Fast immobilized liposome chromatography based on penetrable silica microspheres for screening and analysis of permeable compounds

In the present study, an immobilized liposome chromatography (ILC) stationary phase based on penetrable silica microspheres was prepared. The silica possessed mesopores and penetrable macropores, which afforded sufficient surface area and fast mass transfer, respectively. Compared with the ILC column based on common porous silica gels, the penetrable silica had larger capacity for liposomes' immobilization, lower backpressure and higher separation efficiency. Twenty-two kinds of drugs were used as tested analytes and their retention behaviors on newly prepared ILC column were investigated in detail. Column temperature and pH of mobile phase were both key factors affecting the retention of solutes. The retention of these drugs on ILC column reflected their permeability in vivo. Furthermore, the methanolic aqueous extracts of three traditional Chinese medicines (TCMs), Radix Liquiritiae, Scutellaria Baicalensis and Flos Sophorae, were screened on this novel ILC column. Effects of column temperature and eluent pH on chromatographic behaviors of components of the TCM methanolic extracts were also studied. Several permeable components can be found, indicating that they are potentially active components in the TCMs. It is also found that the as-prepared ILC column remained stable in at least 1 month and the relative standard deviations of adjusted retention times for solutes were lower than 9.0%. The proposed ILC based on the penetrable silica microspheres is promising for the fast and low-pressure separation, especially for fast screening of permeable compounds and modeling the drug-membrane interaction in vitro. It would be a useful approach to predict the permeability of potential active drugs. (C) 2012 Elsevier B.V. All rights reserved.