Physical and chemical penetration enhancers in transdermal drug delivery system

There is considerable interest in the skin as a site of drug application for both local and systemic effect. However, the skin, in particular the stratum corneum, possesses a formidable barrier to drug penetration thereby limiting topical and transdermal bioavailability. Skin penetration enhancement techniques have been developed to improve bioavailability and to increase the range of drugs for which topical and transdermal delivery is a viable option. The permeation of drug through skin can be enhanced by both chemical penetration enhancement and physical methods. In this review, we have discussed the physical and chemical penetration enhancement technology for transdermal drug delivery as well as the probable mechanisms of action.