EFFECT OF CHEMICAL PENETRATION ENHANCERS ON SKIN PERMEATION: A REVIEW

Abstract

Transdermal drug delivery has attracted considerable attention over the past 2-3 decades in regard of its many potential advantages. Skin penetration enhancers have been used to improve bioavailability and increase the range of drugs to be administered by topical and transdermal route. 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. The mechanism of action of penetration enhancers are used as an aid in potential clinical applications. Chemical penetration enhancers are present in a large number of transdermal, dermatological, and cosmetic products to aid dermal absorption of curatives and aesthetics. 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 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.