Ultrasound contrast agents used for localized drug delivery

The delivery of chemotherapy can be improved and localized using engineered drug delivery vehicles. Localized drug delivery would decrease the systemic side effects of toxic chemotherapy drugs. The unique delivery agents we are examining are provided by ImaRx Pharmaceuticals, and consist of an outer lipid shell with an inner oil layer and a gas core. The three microsphere types investigated contained soybean oil, corn oil, and triacetin, within the outer layer. These structures are 0.5-8 /spl mu/m in diameter at rest and thus can carry a large payload compared to nanoscale drug delivery systems. The oil shells of these delivery agents can be loaded with paclitaxel or other hydrophobic drugs. Oil layers of these acoustically active lipospheres range from 0.3-1.5 /spl mu/m in thickness. We show these drug delivery vehicles can be fragmented using ultrasound thus releasing their payload in a localized area.