Simultaneous determination of tricaprylin, DPPG and DEPC in propofol liposomes by a methyl esterification method and GC-FID analysis

As a novel injection preparation, propofol liposomes have extensive application prospects in clinical practice, and lipid components in them need to be quantified for quality control. In this study, a simple and accurate GC-FID method coupled with a methyl esterification pretreatment was developed for simultaneous determination of three main excipients (tricaprylin, TA; dipalmitoyl phosphatidylglycerol, DPPG; 2-dierucoyl-sn-glycero-3-phosphocholine, DEPC) in propofol liposomes with stearic acid used as the internal standard (IS). Response surface methodology was utilized for optimizing three factors of the methyl esterification reaction (the temperature, BF3 concentration and reaction time were optimized to be 75.0 °C, 14.5% and 6.5 min, respectively). Under optimum conditions, the average methyl esterification rate of the three analytes reached 96.43 ± 0.16% (n = 3). Moreover, multiple sample solutions could be simultaneously prepared, which would promote the efficiency and accuracy of quantitative analysis. Three calibration curves had good linear regression (r > 0.9999) within the tested ranges, the average recoveries ranged from 98.64% to 102.44% and the RSDs of the precision, repeatability, stability and recoveries were all below 1.53%. Finally, the validated method was successfully applied to the quantitative analysis of the three analytes in six batches of propofol liposomes.