Studies on the metabolism of a triptolide derivative (5R)-5-hydroxytriptolide in vitro / 药学学报

The purpose of current study is to investigate the metabolic profile of a triptolide derivative (5R)-5-hydroxytriptolide in vitro. (5R)-5-Hydroxytriptolide was incubated with the hepatocytes of human, monkey, dog, rat or mouse, respectively. Compared with inactivated hepatocytes, four metabolites were identified in hepatocytes from all five species: oxidative ring-opening metabolite (M1), glutathione-conjugating metabolite (M2), and monooxidative combined with glutathione-conjugating metabolites (M3-1 and M3-2), respectively. In human or rat liver microsomes, seven metabolites of (5R)-5-hydroxytriptolide were found, dehydrogenated metabolite (M4) and monooxidative metabolites (M5-1–M5-6), respectively. Reference standards for the metabolites were obtained either through chemical semisynthesis or biotransformation through rat primary hepatocytes. The structures of five metabolites were confirmed, which were 12,13-epoxy ring-opening metabolite M1, 12-glutathione-conjugating metabolite M2, (16S)-, (2R)- and (19R)-monohydroxylated metabolites M5-1, M5-4, and M5-5, respectively. In vitro activity assay revealed that only (2R)-hydroxylated metabolite exhibited weak immunosuppressive activity with less than one-tenth the activity of its parent drug, and a significant decrease in toxicity was observed. It is suggested that (5R)-5-hydroxytriptolide might undergo metabolic inactivation and detoxification in vivo.

The enantioselective pharmacokinetic study of desvenlafaxine sustained release tablet in Chinese healthy male volunteers after oral administration / 药学学报

A chiral LC-MS/MS method for the simultaneous analysis of desvenlafaxine (DVS) enantiomers in human plasma was developed and applied to a pharmacokinetic study on 12 Chinese healthy volunteers. d6-Desvenlafaxine was used as internal standard (IS). Chromatographic separation was performed on the Astec Chirobiotic V chiral column (150 mm x 4.6 mm, 5 μm). The assay was linear over the concentration range of 0.500-150 ng x mL(-1) for both enantiomers (r2 > 0.99). The method was successfully applied to a stereoselective pharmacokinetic study of 100 mg desvenlafaxine sustained release tablets on 12 Chinese healthy volunteers under fasting conditions. The results showed that the pharmacokinetic parameters were similar to both enantiomers in Chinese healthy volunteers. The AUC(0-t), and C(max) of the two enantiomers were about 1.5 times higher than those of blacks and whites reported in the literature.

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.

Cancer risk and key components of metabolic syndrome: a population-based prospective cohort study in Chinese / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The key components of metabolic syndrome (MS) are waist circumference, blood pressure, fast blood glucose, high density lipoprotein cholesterol (HDL-c) and triglycerides (TG). These components have, separately and jointly, been associated with an increased risk of cardiovascular diseases. In this study, we aimed to explore the association between MS components and cancer risk in a population-based cohort in China.</p><p><b>METHODS</b>We established a population-based cohort with 17 779 individuals aged 35 and above at baseline in 2004 and 2005 in Changzhou, Jiangsu Province, China. All participants were face-to-face interviewed to complete a questionnaire and were accepted physical examinations including blood tests for glucose and lipids and physical measurements for obesity and blood pressure. In 2009, a total of 16 284 subjects (6886 men and 9398 women, 91.6%) attended the flow-up interviews and the participants or their family members reported all the hospitalizations and diseases including cancer occurred during the follow-up period. Multivariate Cox regression was used to estimate the hazard ratios (HRs) of metabolic syndrome components and cancer incidence.</p><p><b>RESULTS</b>There was a dose-response association between cancer risk and the number of MS components presented at baseline (P for trend = 0.012) and the HR (95% confidence interval (CI)) was 2.63 (1.27 - 5.45) for subjects carrying 3 or more metabolic syndrome components after adjustment for possible confounding factors. Specifically, the multivariate-adjusted HRs (95%CIs) for cancer risk in subjects with central obesity, high fasting glucose, low HDL-c were 1.94 (1.01 - 3.74), 2.04 (1.10 - 3.77) and 2.05 (1.09 - 3.88), respectively.</p><p><b>CONCLUSIONS</b>In this population-based, prospective cohort study in China, we found MS components, e.g., central obesity, high fasting glucose, low HDL-c were risk factors for cancer development. Early intervention of MS components may be also beneficial to reduce cancer burden.</p>