Antidermatophytic Activity and Skin Retention of Clotrimazole Microemulsion and Microemulsion-Based Gel in Comparison to Conventional Cream

Antifungal activity, skin permeation and skin retention of water-in-oil microemulsion (ME) and microemulsion-based gel (MBG) containing clotrimazole (CTZ) were evaluated in comparison to a conventional CTZ cream.CTZ-ME and CTZ-MBG containing 1% w/w of CTZ were produced. Antifungal activity against Trichophyton mentagrophytes was assessed by the agar diffusion method. Pig skin was used in the in vitro penetration study using modified Franz diffusion cells. Drug amounts which permeated into the receptor fluid, retained in the skin membrane and remained in the donor compartment were analyzed by a validated HPLC technique.CTZ-ME and CTZ-MBG exhibited inhibition zones against T. mentagrophytes whereas the conventional cream did not reveal any inhibition zone in the assay. While no CTZ was detected in the receptor fluid up to 24 h following the in vitro penetration study from all tested formulations, the amount of CTZ retained in the skin membrane when applying CTZ-ME and CTZ-MBG was remarkably higher than that when applying the cream.Results revealed the capacity of ME and MBG in improving skin bioavailability of CTZ while reducing the risk of systemic side effects. Thereby, ME and MBG could increase the efficacy of CTZ for dermatophytosis treatment in comparison to conventional cream.