This overview focuses on the physical, biochemical, and chemical means of penetration enhancement, as well as the classification and mechanisms of chemical penetration enhancers, their application in transdermal drug delivery, and trends and development in penetration enhancement. The use of many of these agents resulted in unpleasant or toxic side effects. Several approaches have been utilized to facilitate entry of drugs into the lower skin layers. However, in recent years there has been a search for compounds that exhibit low toxicity, and maintain their enhancing activity.
More recently, there has been interest in agents that may be used in topical formulations to prevent the passage of active ingredients or excipients into the lower skin layers. Cookies are used by this site.