Improvement of the microbiological activity of topical ketoconazole using microemulsion systems

The present study aimed to develop microemulsion formulae for topical delivery of ketoconazole (KTZ) with enhanced microbiological activity to avoid the systemic side effects. Different oils were screened for drug solubility and two oils, namely Labrafil M 2125 and IPM, were selected. Different surfactants and cosurfactants were screened for development of microemulsions. Pseudoternary phase diagrams of the selected oils were constructed using Tween 80 as surfactant and isopropanol as cosurfactant in the ratio of 3:1. Various KTZ microemulsions were prepared and characterized for their physical stability, microbiological activity, and rheological properties. The prepared microemulsions were clear and the fluid showed Newtonian flow. Assessment of microbiological activity using agar cup diffusion method showed a marked enhancement of antifungal activity compared to a marketed product. Accelerated stability showed that KTZ subjected to severe degradation in microemulsions prepared using Labrafil M 2125 and was more stable in microemulsions prepared using IPM.