Formulation and Evaluation of Transdermal Patches

Transdermal drug delivery enjoys several advantages over other routes of administration. A transdermal patch is a medicated adhesive patch that is placed on skin to deliver a time release dose of medication through skin for treating a systemic illness. The transdermal therapeutic system is of particular clinical significance for prevention and long term treatment of chronic diseases like Rheumatoid Arthritis, Osteoarthritis, Ankylosing Spondylitis, Dysmenorrhea, Acute Gout and Pain. The benefits of using transdermal drug delivery system include improved systemic bioavailability resulting from bypassing first pass hepatic metabolism. Treatment may also be terminated quickly by merely removing the patch whenever needed. The aim in development of new transdermal drug delivery devices is to obtain a controlled, predictable and reproducible entry of the drug into blood stream of the patient. Transdermal device act as the reservoir and controls the rate of drug transfer. When the transdermal drug flux is controlled by device instead of the skin, delivery of the drug is more reproducible, leading to smaller inter and intra subject variation because the drug release from device.