Preparation Of Immobilized Liposome Chromatography Stationary Phase And Its Applications

Biomembrane chromatography has drawn more and more attention as a powerful tool to study the interactions between solutes and biological membrane recently. And one important branch of it is immobilized liposome chromatography (ILC). Liposomes, t he e nclosed v esicles s pontaneously formed b y n ative p hospholipids o r their analogs in water, are always regarded as a good model of biological membrane.In this paper, coating and covalent bonding methods had been developed to immobilize liposomes on silica gel particles as ILC stationary phases for liquid chromatography. Stabilities and selectivities of stationary phases prepared by the two methods had been studied and compared.The apparent permeability coefficient (Papp) of drugs through small intestine, is one of important factors to evaluate drugs' biological activity. It had been indicated that there are good linear correlation between drugs retention on ILC and their Papp, so it is possible to predict drugs intestinal absorption by their retention on ILC. Better correlation could be achieved by using combination result of drugs at three eluent pH values (pH 5.4, 7.0 and 7.4) than the result at any single pH.ILC h ad b een applied t o s creen p ermeable c omponents i n T raditional C hinese Medicines (TCMs), testing extracts from Radix Angelica Sinensis. By combination of ILC with immobilized serum protein chromatography (ISPC) and reversed-phase liquid chromatography (RP-HPLC), a method had also been proposed to screen andanalyze the bioavailable components in Ligusticum Wallichii. Because the permeability through cell membrane and binding ability with serum proteins of drugs play a very crucial role for them to exhibit activity, which can well be modeled by ILC and ISPC, respectively, better correlation with bioactivity of TCMs in vivo is expected when synthetically evaluating retentions of bioactive compounds on ILC and ISPC.ILC had also been applied in the study of interactions between proteins and biological membrane. It had been proved that pH, ion strength, Ca2+ concentration of eluent as well as surface charge of ILC stationary phase, all had effects on the interactions with different degree for different proteins and differences in conformation and composition of proteins may be mainly responsible for it.