Voriconazole and sertaconazole loaded colloidal nano-carriers for enhanced skin deposition and improved topical fungal treatment

Abstract

This study was carried out to explore the feasibility of microemulsion formulation as a nano-sized colloidal carrier for dermal delivery of two azole antifungal drugs, voriconazole and sertaconazole. The pseudoternary phase diagrams were constructed to identify the area of microemulsion existence and the optimum compositions were determined based on oleic acid, Tween 80, ethanol and water. The microemulsions were characterized in terms of optical isotropy, conductivity, pH and refractive index, globule size and its distribution and thermodynamic stability. In vitro penetration and the localization of voriconazole and sertaconazole into deeper skin layers from the developed microemulsions were investigated in comparison with their conventional topical formulations. The results showed that microemulsions significantly enhanced drug retention in the skin. The improved skin deposition of microemulsions was further visualized through confocal laser scanning microscope. Moreover, the interaction between the microemulsion components and skin was clarified by ATR-FTIR spectroscopy. The in vitro antifungal activity assay covered four Candida species and the results showed that therapeutic drug levels covering the minimum inhibitory concentration (MIC) could be reached by topical application of the formulated microemulsions of both antifungal drugs. In conclusion, microemulsion could be a potential colloidal carrier for improving topical delivery of voriconazole and sertaconazole.