Optimization the formulation parameters in preparation of α-tocopherol nanodispersions using low-energy solvent displacement technique.

Abstract

α-Tocopherol is the main compound of vitamin E with great antioxidant activity. However, like other functional lipid bioactive compounds, it suffers from low bioavailability due to its low water solubility and liable chemical structure. A bottom-up procedure based on a solvent-displacement method was constructed for fabrication of α-tocopherol nanodispersions using response surface methodology (RSM). The effects of main formulation parameters, namely, weight ratio of emulsifier to α-tocopherol and volumetric percent of acetone to water on the average particle size (nm), polydispersity index, concentration of α-tocopherol loss (% w/w) and turbidity of the nanodispersions were evaluated and optimized to gain the most desirable nanodispersions (least particle size, polydispersity index, turbidity and highest α-tocopherol concentrations). Second order regression equations, holding quite high coefficients of determination (R2 and adjusted R2>0.882), were significantly (p-value<0.05) fitted for predicting the α-tocopherol nanodispersion characteristics variations as functions of studied formulation parameters. A multiple optimization analysis offered 6.5 and 10% for weight ratio of Tween 20 to α-tocopherol and volume percent of acetone, respectively, as overall optimum values for studied parameters. Statistically insignificant differences between experimental and predicted values of studied responses, verified the satisfactoriness of presented models for explaining the response characteristics as a function of formulation parameters. Thus, the employed solvent-displacement technique may provide the most desired water dispersible α-tocopherol nanoparticles for several water-based foods, cosmetic nutraceutical formulations.