A Review on Transdermal Drug Delivery System

Nowadays about 74% of drugs are taken orally and are found not to be as effective as required. To improve such characters transdermal drug delivery system was emerged. Drug delivery through the skin to attain a systemic effect of a drug is commonly known as transdermal drug delivery and differs from traditional topical drug delivery. Transdermal drug delivery systems (TDDS) are dosage forms involves 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. The adhesive of the transdermal drug delivery system is critical to the safety, efficacy and quality of the product. Topical administration of therapeutic agents offers many advantages over conventional oral and invasive methods of drug delivery. Several important advantages of transdermal drug delivery are limitation of hepatic first pass metabolism, enhancement of therapeutic efficiency and maintenance of steady plasma level of the drug. This review article provides an overview of advantages and disadvantages, factors affecting transdermal drug delivery, components and types of transdermal drug delivery, methods of preparation and methods of evaluation.