Topical Efinaconazole solution (0.25 to 1%) is dose-dependently effective in treating both dermatophytoses, for 10 guinea pigs with interdigital tinea pedis or tinea corporis is investigated. The follow up study performs on day-30 and day-9 posttreatment demonstrated that the relapse rates for 1% Efinaconazole-treated animals with tinea pedis and for those with tinea corporis are 20 and 30%, respectively. When a single dose of 1% Efinaconazole is applied to the back skin 48 hours before fungal inoculation, 9 of the 10 animals are protected from the dermatophytosis, suggesting that active Efinaconazole is retained in skin tissue for at least 48 hours after dosing.