Transungual drug delivery: an update

Topical therapy continues to be the treatment of choice for the patients and clinicians in treating certain infections of the nails. Topical treatment is widely accepted as an adjunct with oral therapy to improve the cure rates, reduce the treatment duration, cut down the treatment cost and enhance the therapeutic outcomes. However, effectiveness of topical therapy continues to pose a challenge owing to the poor permeability of the nail plate to many therapeutic agents and the prolonged treatment periods. Research over the past one decade has been focused to improve the transungual permeation using chemical penetration enhancers, mechanical methods and physical methods. Disrupting the dorsal surface of the nail by treating with pénétration enhancers or etching agents or abrasion or filing of the nail plate has proved to drastically improve the efficacy of topical therapy. The present review is an effort to update the different chemical enhancers and etching agents used to enhance the transungual permeability.