Formulation, optimization and characterization of microemulsions as a delivery stystem for vitamin E
The objective of this research was to formulate dilutable food-grade (microemulsions) MEs for the controlled release of oil-soluble compounds. The MEs developed consisted of water, Tween 80, ethanol, tricaprylin and propylene glycol. Formulated MEs were studied with particle size measurement, conductance, rheology and DSC measurements. Phase transitions from oil-continuous to water-continuous domains via bicontinuous structures were identified and studied along two dilution lines. Water-continuous MEs (70 wt%) were loaded with vitamin E at their maximum solubilization capacity. Fluorescence of vitamin E was used to model release from the oil domains, resulting from the addition of NaCl, NaOH, HCl or water to the loaded MEs. Overall, this study demonstrated that MEs could be successfully used to release labile oil-soluble molecules in a controllable manner.