Permeation enhancers compatible with transdermal drug delivery systems: part II: system design considerations

Part I of this article reviewed the classification, chemistry, properties, selection, and use of skin permeation enhancers in transdermal drug delivery systems and dermal patches. In Part II, the authors discuss ideal properties of enhancers and describe various enhancers' actions on the skin, as well as interaction among permeation enhancers and other transdermal delivery system components, such as backing materials, pressure-sensitive adhesives, membranes, and release liners. Adhesive properties critical to the optimization of a transdermal formulation are discussed.