Onychomycosis is the most common disease of nails and constitutes about a half of all nail abnormalities. The thickness of the nails become the major challenge in developing a topical formulation for treatment on OM. In this study, penetration enhancers are used to enhance the solubility and permeability of the drug enconazole nitrate into the nail and the skin. It turns out of all the penetration enhancers, thiourea is the best choice because it can improve the solubility and nail penetration of econazole nitrate at the same time. / Pharmaceutical Sciences