TRANSDERMAL DRUG DELIVERY SYSTEM: A REVIEW

Topical formulations containing drugs showing systemic action are called transdermal delivery systems (TDS) or transdermal therapeutic systems (TTS). Transdermal delivery may be defined as the delivery of a drug through ‘intact ’ skin so that it reaches the systemic circulation in sufficient quantity, to be beneficial after administration of a therapeutic dose. Transdermal systems are ideally suited for diseases that demand chronic treatment. Hence, anti-diabetic agents of both therapeutic and prophylactic usage have been subjected to transdermal investigation. Advantages1: a) Can avoid gastrointestinal drug absorption difficulties covered by gastrointestinal pH, enzymatic activity and drug interaction with food, drink and other orally administration drug. b) Can substitute for oral administration of medication when the route is unsuitable as with vomiting and diarrhea. c) To avoid the first pass effect e.g. Transdermal Nitroglycerin. It is rapidly metabolized by the liner when taken orally. d) Noninvasive, avoiding the inconvenience of parenteral therapy. e) They provided extended therapy with a single application, improving compliance over other dosage forms requiring more frequent dose administration e.g. Transdermal clonidine 7 day. f) The activity of drugs having a start half life is extended through the reservoir of drug in the therapeutic delivery system and its controlled release. g) Drug therapy may be terminated rapidly by removal of the application from the surface of the skin.