Transdermal diffusion of drug molecules

Abstract

The diffusion of drug molecules directly across the skin and their subsequent absorption into the blood presents a novel and potentially beneficial method of controlled drug delivery. The principles governing these diffusion processes and the design of transdermal delivery systems are described. The use of electrically assisted transdermal delivery, which is a technique that both extends the range of drugs that may be administered in this way and offers scope for the variation, control and monitoring of their delivery rates, will also be discussed. Experimental data are presented for the passive and iontophoretically assisted transdermal delivery of a number of compounds.