Chemical Penetration Enhancers in Topical Application and Their Synergistic Combination

Abstract

In the development of a dermal pharmaceutical and cosmetic formulation, the choice of suitable excipients able to deliver the drug or pharmaceutically active substance at the site of their action represents an important factor. The key moment is the passage through the stratum corneum that is the least permeable skin layer with the strongest barrier ability. Its permeability can be reversibly changed through a group of special excipients known as chemical penetration enhancers. There are innumerable substances that exhibit enhancer activity and it is more than likely that the number will increase further. The paper provides a brief overview and characteristics of the most important and used enhancers in topical and transdermal application. It draws the attention to synergistic combinations of penetration enhancers by consistently searching for the scientific studies of recent years.