ABSTRACT
The choice of drugs to be delivered transdermally is a most difficult one, and careful consideration should be given to each application before large expenditures are committed to clinical testing. Tasks significant in transdermal delivery include regulation of heat and water loss (hydration, occlusion), resistance to mechanical stress (ultrasonic enhancement), and protection of the host from toxic materials (drugs, enhancers). Most drugs are adequately administered by oral medication, so it is imperative that an important clinical need be addressed for any proposed transdermal delivery system. In addition to skin, drug, and drug-skin interactions, drug pharmacokinetics and design of the transdermal delivery device are also very important. Based on the parameters most important to transdermal delivery, this chapter is divided into three sections: skin as a barrier membrane and an an immunologic organ; the pharmacokinetics of skin permeation, and transdermal devices.
