Design, Development and Evaluation of Novel Nanoemulsion of Terbinafine HCl

Terbinafine hydrochloride is a synthetic antifungal drug. It is slightly soluble in water (3mg/ml) and having high permeability through stomach. This results in poor bioavailability after oral administration. Therefore nanoemulsion containing terbinafine HCl was prepared with a view to increase its bioavailability. The pseudo-ternary phase diagrams were developed using the aqueous titration method. Surfactant (Tween 80) and co-surfactant (Ethanol) were mixed (Smix) in different volume ratios (1:0, 1:1, 1:2, 1:3, 1:4, 2:1, 3:1, 4:1). Olive oil optimized as an oil phase based on the solubility study. For each phase diagram, oil (olive oil) and specific smix ratios were mixed thoroughly in different volume ratios from 1:7 to 7:1. Different combinations of oil and smix (1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 2:1, 3:1, 4:1, 5:16:1, 7:1) were made for the study to delineate the boundaries of the phases precisely formed in the phase diagrams. The formulated nanoemulsions were evaluated for drug release, dispersibility, viscosity, surfactant concentration, electroconductivity and TEM analysis. The in vivo studies revealed that there was 2.38-fold increase in bioavailability as compared to that of drug suspension when Terbinafine HCl was given as a nanoemulsion.