Natural products as potential drug permeation enhancer in transdermal drug delivery system

Permeation enhancers are defined as substances that are capable of promoting penetration of drugs into skin and transdermal therapeutic systems offers a more reliable mean of administering drug through the skin. Skin is a natural barrier so it is necessary to employ enhancement strategies to improve topical bioavailability. This review explores that natural products have got potential to enhance the permeation of the drug through skin by reversibly reducing the skin barrier resistance. The use of natural products is the most reliable means of permeation enhancement of transdermally administered drugs and permits the delivery of broader classes of drugs through the stratum corneum. They are safe, non-toxic, pharmacologically inert, non-irritating, and non-allergenic to use as permeation enhancers. The present review initially highlights the current status of natural products on the basis of SAR studies which have shown significant enhancer activities.