**Exhibit 10.23**

**ROYALTY TERMINATION AGREEMENT**

**THIS ROYALTYTERMINATION AGREEMENT** (this “Agreement”) is made as of November 17, 2010, by and between BIOVEST INTERNATIONAL, INC., a Delaware corporation (“Biovest”), and ACCENTIA BIOPHARMACEUTICALS, INC., a Floridacorporation (“Accentia”). 

**RECITALS**

**WHEREAS**, pursuant to that certain Royalty Agreement dated as of October 31, 2006, as amended by a letteragreement dated February 5, 2008 (the “Royalty Agreement”), by and between Biovest and Accentia, Biovest granted to Accentia a royalty equal to nineteen and one-half percent (19.5%) of net sales and licensing revenuereceived by Biovest from any Biovest Biologic Products (the “Royalty”); 

**WHEREAS**,pursuant to that certain Term Loan and Security Agreement (the “Security Agreement”) dated as of November 17, 2010, by and among Biovest, the Lenders party thereto and Agent, the parties hereto, in consideration for theacceptance by certain of the Prepetition Lenders of the allowed secured claims against Biovest as provided therein and other consideration, have agreed, among other things, to the termination of the Royalty Agreement and the Royalty; and 

**WHEREAS**, pursuant to the terms and conditions of the Security Agreement and the Confirmed Plan, Biovest andAccentia hereby desire to terminate the Royalty Agreement and the Royalty effective as of the date of this Agreement. 

**NOW, THEREFORE**, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto hereby agree as follows: 

1.         Capitalized terms used but not defined herein shall have the meaningsascribed to them in the Security Agreement. 

2.         The partieshereto agree that the above Recitals are true and correct in all respects. 

3.        The parties hereto hereby consent to the termination of the Royalty Agreement and the Royalty (and all of the rights and obligations created thereunder) effective as of the date of this Agreement.

4.         Accentia hereby acknowledges and agrees that it shall haveno claims of any nature whatsoever against Biovest as a result of the termination of the Royalty Agreement and the Royalty. 

5.         This Agreement shall be binding upon the parties hereto and their respective successors and assigns. The parties hereto agree that this Agreement isfully and adequately supported by consideration, is fair and reasonable, and that they have had the opportunity to discuss this matter with counsel of their choice. This Agreement may be executed in one or more counterparts, each of which shall bedeemed an original and all of which together shall be deemed to constitute one agreement. It is understood and agreed that if facsimile copies of this Agreement bearing facsimile signatures are exchanged between the parties hereto, such copies

 
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shall in all respects have the same weight, force and legal effect and shall be fully as valid, binding, and enforceable as if such signed facsimile copies were original documents bearingoriginal signature. 

6.         THIS AGREEMENT SHALL BE GOVERNED BY,AND CONSTRUED, INTERPRETED AND ENFORCED ACCORDING TO, THE LAWS OF THE STATE OF FLORIDA, WITHOUT REGARD TO PRINCIPLES OF CONFLICT OF LAWS PROVISIONS THEREOF. ANY ACTION BROUGHT CONCERNING THE TRANSACTIONS CONTEMPLATED BY THIS AGREEMENT SHALL BEBROUGHT ONLY IN THE STATE COURTS OF FLORIDA OR IN THE FEDERAL COURTS LOCATED IN THE STATE OF FLORIDA. The prevailing party shall be entitled to recover from the other party its reasonable attorneys’ fees and costs. Wherever possible eachprovision of this Agreement shall be interpreted in such manner as to be effective and valid under applicable law, but if any provision of this Agreement shall be prohibited by or invalid under such law, such provision shall be ineffective to theextent of such prohibition or invalidity, without invalidating the remainder of such provision or the remaining provisions of this Agreement. 

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**IN WITNESS WHEREOF**, the undersigned have executed this RoyaltyTermination Agreement as of the date first above written. 

 
BIOVEST INTERNATIONAL, INC.By: 
/s/ David Moser
Name: David MoserTitle: SecretaryACCENTIA BIOPHARMACEUTICALS, INC.By: 
/s/ Samuel S. Duffey
Name: Samuel S. DuffeyTitle: President
 
ACCEPTED AND AGREED:LV ADMINISTRATIVE SERVICES, INC.By: 
/s/ Patrick Regan
Name: Patrick ReganTitle: Authorized SignatoryLAURUS MASTER FUND, LTD. (IN LIQUIDATION)By: 
/s/ Russell Smith
Name: Russell SmithTitle: Joint Official Liquidator (with no personal liability)VALENS U.S. SPV I, LLCBy: 
/s/ Patrick Regan
Name: Patrick ReganTitle: Authorized SignatoryVALENS OFFSHORE SPV I, LTD.By: 
/s/ Patrick Regan
Name: Patrick ReganTitle: Authorized SignatoryVALENS OFFSHORE SPV II, CORP.By: 
/s/ Patrick Regan
Name: Patrick ReganTitle: Authorized SignatoryPSOURCE STRUCTURED DEBT LIMITED
By: PSource Capital Ltd., It’s Investment Consultant
By:
 
/s/ Charles Lews

Name: Charles Lews

Title: Authorized Signatory