Enhancement of oral bioavailability of vitamin E by spray-freeze drying of whey protein microcapsules

Vitamin E microcapsules were effectively prepared using three different techniques: spray drying, freeze-drying and spray freeze-drying with whey protein isolate as an encapsulating agent. The quality of microcapsules was evaluated by particle size distribution, surface morphology, encapsulation efficiency, moisture content, flow properties (Hausner ratio), dis-solution properties and in vivo oral bioavailability. Vitamin E microcapsules prepared by spray drying, freeze-drying and spray freeze-drying techniques showed maximum encapsulation efficiencies of 89.6 +/- 2.58, 86.1 +/- 1.44, and 89.3 +/- 2.56 respectively. Both freeze-dried and spray freeze-dried microcapsules showed excellent dissolution behavior with higher ODmax and dissolution rates (k(0)) than the spray-dried microcapsules due to the presence of numerous porous internal structures. Oral bioavailability study performed in male Wistar rats showed enhanced values of maximum plasma concentration (C-max) and area under the curve (AUC) for spray freeze-dried microcapsules. The overall results demonstrate that the spray freeze-drying based microencapsulation technique could be a promising strategy to enhance the oral bioavailability of poorly water-soluble bioactive compounds like vitamin E. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.