Approaches and Current Trends of Transdermal Drug Delivery System-A Review

The human skin is one of the most readily accessible organ/surface of the human body for drug delivery. Skin of an average adult body covers a surface of approximately 2 m² and receives about one-third of the blood circulating through the body. Today about 74% of drugs taken orally are not effective as desired. Transdermal drug delivery system has emerged as an effective delivery system to improve such characters. Transdermal Drug Delivery System (TDDS) is the system in which the delivery of the drug occurs by the means of skin and deliver specific dose of the medicine (drug) into the bloodstream over a period of time. This includes high bioavailability, absence of first pass hepatic metabolism effect, steady drug plasma concentration, and the fact that therapy is non-invasive and also reduces dosing frequency.

This review article covers a brief outline of TDDS, its advantages over conventional dosage forms, drug delivery routes across human skin, penetration enhancers, the principles of transdermal permeation, various components of transdermal patch, types of Transdermal patches, approaches of transdermal patch, its application with its limitation with relevant examples, when these are used and when their use should be avoided.