Transdermal drug delivery using ultrasound-theory, understanding and critical analysis.

This review focuses on a unique transdermal drug delivery enhanced by the action of ultrasound, referred as sonophoresis. Sonophoresis is an active form of transdermal delivery which enhances the transport of permeants, such as drugs through cell membranes as a result of ultrasonic energy. Ultrasonic sound waves cause acoustic cavitation, the resultant effects of which microscopically disrupt the lipid bilayers of the stratum corneum and thereby influencing the influx of permeants. Sonophoresis increases the penetration of various low molecular weight drugs as well as high molecular weight proteins. The objective of this review is to account the role of ultrasound parameters and the associated cavitational effects, gained through a number of investigations, in order to facilitate the understanding of this method.