ASSET PURCHASE AGREEMENT

Exhibit 2.2

ASSET PURCHASE AGREEMENT

     ASSET PURCHASE AGREEMENT dated as of the 14th day of September, 2007, by and between Sontra Medical Corporation, a Minnesota Corporation having its principal office at 10 Forge Parkway, Franklin, Massachusetts 02038 (“Buyer”), and DP Pharmaceuticals, LLC, a North Carolina limited liability company, having its principal office at 4364 South Alston Avenue, Durham, North Carolina 27713 (“Seller”).

     WHEREAS, Seller is the owner of a package of proprietary information which has been filed with the United States Food and Drug Administration (the “FDA”) known as Drug Master File No. 4670 (“DMF 4670”), a Type V Drug Master File (non-clinical), related to toxicology studies for the development of a product known as Azone (the “Product”) and certain trademarks and trademark applications, set forth on Schedule A attached hereto, related to the Product (together with DMF 4670, the “Assets”); and

     WHEREAS, Seller desires to sell and Buyer desires to purchase all of Seller’s right, title and interest in and to the Assets, on the terms and subject to the conditions herein set forth;

     NOW, THEREFORE, in consideration of the premises and the mutual covenants, agreements, representations and warranties herein set forth, and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto, intending to be legally bound, agree as follows:

ARTICLE I
DEFINITIONS

     Section 1.1 Definition of Terms : Except where otherwise expressly indicated, the terms defined in this Section 1.1, whenever used in this Agreement, shall have the respective meanings indicated below.

     “ Agreement ”: means this Asset Purchase Agreement.

     “ Consent ”: means any consent, approval, authorization, waiver, permit, grant, franchise, concession, agreement, license, exemption or order of, registration, certificate, declaration or filing by or with, or report or notice to, any Person, including any governmental authority.

     “ Encumbrance ”: means any mortgage, pledge, deed of trust, hypothecation, right of others, claim, security interest, encumbrance, grant, assignment, transfer, set over, conveyance, sale, lease, sublease, license, sublicense, agreement, adverse claim, right, title or interest, imperfection or defect in title, easement, assessment, covenant, encroachment, burden, title retention agreement, voting trust agreement, interest, equity, option, lien, right of first refusal, charge, liability, debt, duty or obligation or other restriction or limitation of any kind.

     “ Person ”: means any natural person, firm, partnership, association, corporation, company, limited liability company, trust, business trust, governmental authority or other entity.

ARTICLE 2
SALE AND PURCHASE OF ASSETS

     Section 2.1 Assets . Upon the terms and subject to the conditions set forth in this Agreement, Seller hereby sells, assigns, grants, conveys, delivers or otherwise transfers to Buyer, and Buyer hereby purchases from Seller, all of Seller’s right, title and interest in the Assets.

     Section 2.2 Effective Date and Closing Date . The Effective Date of this Agreement and the Closing Date of this Agreement shall be the date this Agreement is fully executed by the Buyer and the Seller.

ARTICLE 3
CONVEYANCES AND TRANSFER

     Section 3.1 FDA Notification . The Seller shall provide the necessary regulatory documents to the FDA, in the form generally required by the FDA, informing the FDA of the transfer of ownership in connection with the transactions contemplated by this Agreement, including, but not limited to, a letter signed by an authorized representative of Seller with substantially the following information:

	(a)		Name of Buyer or its designee as transferee;
	(b)		Address of Buyer or its designee transferee;
	(c)		Name of responsible official or representative of Buyer or its designee as transferee;
	(d)		Effective date of transfer pursuant to this Agreement;
	(e)		Signature of the authorized representative of Seller effecting the transfer; and
	(f)		Typewritten name and title of the authorized representative of Seller effecting the transfer.

     Section 3.2 Trademarks, Etc . The Seller shall file the Assignment of Trademarks, in substantially the form attached hereto as Exhibit A , with the United States Patent and Trademark Office (“PTO”) and shall make such other filings and take such other actions as is generally required by the PTO to transfer and assign the ownership of the trademarks and trademark applications set forth on Schedule I .

     Section 3.3 Conveyances . At any time and from time to time after the Closing Date, Seller will, upon the request of Buyer and at Buyer’s expense, do, execute, acknowledge and deliver, or will cause to be done, executed, acknowledged or delivered, all such further acts, deeds, assignments, grants, transfers, conveyances, powers of attorney or assurances as may reasonably be required by Buyer to confirm in Buyer the assignment, transfer, grant or conveyance of the Assets to Buyer.

ARTICLE 4
THE PURCHASE PRICE AND PAYMENT THEREOF

     Section 4.1 Purchase Price . The purchase price to be paid by Buyer to Seller for the Assets shall be Sixty Thousand US Dollars (US $60,000.00). The Purchase Price shall be paid in cash to Seller on the Closing Date by wire transfer or such other means as may be agreed to by the parties.

     Section 4.2 No Liabilities . Except as otherwise provided in Section 7.2, Buyer will not assume, an