $399,000   $499,000     over
        --------   --------   --------   --------
<S>     <C>        <C>        <C>        <C>
2002      _____      _____      _____      _____

2003      _____      _____      _____      _____

2004      _____      _____      _____      _____
</TABLE>

     (b)  joint income:

<TABLE>
<CAPTION>
        $200,000   $300,000   $400,000   500,000
           to         to         to        and
        $299,000   $399,000   $499,000     over
        --------   --------   --------   --------
<S>     <C>        <C>        <C>        <C>
2002      _____      _____      _____      _____

2003      _____      _____      _____      _____

2004      _____      _____      _____      _____
</TABLE>

C8.  Investment experience:

     (a)  The frequency with which you invest in marketable securities is:

          [ ] often   [ ] occasionally   [ ] never

     (b)  The frequency with which you invest in unmarketable securities (such
          as private placement offerings) is:

          [ ] often   [ ] occasionally   [ ] never

                                        9

<PAGE>

     (c)  Have you previously participated in private placement offerings in the
          last 5 years?

               _____                              _____
               Yes                                No

     (d)  If you answered "yes" to (c) above, state the private placements in
          which you participated in the last 5 years.

        Amount          Name of
Year   Invested         Entity
----   --------         -------

1999    $_____     ________________

2000    $_____     ________________

2001    $_____     ________________

2002    $_____     ________________

2003    $_____     ________________

                                       10

<PAGE>

C9.  (a) Have you been afforded an opportunity to investigate the Company and
     review relevant factors and documents pertaining to the officers, directors
     and the Company and its business and to ask questions of a qualified
     representative of the Company regarding this investment and the properties,
     operations, and methods of doing business of the Company?

               _____                              _____
               Yes                                No

     (b) Do you understand the nature of an investment in the Company and the
     risk associated with such an investment?

               _____                              _____
               Yes                                No

     (c) Do you understand that there is no guarantee of any financial return on
     this investment?

               _____                              _____
               Yes                                No

     (d) Do you understand that this investment is not liquid?

               _____                              _____
               Yes                                No

     (e) Do you have adequate means of providing for your current needs and
     personal contingencies in view of the fact that this is not a liquid
     investment?

               _____                              _____
               Yes                                No

     (f) Are you aware of the Company's business affairs and financial
     condition, and have you acquired all such information about the Company as
     you deem necessary and appropriate to enable you to reach an informed and
     knowledgeable decision to acquire the Shares?

               _____                              _____
               Yes                                No

     (g) Do you have a "pre-existing relationship" with the Company or any of
     its officers, directors or controlling person?

               _____                              _____
               Yes                                No

     (For purposes hereof, "Pre-existing relationship" means any relationship
consisting of person or business contacts of a nature and duration such as would
enable a reasonable prudent

                                       11

<PAGE>

Subscriber to be aware of the character, business acumen, and general business
and financial circumstances of the person with whom such relations exists.)

     If so, please name the individual or other person with whom you have a
pre-existing relationship and describe the relationship:

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

                                       12

<PAGE>

SECTION D: CORPORATE OFFEREES OR PARTNERSHIP OFFEREES

D1.  General Information

     Legal name of Corporation or Partnership

     ___________________________________________________________________________

     Fictitious name (d/b/a): __________________________________________________

     ___________________________________________________________________________

     State or Place of Incorporation: __________________________________________

     Date of Incorporation: ____________________________________________________

     If Partnership, type: ____________ General   ____________ Limited

     Federal I.D. Number: ______________________________________________________

     Fiscal Year Ends: _________________________________________________________

     Number of Equity Owners: __________________________________________________

     Name and Title of Authorized Person Executing Questionnaire:

     ___________________________________________________________________________

D2.  Business Address: _________________________________________________________

     ___________________________________________________________________________

     If Partnership, type: ____________ General   ____________ Limited

     Mailing Address (if different): ___________________________________________

     Telephone Number: [ ] _______________   Facsimile Number: [ ] _____________

D3.  Name of Primary Bank: _____________________________________________________

     Address: __________________________________________________________________

     Telephone Number: [ ] _____________________________________________________

     Account Type and Number: __________________________________________________

     Person Familiar with your Account: ________________________________________

                                       13

<PAGE>

     Was the corporation or partnership formed for the specific purpose of
     purchasing Securities in the Offering?

               _____                              _____
               Yes                                No

     Check if applicable to the corporation:

     Subchapter S ___________________   Professional ___________________________

D4.  The undersigned represents and warrants as follows:

     (a)  The corporation or partnership, as the case may be, has been duly
          organized (if a partnership) is validly existing as a corporation or
          partnership in good standing under the laws of the jurisdiction of its
          incorporation or formation with full power and authority to enter into
          the transactions contemplated by the Subscription Agreement;

     (b)  (i) The officers or partners of the undersigned who, on behalf of the
          undersigned, have considered the purchase of the Securities and the
          advisers, if any, of the corporation or the partnership, as the case
          may be, in connection with such consideration are named below in this
          Questionnaire, and such officers and advisors or partners, if any,
          were duly authorized to act for the corporation or the partnership in
          reviewing such investment;

          (ii) The names and positions of the officers or partners, of the
          undersigned who, on its behalf, have reviewed the purchase of the
          Securities are as follows:

          __________________________________   _________________________________

          __________________________________   _________________________________

          (iii) In evaluating the merits and risks of the purchase of the
          Securities, the corporation or the partnership, as the case may be,
          intends to rely upon the advice of, or will consult with, the
          following persons:

          __________________________________   _________________________________

          __________________________________   _________________________________

                                       14

<PAGE>

     (c)  The officers of the corporation (if not Accredited Investors) or the
          partners of the partnership who, on its behalf, have considered the
          purchase of the Securities and the advisors, if any, of the
          corporation or the partnership who, in connection with such
          consideration, together have such knowledge and experience in
          financial and business matters that such offering(s), partner(s) and
          such advisor(s), if any, together are capable of evaluating the merits
          and risks of the purchase of Securities and of making an informed
          investment decision;

     (d)  Together with any corporation or group of corporations with which it
          files a consolidated federal income tax return, the undersigned has
          reserves and/or net worth adequate to permit it to satisfy any tax or
          other liabilities arising from its personal liability with respect to
          the investment and the operation thereof;

     (e)  The total assets of the corporation or the partnership are in excess
          of $ ________;

     (f)  The corporation or the partnership has had, during each of the past
          two years, gross income from all sources of at least $ ________ and
          $ ________, respectively;

     (g)  The undersigned expects the corporation or the partnership to have
          during the current and the next tax year, gross income from all
          sources of at least $ _______ and

     (h)  The undersigned knows of no pending or threatened litigation the
          outcome of which could adversely affect the answer to any question
          hereunder.

     (i)  Indicate the following if a partnership Subscriber:

          (1)  The date the partnership was formed and state of formation:

               ___________________________________________________________

          (2)  The names of each partner in the partnership:

               ___________________________________________________________

               ___________________________________________________________

               ___________________________________________________________

               ___________________________________________________________

               ___________________________________________________________

               ___________________________________________________________

                                       15

<PAGE>

SECTION E: TRUST OFFEREES

E1.  General Information

     Legal Name: _______________________________________________________________

     State or Place of Formation: ______________________________________________

     Date of Formation: ________________________________________________________

     Federal I.D. Number: ___________   Fiscal Year Ends: ______________________

     Number of Beneficiaries: __________________________________________________

     Principal Purpose: ________________________________________________________

     Was the trust formed for the specific purpose of purchasing the Securities?

               _____                              _____
               Yes                                No

E2.  Business Address: _________________________________________________________

     ___________________________________________________________________________

     Telephone Number:[ ] ______________________________________________________

     Facsimile Number:[ ] ______________________________________________________

     Mailing Address: __________________________________________________________

     ___________________________________________________________________________

E3.  Authorization: If the trust was established in connection with a deferred
     compensation plan, please attach a copy of the trust's organizational
     documents and a properly certified copy of the resolutions adopted by the
     trust's board of directors authorizing the trust to purchase the Shares and
     authorizing the trustee named below to execute on behalf of the trust all
     relevant documents necessary to subscribe for and purchase the Shares. In
     all cases, please attach a properly certified copy of the resolutions
     adopted by the trustees of the trust authorizing the trust to purchase
     Shares and authorizing the trustee named below to execute on behalf of the
     trust all relevant documents necessary to subscribe for and purchase the
     Shares.

Name of Trustee Authorized and Executing Questionnaire:

________________________________________________________________________________

                                       16

<PAGE>

E4.  Name of Primary Bank: _____________________________________________________

     Address: __________________________________________________________________

     ___________________________________________________________________________

     Telephone Number: [ ] _____________________________________________________

     Facsimile Number: [ ] _____________________________________________________

     Account Type and Number: __________________________________________________

     Person Familiar with your Account: ________________________________________

                                       17

<PAGE>

SECTION F: QUALIFIED PENSION PLAN ("PLAN") OFFEREES

F1.  Please check one:

_________ a.   The Plan requires the investment of each beneficiary or
               participant to be held in a segregated account and the Plan
               allows each beneficiary or participant to make his own investment
               decisions and, the decision to purchase the Shares has been made
               by the beneficiary or the participant and such beneficiary or
               participant is an Accredited Investor (Please have each such
               beneficiary or participant execute a separate Questionnaire).

                                       OR

_________ b.   The investment decisions made for the Plan are made by a plan
               fiduciary, whether a bank, an insurance company, or a registered
               investment advisor.

                                       OR

_________ c.   The Plan has total assets exceeding $5,000,000.

F2.  General Information

     Legal Name: _______________________________________________________________

     State or Place of Formation: ______________________________________________

     Date of Formation: ________________________________________________________

     Federal I.D. Number: ___________   Fiscal Year Ends: ______________________

     Number of Beneficiaries:___________________________________________________

     Principal Purpose: ________________________________________________________

F3.  Business Address:

     Telephone Number: [ ] _____________________________________________________

     Facsimile Number: [ ] _____________________________________________________

     Mailing Address: __________________________________________________________

     ___________________________________________________________________________

F4.  Authorization: If the investment decision is being made by a beneficiary or
     participant of a Plan, please attach applicable trust documents which
     permit each beneficiary or participant to make his own investment
     decisions. In all other cases, please attach a properly certified copy of
     the resolutions adopted by the trustees of the Plan trust authorizing the
     Plan to purchase

                                       18

<PAGE>

     the Shares and authorizing the fiduciary named below to execute on behalf
     of the Plan all relevant documents necessary to subscribe for and purchase
     the Shares.

     Name of Trustee Authorized and Executing Questionnaire:

     ___________________________________________________________________________

F5.  Name of Primary Bank: _____________________________________________________

     Address: __________________________________________________________________

     ___________________________________________________________________________

     Telephone Number: [ ] _____________________________________________________

     Facsimile Number: [ ] _____________________________________________________

     Account Type and Number: __________________________________________________

     Person Familiar with your Account: ________________________________________

                                       19

<PAGE>

SECTION G: REPRESENTATIONS AND WARRANTIES BY ALL SUBSCRIBERS

     By signing this Questionnaire, the undersigned hereby confirms the
following statements:

     (a) I have read the Confidential Private Offering Memorandum and this
Subscription Agreement and other accompanying documents of the Company, and am
aware of and understand the risk factors disclosed therein related to the
Company and an investment in the Company.

     (b) I am aware that the offering of the Shares involves securities for
which no market exists, thereby requiring any investment to be maintained for an
indefinite period of time. The Company is not a reporting company under the
Securities and Exchange Act of 1934, and therefore does not file periodic
reports with the SEC.

     (c) I acknowledge that any delivery to me of the Confidential Private
Offering Memorandum relating to the Shares prior to the determination by the
Company of my suitability as an Subscriber shall not constitute an offer of the
Shares until such determination of suitability shall be made, and I agree that I
shall promptly return the Confidential Private Offering Memorandum and the other
Offering Documents to the Company upon request.

     (d) I also understand and agree that, although the Company and the
Placement Agent will use their respective best efforts to keep the information
provided in answers to this Questionnaire strictly confidential, the Company and
the Placement Agent or their respective counsel may present this Questionnaire
and the information provided in answer to it to such parties as they may deem
advisable if called upon to establish the availability under any federal or
state securities laws of an exemption from registration of the private placement
or if the contents thereof are relevant to any issue in any action, suit or
proceeding to which the Company, the Placement Agent or their respective
affiliates is a party, or by which they are or may be bound or as otherwise
required by law or regulatory authority.

     (e) I realize that this Questionnaire does not constitute an offer to sell
or a solicitation of an offer to buy the Shares or any other security of the
Company but is merely a request for information.

     (f) I understand that the Shares are being offered without registration
under the Securities Act in reliance upon the private offering exemption
contained therein, and that such reliance is based in part on the information
herein supplied. For the foregoing reasons and to induce the Company to issue
and deliver the Securities to me, I represent and warrant that the information
stated herein is true, accurate and complete, and I agree to notify and supply
corrective information promptly to the Company as provided above if any of such
information becomes inaccurate or incomplete.

     (g) The individual signing below on behalf of any entity hereby warrants
and represents that he/she is authorized to execute this questionnaire on behalf
of such entity.

     (h) The undersigned is able to bear the economic risk of the investment and
can afford a complete loss of such investment.

                                       20

<PAGE>

     (i) Subject to the terms and conditions hereof and on the basis of the
representations and warranties hereinafter set forth, the Company hereby agrees
to issue and sell to the Subscriber and the Subscriber agrees to purchase from
the Company, upon Closing, the Shares as described in the Memorandum at a price
per Share of $2.00. The Company or the Placement Agent may reject any
subscription in whole or in part.

     (j) The Subscriber acknowledges and agrees that there is a "minimum"
offering amount of $2,000,000 in aggregate gross proceeds prior to release of
funds to the Company.

     (k) In entering into this Agreement and in purchasing the Securities, the
Subscriber further acknowledges that:

          (i) The Company has informed the Subscriber that the Securities have
not been offered for sale by means of general advertising or solicitation.

          (ii) The Securities may not be resold by the Subscriber in the absence
of a registration under the Act or exemption from registration. In particular,
the Subscriber is aware that the Securities will be "restricted securities", as
such term is defined in Rule 144 promulgated under the Securities Act ("Rule
144"), and they may not be sold pursuant to Rule 144, unless the conditions
thereof are met.

          (iii) The following legends (or similar language) shall be placed on
the certificate(s) evidencing the Securities:

                                       21

<PAGE>

     THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
     UNDER THE SECURITIES ACT OF 1933 (THE "ACT"), OR ANY STATE SECURITIES LAWS
     AND NEITHER SUCH SECURITIES NOR ANY INTEREST THEREIN MAY BE OFFERED, SOLD,
     PLEDGED, ASSIGNED OR OTHERWISE TRANSFERRED UNLESS (1) A REGISTRATION
     STATEMENT WITH RESPECT THERETO IS EFFECTIVE UNDER THE ACT AND ANY
     APPLICABLE STATE SECURITIES LAWS, OR (2) THE COMPANY RECEIVES AN OPINION OF
     COUNSEL TO THE HOLDER OF SUCH SECURITIES, WHICH COUNSEL AND OPINION ARE
     REASONABLY SATISFACTORY TO THE COMPANY, THAT SUCH SECURITIES MAY BE
     OFFERED, SOLD, PLEDGED, ASSIGNED OR TRANSFERRED IN THE MANNER CONTEMPLATED
     WITHOUT AN EFFECTIVE REGISTRATION STATEMENT UNDER THE ACT OR APPLICABLE
     STATE SECURITIES LAWS.

     THE CORPORATION WILL FURNISH WITHOUT CHARGE TO EACH STOCKHOLDER WHO SO
     REQUESTS, A FULL STATEMENT OF ALL OF THE POWERS, DESIGNATIONS, PREFERENCES
     AND RELATIVE, PARTICPATING OPTIONAL OR OTHER SPECIAL RIGHTS OF EACH CLASS
     OF STOCK OR SERIES THEROF AUTHORIZED TO BE ISSUED BY THE CORPORATION AND
     THE QUALIFICATIONS, LIMITATIONS OR RESTRICTIONS OF SUCH PREFERENCES AND/OR
     RIGHTS.

     THE SHARES OF STOCK REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO A
     SUBSCRIPTION AGREEMENT TO WHICH THE CORPORATION IS A PARTY. THE AGREEMENT
     INCLUDES A LOCK-UP AGREEMENT BY THE HOLDER IN THE EVENT OF AN UNDERWRITTEN
     OFFERING AND PROVIDES THAT NONE OF SUCH SHARES, OR ANY INTEREST THEREIN,
     SHALL BE TRANSFERRED, PLEDGED, ENCUMBERED OR OTHERWISE DISPOSED OF WITHOUT
     FIRST OFFERING SUCH SHARES TO THE CORPORATION IN ACCORDANCE WITH SUCH
     AGREEMENT. COPIES OF SUCH AGREEMENT ARE ON FILE IN THE OFFICE OF THE
     CORPORATION AND WILL BE MADE AVAILABLE FOR INSPECTION TO ANY PROPERLY
     INTERESTED PERSON WITHOUT CHARGE UPON WRITTEN REQUEST.

          (iv) The Company may at any time place a stop transfer order on its
transfer books against the Securities. Such stop order will be removed, and
further transfer of the Securities will be permitted upon an effective
registration of the respective Securities, or the receipt by the Company of an
opinion of counsel satisfactory to the Company that such further transfer may be
effected pursuant to an applicable exemption from registration.

          (v) The purchase of the Securities involves risks which the Subscriber
has evaluated, and the Subscriber is able to bear the economic risk of the
purchase of such securities and the loss of its entire investment.

                                       22

<PAGE>

     (l) The Subscriber agrees to indemnify and hold harmless the Company, the
officers, directors, employees, agents, counsel and affiliates of the Company,
and each other person, if any, who controls the Company, within the meaning of
Section 15 of the Act or Section 20 of the Securities and Exchange Act of 1934,
as amended, against any and all losses, liabilities, claims, damages and all
expenses reasonably incurred in investigating, preparing or defending against
any litigation commenced or threatened or any claim whatsoever arising out of or
based upon any false representation or warranty or breach or failure by the
Subscriber to comply with any covenant or agreement made by the Subscriber
herein or in any other document furnished by the Subscriber to any of the
foregoing in connection with this transaction.

     (m) The Subscriber hereby acknowledges and agrees, subject to any
applicable state securities laws that the subscription and application hereunder
are irrevocable, that the Subscriber is not entitled to cancel, terminate or
revoke this Subscription Agreement and that this Subscription Agreement shall
survive the death or disability of the Subscriber and shall be binding upon and
inure to the benefit of the Subscriber and his heirs, executors, administrators,
successors, legal representatives, and assigns. If the Subscriber is more than
one person, the obligations of the Subscriber hereunder shall be joint and
several, and the agreements, representations, warranties, and acknowledgments
herein contained shall be deemed to be made by and be binding upon each such
person and his heirs, executors, administrators, successors, legal
representatives, and assigns.

     (n) The Company and the Placement Agent have each employed its own legal
counsel in connection with the Offering. The Subscribers have not been
represented by independent counsel in connection with the preparation of the
Memorandum or the terms of this Offering and no investigation of the merits or
fairness of the Offering has been conducted on behalf of the Subscribers.
Prospective Subscribers should consult with their own legal, tax and financial
advisors with respect to the Offering made pursuant to the Memorandum.

     (o) The undersigned hereby acknowledges that officers, affiliates,
employees and directors of the Company and/or the Placement Agent may purchase
Shares in the Offering.

     (p) My answers to the foregoing questions are true and complete to the best
of my information and belief and I will promptly notify the Company of any
changes in the information I have provided.

                                       23

<PAGE>

SECTION H: OTHER COVENANTS AND AGREEMENTS

     (A)  REGISTRATION RIGHTS.

     The Subscriber and the Company agree that the Subscriber shall be entitled
to the registration rights with respect to the Shares as set forth in this
Section H (a).

     (i) Definition of Registrable Securities. As used herein the term
"Registrable Security" means each Share issued in the Offering and any
securities issued upon any stock split or stock dividend in respect thereof;
provided, however, that with respect to any particular Registrable Security,
such security shall cease to be a Registrable Security when, as of the date of
determination; (A) it has been effectively registered under the Act and disposed
of pursuant thereto; (B) registration under the Act is no longer required for
subsequent public distribution of such security; or (B) it has ceased to be
outstanding. The term "Registrable Securities" means any and/or all of the
securities falling within the foregoing definition of a "Registrable Security."
In the event of any merger, reorganization, consolidation, recapitalization or
other change in corporate structure affecting the Common Stock, such adjustment
shall be made in the definition of "Registrable Security" as is appropriate in
order to prevent any dilution or increase of the rights granted pursuant to this
Clause (a) as determined in good faith by the Board of Directors;

     (ii) Registration by the Company. The first time after the date hereof that
the Company files a registration statement under the Act not on Form S-8, S-4 or
another inappropriate form with the Securities and Exchange Commission to
register for sale any of its shares of Common Stock, the Company will include
for resale under the Act in the registration statement the Registrable
Securities. The Company shall not be required to register for resale any
Registrable Securities if at the time of such proposed registration, the
Registrable Securities may be sold without any limitation under Rule 144.
Notwithstanding the foregoing, if the registration statement filed by the
Company is pursuant to an underwritten offering:

          (A) if the underwriter determines in good faith that marketing factors
require the exclusion of all shares held by existing stockholders, no
Registrable Securities shall be included in such registration and the right to
have Registrable Securities included in the first registration statement filed
by the Company shall be deferred to the second registration statement filed by
the Company, which deferral may be continued to the third or subsequent
registration statement so long as the registration statements are pursuant to
underwritten offerings and the underwriter determines in good faith that
marketing factors require exclusion of all shares held by existing stockholders;

          (B) each holder of Registrable Securities ("Holder") shall enter into
an underwriting agreement in customary form with the underwriter and provide
such information regarding Holder that the underwriter shall reasonably request
in connection with the preparation of the prospectus describing such offering,
including completion of NASD Questionnaires; and

          (C) each Holder hereby agrees that such Holder shall not sell,
transfer, make any short sale of, grant any option for the purchase of, or enter
into any hedging or similar transaction with the same economic effect as a sale,
any Registrable Securities for a period specified by the underwriter not to
exceed one hundred eighty (180) days following the effective

                                       24

<PAGE>

date of the registration statement, or such lesser period equal to the lockup
period required of the Company's officers and directors. The Company may impose
stop-transfer instructions with respect to Registrable Securities subject to the
foregoing restriction until the end of said lock-up period. Each Holder agrees
that any transferee of any shares of Registrable Securities shall be bound by
this lock-up agreement and certificates evidencing the Registrable Securities
shall include a legend reflecting this agreement (see above).

     (iii) Covenants of the Company With Respect to Registration. In connection
with the registration in which the Registrable Securities are included, the
Company covenants and agrees as follows:

          (A) The Company shall use its best efforts to have the registration
statement declared effective as soon as possible after filing, and shall furnish
each Holder of Registrable Securities such number of prospectuses as shall
reasonably be requested. In addition, the Company shall file such amendments as
may be required from time to time, in order to keep any registration statement
filed under this Clause (a) effective as provided herein. The registration
statement filed by the Company hereunder shall remain effective for the earlier
of (i) 9 months or (ii) the date that the Registrable Securities may be sold
without volume limitation under SEC Rule 144k.

          (B) The Company shall pay all costs (excluding fees and expenses of
Holder(s) counsel and any underwriting or selling commissions), fees and
expenses in connection with the registration statement filed pursuant hereto
including, without limitation, the Company's legal and accounting fees, printing
expenses, blue sky fees and expenses.

          (C) The Company will take all necessary action which may be required
in qualifying or registering the Registrable Securities included in the
registration statement, for offering and sale under the securities or blue sky
laws of such states as reasonably are requested by the Holder(s), provided that
the Company shall not be obligated to execute or file any general consent to
service of process or to qualify as a foreign corporation to do business under
the laws of any such jurisdiction.

          (D) The Company shall indemnify each Holder of Registrable Securities
to be sold pursuant to the registration statement and each person, if any, who
controls such Holder within the meaning of Section 15 of the Act or Section
20(a) of the Securities Exchange Act of 1934, as amended ("Exchange Act"),
against all loss, claim, damage, expense or liability (including all reasonable
expenses reasonably incurred in investigating, preparing or defending against
any claim whatsoever) to which any of them may become subject under the Act, the
Exchange Act or otherwise, arising from such registration statement, except to
the extent arising under paragraph (E) below.

          (E) Each Holder of Registrable Securities to be sold pursuant to a
registration statement, and their successors and assigns, shall severally, and
not jointly, indemnify the Company, its officers and directors and any
underwriter, and each person, if any, who controls the Company or such
underwriter within the meaning of Section 15 of the Act or Section 20(a) of the
Exchange Act, against all loss, claim, damage or reasonable expense or liability
(including all expenses reasonably incurred in investigating, preparing or
defending against any claim

                                       25

<PAGE>

whatsoever) to which they may become subject under the Act, the Exchange Act or
otherwise, arising (I) from information furnished by or on behalf of such
Holder, or their successors or assigns, for specific inclusion in such
registration statement or (II) as a result of use by the Holder of a
registration statement that the Holder was advised to discontinue; provided,
however, that in no event shall any indemnity hereunder exceed the net proceeds
from the offering received by such Holder.

     (B)  ANTI- DILUTION PROTECTION.

     (i) Unless waived by the Placement Agent on behalf of all investors in the
Offering, during the period commencing on the date hereof and ending upon the
earlier of (A) a date which is three years following the Final Closing Date of
the Offering or (B) the date which is one day prior to the effective date of an
initial public offering, if the Company sells or issues additional shares of
Common Stock, or securities convertible into Common Stock, with a purchase,
exercise or conversion price (the "Share Antidilution Price") of less than the
Share Issue Price (which shall initially be $3.00, as adjusted for stock splits,
stock dividends and the like), with certain exceptions set forth below, the
Company shall promptly issue to each investor in the Offering additional shares
of Common Stock.

     (ii) The number of additional shares of Common Stock issuable to each
investor shall be determined by multiplying the number of Shares purchased by
such investor in the Offering by the result of the following equation: [(Share
Issue Price / Share Antidilution Price) - 1, less any additional shares
previously delivered to such investor pursuant to this section H(b)]. The Share
Antidilution Price shall initially be $2.00 and shall be adjusted in the event
of a subsequent issuance below the Share Antidilution Price then in effect by
multiplying such Share Antidilution Price by a fraction (A) the numerator of
which shall be the number of shares of Common Stock deemed outstanding (as
defined below) immediately prior to such issue or sale, plus the number of
shares of Common Stock which the aggregate consideration received by the Company
for the total number of additional shares of Common Stock or securities
convertible into Common Stock so issued would purchase at the Share Issue Price,
and (B) the denominator of which shall be the number of shares of Common Stock
deemed outstanding (as defined below) immediately prior to such issue or sale,
plus the total number of additional shares of Common Stock or securities
convertible into Common Stock so issued. The number of additional shares issued
to each investor will be rounded down to the nearest whole share, and no
fractional shares will be issued. The number of shares of Common Stock deemed to
be outstanding as of a given date shall be the sum of (x) the number of shares
of Common Stock actually outstanding, (y) the number of shares of Common Stock
into which the then outstanding shares of Preferred Stock could be converted if
fully converted on the day immediately preceding the given date, and (z) the
number of shares of Common Stock which could be obtained through the exercise or
conversion of all other rights, options and convertible securities outstanding
on the day immediately preceding the given date.

     (iii) Notwithstanding the foregoing, the following issuances by the Company
shall not result in any adjustment of the Share Antidilution Price or any
issuance of additional shares to investors in the Offering: (A) shares of Common
Stock issued upon conversion of Preferred Stock, (B) up to 4,000,000 shares of
Common Stock and/or options, and the Common Stock issued pursuant to such
options, (as adjusted for any stock dividends, combinations, splits,
recapitalizations and the like, and net of any repurchases of such shares or
cancellations or

                                       26

<PAGE>

exemptions of such options, warrants or other rights) to employees, officers or
directors of, or consultants or advisors to the Corporation or any subsidiary
pursuant to stock purchase or stock option plans or other arrangements that are
approved by the Board ("Employee Options"), (C) shares of capital stock issuable
upon exercise or conversion of options (other than Employee Options) or warrants
or other securities or rights outstanding as of the date of the Memorandum and
(D) shares of Common Stock issued to third parties in connection with bank loan
or license arrangements or other strategic transactions approved by the Board of
Directors.

     (iv) Within 15 days following any transaction by the Company which would
result in the investors in the Offering being entitled to additional shares of
Common Stock hereunder, the Company shall provide written notice of such
transaction to each investor and the Placement Agent of the terms of such
transaction and shall, within 30 days of consummation of such transaction,
deliver share certificates to the investors (or the Placement Agent on their
behalf) representing any additional shares. Any such additional shares shall be
included in the term "Registrable Securities" in Section G clause (a) above.

     (C) PUT OPTION ON MERGER OR CONSOLIDATION.

     (i) In the event of a merger or consolidation where the Company is not the
surviving entity or sale of substantially all of the assets of the Company
during the term commencing on the Initial Closing of the Offering and ending on
the day prior to the effective date of an initial public offering (a
"liquidation event"), the Company hereby agrees that investors in this Offering
shall have the option to put their shares back to the Company immediately prior
to and conditioned upon consummation of such liquidation event in exchange for a
payment in cash equal to 150% of their original subscription amount (the "Put
Price"); provided, however, in the event that: (A) the third party to the
liquidation event is a reporting company under the Securities and Exchange Act
of 1934; (B) its shares of publicly traded securities are being used as
consideration in the Offering; (C) such securities are traded on either the New
York Stock Exchange, the American Stock Exchange or the Nasdaq Stock Market and
(D) the securities have a closing sales price in excess of $5.00 per share for
the 30 trading days prior to announcement of such transaction and a daily
average volume equal to or in excess of 50,000 shares per day, such payment may
be made in the form of such securities provided that the securities are
immediately available for resale pursuant to Rule 145 or a resale registration
statement.

     (ii) At least 15 days prior to any transaction by the Company which would
result in the investors in the Offering being entitled to exercise their put
rights hereunder, the Company shall provide written notice of such transaction
to each investor and the Placement Agent of the terms of such transaction.
Investors shall have 10 days to notify the Company in writing of their desire to
exercise or not exercise their put rights hereunder, or the Placement Agent may
so notify the Company on behalf of all investors. To the extent that an investor
or the Placement Agent on behalf of such investor, as the case may be, does not
provide the notice as set forth in the immediately preceding sentence, such
investor will be deemed to have irrevocably agreed not to exercise their put
right hereunder.

     (iii) The closing for the purchase of the Shares for which put rights have
been timely exercised hereunder (the "Put Securities") will occur as soon as
practicable following the

                                       27

<PAGE>

consummation of the transaction giving rise to the put rights hereunder by the
Company's prompt payment of the Put Price following receipt of original
certificates for the Put Securities, duly endorsed or accompanied by an
appropriate stock power. If the Company does not have sufficient funds legally
available to pay the Put Price for the Put Securities under the Delaware General
Corporation Law or otherwise, then the Company will purchase the maximum number
of Put Securities for which the Company has funds legally available, pro rata
based upon the number of Put Securities tendered hereunder. The remaining shares
which cannot be purchased because of the lack of funds available to the Company
shall be exchanged for new shares of the merged entity at the Put Price. The
"pro rata" amount shall be determined by percentage of Shares held by the
subscriber relevant to the entire number of Shares sold in the Offering and then
outstanding.

     (D) ISSUANCE OF ADDITIONAL SHARES FOR FAILURE TO TIMELY BECOME REPORTING
COMPANY.

     (i) Unless waived by the Placement Agent on behalf of all investors in the
Offering, in the event that the Company fails to become a reporting company
under the Securities and Exchange Act of 1934 within a date which is 24 months
from the date of the final Closing of the Offering, then the undersigned
subscriber shall be entitled to additional shares of Common Stock of the Company
equal to (A)10% of his initial subscription and (B) thereafter 5% of his initial
subscription for each 90 day period (or part thereof) for any continued failure
by the Company. The number of shares to be received shall be based upon a price
equal to the lower of (x) the price per Share in the Offering or (z) the lowest
price per share received by the Company in connection with any sale of its
common stock (or in the event of the issuance or sale of convertible securities,
the conversion or exercise price) within 6 months of any such date.

     (ii) Within 15 days following the date on which investors in the Offering
become entitled to additional shares of Common Stock hereunder, the Company
shall provide written notice of such entitlement to each investor and the
Placement Agent and shall, within 30 days of consummation of such transaction,
deliver share certificates to the investors (or the Placement Agent on their
behalf) representing any additional shares. Any such additional shares shall be
included in the term "Registrable Securities" in Section G clause (a) above.

     (E) COMPANY RIGHT OF FIRST REFUSAL.

     (i) In the event any Registrable Securities, or any interest therein, are
to be transferred, voluntarily or involuntarily (including, without limitation,
any sale, encumbrance, foreclosure or transfer in lieu thereof, or by operation
of law, any division of marital property on account of divorce or legal
separation being deemed a "transfer" for purposes hereof), the Company (or its
nominees) shall have a right of first refusal as follows:

          (A) the holder of such Registrable Securities shall give the Company
advance written notice detailing all the terms of the proposed transfer. The
Company (or its nominees) shall have the right (but not the obligation),
exercisable upon delivery to the transferring stockholder of written notice of
acceptance within 10 days following receipt of the notice of proposed transfer
described in the preceding sentence, to repurchase all or any of such
Registrable Securities on the terms and conditions set forth in such notice.

                                       28

<PAGE>

          (B) The "Payment Date" for purposes of this paragraph shall be on or
before the 10th day following delivery of the Company's notice of exercise.
Holder will surrender all stock certificates to the Company promptly upon
request on or before the Payment Date.

          (C) Failure by the Company (or its nominees) (without default by the
transferring stockholder) to close such purchase within the above 10-day period
shall give the transferring stockholder the right to transfer such shares or
interest therein on the terms and to the person described in the notice during
the 45 days following expiration of the original 10-day period; provided that
the shares or interest therein to be transferred shall for all purposes remain
subject to the Company's right of first refusal hereunder. If the transferring
stockholder fails to close the proposed transfer on those terms within such
45-day period, the proposed transfer shall again be subject to the terms of this
paragraph.

          (D) Notwithstanding the foregoing, nothing herein shall be construed
to impede or nullify any transfer of such shares made to any trusts in which
holder or a member of holder's immediate family are trustors or the
beneficiaries thereof, or to a partnership, limited liability company or other
entity of which holder and member(s) of holder's immediate family are the sole
equity owners, and in each of the foregoing cases where such trust or entity is
controlled by holder, directly or indirectly, whether or not for adequate
consideration. Such transfers may be made without providing the Company notice
or a right of first refusal. The transferee of such shares shall at all times be
bound by the restrictions provided in this paragraph with regard to future
transactions and shall execute an appropriate instrument to this effect.
Certificates evidencing Shares issued in the Offering will be legended to
reflect the foregoing restrictions (see above). This right of first refusal
shall expire on the date that the Company becomes a reporting company under the
Securities and Exchange Act of 1934.

     (F) AUTHORIZATION OF PLACEMENT AGENT AS AGENT FOR PURPOSES OF SECTION H (B)
AND (C).

     By execution hereof, each undersigned subscriber empowers and authorizes
the First Montauk Securities Corp. to act on behalf of the subscriber, in First
Montauk Securities Corp.'s discretion, to waive the anti-dilution adjustment
described in Section H(b) and/or the exercise or waiver the put right described
in Section H(c).

[signature page appears next]

                                       29

<PAGE>

     IN WITNESS WHEREOF, the undersigned has duly executed this Subscription
Agreement and Questionnaire and agrees to the terms hereof.

Dated: ______________ ___, 200__        FOR INDIVIDUALS:
                                        (INCLUDING PURCHASER REPRESENTATIVE)

                                        ----------------------------------------
                                        (Print Name)

                                        ----------------------------------------
                                        (Signature)

Dated: ______________ ___, 200__        FOR INDIVIDUALS:
                                        (INCLUDING PURCHASER REPRESENTATIVE)

                                        ----------------------------------------
                                        (Print Name)

                                        ----------------------------------------
                                        (Signature)

                                       30

<PAGE>

     IN WITNESS WHEREOF, the undersigned has duly executed this Subscription
Agreement and Questionnaire and agrees to the terms hereof.

Dated: ______________ ___, 200__        FOR CORPORATIONS:

                                        ----------------------------------------
                                        Name of Company

                                        ----------------------------------------
                                        Executive Officer of Company

                                        ----------------------------------------
                                        Signature of Officer

Dated: ______________ ___, 200__        FOR PARTNERSHIPS:

                                        ----------------------------------------
                                        Name of Partnership

                                        ----------------------------------------
                                        Name of Authorized Partner

                                        ----------------------------------------
                                        Signature of Authorized Partner

                                       31

<PAGE>

     IN WITNESS WHEREOF, the undersigned has duly executed this Subscription
Agreement and Questionnaire and agrees to the terms hereof.

Dated: ______________ ___, 200__        FOR TRUSTS:

                                        ----------------------------------------
                                        Name of Trust

                                        ----------------------------------------
                                        Name of Authorized Trustee

                                        ----------------------------------------
                                        Signature of Authorized Trustee

                                       32

<PAGE>

ACCEPTANCE OF SUBSCRIPTION BY THE COMPANY

     The undersigned, ImaRx Therapeutics, Inc. hereby accepts the Subscription
Agreement of ___________________________________as of the date stated below.

Dated: ______________ ___, 200__        ImaRx Therapeutics, Inc.

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

                                       33

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