Simultaneous microencapsulation of hydrophilic and lipophilic bioactives in liposomes produced by an ecofriendly supercritical fluid process.

Organic solvent residues are always a concern with the liposomes produced by traditional techniques. Our objectives were to encapsulate hydrophilic and lipophilic compounds in liposomes using a newly designed supercritical fluid process coupled with vacuum-driven cargo loading. Supercritical carbon dioxide was chosen as the phospholipid-dissolving medium and an ecofriendly substitute for organic solvents. Liposomal microencapsulation was conducted via a 1000-μm expansion nozzle at 12.41MPa, 90°C, and aqueous cargo loading rate of 0.25ml/s. Vitamins C and E were selected as model hydrophilic and lipophilic compounds encapsulated in the integrated liposomes. The average vesicle size was 951.02nm with a zeta potential of -51.87mV. The encapsulation efficiency attained was 32.97% for vitamin C and 99.32% for vitamin E. Good emulsion stability was maintained during storage at 4°C for 20days. Simultaneous microencapsulation in the liposomes was successfully achieved with this supercritical fluid process.