Exhibit 4.5

# GUARANTY AND SECURITY
AGREEMENT

THIS
 GUARANTY  AND  SECURITY  AGREEMENT  dated as of November  20,  2003,  is made by and
among  Alliance Pharmaceutical  Corp.,  a  New  York  corporation  ("Guarantor"),  and
 Technology  Gateway  Partnership,  L.P.,  a California limited partnership ("Secured
Party").

# RECITALS

A.                 The
Secured Party has made an advance of money to PFC Therapeutics, LLC           (PFC),
a wholly-owned subsidiary of the           Guarantor, as evidenced by that certain
Secured Convertible Note executed by PFC           in favor of the Secured Party (the
Note), such           advance being referred to herein
as the Loan.

B.                 The
Secured Party is willing to make the Loan to Guarantor, but only upon the
          condition, among others, that Guarantor shall have executed and delivered to
the           Secured Party this Agreement.

# AGREEMENT

NOW,
THEREFORE, in order to induce the Secured Party to make the Loan and for other good
and valuable consideration, the receipt and adequacy of which are hereby acknowledged, and
intending to be legally bound, Guarantor hereby represents, warrants, covenants and agrees
as follows:

1.    DEFINED
TERMS. When used in this Agreement the following terms shall have           the
following meanings (such meanings being equally applicable to both the           singular
and plural forms of the terms defined):

Collateral
shall have the meaning assigned to such term in Section 4 of this Agreement.

Earnout
means the right of Guarantor to receive royalty payments from the sale of Imagent
products pursuant to that certain Asset Purchase Agreement dated June 18, 2003 by and
between Guarantor and Photogen Technologies, Inc. (the Asset Purchase
Agreement)

Event
of Default means (i) any failure by Guarantor forthwith to pay or
perform any of the Secured Obligations and, (ii) any breach by Guarantor of any warranty,
representation, or covenant set forth herein.

Lien
means any mortgage, lien, deed of trust, charge, pledge, security interest or other
encumbrance.

Secured
Obligations means (a) the right of the Secured Party to receive a
portion of the Earnout pursuant to Section 3 of this Agreement, (b) the obligation of
Guarantor to pay the Secured Party all amounts due under the Note and this Agreement, (c)
the obligation of Guarantor to pay any fees, costs and expenses of the Secured Party under
Section 7(b) hereof, and (d) the obligation of PFC to pay any fees, costs and
expenses of the Secured Party under the Security Agreement executed by PFC in favor of
Secured Party.

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Agreement
means this Guarantee and Security Agreement, as the same may from time to time be amended,
modified, supplemented or restated.

UCC
means the Uniform Commercial Code as the same may from time to time be in effect in the
State of California (and each reference in this Agreement to an Article thereof
(denoted as a Division of the UCC as adopted and in effect in the State of California)
shall refer to that Article (or Division, as applicable) as from time to time in
effect, which in the case of Article 9 shall include and refer to Revised
Article 9 from and after the date Revised Article 9 shall become effective in
the State of California); provided, however, in the event that, by reason of
mandatory provisions of law, any or all of the attachment, perfection or priority of the
Secured Partys security interest in any Collateral is governed by the Uniform
Commercial Code as in effect in a jurisdiction other than the State of California, the
term UCC shall mean the Uniform Commercial Code (including the Articles
thereof) as in effect at such time in such other jurisdiction for purposes of the
provisions hereof relating to such attachment, perfection or priority and for purposes of
definitions related to such provisions. In addition, the term Proceeds shall
be a defined term having the meaning set forth for such term in the UCC, and shall include
all Proceeds now owned, or hereafter acquired, by Guarantor.

2.    GRANT
OF GUARANTEE. Guarantor hereby irrevocably, absolutely and
          unconditionally guarantees full and prompt performance of the Secured
          Obligations to the Secured Party and its successors and assigns. Upon the
          execution and delivery of this Agreement to the Secured Party, this Agreement
          shall be deemed to be finally executed and delivered by the Guarantor and
except           as expressly set forth herein shall not be subject to or affected by any
promise           or condition affecting or limiting the Guarantors liability, and
no           statement, representation, agreement or promise on the part of the Secured
          Party, unless contained herein, forms any part of this Agreement or has induced
          the making hereof or shall be deemed in any way to affect the Guarantors
          liability hereunder. Guarantor acknowledges and agrees that any obligation(s)
of           PFC to Guarantor, or any affiliate of Guarantor, are subordinate to the
Secured           Obligations. Guarantors liability hereunder shall continue
          notwithstanding, and shall be unaltered, unaffected and unimpaired by, the
          bankruptcy, insolvency, reorganization, liquidation, dissolution, winding-up or
          cessation of the existence of PFC.

3.    ABSOLUTE
ASSIGNMENT. Guarantorhereby irrevocably, absolutely           and
unconditionally collaterally assigns to the Secured Party 100% of the           Earnout,
up to an aggregate maximum amount of $500,000, to be paid to Oxygent           Creditors
(as defined in the Asset Purchase Agreement) after January 1, 2006           pursuant to
Section 1.3 of the Asset Purchase Agreement. In connection           therewith, the
Secured Party shall be an Oxygent           Creditor for
all purposes under this Agreement and the           Asset Purchase Agreement. This
Section 2 shall survive the termination of this           Agreement.

4.    GRANT
OF SECURITY INTEREST. As collateral security for the full, prompt,           complete
and final payment and performance when due (whether at stated maturity,           by
acceleration or otherwise) of all the Secured Obligations and in order to
          induce the Secured Party to cause the Loan to be made, Guarantor hereby
          collaterally assigns, conveys, mortgages, pledges, hypothecates and transfers
to           the Secured Party, a security interest in all of Guarantors right,
title           and interest in, to and under the following, whether now owned or
hereafter           acquired, (all of which being collectively referred to herein as the
          Collateral):

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(a)              The
Earnout;

(b)              All
Proceeds of the foregoing and all accessions to, substitutions and           replacements
for and rents, profits and products of the foregoing.

5.    REPRESENTATIONS
AND WARRANTIES. Guarantor hereby represents and warrants           to the Secured
Party that:

(a)              Except
for the security interest granted to the Secured Party under this           Agreement,
Guarantor is the sole legal and equitable owner of each item of the           Collateral
in which it purports to grant a security interest hereunder.

(b)              No
effective security agreement, financing statement, equivalent security or           lien
instrument or continuation statement covering all or any part of the           Collateral
exists, except such as may have been filed by Guarantor in favor of           the Secured
Party pursuant to this Agreement.

(c)              This
Agreement creates a legal and valid security interest on and in all of the
          Collateral in which Guarantor now has rights.

(d)              Guarantors
taxpayer identification number is, and chief executive office,           principal place
of business, and the place where Guarantor maintains its records           concerning the
Collateral are presently located at the address set forth on the           signature page
hereof.

(e)              In
the event the Company does not (i) receive a commitment for a Financing (as
          defined below) by January 15, 2004, and (ii) close a Financing by January 31,
          2004, Guarantor agrees to vote all of its units of membership interest of PFC
in           favor of amending PFCs Limited Liability Company Operating Agreement
to           provide that Secured Party shall have the right to designate a majority of
the           members of PFCs Board of Managers.

6.    COVENANTS.
Unless the Secured Party otherwise consents (which consent           shall not be
unreasonably withheld), Guarantor covenants and agrees with the           Secured Party
that from and after the date of this Agreement and until the           Secured
Obligations have been performed and paid in full:

(a)              Guarantor
shall not sell, lease, transfer or otherwise dispose of any of the           Collateral
(each, a Transfer), or attempt or           contract to
do so.

(b)              Guarantor
shall not change its jurisdiction of organization or relocate its           chief
executive office, principal place of business or its records from such
          address(es) provided to the Secured Party pursuant to Section 5(d)          above
without at least seven (7) days prior notice to the Secured Party.

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(c)              Guarantor
shall not, directly or indirectly, create, permit or suffer to exist,           and shall
defend the Collateral against and take such other action as is           necessary to
remove, any Lien on the Collateral, except the Lien granted to the           Secured
Party under this Agreement.

(d)              At
any time and from time to time, upon the written request of the Secured           Party,
and at the sole expense of Guarantor, Guarantor shall promptly and duly           execute
and deliver any and all such further instruments and documents and take           such
further action as the Secured Party may reasonably deem necessary or           desirable
to obtain the full benefits of this Agreement, including, without           limitation,
executing, delivering and causing to be filed any financing or           continuation
statements (including in lieu continuation statements)           under the
UCC with respect to the security interests granted hereby Guarantor           also hereby
authorizes the Secured Party to file any such financing or           continuation
statement (including in lieu continuation statements)           without the
signature of Guarantor.

(e)              Within
thirty (30) days of the execution of this Agreement, Guarantor shall           cause
Photogen to execute and deliver an Acknowledgement substantially in the           form
attached hereto as Exhibit A (the Acknowledgment).

7.    RIGHTS
AND REMEDIES UPON DEFAULT.Beginning on the date which is ten           (10)business
daysafter any Event of Default shall have occurred           and while such Event
of Default is continuing:

(a)              The
Secured Party may exercise in addition to all other rights and remedies           granted
to the Secured Party under this Agreement, all rights and remedies of a           secured
party under the UCC. Without limiting the generality of the foregoing,
          Guarantor expressly agrees that in any such event the Secured Party, without
          demand of performance or other demand, advertisement or notice of any kind
          (except the notice specified below of time and place of public or private sale)
          to or upon Guarantor or any other person, may forthwith collect, receive,
          appropriate and realize upon the Collateral, or any part thereof, and may
          forthwith sell, lease, assign, give an option or options to purchase or sell or
          otherwise dispose of and deliver said Collateral (or contract to do so), or any
          part thereof, in one or more parcels at public or private sale or sales, at any
          exchange or brokers board or at the Secured Partys offices or
          elsewhere at such prices as it may deem commercially reasonable, for cash or on
          credit or for future delivery without assumption of any credit risk. The
Secured           Party shall apply the net proceeds of any such collection, recovery,
receipt,           appropriation, realization or sale as provided in Section 7(d),
below, with           Guarantor remaining liable for any deficiency remaining unpaid
after such           application. Guarantor agrees that the Secured Party need not give
more than           twenty (20) days notice of the time and place of any public
sale or of the           time after which a private sale may take place and that such
notice is           reasonable notification of such matters.

(b)              Guarantor
also agrees to pay all fees, costs and expenses of the Secured Party,
          including, without limitation, reasonable attorneys fees, incurred in
          connection with the enforcement of any of its rights and remedies hereunder.

(c)              Guarantor
hereby waives presentment, demand, protest or any notice (to the           maximum extent
permitted by applicable law) of any kind in connection with this           Agreement or
any Collateral.

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(d)              The
Proceeds of any sale, disposition or other realization upon all or any part           of
the Collateral shall be distributed by the Secured Party in the following           order
of priorities:

FIRST,
to the Secured Party in an amount sufficient to pay in full the reasonable costs of the
Secured Party in connection with such sale, disposition or other realization, including
all fees, costs, expenses, liabilities and advances incurred or made by the Secured Party
in connection therewith, including, without limitation, reasonable attorneys fees;

SECOND,
to the Secured Party in an amount equal to the then unpaid Secured Obligations of the
Secured Party; and

FINALLY,
upon payment in full of the Secured Obligations, to Guarantor or its representatives, in
accordance with the UCC or as a court of competent jurisdiction may direct.

8.    INDEMNITY.
Guarantor agrees to defend, indemnify and hold harmless the           Secured Party and
their officers, employees, and agents against (a) all           obligations, demands,
claims, and liabilities claimed or asserted by any other           party in connection
with the transactions contemplated by this Agreement and (b)           all losses or
expenses in any way suffered, incurred, or paid by the Secured           Party as a
result of or in any way arising out of, following or consequential to
          transactions between or among the Secured Party and Guarantor, whether under
          this Agreement or otherwise (including without limitation, reasonable attorneys
          fees and expenses), except for losses arising from or out of the gross
          negligence or willful misconduct of the Secured Party, as applicable.

9.    REINSTATEMENT.
This Agreement shall remain in full force and effect and           continue to be
effective should any petition be filed by or against Guarantor           for liquidation
or reorganization, should Guarantor become insolvent or make an           assignment for
the benefit of creditors or should a receiver or trustee be           appointed for all
or any significant part of Guarantors property and           assets, and shall
continue to be effective or be reinstated, as the case may be,           if at any time
payment and performance of the Secured Obligations, or any part           thereof, is,
pursuant to applicable law, rescinded or reduced in amount, or must           otherwise
be restored or returned by any obligee of the Secured Obligations,           whether as a
voidable preference, fraudulent conveyance,          or
otherwise, all as though such payment or performance had not been made. In           the
event that any payment, or any part thereof, is rescinded, reduced, restored           or
returned, the Secured Obligations shall be reinstated and deemed reduced only
          by such amount paid and not so rescinded, reduced, restored or returned.

10.    FINANCING. In
the event the Note is not converted in connection with a           Financing, (a) the
Note shall be terminated; and (b) the Guarantor and the           Secured Party shall
take all actions necessary to amend this agreement to (i)           terminate the
guarantee granted pursuant to Section 2 of this Agreement; and           (ii) provide
that Guarantor, pursuant to Section 3 of this Agreement,           irrevocably,
absolutely, and unconditionally collaterally assigns to the Secured           Party 100%
of the Earnout, up to an aggregate maximum amount of $1,500,000, to           be paid to
Oxygent Creditors after January 1, 2006 pursuant to Section 1.3 of           the Asset
Purchase Agreement. For purposes of this Agreement, Financing means
a financing pursuant to which           PFC receives gross proceeds of $10,000,000 (or
such other amount approved by the           Secured Party) from one or more investors,
strategic partners, or other sources           (or any combination of the foregoing). By
way of example, the equity financing           contemplated by the Term Sheet dated
November 7, 2003 by and among Guarantor and           SRS Capital-West, Inc. (as the same
may be amended, modified, supplemented or           restated from time to time) would be
a Financing under this Agreement.

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11.    MISCELLANEOUS.

(a)              Any
amendment of this Agreement shall require the written consent of the           Guarantor
and the Secured Party.

(b)              Subject
to Sections 3 and 9 hereof, this Agreement shall terminate           upon the
payment and performance in full of the Secured Obligations.

(c)              This
Agreement and all obligations of Guarantor hereunder shall be binding upon           the
successors and assigns of Guarantor, and shall, together with the rights and
          remedies of the Secured Party hereunder, inure to the benefit of the Secured
          Party, any future holder of any of the indebtedness and their respective
          successors and assigns. No sales of participations, other sales, assignments,
          transfers or other dispositions of any agreement governing or instrument
          evidencing the Secured Obligations or any portion thereof or interest therein
          shall in any manner affect the lien granted to the Secured Party hereunder.

(d)              In
all respects, including all matters of construction, validity and           performance,
this Agreement and the Secured Obligations arising hereunder shall           be governed
by, and construed and enforced in accordance with, the laws of the           State of
California applicable to contracts made and performed in such state,           without
regard to the principles thereof regarding conflict of laws, except to           the
extent that the UCC provides for the application of the law of           Guarantors
State.

(e)              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.

(f)              Any
and all notices required or permitted to be given to a party pursuant to the
          provisions of this Agreement will be in writing and will be effective and
deemed           to provide such party sufficient notice under this Agreement on the
earliest of           the following: (i) at the time of personal delivery, if
delivery is in           person; (ii) at the time of transmission by facsimile, addressed
to the other           party at its facsimile number specified herein (or hereafter
modified by           subsequent notice to the parties hereto), with confirmation of
receipt made by           both telephone and printed confirmation sheet verifying
successful transmission           of the facsimile; (iii) one (1) business day after
deposit with an express           overnight courier for United States deliveries, or two
(2) business days after           such deposit for deliveries outside of the United
States, with proof of delivery           from the courier requested; or (iv) three (3)
business days after deposit in the           United States mail by certified mail (return
receipt requested) for United           States deliveries. All notices for delivery
outside the United States will be           sent by facsimile or by express courier. All
notices not delivered personally or           by facsimile will be sent with postage
and/or other charges prepaid and properly           addressed to the party to be notified
at the address or facsimile number as           follows, or at such other address or
facsimile number as such other party may           designate by one of the indicated
means of notice herein to the other parties           hereto as follows:

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if
to the Secured Party, at 18881 VonKarman Avenue, Suite 330, Irvine, CA 92612;  Facsimile (949) 752-0223.

if
to the Guarantor,  marked "Attention:  President",  at 6175 Lusk Blvd., San Diego, CA
92121; Facsimile: (858) 410-5306.

[Signature pages
follow.]

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IN
WITNESS WHEREOF, each of the parties hereto has caused this Agreement to be executed
and delivered by its duly authorized officer on the date first set forth above.

|ADDRESS OF GRANTOR                        | Alliance Pharmaceutical Corp.          
|----------------------------------------- | ---------------------------------------
|6175 Lusk Boulevard                       | /s/ Duane J. Roth                      
|San Diego, CA 92121                       | Chairman and Chief Executive Officer   
|TAXPAYER IDENTIFICATION NUMBER OF GRANTOR | JURISDICTION OF ORGANIZATION OF GRANTOR
|                                          | New York                               

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IN
WITNESS WHEREOF, each of the parties hereto has caused this Agreement to be executed
and delivered by its duly authorized officer on the date first set forth above.

# SECURED PARTY:

| | Technology Gateway Partnership, L.P.                                 
| | ---------------------------------------------------------------------
| | /s/ Thomas O. Gephart                                                
| | Thomas O. Gephart, Managing Partner of Ventana Capital Partners, LLC,
| | the General Partner of Technology Gateway Partnership, L.P.          

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# EXHIBIT A

# ACKNOWLEDGEMENT