**Exhibit 4.3**

 

**FORM OF SECURED PROMISSORY NOTE**

 

| **$[Amount]** |   | **[Date]** |
|---------------|--------|------------|

 

Forvalue received, Photogen Technologies, Inc., a Nevada corporation (the“Company”), hereby absolutely and unconditionally promises to pay to the orderof                                      ,or registered assigns (the “Payee”), the principal sum of[$                     ],together with interest thereon, in lawful money of the United States, all ashereinafter provided.

 

**Section 1.****                 ****Payable on Demand.**  The entire principal amount hereof, togetherwith all interest incurred thereon and all fees and expenses (if any) duehereunder, shall be due and payable ON DEMAND. The Payee’s right to make such demand shall be unconditional andunlimited.  The Company agrees that thePayee may make such demand in the exercise of the Payee’s sole discretion.  The Company agrees that, in exercising itsdiscretion, the Payee may make demand for any reasons that it deemsappropriate, and such reasons may be related or unrelated to the Company, itsbusiness or financial condition or prospects. The Payee’s right to make demand shall be a continuing right, andacceptance by the Payee of any payment after demand shall not be deemed awaiver of such right to make demand on any other occasion.

 

**Section 2.****                 ****Interest Rate.**  The unpaid principal balance outstanding,from time to time, hereunder shall accrue interest at a rate equal to 7.25% perannum.  Interest shall be compoundedmonthly and shall be computed on the basis of a 360-day year and a 30-daymonth.  Notwithstanding any otherprovision of this Note, the Payee does not intend to charge and the Companyshall not be required to pay any interest or other fees or charges in excess ofthe maximum permitted by applicable law; and any payments in excess of such maximumshall be refunded to the Company or credited to reduce principal hereunder.

 

**Section 3.****                 ****Place and Manner of Payment.**  Principal and interest shall be payable inlawful money of the United States of America, at[                                  ]or at such other address as the Payee or any subsequent holder may designatefrom time to time to the Company in writing. If any day on which a payment is due pursuant to the terms of this Noteis not a business day, such payment shall be due on the next business dayfollowing.  Should all or any part ofthe indebtedness represented by this Note be collected by action at law, or inbankruptcy, insolvency, receivership or other court proceedings, or should thisNote be placed in the hands of attorneys for collection after default, theCompany hereby promises to pay to the Payee, upon demand by the Payee at anytime, in addition to the outstanding principal balance of, accrued interest andall (if any) other amounts payable on or in respect of this Note, all courtcosts and reasonable attorneys’ fees and other collection charges and expensesincurred or sustained by the Payee.  Allpayments received by the Payee hereunder will be applied first to costs ofcollection and fees, if any, then to interest and the balance to principal.

 

**Section 4.****                 ****Security for Note.**  This Note is secured by that certainSecurity Agreement, dated as of May 1, 2003, as amended on June 9, 2003and August 12, 2003; Intellectual Property Security Agreement, dated as ofMay 1, 2003, as amended on June 9, 2003 and August 12, 2003; SecurityAgreement dated as of June 18, 2003, as amended on August 12, 2003;and Patent

 

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and Trademark SecurityAgreement, dated as of June 18, 2003 as amended on August 12, 2003(collectively, the “Security Agreements”). The Security Agreements grant the Payee certain rights with respect tothe Collateral upon an Event of Default (as defined in each of the SecurityAgreements).

 

**Section 5.****                 ****No Waiver; Remedies Cumulative.**  No failure or delay in exercising any rightor remedy hereunder operates as a waiver thereof.  No single or partial exercise of any right or remedy hereunderprecludes any other or further exercise of any right or remedy hereunder orthereunder.  The exercise of any rightor remedy hereunder does not preclude the simultaneous or later exercise of anyother rights or remedies available at law or in equity.  No amendment or waiver of any provision ofthis Note, nor consent to any departure by Company herefrom, shall in any eventbe effective unless the same shall be in writing and signed by Payee, and thensuch waiver or consent shall be effective only in the specific instance and forthe specific purpose for which given.

 

**Section 6.****                 ****Governing Law. **This Note, and all matters arising directly orindirectly herefrom, shall be governed by and construed in accordance with thelaws of the Commonwealth of Massachusetts, notwithstanding the choice of law orconflicts of law principles thereof. This Note shall have the effect of a sealed instrument.  Company and, by accepting this Note, thePayee hereby (a) irrevocably consent and submit to the sole exclusivejurisdiction of the state and federal courts located in the Commonwealth ofMassachusetts in connection with any suit, action or other proceeding directlyor indirectly arising out of or relating to this Note, and (b) irrevocablywaive, to the fullest extent permitted by law, any objection that it may now orhereafter have to the laying of the venue of any such suit, action orproceeding in any such court or that any such suit, action or proceeding whichis brought in any such court has been brought in an inconvenient forum.

 

**Section 7.****                 ****Headings.**  All headings in this Agreement are forconvenience of reference only and do not affect the meaning of any provision.

 

**Section 8.****                 ****Partial Invalidity. **In the event any one or more of the provisionsof this Note shall for any reason be held to be invalid, illegal orunenforceable, in whole or in part or in any respect, or in the event that anyone or more of the provisions of this Note operate or would prospectivelyoperate to invalidate this Note, then and in any such event, such provision(s)only shall be deemed null and void and shall not affect any other provision ofthis Note and the remaining provisions of this Note shall remain operative andin full force and effect and in no way shall be affected, prejudiced, ordisturbed thereby.  The Company will atall times in good faith assist, insofar as it is able, in the carrying out ofall of the provisions of this Note in a reasonable manner and in the taking ofall other action which may be necessary in order to protect and preserve therights of the Payee set forth herein.

 

**Section 9.****                 ****Waivers.**  Company hereby expressly and irrevocablywaives notice of acceptance, presentment, demand, notice of nonpayment, demandfor payment, protest, notice of protest, notice of dishonor, suit and all otherconditions precedent in connection with the delivery, acceptance, collectionand/or enforcement of this Note or any collateral or security therefor.

 

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**Section 10.****          ****Successors and Assigns.**  This Note shall be binding on Company andits successors and assigns and shall inure to the benefit of Payee and itssuccessors and assigns.  The term“Payee” in this Note shall refer to the person originally holding this Note orto any other future holder of this Note.

 

**Section 11.****          ****No Jury Trial. **THE COMPANY HEREBYKNOWINGLY, VOLUNTARILY AND INTENTIONALLY WAIVES ANY RIGHTS IT MAY NOW HAVE ORHEREAFTER HAVE TO A TRIAL BY JURY IN RESPECT TO ANY SUIT, ACTION OR PROCEEDINGARISING OUT OF OR RELATING TO THIS NOTE.

 

**IN WITNESS WHEREOF,** the Company has causedthis Note to be duly executed and delivered as of the date first written above.

 
|   | **PHOTOGEN TECHNOLOGIES, INC.** |
|--------|---------------------------------|
|   |                            |
|   |                            |
|   |                            |   |
|   | By:                        | Taffy Williams |
|   | Its:                       | Chief Executive Officer |
|        |                                 |  |  |

 

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