Terbinafine Hydrochloride Nanoemulsion Gel for Transdermal Delivery in Fungal Infection: Ex-vivo and In-vivo Evaluation

Background: Terbinafine (TFH), an allylamine derivative, is the most effective antifungal agent. Objective: The present investigation was focused to formulate and optimize nanoemulsion of TFH and converting them as a suitable transdermal Terbinafine Nanoemulsion Gel (TFNG) to improve therapeutic efficacy, better dispersity, and storage stability in the treatment of fungal infection. Methods: The nanoemulsion was prepared by water titration method and characterized for droplet size, polydispersity index (PDI), refractive index, drug content, viscosity, and morphology. The nanoemulsion formulation was incorporated into the gel for controlled release and evaluated for pH, drug content, and viscosity. Ex-vivo permeation study was conducted using human cadaver skin on TFNG and a marketed gel. Results: The formulation A1 showed the desired droplet size (133.0 ± 10.5 nm), PDI (0.174 ± 0.01), refractive index (1.334±0.05), drug content (99.12 ± 2.5 %) and viscosity (45.85 ± 4.60 cp). In ex-vivo permeation study, TFNG showed a significant (p<0.05) prolonged release of TFH. TFNG showed a significant antifungal activity against Candida albicans compared to marketed gel. Skin irritation study shows that the formulation is safe for dermatological use. No significant changes (p>0.05) were found in the values of pH, drug content and viscosity over the period of 3 months. Conclusion: In conclusion, TFNG was found to have great potential to serve as a transdermal preparation, excellent antifungal activity, and safe with better storage stability.