BOSTON, Feb. 24, 2005 – Acusphere, Inc. (NASDAQ: ACUS), today announced that it closed its public offering of 6.5% convertible exchangeable preferred stock for estimated net proceeds of approximately $41.5 million, after deducting underwriting discounts and commissions and estimated offering expenses. Acusphere is a specialty pharmaceutical company that develops new drugs and improved formulations of existing drugs using its proprietary microparticle technology.