Characterization and Stability Study of Itraconazole-Loaded Microemulsions for Skin Application

Abstract

Dermatophytosis is a common disease in tropical regions and it can be treated with antifungal drugs via oral and topical administration. Topical liquid dosage form of an antifungal drug provides advantages such as reducing systemic adverse reactions, spreading on the applied area thoroughly, and convenience for patient using. This study aimed to investigate the microemulsion systems for preparing itraconazole-loaded microemulsions for topical usage. Microemulsion formation of systems consisting of different types of oil phase, aqueous phase, and surfactant was studied by titration method. Blank microemulsions were selected from the phase diagram with large microemulsion region for incorporation with itraconazole 1% w/w. The obtained formulations were observed and compared the present appearances with their blank counterparts. Stability of the formulations after being stored in light-protected glass containers at ambient temperature (28±2°C) for 8 weeks was evaluated. The drug content was quantitatively analyzed using UV-visible spectroscopy. The results showed that among 12 systems with various excipients, the optimized system was composed of 3:1 clove oil:oleic acid as oil phase, 1:1 water:propylene glycol as aqueous phase, and Tween 80 as surfactant. Incorporation of the active drug into the four selected blank microemulsions did not affect on appearances and microemulsion type. Viscosity and pH values of all prepared formulations were determined in acceptable criteria for skin application. However, low chemical stability was found when all formulations were kept under the investigated condition. Therefore, in the further study, the formulations should be improved to enhance chemical stability of the active drug.