Review: Transdermal Patch

Transdermal drug delivery systems (TDDS) or “patches,” are dosage forms designed to deliver effective amount of drug across a patient’s skin. In order to deliver therapeutic agents through the human skin for systemic effects, the comprehensive morphological, biophysical and physicochemical properties of the skin are to be considered. Transdermal delivery is advantageous over injectables and oral routes by increasing patient compliance and avoiding first pass metabolism respectively. 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. The evidence of percutaneous drug absorption found through measurable blood levels of the drug, detectable excretion of the drug and its metabolites in the urine and through the clinical response of the patient to the administered drug therapy.