DEVELOPMENT AND OPTIMIZATION OF A TERBINAFINE HYDROCHLORIDE MICROEMULGEL FOR ENHANCED TOPICAL DELIVERY AND ANTIFUNGAL EFFICACY

Abstract

This study investigates the development of a microemulgel-based drug delivery system for topical administration of Terbinafine Hydrochloride, aimed at improving solubility, skin permeability, and therapeutic effectiveness. Among the tested oils, maximum solubility of terbinafine was achieved in propylene glycol, while Tween 80 and polyethylene glycol 400 were employed as surfactant and co-surfactant, respectively. A pseudo-ternary phase diagram identified an optimal 1:2 Smix ratio, and Central Composite Design was applied to generate thirteen formulations varying in oil and Smix concentration. Transmittance analysis revealed that a composition containing 27.93% Smix and 6.51% oil phase provided maximum clarity. The optimized microemulsion was subsequently incorporated into gel matrices containing carbopol 934 and hydroxypropyl methylcellulose (HPMC). Comprehensive evaluation, including rheological analysis, drug content, spreadability, extrudability, and in vitro antifungal activity against Tinea pedis, was performed. Ex vivo permeation studies using goat skin demonstrated that the formulation containing 0.45 g carbopol 934 and 0.3 g HPMC exhibited superior drug release and skin penetration compared to other variants. Notably, this optimized microemulgel outperformed commercially available terbinafine ointment, highlighting its potential as a promising alternative for improved antifungal therapy.