Carboxymethylchitosan-coated proliposomes containing coix seed oil: Characterisation, stability and in vitro release evaluation

In this research, carboxymethylchitosan (CMCS)-coated proliposomes (CM-PL) were prepared in an attempt to deliver coix seed oil (CSO) using conventional ethanol injection followed by surface modification and spray drying. Conventional uncoated liposomes (un-L), CMCS-coated liposomes (CM-L) and uncoated proliposomes (un-PL) were also prepared for comparison. The morphology, encapsulation efficiency (EE), particle size, zeta potential, stability, and CSO release performance were investigated for all samples. The results indicated that CM-PL possessed smoother surface, better heterogeneous size distribution, higher EE and improved stability compared with other samples. Transmission electron microscopy (TEM) showed that rehydrated CM-PL were spherical particles with CMCS layers surrounding the surface of conventional liposomes. The coating mechanism was probably due to H-bonding interactions between CMCS and the interfacial regions of the phosphatidylcholine bilayer. In addition, controlled release of CSO from coated proliposomes was obtained with more sustained release in simulated intestinal fluid (SIF) than in simulated gastric fluid (SGF). (C) 2011 Elsevier Ltd. All rights reserved.