Measurement of Entrapment Efficiency in Liposome by Solid Phase Extraction Combining with High Performance Liquid Chromatography

A solid phase extraction-high performance liquid chromatography method was developed to measure the entrapment efficiency of paclitaxel liposome.The method used C18 as packing material which has the size of 40-60μm and the cotton after silylation as disk.The liposome was eluted by 5%glucose,and paclitaxel was eluted by methanol.In the concentration range between 10ng/mL and 5.0μg/mL of paclitaxel,the calibration curve had a good linear relationship(r2=0.996).The detection limit of paclitaxel was 5.0ng/mL(S/N=3).The recoveries of paclitaxel ranged from 95% to 105%,and relative standard deviations of liposome entrapment efficiency was from 0.3%to 1.8%.The method was simple and accurate,and it may be applied in measuring the entrapment efficiency of some other liposomes of lip-soluble molecules.