Supercritical fluid extraction of emulsions to nanoencapsulate vitamin E in polycaprolactone

Abstract

Supercritical fluid extraction of emulsions (SFEE) was used to encapsulate a liquid lipophilic compound, concretely vitamin E in polycaprolactone. The influence of the initial formulation on the characteristics of the nanoparticles (encapsulation efficiency, particle size distribution, and morphology) was studied. The obtained particles exhibited a high encapsulation efficiency (around 90%), narrow particle size distribution (polydispersity index between 0.24 and 0.54), and nanoscale particle sizes (between 8 and 276nm). The morphological analysis indicated that the particles were spherical, with a core-shell structure, and non-aggregated. Operating at 8MPa and 313K, with a CO2 flow rate of 7.2kgh−1kg emulsion−1, a low residual concentration of organic solvent (50ppm) was obtained in 240min at a CO2 consumption of 101kg CO2kg acetone−1. Stability tests indicated that the capsules remained unchanged over long storage periods (6 and 12 months).