The use of ultrasound for drug delivery.

Ultrasound has been in use for the last three decades as a modality for diagnostic imaging in medicine. Recent studies have shown that nonthermal ultrasound energy could be applied for targeting or controlling drug release. This new concept of therapeutic ultrasound combined with drugs has induced interest in various medical fields. Enhanced effects of thrombolytic agents such as urokinase and TPA with acoustic energy have been demonstrated. Ultrasound transducer-tipped catheters are being developed for treatment of cardiovascular diseases. Other devices with ultrasound transducers implanted in transdermal drug patches are also being evaluated for possible delivery of insulin through the skin. Echo contrast microbubbles could also be used to carry and release genes to various tissues and lesions. Chemical activation of drugs by ultrasound energy for treatment of cancers is another new field recently termed "sonodynamic therapy." Various examples of ultrasound application are under investigation that could lead to revolutionary drug delivery systems of the future.