PHYSICAL APPROACH TO TRANSDERMAL DRUG DELIVERY: A REVIEW

Abstract

Transdermal drug delivery system (TDDS) is the topically administered medication, which when applied to the skin, delivers the drug through the skin for systemic effect at a predetermined and controlled rate. For the drugs, having the short biological half-life, transdermal drug delivery system is convenient. It overcomes the problems like the hepatic first pass effect, improves the compliance of patients, decreases the administration frequency, and reduce the gastrointestinal side effects, peak and valley levels in the blood are avoided. Due to having an advantage of being non-invasive, this delivery has to fulfill some parameters such as high potency, better permeability through skin and non-irritation for better compliance. Skin serves as a site of drug application for local effect as well as systemic effect. There are wide varieties of drugs for which topical or transdermal is a viable option, skin penetration enhancement techniques have been developed for such drugs. There are a number of physical methods to increase drug delivery via the skin, many of which require the use of devices and some of which hold the promise to significantly expand the spectrum of drugs that can be administered transdermally to include water-soluble molecules and macromolecules. Iontophoresis and electroporation represent electrically assisted, physical approaches to enhance delivery of drugs/macromolecules across the stratum corneum. This review highlights the detailed role of physical penetration and describes their mechanism of action. Keywords: transdermal drug delivery system, stratum corneum, skin penetration enhancer, physical enhancer, iontophoresis.