Intranasal Oleic acid-based nanoemulsion of Diazepam: design, formulation and in-vitro evaluation

Abstract

An O/W nanoemulsion of Diazepam for intranasal administration was formulated aiming at selecting appropriate surfactant components (surfactants and cosurfactants) and ratios when using oleic acid as an oil phase. Triangular ternary phase diagrams were constructed by specialized software. Tween 80 and cremephore EL were studied as surfactants. Ethanol was studied as co-surfactant. Those were used as emulsifiers with ratio 1:1, 1:2 and 1:3. Fourteen nanoemulsion formulas were formulated by low energy emulsification using aqueous titration method. The nanoemulsions were characterized for visual transparency, average globule size, polydispersity index, zeta potential, pH, % transmittance and in-vitro drug release. The formula F3 was chosen as optimum Diazepam nanoemulsion according to results of characterization. Nanoemulsion F3 had a Smix (Tween 80 to Ethanol 1:2): oil: deionized water (50: 10: 40) ratio offered best results with good globule size range (7.5 nm), good PDI (0.22), good percent transmittance (98.5%), pH of 5.7 and highest percent released of Diazepam within the first hour.