Optimisation of the formulation of β-carotene loaded nanostructured lipid carriers prepared by solvent diffusion method

In this study, the optimised β-carotene loaded nanostructured lipid carriers (NLC) were prepared using the solvent diffusion method. Response surface methodology (RSM) was employed in conjunction with a central composite design (CCD) to evaluate the effect of the preparation variables on particle size and β-carotene stability to optimise the NLC formulation. Quadratic polynomial was the best fitted mathematical model for the experimental results. The statistical evaluations revealed that the lipid phase concentration and the surfactant concentration had significant effect on particle size of NLC. In addition, the influence of the liquid lipid to total lipid ratio and temperature on β-carotene degradation was more important. The optimum formulations with minimum particle size (8–15 nm) and low β-carotene degradation (0–3%) were derived from the fitted models and were experimentally examined which demonstrated a reasonable agreement between experimental and predicted values. Transition electron microscopy (TEM) observations exhibited spherical morphology of β-carotene loaded NLC.