Background: Sulconazole (SCZ) is a broad-spectrum transdermally administered anti-fungicidal agent. However, the therapeutic effect of SCZ is generally limited by its poor water solubility. This present study aimed to develop and evaluate sulconazole-loaded nanoemulsions (SCZ-NEs) for enhancement of the transdermal permeation and antifungal activity.
Methods: A spontaneous titration method was applied to prepare the SCZ-NEs. And the optimized formulation of SCZ-NEs was screened by central composite design (CCD). In addition, the characteristics of the SCZ-NEs were evaluated, including particle size, zeta potential, drug loading (DL%) and encapsulation efficiency (EE%). The morphology of SCZ-NEs was observed by transmission electron microscopy (TEM). Franz diffusion cells were used to evaluate the transdermal permeability of the SCZ-NEs. The antifungal activity of the SCZ-NEs was measured by a zone of inhibition (ZOI) test.
Results: The optimized SCZ-NEs possessed a moderate particle size of 52.3±3.8 nm, zeta potential of 23.3±1.2 mV, DL% of 0.47±0.05% and EE% of 87.1±3.2%. The ex vivo skin permeation study verified that the cumulative permeability (Qn) and penetration rate (Js) of the optimized SCZ-NEs were about 1.7-fold higher than that of a commercial reference, miconazole (MCZ) cream and 3-fold higher than that of SCZ-DMSO solution. The optimized SCZ-NEs exhibited zone of inhibition (ZOI) values of 23.5±2.4 and 20.4±2.5 mm against C. albicans  and T. rubrum , which were larger compared with these of the MCZ cream and SCZ-DMSO solution.
Conclusion: SCZ-NEs were effectively developed to overcome the poor solubility of SCZ, promote SCZ permeation through the skin and improve its antifungal activity. Thus, the SCZ-NEs are a promising percutaneous administration for skin fungal infections induced by C. albicans  and T. rubrum .
Keywords: sulconazole, nanoemulsion, central composite design, transdermal delivery, antifungal activity