Sarunyoo Songkro

pp. 299 - 321

Abstract

Transdermal drug delivery has attracted considerable attention over the past 2-3 decades in regard of its many potential advantages. However, the role of the skin as a protective barrier renders skin absorption of most drugs problematic. Therefore, skin penetration enhancers are frequently used in the field of transdermal drug delivery in order to reversibly reduce the
barrier function of the stratum corneum, the outermost layer of the skin. To date, a wide range of chemical compounds have been shown to enhance the skin penetration of therapeutic drugs. This review presents a critical account of the most commonly used chemical penetration enhancers (fatty acids and surfactants), and some newer classes of chemical enhancers (terpenes,
polymers, monoolein, oxazolidinones), with emphasis on their efficacy, mechanism of action, and skin irritation potential. This review also discusses the traditional and more recently developed methods for the screening and evaluation of chemical penetration enhancers, and addresses the continuing problems in the rational selection of a chemical penetration enhancer for a specific drug to be delivered via the transdermal route.