Skin permeation enhancement technology is a rapidly
developing field which would significantly increase the
number of drugs suitable for transdermal drug delivery,
with the result that skin will become one of major routes of
drug administration in the next decade. Elucidation of the
biochemical composition and functioning of the intrinsic
diffusion barrier of the stratum corneum has prompted
investigation of chemical and physical means of enhancing
the percutaneous penetration of poorly absorbed drugs.
Research in this area has proved the usefulness of chemical
penetration enhancers in the enhancement of drug perme-
ation through skin. The role of natural penetration enhancer
inclusion in topical formulations has been well documented
and will undoubtedly, in the future, permit the delivery of
broader classes of drugs through the stratum corneum.
Further researches should focus on skin irritation with a
view to selecting natural penetration enhancers possessing
optimum enhancement effects with minimal skin irritation.