Abstract
Transdermal system is a self contained and discrete dosage form. for systemic action of various drugs. Skin is the main barrier to be overcome for this delivery system. Three mechanisms are involved in skin permeation kinetics such as sorption by stratum, penetration of drug through viable epidermis and uptake of the drug by capillary network in dermal papillary layer. Polymer matrix, drug, permeation enhancers and excipients are main components of transdermal drug delivery systems. Various permeation enhancers are used to overcome these barriers. Recent advances in this system include the formulation of emulgel which contains properties of both emulsion as well as gel.
