<PAGE>

                                                                   EXHIBIT 10.24

     EXECUTIVE EMPLOYMENT AGREEMENT, dated as of February 18, 2004 (this
     "Agreement"), by and between ImaRx Therapeutics, Inc., a Delaware (the
     "Company") and John A. Moore (the "Executive").

     The Company and the Executive desire to set forth in this Agreement the
terms and conditions upon which the Executive will be employed by the Company as
the Chairman and Executive Vice President of the Company. In consideration of
the foregoing recital and the mutual promises, representations, warranties, and
covenants hereinafter set forth, and for other good and valuable consideration,
the receipt and sufficiency of which are hereby acknowledged, the parties hereby
agree as follows:

     1.   CERTAIN DEFINITIONS.

          For the purposes of this Agreement, the following terms shall have the
following meanings:

          "$" means  dollars in the  lawful  currency  of the  United  States of
America.

          "Base Salary" shall have the meaning  assigned to such term in
Section 4.1.

          "Board" means the Board of Directors of the Company.

          "Cause" means Executive shall have (i) been indicted for a felony;
(ii) committed an act of willful misconduct or negligence resulting in a
material loss to the Company; (iii) materially violated any material written
Company policy or rules of the Company, unless cured by Executive within 30 days
following written notice thereof to Executive, (iv) refused to follow the
reasonable written directions given by the Board or its designee or materially
breached any covenant or obligation under this Agreement or other agreement with
the Company, unless cured by Executive within 30 days following written notice
thereof to Executive, or (v) the death or Disability of Executive.

          "Change of Control" means any consolidation or merger of the Company
with or into any other Company or other entity or person, or any other corporate
reorganization, in which the stockholders of the Company immediately prior to
such consolidation, merger or reorganization, own less than fifty percent (50%)
of the Company's voting power immediately after such consolidation, merger or
reorganization, or any transaction or series of related transactions to which
the Company is a party resulting in the sale of substantially all of the
Company's assets or a transfer of the Company's voting power in excess of fifty
percent (50%), excluding any consolidation or merger effected exclusively to
change the domicile of the Company.

          "Common Stock" means the common stock, par value $0.001 per share, of
the Company.

          "Disability" means Executive's adjudication as mentally incompetent,
or the occurrence of a mental or physical disability preventing Executive from
performing his duties for

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ninety (90) or more days within any period of three hundred and sixty five (365)
days or any period of ninety (90) consecutive days. Any question as to the
existence of Disability as to which Executive and the Company cannot agree shall
be determined in writing by a qualified independent physician selected by the
Company. The determination of Disability made in writing by such physician to
Executive and the Company shall be final and conclusive for all purposes.

          "Effective Date" means the first date written above.

          "Good Reason" shall mean (i) a material reduction in Executive's
title, status, authority, or responsibility at the Company; provided however,
that naming Evan C. Unger, M.D. as Chairman of the Board following the hiring of
a new Chief Executive Officer shall not be considered a reduction in Executive's
title, status, or authority or Good Reason under this Agreement or (ii) any
breach by the Company of any material term of this Agreement (including, without
limitation, failure to make any payment or to grant any stock options required
by the terms of this Agreement), which breach is not cured within thirty (30)
days of the Company's receipt from Executive of written notice of such breach.

          "Person" means an individual, partnership, corporation, limited
liability company, limited liability partnership, trust, joint venture, joint
stock company or unincorporated organization.

          "QPO" means the closing of a public offering pursuant to an effective
registration statement under the Securities Act of 1933, as amended, covering
the offer and sale of the Common Stock.

          "Term" means the period commencing on the Effective Date and ending on
the second anniversary thereof, as may be extended by written agreement of the
parties.

          "Termination Date" means the first date on which the Executive is no
longer employed by the Company for any reason.

          "Transferee" means any person or entity to whom or which shares of
Executive Stock have been sold, transferred or assigned, by agreement or
operation of law.

     2.   TERM.

          The Company shall employ Executive for the Term or until the
Termination Date, this being an "at-will" employment agreement, provided that
Section 5 shall govern the amount of compensation to be paid to Executive on and
after the Termination Date. Upon mutual written consent, the parties may extend
the Term at any time, but shall use their best efforts to begin negotiating any
such extension at least ninety (90) days prior to the expiration of the Term.

     3.   POSITION AND DUTIES.

          1.1. General. Executive shall serve as the Chairman of the Board of
Directors and Executive Vice President of the Company and shall be subject to
the supervision of, and

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shall report to, the Board. Executive shall have such duties and authority as
are customarily exercised by a vice president of a business corporation of
similar size and in the same industry as the Company and as may be determined
from time to time by the Board.

          1.2. Election as Board Member. During the Term and until the
Termination Date, the Company agrees to place Executive on the slate of nominees
for election to the Board and take any and all actions within its power and
authority necessary or advisable to appoint Executive to the Board and to
nominate him as Chairman; provided, however, that the Board may replace
Executive with Evan C. Unger, M.D. as Chairman following the hiring of a new
Chief Executive Officer.

     4.   COMPENSATION.

          2.1. Base Salary. (a) Subject to Section 4.1(b) and 4.1(c), commencing
on the Effective Date, the Company shall pay to Executive a base salary at an
annual rate of $125,000 (as may be adjusted from time to time, the "Base
Salary"), payable in accordance with the payroll practices of the Company in
effect from time to time. Base Salary payments shall be subject to withholding
and other applicable taxes.

          (b) Notwithstanding Section 4.1(a) hereof, the Executive's right to
receive the Base Salary shall be subject to the following: (i) the Base Salary
does not start to accrue until the closing of a financing or financings
occurring after the Effective Date in which the Company shall have received
proceeds of at least $3,000,000 in the aggregate, (ii) after receipt by the
Company of financing proceeds after the Effective Date of at least $3,000,000 in
the aggregate, the Base Salary starts to accrue but is not payable to the
Executive until the earlier of an QPO or receipt of additional financing
proceeds which (combined with prior proceeds), equal or exceed $5,000,000, and
(iii) after receipt by the Company of financing proceeds after the Effective
Date of at least $5,000,000, all accrued Base Salary is immediately payable by
the Company to the Executive and all future accruals are payable as provided in
Section 4.1(a) hereof.

          (c) Notwithstanding Section 4.1(a) or 4.1(b) hereof, if at any time
the Company's available cash falls below $750,000, or at such time as any of the
Company's other officers are placed on reduced salary, the Board of Directors
shall have the right to discontinue salary payments to Executive. Any such
discontinued salary payments shall be accrued and shall be paid in a lump sum
payment at such time as the Company's available cash exceeds $1,250,000.

          2.2. Annual Bonus. With respect to each full fiscal year until the
earlier of the end of the Term or the Termination Date, Executive shall be
eligible to receive an annual bonus award, only if, as and when determined by
the Board in its sole discretion. Such bonus, if any, shall be paid no later
than thirty (30) days after the end of the fiscal year.

          2.3. Option Grant. If the Company shall have closed a financing or
financings (including, without limitation, a public offering), in which the
Company shall have received proceeds of at least $3,000,000 in the aggregate,
within 10 business days thereafter the Company shall grant to Executive an
option to purchase 250,000 shares of Common Stock at an exercise price of $2.00
per share (the "Executive Option"). The Executive Option shall be granted

                                      -3-
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pursuant to an option agreement, in substantially the form attached hereto as
Exhibit B (the "Stock Option Agreement"). Notwithstanding the foregoing, if such
financing does not occur upon the earlier of the end of the Term or the
Termination Date, the Company shall have no obligation to grant the Executive
Option. If granted, the Executive Option may be exercised, from time to time,
with respect to all or any part of the then vested shares in accordance with the
following vesting schedule: shares shall vest in 24 equal monthly installments
at the end of each month following the Effective Date; provided, however, all
shares subject to the Executive Option shall immediately vest upon the earlier
of (a) the consummation of a QPO, (b) the consummation of a Change of Control or
(c) termination of Executive's employment by the Company without Cause or by
Executive with Good Reason. If Executive's employment is terminated by the
Company with Cause or by Executive without Good Reason, the unexercised portion
of the Executive Option shall automatically lapse on the Termination Date and
not be exercisable whether or not such options were vested.

          4.4. Employee Benefits. Until the Termination Date, or such later time
as provided in Section 5, Executive shall be entitled to receive health and
disability insurance and the opportunity to participate in any 401(k) plan to
the same extent as such benefits are in effect from time to time for other
executive officers of the Company ("Benefits"); provided, however, that
Executive shall not be entitled to such Benefits to the extent that the same or
similar benefits are available to him from another employer, and the Company
shall not be required to make any employer contribution to Executive's 401(k)
account.

          2.5. Expense Reimbursement. Executive shall be entitled to
reimbursement by the Company for all reasonable travel, lodging, entertainment
and other expenses actually incurred by Executive in connection with the
performance of his duties, against receipts or other appropriate written
evidence of such expenditures as required by the appropriate United States
Internal Revenue Service regulations and, for any expenses in excess of $1,000
individually or $10,000 in the aggregate, subject to the Chief Executive
Officer's prior approval.

     5.   TERMINATION AND SEVERANCE.

          3.1. Termination without Cause or for Good Reason. If during the Term
the Company terminates Executive's employment without Cause, or Executive
terminates his employment with Good Reason, Executive shall be entitled to
receive:

          (a) if the Company shall not have closed on a financing or financings
prior to the first anniversary of the Effective Date (including, without
limitation, a public offering), in which the Company shall have received
proceeds of at least $3,000,000 in the aggregate, a pro rata portion of his Base
Salary and Benefits through the Termination Date and no other payment of any
kind; provided, however, that, if the Company's available cash is below $750,000
as of the Termination Date, or the Company's other officers are placed on
reduced salary, the Board of Directors shall have the right not to make the
salary payment to Executive and such salary payment shall be accrued and shall
be paid in a lump sum payment at such time as the Company's available cash
exceeds $1,250,000;

          (b) if the Company shall have closed on a financing or financings
prior to the

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first anniversary of the Effective Date (including, without limitation, a public
offering), in which the Company shall have received proceeds of at least
$3,000,000 in the aggregate but less than $5,000,000 in the aggregate, (i) a pro
rata portion of his Base Salary and Benefits through the Termination Date plus
(ii) an accruing right to receive his Base Salary and Benefits during the
remainder of the Term; provided that the amounts accrued pursuant to this clause
(ii) shall only be payable to Executive if the Company closes on a financing or
financing during the Term in which the Company shall have received proceeds of
at least $5,000,000 in the aggregate, and only paid at the time such payments
would otherwise have been made had Executive's employment not been terminated;

          (c) if the Company shall have closed on a financing or financings
prior to the first anniversary of the Effective Date (including, without
limitation, a public offering), in which the Company shall have received
proceeds of at least $5,000,000 in the aggregate but less than $15,000,000 in
the aggregate, (i) a pro rata portion of his Base Salary and Benefits through
the Termination Date plus (ii) continued payments of his then current Base
Salary and Benefits for the remainder of the Term; and

          (d) if the Company shall have closed on a financing or financings
prior to the first anniversary of the Effective Date (including, without
limitation, a public offering), in which the Company shall have received
proceeds of at least $15,000,000 in the aggregate, (i) a pro rata portion of his
Base Salary and Benefits through the Termination Date plus (ii) continued
payments of his then current Base Salary and Benefits for the period ending on
the third anniversary of the Effective Date.

Any such payments will be made in accordance with the Company's normal payroll
practices in existence immediately prior to the Termination Date.

          3.2. Termination for Cause or without Good Reason. If (a) the Company
terminates Executive's employment at any time for Cause or (b) Executive
terminates his employment at any time other than for Good Reason, Executive
shall be entitled to receive a pro rata portion of his Base Salary through the
Termination Date. Other than the payments described in this subsection,
Executive shall be entitled to no other payments from the Company.

          3.3. No Additional Effect on Executive Option. The right of Executive
to retain the vested portion of his rights under the Executive Option shall be
governed by the Stock Option Agreement entered into by and between the Company
and Executive and shall not be affected by the provisions of this Section 5.

     6.   PROPRIETARY RIGHTS AGREEMENT AND ARBITRATION AGREEMENT. The parties
acknowledge and incorporate that certain Proprietary Rights Agreement
("Proprietary Rights Agreement") and Arbitration Agreement ("Arbitration
Agreement") executed by Executive, copies of which are attached hereto as
Exhibit A.

     7.   ADDITIONAL COVENANTS.

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          4.1. Voting Agreement. From the date of this Agreement until the
second anniversary thereof, on all matters relating to the election of directors
of the Company, Executive agrees to vote all shares of capital stock of the
Company held by Executive (or shall consent pursuant to an action by written
consent of the holders of capital stock of the Company) so as to elect Evan C.
Unger, M.D. as a member of the Company's Board of Directors.

          4.2. Restriction on Transfer. During the twelve (12) month period
immediately subsequent to the closing of the offering of securities of the
Company conducted with the assistance of First Montauk Securities Corp. ("First
Montauk"), for so long as Executive together with its affiliates holds five
percent (5%) or more of the capital stock of the Company, Executive shall not,
and shall cause its affiliates not to, transfer any shares of capital stock of
the Company without complying with the right of first refusal granted by the
Company to First Montauk pursuant to that certain Letter of Intent dated January
8, 2004, by and between the Company and First Montauk.

     8.   MISCELLANEOUS.

          8.1. Survival. The representations, warranties, covenants and
agreements made herein shall survive the execution of this Agreement.

          8.2. Assignment. This Agreement and the rights and obligations
hereunder shall be assignable only with the prior written consent of each of the
parties; provided, however, that the Company may assign its rights under this
Agreement to the surviving entity pursuant to a sale of substantially all of the
Company's assets, by merger or consolidation or by a sale of all of the
Company's capital stock (provided that the surviving entity shall remain liable
as to all obligations of the Company under this Agreement).

          8.3. Benefits of Agreement. This Agreement and all obligations of the
parties shall be binding upon, and inure to the benefit of, their respective
successors and assigns.

          8.4. Severability. In case any provision of the Agreement shall be
invalid, illegal or unenforceable, the validity, legality and enforceability of
the remaining provisions shall not in any way be affected or impaired thereby,
and the court making the determination of invalidity, illegality, or
unenforceability shall have the power to reduce the scope, duration or area of
the term or provision, to delete specific words or phrases, or to replace any
invalid, illegal, or unenforceable term or provision with a term or provision
that is valid, legal and enforceable and that comes closest to expressing the
intention of the invalid or unenforceable term or provision, and this Agreement
shall be enforceable as so modified.

          8.5. Further Assurances. Each party agrees to execute such other
documents, instruments, agreements and consents, and take such other actions as
may be reasonably requested by the other parties hereto to effectuate the
purposes of this Agreement.

          8.6. Amendment and Waiver. This Agreement may be amended, modified or
waived only with prior written consent of each of the parties.

                                      -6-
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          8.7. Delays or Omissions. 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 by 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 or in
any similar breach, default or noncompliance thereafter occurring. All remedies
shall be cumulative and not alternative.

          8.8. Decisions of the Company and/or the Board. Any determination,
decision, approval, request, demand, action or lack of action to be exercised by
the Company or the Board with regard to this Agreement shall be the
determination, decision, approval, request, demand, action or lack of action of
the members of the Board other than Executive and all members nominated or
appointed by Executive in his capacity as a stockholder of the Company.

          8.9. 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 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. Any notice herein required or permitted to be given
shall be given by depositing the same in the United States first class mail,
postage prepaid, or hand delivered or transmitted by facsimile, in any case with
a copy sent by overnight courier service, and addressed to the parties as
follows:

               If to the Company:     ImaRx Therapeutics, Inc.
                                      1635 East 18th Street
                                      Tucson, AZ  85719
                                      Attention:  Chief Financial Officer
                                      Facsimile:  (520) 791-2437

               With a copy to:        Osborn Maledon
                                      2929 N. Central Avenue, Suite 2100
                                      Phoenix, AZ 85012-2794
                                      Attention:  Christopher S. Stachowiak
                                      Facsimile:  (602) 664-2055

               If to Executive:       John A. Moore
                                      c/o Edson Moore Healthcare Ventures, Inc.
                                      101 Brookmeadow Road
                                      Wilmington, DE 19807
                                      Facsimile:  (302) 994-3086

               With a copy to:        Reitler Brown LLC
                                      800 Third Avenue, 21st Floor
                                      New York, New York  10022
                                      Attention:  Scott H. Rosenblatt, Esq.
                                      Facsimile:  (212) 371-5500

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<PAGE>

or, to such other address or facsimile number as the party to whom notice is to
be given may have furnished to the other parties in writing in accordance
herewith.

          8.10. Titles and Subtitles. The titles of the sections and subsections
of the Agreement are for convenience of reference only and are not to be
considered in construing this Agreement.

          8.11. Counterparts. This Agreement may be executed in any number of
counterparts (facsimile or otherwise), each of which shall be an original, but
all of which together shall constitute one instrument.

          8.12. Pronouns. All pronouns contained herein, and any variations
thereof, shall be deemed to refer to the masculine, feminine or neutral,
singular or plural, as the identity of the parties hereto may require.

          8.13. Governing Law. This Agreement shall be construed in accordance
with, and governed by, the laws of the State of Arizona (without giving effect
to its conflict of laws principles).

          8.14 Prior Agreements. This Agreement, the Stock Option Agreement, the
Proprietary Rights Agreement and the Arbitration Agreement contain the entire
agreement of the parties relating to the subject matter hereof and supersede all
prior agreements and understandings with respect to such subject matter, and the
parties hereto have made no agreements, representations or warranties relating
to the subject matter of this Agreement, the Stock Option Agreement, the
Proprietary Rights Agreement or the Arbitration Agreement that are not set forth
herein or therein.

                            (SIGNATURE PAGE FOLLOWS)

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     IN WITNESS WHEREOF, the parties have executed this Executive Employment
Agreement as of the Effective Date.




                                         THE COMPANY:

                                         IMARX THERAPEUTICS, INC.


                                         By:  /s/ Evan Unger
                                            ------------------------------------
                                             Name: Evan C. Unger, M.D.
                                             Title:   President



                                         THE EXECUTIVE:


                                          /S/ John A. Moore
                                         ---------------------------------------
                                         JOHN A. MOORE


Exhibit A: Attach copy of signed Proprietary Rights Agreement and Arbitration
Agreement.
Exhibit B:  Attach copy of form of Stock Option Agreement.

                 EXECUTIVE EMPLOYMENT AGREEMENT SIGNATURE PAGE
<PAGE>


                            IMARX THERAPEUTICS, INC.

                  AGREEMENT FOR THE RESOLUTION OF ALL DISPUTES
                    ARISING FROM THE EMPLOYMENT RELATIONSHIP
                        THROUGH MEDIATION AND ARBITRATION

I.         SUBJECT AND SCOPE OF AGREEMENT

In order to expedite the resolution of employment related disputes and to
minimize the expense of such disputes for both ImaRx Therapeutics, Inc. (the
Company) and JOHN A. MOORE (the employee), thereby mitigating the disruption of
work and workplace morale which accompanies such disputes, it is hereby agreed
that ALL DISPUTES, CONTROVERSIES, CLAIMS AND MATTERS IN QUESTION ARISING OUT OF
OR RELATING TO THE EMPLOYMENT RELATIONSHIP BETWEEN THE COMPANY AND THE EMPLOYEE
WHICH ARE NOT RESOLVED THROUGH THE "GRIEVANCE PROCEDURE" STATED IN THE COMPANY'S
EMPLOYEE HANDBOOK, SHALL BE SUBJECT TO THE EXCLUSIVE, FINAL, BINDING, SPEEDY,
INEXPENSIVE AND IMPARTIAL CONDITIONS AND PROCEDURES STATED HEREIN. TO THE EXTENT
PERMITTED BY APPLICABLE LAW, THESE PROCEDURES SHALL CONSTITUTE THE SOLE AND
EXCLUSIVE METHOD FOR THE RESOLUTION OF ANY CLAIM BETWEEN THE COMPANY AND ANY
EMPLOYEE, ARISING OUT OF THE EMPLOYMENT RELATIONSHIP AND THERE SHALL BE NO
RECOURSE TO COURT WITH OR WITHOUT A JURY TRIAL. The parties agree to promptly
move to dismiss any such court proceeding if commenced.

Claims covered by this Agreement include claims based on alleged breach of any
employment agreement or promise, breach of implied covenants of

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good faith and fair dealing, alleged discrimination or harassment and/or alleged
breach of any public policy; wrongful discharge under statutory law and common
law; employment discrimination and/or violations based on federal, state and
local statutes, ordinances or governmental regulations including, but not
limited to those based on Title VII of the Civil Rights Act of 1964, the Civil
Rights Act of 1991, the Americans with Disabilities Act (ADA), the Age
Discrimination in Employment Act (ADEA), the Family and Medical Leave Act
(FMLA), the Workers Adjustment and Retraining Notification Act (WARN);
retaliatory discharge or other action, tortious conduct; contractual violations;
other statutory claims and disputes. THIS AGREEMENT ALSO APPLIES TO ANY CLAIMS
OR COUNTERCLAIMS THAT THE COMPANY MAY HAVE AGAINST THE EMPLOYEE.

II. PROCEDURES - MEDIATION

The party initiating these procedures shall be referred to herein as "the
claimant or grievant."

     1.   The claimant shall, within seven (7) days of the specific incident or
          situation giving rise to the dispute, submit to his/her supervisor or
          to the Human Resources Manager if the claimant is an employee, or to
          the employee involved if the claimant is the Company, in writing, the
          subject of the dispute

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          and his/her contentions with respect to it. A written response shall
          be provided within three (3) days (1).

     2.   If the response is unsatisfactory, the claimant shall, within three
          (3) days of receipt of the written response or of the default, demand
          in writing that the dispute be submitted to nonbinding mediation. If
          the dispute involves termination of employment, the claimant shall
          have the option to proceed directly to arbitration. (See III below).

     3.   The mediation conference(s) shall be held before a mediator selected
          from a list of five mediators provided by the Lex Mundi College of
          Mediators, or by any other entity agreed upon by the parties and
          completed within thirty (30) days of the demand. Within two (2) days
          of receipt of a timely written demand for mediation, (or within two
          (2) days of its issuance of such demand when the company is the
          claimant) the Company shall request a list of five mediators who
          reside within 1000 miles of the situs of the dispute from Lex Mundi

____________

(1) Unless otherwise specified, "days" herein means calendar days. A document
is deemed delivered by the sender and received by the addressee at the time it
is postmarked or hand-delivered to the addressee's workstation. The time limits
established in this policy are to be strictly enforced. However, any deadline
may be extended by written agreement of the grievant and the Company.

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<PAGE>

          College of Mediators or from any other entity agreed upon by the
          parties. The parties shall select a mediator from the list provided
          by Lex Mnndi, by each alternatively striking 2 names from said list.
          The remaining mediator shall mediate the dispute. The parties shall
          execute the mediation agreement required by the mediator selected.

     4.   At the mediation conference(s) the spokesperson for the Company will
          be an attorney or other person designated by the Company. The
          claimant's spokesperson will be either himself or herself or an
          attorney employed by the claimant for that purpose.

     5.   The claimant and his or her supervisor will normally attend the
          mediation conference(s). Attendance by others at the mediation
          conference(s) shall be limited to those people actually involved in
          the mediation process.

     6.   All written material presented to the mediator or to the other party
          shall be returned to the party presenting the material at the
          termination of the mediation conference(s).

     7.   Proceedings before the mediator shall be informal in nature. The issue
          mediated will be the same as the issue the parties

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<PAGE>

          have failed to resolve through this process. The rules of evidence
          will not apply, and no record of the mediation conference(s) shall be
          made, except that the mediator may make notes for the purpose of
          aiding the mediation process.

     8.   The mediator may meet separately with the parties during the mediation
          conference(s) but will not have the authority to compel the resolution
          of the dispute.

     9.   The Company and the employee at the mediation conference(s) may accept
          the resolution proposed by the mediator and if accepted at the
          conference(s) such settlement or any settlement resulting from the
          conference(s) shall be in writing and binding upon the parties and
          dispose of the entire dispute but shall not be precedent setting.

     10.  If no settlement is reached during the mediation conference(s), the
          mediator shall provide the parties with an immediate oral advisory
          opinion, unless both parties agree that no opinion shall be provided.
          The mediator shall state the basis for his or her advisory opinion.

     11.  The Company shall bear up to $400.00 of compensation and expenses of
          the mediator and the general administrative


                                     Page 5
<PAGE>


          expenses of the mediation conference(s). Expenses in excess of this
          shall be divided equally between the parties.

III.     PROCEDURES - ARBITRATION

1.   SUBMISSION TO ARBITRATION

If the mediation does not resolve the dispute or, in cases of termination of
employment, if the claimant elected to bypass the mediation process, either
party may submit the dispute to arbitration, if further relief is sought. Such
submission shall be in writing, within ten (10) days of the last mediation
conference or of the claimant's election to bypass the mediation, and shall
state with specificity the issues to be submitted to arbitration and the relief
sought. Copies of the submission and demand for arbitration shall be served by
registered mail on the other party to the dispute and simultaneously upon the
local office of the Federal Mediation and Conciliation Service (FMCS), or at the
requesting party's option, upon the local office of the American Arbitration
Association (AAA).

2.   SELECTION OF ARBITRATOR

With the submission, the FMCS or AAA shall be requested by the party seeking
arbitration to provide a list of five arbitrators. Unless the parties can
otherwise agree to appoint an arbitrator, the arbitrator shall be selected no
later than five days after receipt by the parties of the list in the same method
used for the selection of the mediator.

                                     Page 6
<PAGE>

3.   ARBITRATION PROCESS

The arbitration process shall be under the provisions of the current American
Arbitration Association, National Rules for the Resolution of Employment
Disputes in effect at the time of the submission or under such procedures as are
determined by the arbitrator. Copies of the pertinent procedural rules shall be
obtained by the party submitting the dispute to arbitration and provided to the
other party. Should a discrepancy arise between said procedural rules and the
provisions herein, the latter shall prevail. At the hearing, all witnesses shall
testify under oath and the hearing and record or the proceeding shall be
confidential and not open to the public except to the extent that; (a) the
parties otherwise agree in writing, and (b) may be appropriate in subsequent
proceedings between the parties. A record of the hearing shall be made at the
election of either party and at the Company's expense by verbatim transcription.
The arbitrator shall maintain possession of the record for at least two years
after issuing the award. No person serving as a mediator between the parties may
serve as arbitrator. Neither party may at the arbitration hearing refer to
presentations made by the other at the mediation conference (s), the fact that
such conference(s) were held, or any statements made by the mediator. Any such
references shall be disregarded by the arbitrator. Intentional or repeated
references to matters disclosed only during mediation shall constitute cause for
the arbitrator, in his or her discretion, to summarily find against the party
making such references.

                                     Page 7
<PAGE>

4.   REPRESENTATION AT HEARING AND EVIDENCE

Any such party to the arbitration may be represented by counsel during the
arbitration proceedings. The order of presentation and any disputes that may
arise with respect to the relevance and materiality of the evidence offered
shall be resolved by the arbitrator. Conformity with the rules of evidence shall
not be required.

5.   ARBITRATOR'S DISCRETION

The arbitrator may, in his/her discretion, confer with any party or person and
otherwise conduct his/her own investigation outside the hearing process for the
purpose of obtaining written or oral information. The hearing may be reopened on
the arbitrator's initiative or upon application of a party, at any time before
the award is made. The arbitration shall have thirty (30) days from the closing
of the hearing within which to render the award. The arbitrator shall have no
authority to add to, subtract from, nor modify the policies describing the
employment relationship. The relief awardable by the arbitrator shall, except
where he/she finds a statutory violation, be limited to reinstatement, if the
claimant is an employee who had been terminated and the earnings that said
claimant would otherwise have earned (back-pay), less any unemployment
compensation or other compensation for services that the claimant may have
received from any source during the period. In cases where the Company had
terminated the relationship, if the claimant had failed thereafter to make
diligent efforts to apply or look for a

                                     Page 8
<PAGE>

position which would provide compensation for his services, no back-pay shall be
awarded for that period of time. Where the arbitrator finds a statutory
violation, the remedy shall be limited to those provided for in the pertinent
statute.

6.   TIME LIMITATIONS

The time limitations imposed in this Article shall be strictly complied with,
unless the parties agree, in writing, to extend them. Failure to comply with the
time limitations shall operate as a waiver by the party responsible for such
failure.

7.   ALLOCATION OF EXPENSES, FEES AND COSTS

The expenses of witnesses for either side shall be paid by the party producing
such witnesses. The arbitrator's fees and any other expenses of the arbitrator
including required travel of the arbitrator and the cost of any evidence or
proof produced at the direction of the arbitrator are apportionable and shall be
borne by the party (s) designated by the arbitrator.

8.   FINALITY AND ENFORCEMENT OF AWARD

All decisions of arbitrators pursuant to this Article shall be final, valid,
irrevocable and conclusively binding upon the parties to the dispute. The award
may be entered as a judgment in any court of competent jurisdiction and the
parties agree to stipulate to entry of judgment.

                                     Page 9
<PAGE>

IV.  CONSIDERATION FOR AGREEMENT

An employee's acceptance of an offer of employment or of continued employment by
the Company after notice of this agreement manifest his or her assent to its
terms. Such employment and the Company's commitments contained in this Agreement
constitute part of the consideration he or she receives in exchange for
foregoing any and all right to litigate employment related disputes in a court
of law.

/s/ John A. Moore                        /s/ Jean Carlyle
----------------------                   ------------------------
EMPLOYEE                                 IMARX THERAPEUTICS, INC.


02-23-04                                 02-18-04
----------------------                   ------------------------
DATE:                                    DATE:


                                    Page 10
<PAGE>

                            ImaRx Therapeutics, Inc.



                     INVENTION AND CONFIDENTIAL INFORMATION
                                   AGREEMENT

                                      with

                                 John A. Moore



                                Dated: 02-18-04

<PAGE>


                INVENTION AND CONFIDENTIAL INFORMATION AGREEMENT


          This INVENTION AND CONFIDENTIAL INFORMATION AGREEMENT is made between
John A. Moore, sometimes hereinafter referred to as "Employee," and ImaRx
Therapeutics, Inc., hereinafter referred to as "Company," effective as of the
first day of employment by the Company of the Employee.

          In consideration of: (1) any compensation paid to me by the Company;
(2) my employment as employee, consultant and /or independent contractor, and
continuing employment by the Company; and (3) my access to Confidential
Information (as hereinafter defined) of the Company, I, the undersigned
Employee, hereby agree as follows:

     1.   DEFINITIONS.

          A.   "Agreement Field" refers to the field of imaging Pharmaceuticals
               related to diagnostic imaging techniques of computed tomography,
               magnetic resonance, ultrasound and nuclear medicine as well as
               therapeutic techniques or products related to the disciplines
               (e.g. therapeutic ultrasound and hyperthermia, radiation therapy
               and lasers) and drug and gene delivery.

          B.   "Confidential Information" refers to any information acquired,
               developed, owned or controlled by the Company concerning the
               Company and its products and technology which the Company treats
               as confidential, including without limitation, any and all
               patents and patent rights, copyrights, discoveries, inventions,
               improvements, knowledge, know-how, models, manufacturing or other
               techniques, specifications, ideas, technical data, engineering
               data, formulae, recipes, plans, processes, and any other
               information in the Agreement Field, whether or not patentable,
               copyrightable or otherwise protectable, which are made,
               discovered, conceived, developed or otherwise acquired by the
               Company. Confidential Information also includes names of
               customers and dealers, personal records, financial projections
               and other financial information relating to Company's businesses;
               technological product information, training and operational
               manuals and other things which constitute the property of the
               Company. The term "Confidential Information" shall not include
               information which:

               (i)  is in or becomes available to the public domain, other than
                    through an act or failure to act of one of the parties,
                    contrary to the terms of this Agreement; or

               (ii) can be shown to have already been known to the Employee and
                    which has not been transferred to Company prior to the date
                    of this Agreement; or


                                       1
<PAGE>

               (iii) has been disclosed by a third party, as a matter of right,
                     without restrictions on disclosures and use.

In the event Employee asserts that any information is not Confidential
Information by reason of (i), (ii), or (iii) above, the Employee shall have the
burden of proving the information disclosed is within the terms of such
provisions.

          C.   "Inventions" refers to all discoveries, inventions, improvements,
               processes, plans, designs, specifications, ideas, recipes,
               models, manufacturing or other techniques or know-how, whether or
               not patentable, copyrightable or otherwise protectable, which are
               made, discovered, conceived, or developed, by Employee in the
               Agreement Field either alone or jointly with others.

     2.   ASSIGNMENT OF INVENTIONS. During the term of my employment and for a
period of one year thereafter, I agree to disclose to the Company fully and
promptly, and to assign to the Company, and I do hereby assign to the Company
all right, title and interest to and in, all Inventions made, discovered,
conceived, or developed by me, either alone or jointly with others, during the
period of my employment by the Company, whether or not during normal working
hours, and including during any periods of leaves of absence, which relate in
any way to the Agreement Field or which result in any way from the use of the
Company's premises, time, facilities or Confidential Information.

     3.   PATENTS. I agree that the Company shall have the right to apply for
and use patents, copyrights, trademarks, or other statutory or common law
protections for the Inventions in all countries; and that I will assist the
Company in every lawful way (at the Company's expense) to obtain, and from time
to time enforce patents, copyrights, trademarks, trade secrets, and other
statutory and common law protections for the Inventions, including but not
limited to the execution of documents, and the giving of testimony during and
after my employment by the Company.

     4.   CONFIDENTIAL INFORMATION.

          A.   I agree that during the period of my employment by the Company,
               and during the period extending three years after termination of
               such employment (or for a longer period not to exceed five years
               after such termination in the case of such Confidential
               Information which the Company may specifically designate for this
               purpose), I will not, without written authorization from the
               Company, directly or indirectly use Confidential Information
               belonging to the Company for any purpose other than pursuant to
               my employment by the Company, and that I will not disclose such
               Confidential Information to any person without the express
               written authorization of the Company.

                                       2
<PAGE>

          B.   I agree that I will submit in advance to an officer designated by
               the Company (other than myself) all matters proposed to be
               published or printed for any use other than a confidential
               communication to an authorized recipient.

          C.   I agree that upon termination of my employment by the Company for
               any reason whatsoever, I will promptly deliver to the Company all
               Confidential Information, including any and all notes, memoranda,
               writings, drawings, or other materials embodying or containing
               Confidential Information, however reproduced or recorded (and
               including any and all copies thereof), which are in my
               possession, custody or control.

     5. MODIFICATIONS. This Agreement may be modified only by a duly authorized
and executed writing.

     6. SUCCESSORS AND ASSIGNS. This Agreement shall be binding on, and shall
inure to the benefit of the Company, its affiliates, and their respective
successors and assigns, and the Employee, his heirs, personal representatives
and assigns.

     7. ARBITRATION. Any and all disputes between the parties hereto concerning
the negotiation, interpretation, performance or termination of this Agreement,
shall be resolved through amicable discussion between the parties. Failing
resolution of the issues in dispute in such discussion, any party may, thirty
(30) days after initiation of such discussions, refer the issue for final
resolution by binding arbitration pursuant to the then-existing rules of the
American Arbitration Association. Any party may apply to any court of competent
jurisdiction for injunctive relief or other interim measures. Any application to
a court for such interim measures shall not be deemed incompatible with this
agreement to arbitrate or as a waiver of this agreement. The arbitration shall
be conducted by a single arbitrator, who shall be a lawyer familiar with
technology development and transfer issues, and shall be held, absent agreement
to the contrary, in Tucson, Arizona. In making his award, the arbitrator shall
be guided, in descending priority, by the terms of this Agreement, the terms of
the Research Joint Venture Agreement, the usages of the trade in the place where
the party charged with an act or failure to act is principally located, and by
what he deems just and equitable under the circumstance without reference to the
law of any jurisdiction. The award of the arbitrator shall be final and binding,
and not subject to judicial review. Enforcement of the award may be sought in
any court of competent jurisdiction over the parties or their assets.

     8. WAIVER. Failure by either Party to exert all or any of its rights upon
breach of this Agreement shall not be deemed a waiver of such rights either with
respect to that breach or any subsequent breach.

               9. SEVERABILITY. The invalidity or unenforceability of any
          provisions of this Agreement shall not affect the other provisions
          hereof and this Agreement shall be construed in all respects as if
          said invalid or unenforceable provisions were not

                                       3
<PAGE>

contained herein, The parties agree to cooperate in any revisions or amendments
of this Agreement which may be necessary to effect the intent of the parties in
the event that any provision of this Agreement is deleted as herein provided.

Signed in Tucson, Arizona this 18th day of FEB, 2004.



                                ImaRx Therapeutics, Inc.



                                Jean Carlyle
                                ------------------------------------------------
                                Vice President and Chief Financial Officer






Signed in Tucson, Arizona this 23RD day of FEB, 2004.

                              Employee John A. Moore

<PAGE>

                            IMARX THERAPEUTICS, INC.

                                 2000 STOCK PLAN

                             STOCK OPTION AGREEMENT

Unless otherwise defined herein, the terms defined in the ImaRx Therapeutics,
Inc. 2000 Stock Plan shall have the same defined meanings in this Stock Option
Agreement (the "Option Agreement").

I.   NOTICE OF STOCK OPTION GRANT

     Optionee's Name:           John A. Moore            SS#:  ****************
                                                               ----------------
     Optionee's Address:        c/o Edson Moore Healthcare Ventures, Inc.
                                101 Brookmeadow Road
                                Wilmington, DE 19807

     You have been granted an option to purchase Common Stock of ImaRx
Therapeutics, Inc. (the "Company"), subject to the terms and conditions of the
Plan and this Option Agreement, as follows:


     Grant Number                            99
                                         ______________

     Date of Grant                        03/10/04
                                         _________________

     Vesting Commencement Date           February _____, 2004

     Exercise Price per Share            $ 2.00

     Total Number of Shares Granted      250,000

     Total Exercise Price                $300,000

     Type of Option:                     _______Incentive Stock Option

                                         X  Nonstatutory Stock Option

     Term/Expiration Date:               Ten years from the Date of Grant

     Exercise and Vesting Schedule:

     This Option shall be exercisable in whole or in part, and shall vest
according to the vesting schedule set forth in that certain Employment Agreement
dated February ___, 2004 (the "Employment Agreement"). Additionally, to the
extent applicable, this Option shall be subject to the terms and conditions
(including vesting, change-in-control, and termination) of the Employment
Agreement.

<PAGE>

     Termination Period:

     This Option may be exercised, to the extent it is then vested, for three
months after Optionee ceases to be a Service Provider. Upon death or Disability
of the Optionee, this Option may be exercised, to the extent it is then vested,
for one year after Optionee ceases to be a Service Provider. In no event shall
this Option be exercised later than the Term/Expiration Date as provided above.

II.  AGREEMENT

     1. Grant of Option. The Administrator of the Company hereby grants to the
Optionee named in the Notice of Grant (the "Optionee"), an option (the "Option")
to purchase the number of Shares set forth in the Notice of Grant, at the
exercise price per Share set forth in the Notice of Grant (the "Exercise
Price"), and subject to the terms and conditions of the Plan, which is
incorporated herein by reference. Subject to Section 14(c) of the Plan, in the
event of a conflict between the terms and conditions of the Plan and this Option
Agreement, the terms and conditions of the Plan shall govern. In the event of a
conflict between the terms and conditions of the Plan and this Option Agreement,
on the one hand, and the Employment Agreement, on the other hand, the terms and
conditions of the Plan and Option Agreement shall govern.

     2. Exercise of Option. This Option shall be exercisable during its term in
accordance with the provisions of Section 9 of the Plan as follows:

        (a) Right to Exercise. This Option shall be exercisable cumulatively
according to the vesting schedule set forth in the Employment Agreement. This
Option may not be exercised for a fraction of a Share.

        (b) Method of Exercise. This Option shall be exercisable by delivery of
an exercise notice in the form attached as Exhibit A (the "Exercise Notice")
which shall state the election to exercise the Option, the number of Shares with
respect to which the Option is being exercised, and such other representations
and agreements as may be required by the Company. The Exercise Notice shall be
accompanied by payment of the aggregate Exercise Price as to all Exercised
Shares. This Option shall be deemed to be exercised upon receipt by the Company
of such fully executed Exercise Notice accompanied by the aggregate Exercise
Price.

        No Shares shall be issued pursuant to the exercise of an Option unless
such issuance and such exercise complies with Applicable Laws. Assuming such
compliance, for income tax purposes the Shares shall be considered transferred
to the Optionee on the date on which the Option is exercised with respect to
such Shares.

     3. Optionee's Representations. In the event the Shares have not been
registered under the Securities Act of 1933, as amended, at the time this Option
is exercised, the Optionee shall, if required by the Company, concurrently with
the exercise of all or any portion of this Option, deliver to the Company his or
her Investment Representation Statement in the form attached hereto as Exhibit
B.

     4. Lock-Up Period. Optionee hereby agrees that, if so requested by the
Company or any representative of the underwriters (the "Managing Underwriter")
in connection with any registration of the offering of any securities of the
Company under the Securities Act, Optionee shall not sell or

                                       2
<PAGE>

otherwise transfer any Shares or other securities of the Company during the
180-day period (or such other period as may be requested in writing by the
Managing Underwriter and agreed to in writing by the Company) (the "Market
Standoff Period") following the effective date of a registration statement of
the Company filed under the Securities Act. Such restriction shall apply only to
the first registration statement of the Company to become effective under the
Securities Act that includes securities to be sold on behalf of the Company to
the public in an underwritten public offering under the Securities Act. The
Company may impose stop-transfer instructions with respect to securities subject
to the foregoing restrictions until the end of such Market Standoff Period.

     5. Method of Payment. Payment of the aggregate Exercise Price shall be by
any of the following, or a combination thereof, at the election of the Optionee:

          (a) cash;

          (b) check;

          (c) consideration received by the Company under a formal cashless
exercise program adopted by the Company in connection with the Plan; or

          (d) surrender of other Shares which, (i) in the case of Shares
acquired upon exercise of an option, have been owned by the Optionee for more
than six (6) months on the date of surrender, and (ii) have a Fair Market Value
on the date of surrender equal to the aggregate Exercise Price of the Exercised
Shares.

     6. Restrictions on Exercise. This Option may not be exercised if the
issuance of such Shares upon such exercise or the method of payment of
consideration for such shares would constitute a violation of any Applicable
Law.

     7. Non-Transferability of Option. This Option may not be transferred in any
manner otherwise than by will or by the laws of descent or distribution and may
be exercised during the lifetime of Optionee only by Optionee. The terms of the
Plan and this Option Agreement shall be binding upon the executors,
administrators, heirs, successors and assigns of the Optionee.

     8. Term of Option. This Option may be exercised only within the term set
out in the Notice of Grant, and may be exercised during such term only in
accordance with the Plan and the terms of this Option.

     9. Tax Consequences. Set forth below is a brief summary as of the date of
this Option of some of the federal tax consequences of exercise of this Option
and disposition of the Shares. THIS SUMMARY IS NECESSARILY INCOMPLETE, AND THE
TAX LAWS AND REGULATIONS ARE SUBJECT TO CHANGE. THE OPTIONEE SHOULD CONSULT A
TAX ADVISER BEFORE EXERCISING THIS OPTION OR DISPOSING OF THE SHARES.

          (a) Exercise of NSO. There may be a regular federal income tax
liability upon the exercise of an NSO. The Optionee will be treated as having
received compensation income (taxable at ordinary income tax rates) equal to the
excess, if any, of the Fair Market Value of the Exercised Shares on the date of
exercise over the Exercise Price. If Optionee is an Employee or a former
Employee, the Company will be required to withhold from Optionee's compensation
or

                                       3
<PAGE>

collect from Optionee and pay to the applicable taxing authorities an amount in
cash equal to a percentage of this compensation income at the time of exercise,
and may refuse to honor the exercise and refuse to deliver Shares if such
withholding amounts are not delivered at the time of exercise.

     10. Entire Agreement; Governing Law. The Plan is incorporated herein by
reference. The Employment Agreement, the Plan and this Option Agreement
(including all exhibits attached hereto) constitute the entire agreement of the
parties with respect to the subject matter hereof and supersede in their
entirety all prior undertakings and agreements of the Company and Optionee with
respect to the subject matter hereof, and may not be modified adversely to the
Optionee's interest except by means of a writing signed by the Company and
Optionee. This Option Agreement is governed by the internal substantive laws but
not the choice of law rules of the State of Arizona.

     11. No Guarantee of Continued Service. OPTIONEE ACKNOWLEDGES AND AGREES
THAT THE VESTING OF SHARES PURSUANT TO THE VESTING SCHEDULE HEREOF IS EARNED
ONLY PURSUANT TO THE EMPLOYMENT AGREEMENT. OPTIONEE FURTHER ACKNOWLEDGES AND
AGREES THAT THIS AGREEMENT, THE TRANSACTIONS CONTEMPLATED HEREUNDER AND THE
VESTING SCHEDULE SET FORTH HEREIN DO NOT CONSTITUTE AN EXPRESS OR IMPLIED
PROMISE OF CONTINUED ENGAGEMENT AS A SERVICE PROVIDER FOR THE VESTING PERIOD,
FOR ANY PERIOD, OR AT ALL, AND SHALL NOT INTERFERE IN ANY WAY WITH OPTIONEE'S
RIGHT OR THE COMPANY'S RIGHT TO TERMINATE OPTIONEE'S RELATIONSHIP AS A SERVICE
PROVIDER AS SET FORTH IN THE EMPLOYMENT AGREEMENT.

                           [Signature Page to Follow]

                                       4
<PAGE>

     Optionee acknowledges receipt of a copy of the Plan and represents that he
or she is familiar with the terms and provisions thereof, and hereby accepts
this Option subject to all of the terms and provisions thereof. Optionee has
reviewed the Plan and this Option in their entirety, has had an opportunity to
obtain the advice of counsel prior to executing this Option and fully
understands all provisions of the Option. Optionee hereby agrees to accept as
binding, conclusive and final all decisions or interpretations of the
Administrator upon any questions arising under the Plan or this Option. Optionee
further agrees to notify the Company upon any change in the residence address
indicated below.


OPTIONEE                                 IMARX THERAPEUTICS, INC.

                                      By:
________________________________         _______________________________________
Signature                                  Evan C. Unger

                                           President & CEO
_______________________________       __________________________________________
Print Name                               Title


_______________________________
Spouse signature

________________________________
Print Name


________________________________


________________________________
Residence Address


                                       5
<PAGE>

                                    EXHIBIT A

                                 2000 STOCK PLAN

                                 EXERCISE NOTICE

                            ImaRx Therapeutics, Inc.
                                 1635 East 18th
                              Tucson, Arizona 85719

Attention:  Stock Plan Administrator

     1. Exercise of Option. Effective as of today, ________________, ____, the
undersigned ("Optionee") hereby elects to exercise Optionee's option (the
"Option") to purchase ________________ shares of the Common Stock (the "Shares")
of ImaRx Therapeutics, Inc. (the "Company") under and pursuant to the 2000 Stock
Plan (the "Plan") and the Stock Option Agreement dated ______________, _____
(the "Option Agreement").

     2. Delivery of Payment. Purchaser herewith delivers to the Company the full
purchase price of the Shares, as set forth in the Option Agreement.

     3. Representations of Optionee. Optionee acknowledges that Optionee has
received, read and understood the Plan and the Option Agreement and agrees to
abide by and be bound by their terms and conditions.

     4. Rights as Shareholder. Until the issuance of the Shares (as evidenced by
the appropriate entry on the books of the Company or of a duly authorized
transfer agent of the Company), no right to vote or receive dividends or any
other rights as a shareholder shall exist with respect to the optioned stock,
notwithstanding the exercise of the Option. The Shares shall be issued to the
Optionee as soon as practicable after the Option is exercised. No adjustment
shall be made for a dividend or other right for which the record date is prior
to the date of issuance except as provided in Section 12 of the Plan.

     5. Company's Right of First Refusal. Before any Shares held by Optionee or
any transferee (either being sometimes referred to herein as the "Holder") may
be sold or otherwise transferred (including transfer by gift or operation of
law), the Company or its assignee(s) shall have a right of first refusal to
purchase the Shares on the terms and conditions set forth in this Section (the
"Right of First Refusal").

          (a) Notice of Proposed Transfer. The Holder of the Shares shall
deliver to the Company a written notice (the "Notice") stating: (i) the Holder's
bona fide intention to sell or otherwise transfer such Shares; (ii) the name of
each proposed purchaser or other transferee ("Proposed Transferee"); (iii) the
number of Shares to be transferred to each Proposed Transferee; and (iv) the
bona fide cash price or other consideration for which the Holder proposes to
transfer the

                                       1

2000 Stock Plan Exercise Notice
<PAGE>

Shares (the "Offered Price"), and the Holder shall offer the Shares at the
Offered Price to the Company or its assignee(s).

          (b) Exercise of Right of First Refusal. At any time within thirty (30)
days after receipt of the Notice, the Company and/or its assignee(s) may, by
giving written notice to the Holder, elect to purchase all, but not less than
all, of the Shares proposed to be transferred to any one or more of the Proposed
Transferees, at the purchase price determined in accordance with subsection (c)
below.

          (c) Purchase Price. The purchase price ("Purchase Price") for the
Shares purchased by the Company or its assignee(s) under this Section shall be
the Offered Price. If the Offered Price includes consideration other than cash,
the cash equivalent value of the non-cash consideration shall be determined by
the Board of Directors of the Company in good faith.

          (d) Payment. Payment of the Purchase Price shall be made, at the
option of the Company or its assignee(s), in cash (by check), by cancellation of
all or a portion of any outstanding indebtedness of the Holder to the Company
(or, in the case of repurchase by an assignee, to the assignee), or by any
combination thereof within 30 days after receipt of the Notice or in the manner
and at the times set forth in the Notice.

          (e) Holder's Right to Transfer. If all of the Shares proposed in the
Notice to be transferred to a given Proposed Transferee are not purchased by the
Company and/or its assignee(s) as provided in this Section, then the Holder may
sell or otherwise transfer such Shares to that Proposed Transferee at the
Offered Price or at a higher price, provided that such sale or other transfer is
consummated within 120 days after the date of the Notice, that any such sale or
other transfer is effected in accordance with any applicable securities laws and
that the Proposed Transferee agrees in writing that the provisions of this
Section shall continue to apply to the Shares in the hands of such Proposed
Transferee. If the Shares described in the Notice are not transferred to the
Proposed Transferee within such period, a new Notice shall be given to the
Company, and the Company and/or its assignees shall again be offered the Right
of First Refusal before any Shares held by the Holder may be sold or otherwise
transferred.

          (f) Exception for Certain Family Transfers. Anything to the contrary
contained in this Section notwithstanding, the transfer of any or all of the
Shares during the Optionee's lifetime or on the Optionee's death by will or
intestacy to the Optionee's immediate family or a trust for the benefit of the
Optionee's immediate family shall be exempt from the provisions of this Section.
"Immediate Family" as used herein shall mean spouse, lineal descendant or
antecedent, father, mother, brother or sister. In such case, the transferee or
other recipient shall receive and hold the Shares so transferred subject to the
provisions of this Section, and there shall be no further transfer of such
Shares except in accordance with the terms of this Section.

                                       2

2000 Stock Plan Exercise Notice
<PAGE>

          (g) Termination of Right of First Refusal. The Right of First Refusal
shall terminate as to any Shares upon (i) the first sale of Common Stock of the
Company to the general public pursuant to a registration statement filed with
and declared effective by the Securities and Exchange Commission under the
Securities Act of 1933, as amended, or (ii) in the event of any "Change in
Control," as that term may be defined in the Employment Agreement. Additionally,
the Right of First Refusal shall not apply to any proposed transfer to be made
as part of a transaction or series of transactions that give rise to a Change in
Control.

     6. Tax Consultation. Optionee understands that Optionee may suffer adverse
tax consequences as a result of Optionee's purchase or disposition of the
Shares. Optionee represents that Optionee has consulted with any tax consultants
Optionee deems advisable in connection with the purchase or disposition of the
Shares and that Optionee is not relying on the Company for any tax advice.

     7. Restrictive Legends and Stop-Transfer Orders.

          (a) Legends. Optionee understands and agrees that the Company shall
cause the legends set forth below or legends substantially equivalent thereto,
to be placed upon any certificate(s) evidencing ownership of the Shares
together with any other legends that may be required by the Company or by state
or federal 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, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL REGISTERED
     UNDER THE ACT OR, IN THE OPINION OF COMPANY COUNSEL SATISFACTORY TO THE
     ISSUER OF THESE SECURITIES, SUCH OFFER, SALE OR TRANSFER, PLEDGE OR
     HYPOTHECATION IS IN COMPLIANCE THEREWITH.

     THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN
     RESTRICTIONS ON TRANSFER AND RIGHT OF FIRST REFUSAL OPTIONS HELD BY THE
     ISSUER OR ITS ASSIGNEE(S) AS SET FORTH IN THE EXERCISE NOTICE BETWEEN THE
     ISSUER AND THE ORIGINAL HOLDER OF THESE SHARES, A COPY OF WHICH MAY BE
     OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. SUCH TRANSFER RESTRICTIONS
     AND RIGHT OF FIRST REFUSAL ARE BINDING ON TRANSFEREES OF THESE SHARES.

     THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO AN AGREEMENT
     PROVIDING FOR A MARKET STANDOFF RESTRICTION FOLLOWING THE INITIAL PUBLIC
     OFFERING OF THE COMPANY'S SECURITIES, A COPY OF WHICH IS ON FILE AT THE
     PRINCIPAL OFFICE OF THE COMPANY.

                                       3

2000 Stock Plan Exercise Notice
<PAGE>


               (b) Stop-Transfer Notices. Optionee agrees that, in order to
ensure compliance with the restrictions referred to herein, the Company may
issue appropriate "stop transfer" instructions to its transfer agent, if any,
and that, if the Company acts as a registrar and transfer agent for its own
securities, it may make appropriate notations to the same effect in its own
records.

               (c) Refusal to Transfer. The Company shall not be required (i) to
transfer on its books any Shares that have been sold or otherwise transferred in
violation of any of the provisions of this Exercise Notice or (ii) to treat as
owner of such Shares or to accord the right to vote or pay dividends to any
purchaser or other transferee to whom such Shares shall have been so
transferred.

          8. Successors and Assigns. The Company may assign any of its rights
under this Exercise Notice to single or multiple assignees, and the terms and
conditions of this Exercise Notice shall inure to the benefit of the successors
and assigns of the Company. Subject to the restrictions on transfer herein set
forth, the terms and conditions of this Exercise Notice shall be binding upon
Optionee and his or her heirs, executors, administrators, successors and
assigns.

          9. Interpretation. Any dispute regarding the interpretation of this
Exercise Notice shall be submitted by Optionee or by the Company forthwith to
the Administrator which shall review such dispute at its next regular meeting.
The resolution of such a dispute by the Administrator shall be final and binding
on all parties.

          10. Governing Law. This Exercise Notice is governed by the laws of the
State of Arizona.


Submitted by:                                        Accepted by:

OPTIONEE                                 ImaRx Therapeutics, Inc.

                                         By:
________________________________            ____________________________________
Signature                                Name:
                                              __________________________________

________________________________         _______________________________________
Print Name                               Title

Address:                                 Address:

                                         1635 East 18th Street
________________________________

                                         Tucson, Arizona  85719
________________________________


________________________________
Spouse Signature


________________________________         _______________________________________
Signature                                Date received

                                       4

2000 Stock Plan Exercise Notice
<PAGE>

                                    EXHIBIT B

                       INVESTMENT REPRESENTATION STATEMENT

OPTIONEE       :

COMPANY        :             IMARX THERAPEUTICS, INC.

SECURITY       :             COMMON STOCK

AMOUNT         :

DATE           :

In connection with the purchase of the above-listed Securities, the undersigned
Optionee represents to the Company the following:

          (a) Optionee is aware of the Company's business affairs and financial
condition and has acquired sufficient information about the Company to reach an
informed and knowledgeable decision to acquire the Securities. Optionee is
acquiring these Securities for investment for Optionee's own account only and
not with a view to, or for resale in connection with, any "distribution" thereof
within the meaning of the Securities Act of 1933, as amended (the "Securities
Act").

          (b) Optionee acknowledges and understands that the Securities
constitute "restricted securities" under the Securities Act and have not been
registered under the Securities Act in reliance upon a specific exemption
therefrom, which exemption depends upon, among other things, the bona fide
nature of Optionee's investment intent as expressed herein. In this connection,
Optionee understands that, in the view of the Securities and Exchange
Commission, the statutory basis for such exemption may be unavailable if
Optionee's representation was predicated solely upon a present intention to hold
these Securities for the minimum capital gains period specified under tax
statutes, for a deferred sale, for or until an increase or decrease in the
market price of the Securities, or for a period of one year or any other fixed
period in the future. Optionee further understands that the Securities must be
held indefinitely unless they are subsequently registered under the Securities
Act or an exemption from such registration is available. Optionee further
acknowledges and understands that the Company is under no obligation to register
the Securities. Optionee understands that the certificate evidencing the
Securities will be imprinted with a legend which prohibits the transfer of the
Securities unless they are registered or such registration is not required in
the opinion of counsel satisfactory to the Company and with any other legend
required under applicable state securities laws.

          (c) Optionee is familiar with the provisions of Rule 701 and Rule 144,
each promulgated under the Securities Act, which, in substance, permit limited
public resale of "restricted securities" acquired, directly or indirectly from
the issuer thereof, in a non-public offering subject to the satisfaction of
certain conditions. Rule 701 provides that if the issuer qualifies under Rule
701 at the time of the grant of the Option to the Optionee, the exercise will be
exempt from registration

                                       1

2000 Stock Plan Exercise Notice
<PAGE>

under the Securities Act. In the event the Company becomes subject to the
reporting requirements of Section 13 or 15(d) of the Securities Exchange Act of
1934, ninety (90) days thereafter (or such longer period as any market stand-off
agreement may require) the Securities exempt under Rule 701 may be resold,
subject to the satisfaction of certain of the conditions specified by Rule 144,
including: (1) the resale being made through a broker in an unsolicited
"broker's transaction" or in transactions directly with a market maker (as said
term is defined under the Securities Exchange Act of 1934); and, in the case of
an affiliate, (2) the availability of certain public information about the
Company, (3) the amount of Securities being sold during any three month period
not exceeding the limitations specified in Rule 144(e), and (4) the timely
filing of a Form 144, if applicable.

                  In the event that the Company does not qualify under Rule 701
at the time of grant of the Option, then the Securities may be resold in certain
limited circumstances subject to the provisions of Rule 144, which requires the
resale to occur not less than one year after the later of the date the
Securities were sold by the Company or the date the Securities were sold by an
affiliate of the Company, within the meaning of Rule 144; and, in the case of
acquisition of the Securities by an affiliate, or by a non-affiliate who
subsequently holds the Securities less than two years, the satisfaction of the
conditions set forth in sections (1), (2), (3) and (4) of the paragraph
immediately above.

            (d) Optionee further understands that in the event all of the
applicable requirements of Rule 701 or 144 are not satisfied, registration under
the Securities Act, compliance with Regulation A, or some other registration
exemption will be required; and that, notwithstanding the fact that Rules 144
and 701 are not exclusive, the Staff of the Securities and Exchange Commission
has expressed its opinion that persons proposing to sell private placement
securities other than in a registered offering and otherwise than pursuant to
Rules 144 or 701 will have a substantial burden of proof in establishing that an
exemption from registration is available for such offers or sales, and that such
persons and their respective brokers who participate in such transactions do so
at their own risk. Optionee understands that no assurances can be given that any
such other registration exemption will be available in such event.

                                             Signature of Optionee:

                                             ___________________________________

                                             Date:______________________________

                                        2