Abstract
This study was conducted to investigate the possibility of applying a supercritical process to incorporate rose essential oil into liposomes. By rapid expansion of the supercritical solution of the lipid materials and rose essential oil into a surfactant solution, the liposomes entrapping rose essential oil were formed. In this process, the surfactant provided stabilization for liposomes by preventing flocculation and agglomeration resulting from particle collisions during the spraying process. The encapsulating performance and particle size distribution of liposomes could be controlled by changing preβexpansion and expansion processing conditions. According to analysis by differential scanning calorimetry (DSC), the morphology and particle size, the liposomes formed were doubleβlayered vesicles entrapping the rose essential oil with a particle size of less than 100βnm. Compared with the liposomes prepared by thinβfilm dispersion, the liposomes formed by the supercritical process exhibited higher encapsulation efficiency and smaller particle size with a unimodal distribution, which achieved the standards of Chinese Pharmacopoeia. The results suggest the supercritical process facilitated a more controllable operation for selfβassembly of liposomes incorporating heatβsensitive components from natural products in the CO~2~ medium. Copyright Β© 2010 John Wiley & Sons, Ltd.