Nanocharacterization of liposomes for the encapsulation of water soluble compounds from Cordyceps sinensis CS1197 by a supercritical gas anti-solvent technique†
Nano-liposomes were designed for the sustained release of water soluble compounds from C. sinensis CS1197 using a supercritical gas anti-solvent (SC-GAS) method at various pressures, temperatures and Tween 80 concentrations. The SC-GAS method was compared to the Bangham method of liposome production in terms of mean diameter, coefficient of uniformity (Cu), encapsulation efficiency, morphology, viscosity and actual energy required for liposome formation. Liposome production via the SC-GAS method under optimized formulation conditions, i.e., 180 bar; 50 °C; 0.75% Tween 80; and a depressurization rate of 25 bar min−1, yielded nano-liposomes exhibiting the lowest Cu value (1.10 ± 0.012) with a mean diameter of 0.072 ± 0.002 μm and better encapsulation efficiencies of 75.48 ± 2.5, 74.9 ± 2.1 and 70.23 ± 2.9% for adenosine, cordycepin and polysaccharides, respectively. Nano-liposomes were characterized using FTIR, XRD, DSC and TGA techniques. The stability indices and viscosities of the prepared liposome suspensions indicated good stability of up to 2 months and near-Newtonian behavior. The in vitro release of CS1197 water soluble compounds exhibited biphasic and sustained release patterns.