Synthesis, acoustic stability, and pharmacologic activities of papaverine-loaded echogenic liposomes for ultrasound controlled drug delivery.

Background: development of encapsulated therapeutics that could be released upon ultrasound exposure has strong implications for enhancing drug effects at the target site. We have developed echogenic liposomes (ELIP) suitable for ultrasound imaging of blood flow and ultrasound-mediated intravascular drug release. Papaverine was chosen as the test drug because its clinical application requires high concentration in the target vascular bed but low concentration in the systemic circulation.