Review on Transdermal Drug Delivery System

Abstract

Transdermal drug delivery system is an essential part of novel drug distribution system. The topically administered medications in the form of patches which when applied to the skin deliver the drug .For operative TDDS the drug are easily able to penetrate the skin and easily reach the target site. TDDS avoids the first pass metabolism, less frequency of administration, reduction gastrointestinal side effects. Adverse effects are minimized due to steady and optimum blood concentration. It has greater bioavailability and efficacy of drug. The human skin is multi-layered organ composed of many histological layers. Skin is the largest organ in the body. Its major functions are protection of major or vital internal organs for the external influences, temperature regulations, control of water output and sensation. Polymer should be chemically non-reactive, should not decompose on storage, should be non-toxic, cost should not be high. E.g. - cellulose derivatives, zein, gelatin etc. Backing films play a vital role in the transdermal patch and the role of the film is to protect the active layer. Transdermal patches can be evaluated by interaction studies thickness, weight uniformity, drug content, in vitro study,moisture content, swelling index basic component of TDDS.