Determination of 20(S)-ginsenoside Rh1 and its aglycone 20(S)-protopanaxatriol in rat plasma by sensitive LC-APCI-MS method and its application to pharmacokinetic study

Determination of Dammar-20(22)E,24-Diene-3β,6α,12β-Triol in rat plasma by LC-MS/MS and its application in a pharmacokinetic study

Dammar-20(22)E,24-Diene-3β,6α,12β-Triol (YNPT2), as one of the main pharmacological and active components of Panax ginseng, promotes ubiquitination and degradation of hypoxia inducible factor Ia through proteasome, which reduces the content of hypoxia inducible factor Ia in tumor cells. Therefore, it is widely used in tumor inhibition. A sensitive and specific bioanalytical method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the quantification of YNPT2 rat plasma has been developed. Buspirone was used as the internal standard (IS). A 50 μl aliquot of rat plasma sample was deproteinized by 150 μl methanol-acetonitrile (1:1,v:v), vortex-mixed for 1 min and centrifuged at 15,000 r/min for 10 min at 4 °C. Then, 120 μl of supernatant was pipetted out into the autosampler vials and analyzed by LC-MS/MS with 10 μl injection volume. Chromatographic separation was performed on an Agilent ZORBAX XDB-C₁₈ column (2.1 × 50 mm, 3.5 µm) with mobile phases consisting of water containing 5 mM ammonium acetate (mobile phase A) and acetonitrile (mobile phase B) at a flow rate of 0.6 ml/min over a total run time of 4.0 min. YNPT2 and buspirone (IS) were detected and quantified using positive electrospray ionization in multiple reaction monitoring (MRM) mode with transitions of m/z 441.4 → 109.1 for YNPT2 and m/z 386.3 → 122.1 for IS. The linear range was 5-2000 ng/ml with the square regression coefficient (r²) of 0.9972, and the lower limit of quantification (LLOQ) was 5 ng/ml. The intra-day and inter-day precision deviations of YNPT2 ranged from 3.8 to 6.9% and 3.5-5.8%, and accuracy error ranged from -7.4-5.9% and -9.2-11.9%. The average extraction recovery of YNPT2 in rat plasma was between the range of 98.5%-102.7%. This method was successfully applied to study the pharmacokinetics of YNPT2 in rats after intragastric administration at a single dose of 10.0 mg/kg and after intravenous injection at a single dose of 2.0 mg/kg.

Pharmacokinetic and Metabolism Studies of 12-Riboside-Pseudoginsengenin DQ by UPLC-MS/MS and UPLC-QTOF-MSE

Pharmacokinetic and metabolism studies of 12-riboside-pseudoginsengenin DQ (RPDQ), a novel ginsenoside with an anti-cancer effect, were carried out, aiming at discussing the characteristics of the ginsenoside with glycosylation site at C-12. In the pharmacokinetic analysis, we developed and validated a method by UPLC-MS to quantify RPDQ in rat plasma. In the range of 5–1000 ng/mL, the assay was linear (R² > 0.9966), with the LLOQ (lower limit of quantification) being 5 ng/mL. The LOD (limit of detection) was 1.5 ng/mL. The deviations of intra-day and inter-day, expressed as relative standard deviation (RSD), were ≤ 3.51% and ≤ 5.41% respectively. The accuracy, expressed as relative error (RE), was in the range –8.82~3.47% and –5.61~2.87%, respectively. The recoveries were in the range 85.66~92.90%. The method was then applied to a pharmacokinetic study in rats intragastrically administrated with 6, 12, and 24 mg/kg RPDQ. The results showed that RPDQ exhibited slow oral absorption (T_max = 7.0 h, 7.5 h, and 7.0 h, respectively), low elimination (t_1/2 = 12.59 h, 12.83 h, and 13.74 h, respectively) and poor absolute bioavailability (5.55, 5.15, and 6.08%, respectively). Moreover, the investigation of metabolites were carried out by UPLC-QTOF-MS. Thirteen metabolites of RPDQ were characterized from plasma, bile, urine, and feces of rats. Some metabolic pathways, including oxidation, acetylation, hydration, reduction, hydroxylation, glycine conjugation, sulfation, phosphorylation, glucuronidation, glutathione conjugation, and deglycosylation, were profiled. In general, both the rapid quantitative method and a good understanding of the characteristics of RPDQ in vivo were provided in this study.