Percutaneous absorption: transdermal drug delivery systems

Transdermal drug delivery systems are topical devices designed originally to deliver a potent drug to the surface of the skin at a controlled rate. This rate was intended to be well below the maximum that human skin can accept. Thus, the fundamental concept of this novel dosage form was that the device, and not the stratum corneum, should control the flux of drug diffusing through the epidermis and dermis and passing into the general circulation via the capillaries.