The Study Of Geniposide On Toxicokinetics In Rats

Objective:The purpose of this study is to develop an accurate,reliable and efficient high performance liquid chromatography-tandem mass spectrometric?LC-MS/MS?method to simultaneously quantify geniposide and its metabolite genipin in rat plasma or tissue homogenate,and to simultaneously determine geniposide and genipin in rat plasma after oral administration of geniposide at a single dose,and to investigate the influence of different dosages?including normal dosage and the low,moderate,high toxic dosages?of geniposide and the gender on pharmacokinetics of geniposide and genipin in rats,and to elucidate the regulations of tissue distribution of geniposide and genipin in rats after oral administration of geniposide at different dosages?including normal dosage and toxical dosages?.Methods:Plasma or tissue samples were pretreated by liquid-liquid extraction with ethyl acetate.Paeoniflorin was used as the internal standard.The chromatographic separation was carried out on an Agilent ZORBAX Eclipse plus-C₁₈?150 mm × 2.1 mm i.d.,3.5? m?column.The mass analyses were performed in an API 4000+ triple-quadrupole mass spectrometer via multiple reaction monitoring?MRM?with positive scan mode.The plasma samples were collected from the ocular vein into heparinized tubes after oral administration of geniposide at a single dose.The concentrations of geniposide and genipin in rat plasma and tissue was detected by LC-MS/MS,and mean concentration-time curves of geniposide and genipin and main pharmacokinetic parameters of geniposide in rat plasma and tissue homogenate after oral administration of geniposide were obtained with DAS2.1.1 program software.Results:?1?The results showed that the calibration curves were linear in the concentrations range of 64.5-12900 ng/mL for geniposide and 14.8-2960ng/mL for genipin in plasma,respectively.The intra-day precision of this method was less than 5.2%,and the inter-day precision was less than 11.5%.?2?The calibration curves were linear in the concentrations range of 10.2-2020 ng/mL for geniposide and 4.8-960ng/mL for genipin in tissue homogenate,respectively.The intra-day precision of this method was less than 7.25%,and the inter-day precision was less than 13.86%,respectively.?3?The conspicuous differences were presented on AUC and Cmax of geniposide in rat plasma between normal dosage group and the three toxic dosage groups.?4?There was no difference on AUC and Cmax of geniposide in rat plasma between male group and female group.?5?The AUC values in tissues of geniposide in the order of kidney>plasma>spleen>lung>liver>heart>brain in normal dosage group and in the order of kidney>plasma>liver>spleen>lung>heart>brain in toxic dosage groups,respectively.While the AUC values in tissues of genipin in the order of kidney>plasma>liver>spleen>lung>heart>brain in toxic dosage groups in,and in the order of liver>plasma>kidney>spleen>heart>lung>brain in toxic groups.Conclusion:The two validated methods were successfully applied to quantify plasma and tissue homogenate concentrations of geniposide and genipin in rats after intragastric administration of geniposide at different doses.The conspicuous differences were presented on pharmacokinetics of geniposide in rat plasma between normal dosage group and the three toxic dosage groups.There was no influence of gender on pharmacokinetics of geniposide,where as which of genipin was existed in rats on pharmacokinetics after oral administration of geniposide by a single dose.The toxicity of geniposide at a high dosage was be related to the regulations of tissue distribution of geniposide and genipin in rats after oral administration of geniposide,and genipin was main stored in liver which was possibly the main reason of hepatotoxicity of geniposide at a high dosage.