Pharmacokinetic Studies On 20 (S)- Protopanaxadiol And Yijinsheng Caps And Domperidone

A simple, rapid and sensitive method for the determination of 20 (s) - protopanaxadiol using ginsenoside Rh2 as internal standard has been developed and validated for the first time. The method was applied in preclinical pharmacokinetics studies in vivo of 20(s)- protopanaxadiol and yijinsheng caps. It is the first time to clarify the metabolism mechanisms of 20 (s) - protopanaxadiol after comparing the result of LC/MS/MS with isotopic tracer method. An analytical method was developed and validated for studying the pharmacokinetics of domperidone in healthy volunteers by LC/MS/MS.1 The method to determination of 20 (s) - protopanaxadiol and its metabolite in biological samplesLC/MS/MS: An LC/MS/MS method was developed and validated for determination of 20 (s) - protopanaxadiol and its metabolite in biological samples with Rh2 as the internal standard. The analytical method was optimized by the investigations on chromatographic conditions, mass spectrometric conditions, extraction methods and selection of internal standard. The analyte and internal standard were extracted from plasma samples by 3 ml diethyl ether-dichloromethane (60:40 v/v), and separated on a Zorbax Extend C18 column (50 mm×2.1 mm I.D.,3.5μm) with the mobile phase consisting of acetonitrile:water: 10 mmol/L ammonium acetate (45:45:10, v/v/v) at a flow rate of 0.4 mL/min. Detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode via electrospray ionization (ESI) source. The analytical method developed in present thesis was better in sensitivity, linear range and determining velocity than those methods reported in literatures. Isotopic tracer method: According to literatures, we developed and validated the isotopic tracer method, which had highly selective and sensitive for the determination of sum concentrations of 20 (s) - protopanaxadiol and its metabolite in urine, feces, bile and had acceptable precision and accuracy.2 Pharmacokinetic characteristics of 20 (s) - protopanaxadiolAbsorption: The absolute bioavailability for wistar rats and beagle dogs were 28.5% and 11.0% show a low bioavailability of 20 (s) - protopanaxadiol. Comparing with the results of [3H] isotopic tracer method:"the recovery of 36h after an oral dose of [3H] 20 (s) - protopanaxadiol to wistar rats was 82.7% in bile", it was revealed high absorption rate more than 82.7% and 20 (s) - protopanaxadiol suffered a strong first–pass metabolism to produce conjugated metabolite. The statistical results of the pharmacokinetics parameter for 20 (s)– protopanaxadiol in individual show small difference, more difference for race.plasma protein combination rate: The results of plasma protein combination rate in 24 h on three concentration levels were more than 97%; the mean value was 98.02% which show high plasma protein combination rate of 20 (s)– protopanaxadiol in plasma in combination mode.Disposition in tissue: The drug was mainly distributed in intestinal contents, heart, pancreas and smooth muscle after oral dose for 2 h. The elimination of 20 (s)– protopanaxadiol from the tissues was rapid and it was indicated that the drug did not readily accumulated in vivo.Elimination: we used LC/MS/MS for determination of 20 (s)– protopanaxadiol and [3H] isotopic tracer method for sum concentrations of 20 (s) - protopanaxadiol and its metabolite. The drug metabolized abroad after oral dose and eliminated through faces and urine. The recovery of 36h after an oral dose of [3H] 20 (s) - protopanaxadiol to wistar rats was 82.7% in bile and 59.6% in faces for 96 h. It show that the drug and metabolite suffered strong hepatic–intestinal cycle.Compartment mode: the pharmacokinetic characteristics of 20 (s)– protopanaxadiol fit three compartment after intravenous injection for both rat and dog and fit two compartment after oral dose. The pharmacokinetic characteristics of 20 (s)– protopanaxadiol after intravenous injection was more complex than oral dose. Eliminationkinetics mode: the dose-independent pharmacokinetics was observed both in rat and in dog after investigating AUC0-t, AUC0-∞and Cmax in three concentration levels.3 Pharmacokinetic characteristics of 20 (s)– protopanaxadiol capsThe pharmacokinetic characteristics of 20 (s)– protopanaxadiol fit three compartment after intravenous injection 20 (s)– protopanaxadiol and fit one compartment after oral dose 20 (s)– protopanaxadiol caps in dog vivo. The mean absolute bioavailability for beagle dogs was 17.07%.4 Metabolism of 20 (s)– protopanaxadiolThe experiment for metabolism of 20 (s)– protopanaxadiol by LC/MS/MS was carried out after collected 0-12 h bile samples. The drug metabolized abroad after oral dose and eliminated through faces and urine. The main metabolite was epimers diastereomer, we didn't find 20 (s)– protopanaxadiol -O-glucuronide.5 Pharmacokinetic characteristics of domperidoneThe concentrations of domperidone in human plasma samples at different time points were determined by LC/MS/MS and the plasma concentrations-time profiles were obtained. The pharmacokinetic parameters were described by the obtained data. 6 Conclusions The pharmacokinetic evaluations on 20 (s)– protopanaxadiol in animals was carried out in this thesis, based on which the drug development was promoted for these compounds. The analytical methods, established and successfully applied here, would be quite valuable references for the determinations of the other saponins in biosamples.The LC/MS/MS method was suitable for the pharmacokinetic study of domperidone in human and the therapeutic drug monitoring with the advantage of accuracy, sensitivity and high speed.