Revolutionized Topico-Systemic Era: Transdermal Drug Delivery System

At present oral route is one of the most widely accepted route of drug administration, but owing to its drawbacks of low bioavailability as a result of hepatic first pass metabolism a new system was introduced for controlled delivery of drug. Transdermal drug delivery has been accepted as a potential non-invasive route of drug administration, with advantages of prolonged therapeutic action, decreased side effects, easy use and better patient compliance. Transdermal drug delivery system (TDDS) involves drug transport to viable epidermal and/or dermal tissue of the skin for local therapeutic effect while a major fraction of drug is transported into systemic blood circulation. Transdermal patch is a medicated adhesive patch that is placed on the skin to deliver a specific dose of medication through the skin and into the bloodstream. An advantage over other routes is that the patch provides a controlled release of medication into the patient, usually through either a porous membrane covering a reservoir of medication or through body heat melting thin layers of medication embedded in the adhesive. The present review describes various types of Transdermal patches, permeation strategies, their methods of preparation, evaluation techniques and their future trends.