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 micro encapsulation was conducted via a 1000-mu m expansion nozzle at 12.41 MPa, 90 degrees C, and aqueous cargo loading rate of 0.25 ml/s. Vitamins C and E were selected as model hydrophilic and lipophilic compounds encapsulated in the integrated liposomes. The average vesicle size was 951.02 nm with a zeta potential of -51.87 mV. 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 20 days. Simultaneous microencapsulation in the liposomes was successfully achieved with this supercritical fluid process.