Development of formulation and evaluation of topical micro emulsion gel loaded with terbinafine HCL micro emulsion

Fungal infections, particularly in immunocompromised patients, present significant health challenges and are often difficult to treat with conventional topical therapies due to bioavailability issues. This study explores the development of a topical gel formulation using solid lipid nanoparticles (SLNs) loaded with Terbinafine, an antifungal agent, to improve drug delivery and efficacy. SLNs were prepared by a solvent diffusion method and optimized with stearic acid and poloxamer 188. The formulation with the highest entrapment efficiency (SLN F6) exhibited 92.13% ± 0.975. The optimized SLN formulation was incorporated into a gel base containing carbopol 934, resulting in SLN gel G3 with 1.5% carbopol showing the highest drug entrapment (91.39% ± 0.187). The gel was evaluated for physicochemical properties, including viscosity (369 cP), pH (6.12 ± 0.255), and spreadability (4.5). In vitro release studies indicated controlled drug release, fitting best with the Higuchi and Korsmeyer-Peppas models. FTIR analysis confirmed no significant interactions between the drug and excipients, supporting the formulation's purity and effectiveness. Scanning electron microscopy (SEM) confirmed the spherical shape and smooth surface of the nanoparticles. This study demonstrates that Terbinafine-loaded SLNs in a topical gel formulation provide a promising approach for sustained drug delivery in treating fungal infections.