Acusphere Receives U.S. Patent For Drug Delivery Technology.

Technology Enables Efficient Controlled-Release of Hydrophobic Drugs

WATERTOWN, Mass. -- Acusphere, Inc. announced today the issuance of U.S. Patent No. 7,160,557 B2, entitled "Matrices Formed of Polymer and Hydrophobic Compounds for Use in Drug Delivery." The patent covers the sustained drug release features of Acusphere's porous microparticle formulations using a biodegradable shell material. These porous microparticle formulations have tightly controlled size distributions, and can allow drugs to be released over periods of time ranging from days to weeks by intravenous, inhalation, subcutaneous, or oral routes of administration. The technology is applicable to both water soluble and water insoluble drugs.

"Controlled-release of drug delivery represents an intriguing potential application for our technology and this new patent expands Acusphere's intellectual property protection in this important area," commented Sherri C. Oberg, President and CEO of Acusphere. "There are many drugs currently on the market and many more in development that do not have ideal delivery characteristics and could potentially benefit from controlled release reformulation. We are actively investigating ways to couple our technology with such drugs as we look to expand our product pipeline."

About Acusphere, Inc.

Acusphere (NASDAQ: ACUS) is a specialty pharmaceutical company that develops new drugs and improved formulations of existing drugs using its proprietary microsphere technology. Acusphere's three initial product candidates are designed to address large unmet clinical needs within cardiology, oncology and asthma. These product candidates were created using proprietary technology that enables Acusphere to control the porosity and size of nanoparticles and microspheres in a versatile manner that allows them to be customized to address the delivery needs of a variety of drugs. Acusphere's lead product candidate, Imagify[TM] (perflubutane polymer microspheres) injectable suspension, is a cardiovascular drug in Phase 3 clinical development. Imagify is designed to enable ultrasound to compete more effectively with nuclear stress testing, the leading procedure for detecting coronary heart disease. An estimated 11.9 million procedures are done each year in the U.S. to detect coronary heart disease, the leading cause of death in the United States. For more information about Acusphere visit the Company's web site at www.acusphere.com. "Acusphere" is a trademark of Acusphere, Inc.

Forward-looking Statements

The above press release contains forward-looking statements regarding the application of Acusphere's proprietary microparticle technology which are made pursuant to the safe harbor provisions of Section 21E of the Securities Exchange Act of 1934. Investors are cautioned that statements in this press release, including statements relating to the opportunity from application of the Company's controlled-release technology and the benefits that may be derived from the application of such technology, constitute forward-looking statements which involve risks and uncertainties. The Company's actual results may differ materially from those anticipated in these forward-looking statements based upon a number of factors, including anticipated operating losses and existing capital obligations, uncertainties associated with research, development, testing and related regulatory approvals, including uncertainties regarding the ultimate outcome of Acusphere's Phase 3 clinical trials for Imagify and uncertainties regarding the number of patients required to complete the Phase 3 clinical trials, unproven markets, future capital needs and uncertainty of additional financing, lack of sales and marketing experience, uncertainties regarding the cost, timing and ultimate success of the qualification of the Company's commercial manufacturing facility in accordance with applicable regulatory requirements, complex manufacturing,

high quality requirements, lack of commercial manufacturing experience, dependence on third-party manufacturers, suppliers and collaborators, competition, uncertainties associated with intellectual property, loss of key personnel, uncertainties associated with market acceptance and adequacy of reimbursement, technological change and government regulation, and other risks and challenges detailed in the Company's filings with the U.S. Securities and Exchange Commission, including the Company's Quarterly Report on Form 10-Q for the quarter ended September 30, 2006. Readers are cautioned not to place undue reliance on any forward-looking statements, which speak only as of the date of this press release. The Company undertakes no obligation to publicly release the results of any revisions to these forward-looking statements that may be made to reflect events or circumstances that occur after the date of this press release or to reflect the occurrence of unanticipated events.