ABSTRACT:
Transdermal drug delivery system is topically administered medicaments in the form of patches that deliver drugs for systemic effects at a predetermined and controlled rate. These devices allow for pharmaceuticals to be delivered across the skin barrier. Skin is a protective layer of the body, which acts as a barrier against physical, chemical and microbiological invasions. It also regulate the body temperature and blood pressure. The human skin is a readily accessible surface for drug delivery. In addition, Transdermal systems are non-invasive and can be self administered. Transdermal patch is the formulation which is expected to increase the solubility and bioavailability by penetrating poorly water soluble compounds through skin, and it is also possible for this formulation to decrease over-dosing and to avoid hepatic first pass metabolism. Transdermal delivery also has advantages over hypodermic injections, which are painful, generate dangerous medical waste and pose the risk of disease transmission by needle re-use. It has a variety of advantages compared with the oral route. This article mainly describes about composition of patch, types of patches and also explains detailed about evaluation of patches.