Delivery of drugs with ultrasound

In this article we discuss the potential role of microbubbles, traditionall y used as ultrasound contrast agents, for site-specific drug delivery. To r each this goal, microbubbles capable of carrying a drug payload are being d eveloped. To ensure that these microbubbles reach sufficient local concentr ation at disease sites, specific targeting for diseased tissues can be acco mplished using several strategies. These strategies rely on either the intr insic properties of microbubble shells or conjugation of monoclonal antibod ies or other ligands to these shells that recognize antigens expressed in r egions of disease. Site-specific delivery of antiinflammatory, antineoplast ic, and thrombolytic drugs with microbubbles can be further enhanced by the ability to locally destroy microbubbles within an acoustic field, thereby releasing drugs and improving drug efficacy without systemic adverse effect s. In the case of thrombi, ultrasound-mediated microbubble destruction also may facilitate the process of clot Lysis. This review also will consider c urrent limitations and technological advances required for the development of this field.