Abstract
Transdermal delivery represents an attractive alternative to oral delivery of drugs and is poised to provide an alternative to hypodermic injection too. Transdermal drug delivery system which can deliver medicines via the skin portal to systemic circulation at a predetermined rate and maintain clinically effective concentration over a prolonged period of time. To date many chemical and physical approaches have been applied to increase the efficacy of the material transfer across the intact skin. Improvement in physical permeation-enhancement technologies has led to renewed interest in transdermal drug delivery. Some of these novel advanced transdermal permeation enhancement technologies include: iontophoresis, electroporation, ultrasound, microporation, radiofrequency and microneedles to open up the skin. This review focus on some existing and novel physical approaches intended for skin penetration enhancement of drugs.