An LC-MS/MS method for the simultaneous determination of amygdalin and paeoniflorin in human urine and application to urinary excretion study

The study aims to develop an LC-MS/MS method for the simultaneous determination of amygdalin and paeoniflorin in urine samples, and to investigate their urinary excretion characteristics in healthy volunteers after intravenous infusion administration of Huoxue-Tongluo lyophilized powder for injection (HTLPI). The urine samples were extracted by methanol, and then separated on a Hedera ODS-2 column with a mobile phase of acetonitrile and 5 mmol·L^-1 ammonium acetate buffer solution containing 0.05% formic acid (20:80). Electrospray ionization source was applied and operated in the positive ion mode using MRM. The method exhibited good linearity over the concentration range of 0.03-40 μg·mL^-1. The values on both the occasions (intra- and inter-day) were all within 15% at three concentration levels. No matrix effect and carry-over effect were observed. Amygdalin and paeoniflorin were stable in human urine under different storage conditions. Approximately 79.6% of the administered amount of amygdalin was excreted unchanged in urine within 24 h and which was 48.4% for paeoniflorin. The developed LC-MS/MS method can be applied to evaluate the urinary excretion of amygdalin and paeoniflorin.