Ungual formulations: Topical treatment of nail diseases

Abstract

The human nail can be afflicted by several disease states. Approximately 50% of all problems result from fungal infections, and brittle nail syndrome affects approximately 20% of the population. For the topical treatment of nail diseases, however, it is a prime requirement that the active ingredient is capable of penetrating into and diffusing though the nail plate. Experimental techniques for investigation of the penetration and distribution of chemicals into and through the nail plate have demonstrated that it is possible to deliver drugs to the nail following topical application. This research has led the development of newer more effective topical products and regimens for treatment of onychomycoses and other nail diseases. In this chapter, nail structure and chemical composition will be discussed together with an overview of the permeation of molecules through the nail plate, and this will be followed by a review of selected clinical studies designed to determine the efficacy of topical treatment for nail diseases.