Vitamin E nanoemulsions characterization and analysis

The aims of this work were to characterize vitamin E/canola oil nanoemulsions and to develop a practical RP-HPLC method for vitamin E acetate estimation in the canola oil nanoemulsions. Currently available methods to analyze vitamin E in lipid-emulsions are time-consuming and do not allow adequate separation of vitamin E and its esters. The nanoemulsions were characterized for partition coefficient between emulsion phases, drug loading, free drug, micellar solubilization, encapsulation efficiency and vitamin E concentration in the emulsion external aqueous phase as a function of time. Formulation stability under stress conditions was also evaluated. The nanoemulsions were stable during the test period at 25 and 32 degrees C with no significant change in mean droplet diameter. The results suggest that prolonged release of lipophilic drugs can be achieved using nanoemulsions. The RP-HPLC method developed showed linearity, selectivity and efficiency. To the best of our knowledge, this is the first practical method for vitamin E analysis in lipid-emulsions. This method may also be applied to the analysis of vitamin E and its esters in other lipid formulations, and for quality control purposes. (c) 2014 Elsevier BY. All rights reserved.