The present study was aimed to optimize, develop, and evaluate microemulsion and microemulsion-based gel as a vehicle for transungual drug delivery of terbinafine hydrochloride for the treatment of onychomycosis. D-optimal mixture experimental design was adopted to optimize the composition of microemulsion having amount of oil (X _{1}), Smix (mixture of surfactant and cosurfactant; X _{2}), and water (X _{3}) as the independent variables. The formulations were assessed for permeation (micrograms per square centimeter per hour; Y _{1}), particle size (nanometer; Y _{2}), and solubility of the drug in the formulation (milligrams per milliliter; Y _{3}). The microemulsion containing 3.05% oil, 24.98% Smix, and 71.96% water was selected as the optimized formulation. The microemulsion-based gel showed better penetration (∼5 folds) as well as more retention (∼9 fold) in the animal hoof as compared to the commercial cream. The techniques used to screen penetration enhancers (hydration enhancement factor, ATR-FTIR, SEM, and DSC) revealed the synergistic effect of combination of urea and n-acetyl cysteine in disruption of the structure of hoof and hence, leading to enhanced penetration of drug.
【저자키워드】 Hydration, microemulsion, scanning electron microscopy, Nail, transungual drug delivery, terbinafine hydrochloride, differential scanning calorimetry,