Liposomal encapsulation of curcumin employing soy lecithin in ultrasonic environment under dense carbon dioxide

Supercritical carbon dioxide (SCCO₂) and deionized water in an ultrasonication environment were employed as a medium for liposome preparation and curcumin encapsulation in a single-step process. As a starting material, soy lecithin was extracted from soybean seed by using water at subcritical conditions. The experiments were performed in batch processes at various temperatures (50–70 °C) and pressures (15–25 MPa) for 90 min. Under each operating condition, the generated liposomes with or without curcumin seemed to possess a spherical or spherical-like morphology with a diameter of less than 100 nm. However, a particle size analyzer (PSA) showed that their diameters were much larger (approximately 500 nm). The zeta potential values indicated that the nanosuspension system containing encapsulated curcumin possessed good stability. The uniqueness of this work lies in the method for encapsulating curcumin using the generated liposomes in an ultrasonic environment using a mixture of SCCO₂-water. The produced liposomes were derived from soy lecithin that was extracted from soybean seeds by applying water under subcritical conditions.