A REVIEW: TRANSDERMAL DRUG DELIVERY SYSTEM: FUTURE DIRECTION

A 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. The transdermal drug delivery system is one of the novel drug delivery systems which overcome arise from the conventional dosage. Transdermal patches are pharmaceutical preparation of varying sizes, containing one or more active ingredients to the systemic circulations. The review gives valuable information about the transdermal patch like its advantage, disadvantage, mechanism of action, types of transdermal patch, factors basic components, methods and evaluation, application of a transdermal patch. A wide variety of pharmaceuticals are now available in transdermal patch form. Transdermal drug delivery systems (TDDS) are dosage forms that involve drug transport to viable epidermal and or dermal tissues of the skin for local therapeutic effect while a very major fraction of drug is transported into the systemic blood circulation. However, the skin, in particular the stratum corneum, poses a formidable barrier to drug penetration thereby limiting topical and transdermal bioavailability. Skin penetration enhancement techniques have been developed to improve bioavailability and increase the range of drugs for which topical and transdermal delivery is a viable option. During the past decade, the number of drugs formulated in the patches has hardly increased, and there has been little change in the composition of the patch systems. It is intended to improve the therapeutic efficacy and safety, maintain the steady state plasma level of drugs and overcome the significant drawbacks of the conventional oral dosage forms and parenteral preparations. It is ideally suited for the diseases that demand chronic treatment with frequent dosing. This review deals with a brief insight on the introduction, the formulation aspects, the physical and chemical enhancers explored or being explored to enhance the transdermal delivery of drugs across the stratum corneum, the evaluation parameters(physicochemical, in vitro, in vivo studies) and therapeutic applications of TDDS.