Identification of metabolites and pharmacokinetics of mogrol in rat plasma / 药学学报

Mogrol is the aglycone of seven kinds of mogrosides and siamenoside I. Mogrol has drawn more attention in recent years for its anti-leukemia and anti-diabetes activities. An ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) method was applied to identify the main metabolites of mogrol in rat plasma. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for determination of the main components in rat plasma. After an oral administration of 100 mg·kg-1 mogrol in rats, 13 metabolites were detected along the main component of parent drug in the plasma. The major metabolites were oxidated and dehydrogenated products. In this study, mogrol was quantitative analyzed using lithium carbonate reagent with high sensitivity. The assay was linear in concentration range 5.00-1 000 ng·mL-1 with intra-and inter-day precision within 9.3% and accuracy in range of -4.5% to 2.9%. Mogrol was absorbed into the blood very fast after oral administration, and the time to reach maximum concentration (tmax) was 1.67 h. The half-life (t1/2) of mogrol in rats was 2.34 h, and the oral absolute bioavailability was 3.5%.

Simultaneous determination of donafenib and its N-oxide metabolite in human plasma by liquid chromatography-tandem mass spectrometry / 药学学报

Donafenib is the deuterium derivative of sorafenib, and is an anti-tumor drug in clinical trials. An accurate and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of donafenib and its N-oxide metabolite in human plasma. The analytes and internal standards (sorafenib and sorafenib N-oxide) were extracted from plasma by protein precipitation with acetonitrile, and separated on a Gemini C18 (50 mm×2.0 mm, 5 μm) column using a gradient elution procedure. The mobile phase consisted of acetonitrile and 5 mmol·L-1 ammonium acetate (0.2% formic acid) at a flow rate of 0.7 mL·min-1. The total run time was 5.0 min. Positive electrospray ionization was performed using multiple reaction monitoring (MRM) with transitions of m/z 468.2→273.2 for donafenib and m/z 465.2→270.2 for its internal standard sorafenib, m/z 484.2→289.2 for donafenib N-oxide and m/z 481.2→286.2 for its internal standard sorafenib N-oxide. The standard curves were linear in the range of 5.00-5 000 ng·mL-1 for donafenib, and 1.00-1 000 ng·mL-1 for donafenib N-oxide. The method was validated and successfully applied to the pharmacokinetics study of donafenib tosylate tablets in volunteers.

Determination of anaprazole in human plasma by LC-MS/MS in pharmacokinetic study / 药学学报

Anaprazole is a proton pump inhibitor clinically used for curing peptic ulcer. A rapid, sensitive and convenient LC-MS/MS method was first established for the determination of anaprazole in human plasma. d3, 13C-anaprazole was used as internal standard (IS). After extraction from human plasma by protein precipitation with acetonitrile, all components were separated on an Extend C18 column (100 mm×4.6 mm, 3.5 μm). The assay was linear over the concentration range of 5.00-3 000 ng·mL-1 (r2 > 0.995). The method was successfully applied to a pharmacokinetic study of 40 mg anaprazole enteric-coated tablets in 14 Chinese healthy volunteers under fasting or high fat diet conditions. Cmax was (1 020±435) ng·mL-1 and AUC0-t was (2 370±754) h·ng·mL-1 under fasting condition. And Cmax was (538±395) ng·mL-1 and AUC0-t was (1 610±650) h·ng·mL-1 under high fat diet condition. The plasma results suggest that the exposure of anaprazole is reduced by the high fat diet.

A simple method for quantification of tapentadol in dog plasma by liquid chromatography-tandem mass spectrometry and evaluation of the effects of conjugated metabolites on tapentadol / 药学学报

Tapentadol is a novel drug of opioid pain reliever, which is extensively metabolized primarily through conjugation. Tapentadol glucuronide and tapentadol sulfate are major drug-related metabolites in circulation. The objectives of this study were to develop a simple and rapid method to determine tapentadol and evaluate the effects of conjugated metabolites on tapentadol quantification using liquid chromatography with tandem mass spectrometry in dog plasma. The analyte and tramadol (IS) were extracted from plasma by protein precipitation with methanol, and chromatographied on a XDB C18 (50 mm×4.6 mm, 1.8 μm) column using a mobile phase of methanol and 5 mmol·L-1 ammonium acetate (0.01% ammonia). Mass spectrometric detection was performed using the m/z 222→121 transition for tapentadol and the m/z 264→58 transition for the internal standard tramadol, the m/z 398→m/z 121 transition for glucuronides conjugate and the m/z 302→m/z 222 transition for sulfate conjugate. Conjugated metabolites could undergo in-source conversion to generate an ion that interfered the quantification of tapentadol. Chromatographic separation was achieved to elimination interferences due to in-source conversion of the conjugated metabolites. The standard curves were demonstrated to be linear in the range of 0.100 to 20.0 ng·mL-1 for tapentadol. The intra-and inter-day precisions were within 5.1%, and accuracy ranged from -3.2% to 0. This method was successfully applied to the pharmacokinetics of tapentadol hydrochloride sustained release tablets in Beagle dogs.

Simultaneous determination of sivelestat and its metabolite XW-IMP-A in human plasma using HPLC-MS/MS / 药学学报

A simple and rapid method was developed based on high performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) to determine sivelestat and its metabolite XW-IMP-A in human plasma. After a simple protein precipitation, the samples and internal standards were analyzed on a C18 column by a gradient elution program. The mobile phase consisted of 30% acetonitrile in methanol and 5 mmol · L(-1) ammonium acetate at a flow rate of 0.7 mL · min(-1). The mass spectrometric data was collected in multiple reaction monitoring mode (MRM) in the negative electrospray ionization. The standard curves were linear in the range of 10.0-15,000 ng · mL(-1) for sivelestat, and 2.50-1000 ng · mL(-1) for XW-IMP-A. The low limits of quantitation were identified at 10.0 and 2.50 ng · mL for sivelestat and XW-IMP-A, respectively. The intra- and inter-day precision were within 11.3% and 13.1% for sivelestat and XW-IMP-A, and accuracy was 0.3% and 0.6% for sivelestat and XW-IMP-A, within the acceptable limits across all concentrations. The method was successfully validated in the pharmacokinetic study of sivelestat in healthy Chinese volunteers.

Determination of γ-aminobutyric acid in human plasma by LC-MS/MS and its preliminary application to a human pharmacokinetic study / 药学学报

A rapid, sensitive and convenient LC-MS/MS method was developed for the determination of γ-aminobutyric acid (GABA) in human plasma. d2-γ-Aminobutyric acid (d2-GABA) was synthesized as internal standard (IS). After extraction from human plasma by protein precipitation with acetonitrile, all analytes were separated on a Luna HILIC column (100 mm x 3.0 mm, 3 μm) using an isocratic mobile phase of water: acetonitrile: formic acid (20 : 80 : 0.12) with a flow rate of 0.5 mL x min(-1). Acquisition of mass spectrometric data was performed in multiple reaction monitoring mode (MRM) in positive electrospray ionization using the transitions of m/z 104 --> 69 for GABA and m/z 106 --> 71 for d2-GABA. The method was linear in the concentration range of 5.00 to 1 000 ng x mL(-1). The intra- and inter-day precisions were within 9.9%, and accuracy ranged from 99.1% to 104%, within the acceptable limit across all concentrations. The method was successfully applied to a pharmacokinetic study of GABA tablets in healthy Chinese volunteers.

Liquid chromatography-tandem mass spectrometry simultaneous determination of repaglinide and metformin in human plasma and its application to bioequivalence study / 药学学报

A simple, sensitive, selective, and reproducible liquid chromatography-tandem mass spectrometric method was developed for the simultaneous determination of repaglinide and metformin in human plasma using d5-repaglinide and d6-metformin as internal standards (ISs). After a simple protein precipitation using acetonitrile as the precipitation solvent, both analytes and ISs were separated on a Venusil ASB C 18 (150 mm x 4.6 mm, 5 microm) via gradient elution using acetonitrile--10 mmol x L(-1) ammonium acetate as the mobile phase. A chromatographic total run time of 7.5 min was achieved. Mass spectrometric detection was conducted with atmospheric pressure chemical ionization under positive-ion and multiple-reaction monitoring modes. The method was linear over the 0.2 to 60.0 ng x mL(-1) concentration range for repaglinide and over the 4 to 1 000 ng x mL(-1) range for metformin. For both analytes, the intra- and inter-accuracies and precisions were within the +/- 15% acceptable limit across all concentrations. The validated method was successfully applied to a clinical bioequivalence study.