Abstract
Topical therapy is highly desirable in treating nail disorders due to its localized effects, which results in minimal adverse systemic events and possibly improved adherence. The absorption of drugs into the nail unit, to the nail plate, is highly desirable to treat nail disorders; however, the effectiveness of topical therapies is limited by minimal drug permeability through the nail plate. Nail permeability is however quite low and limits topical therapy to early/mild disease states such as onychomycosis (fungal infections of the nail). Current research on nail permeation that focuses on altering the nail plate barrier by means of chemical treatments, penetration enhancers as well as physical and mechanical methods is reviewed also the recent research into ungual drug delivery is reviewed, a new method of nail sampling is examined. Finally limitations of current ungual drug permeability studies are briefly discussed and the factors, which affect drug uptake and permeation through the nail plate such as solute molecular size, hydrophilicity/hydrophobicity, charge, and the nature of the vehicle, are then discussed, and drug containing nail lacquers which, like cosmetic varnish, are brushed onto the nail plates to form a film, and from which drug is released and penetrated into the nail those are reviewed. It can be said that better the formulation, higher are the chances of achieving the success.
