Simultaneous HPLC-MS determination of loganin, morroniside and paeoniflorin in rat plasma; pharmacokinetics of Liuwei dihuang pills

Abstract

A novel high performance liquid chromatography-mass spectrometry method for simultaneous determination of loganin, morroniside and paeoniflorin in rat plasma was developed, validated and applied to pharmacokinetic study of Liuwei Dihuang pills. Samples were prepared by liquid-liquid extraction with ethyl acetate. Separation was performed on a Wondasil C 18 column (150×4.6 mm, 5 μm) using a mixture of methanol and 0.02 % formic acid water solution (28:72, v/v) as the mobile phase. The flow rate and column temperature were set at 0.7 ml/min and 30°. The compounds were detected in selected ion monitoring mode using an ESI source in the negative mode. The method was linear over the ranges of 5-1000 ng/ml for the three analytes, with all determined correlation coefficients exceeding 0.993. All of the lower limits of quantification of the three analytes were 5 ng/ml. The intra-day and inter-day precisions were less than 7.50 %, and the accuracy ranged from –6.57 to 7.90 %. The mean recoveries of the analytes were higher than 68.86 %, and the matrix effects were between 92.35 and 103.54 %. This method was simple, sensitive and reliable, and could be used to monitor pharmacokinetics of loganin, morroniside and paeoniflorin. Moreover, this study might be helpful for quality control and guiding the clinical application of Liuwei Dihuang pills.