Yan Li

Fourth Military Medical University, Xi’an, Liaoning, China

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Publications (3)8.71 Total impact

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    ABSTRACT: A sensitive, selective and efficient liquid chromatographic/tandem mass spectrometric (LC/MS/MS) method was developed and validated for the determination of glucosamine in healthy human urine. Urine samples were extracted by acetonitrile and derivatized with o-phthalaldehyde/3-mercaptopropionic acid. Analysis was then carried out using ESI source and methanol/0.2% ammonium acetate-0.1% formic acid mobile phase gradient elution, with tolterodine tartrate as the internal standard. The linear calibration curve ranged from 0.41μg/ml to 82.7μg/ml. The intra-day and inter-day precisions were less than 3.93% and 10.0%, respectively. The extraction recoveries determined at three concentration levels were higher than 88.6%. The method was successfully applied for determining the urine concentration of glucosamine up to 24h after oral administration of 1g glucosamine sulfate dispersible table (containing 785.08mg glucosamine) from a clinical pharmacokinetic study in healthy volunteers.
    No preview · Article · Apr 2011 · Journal of pharmaceutical and biomedical analysis
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    ABSTRACT: A sensitive and rapid LC-MS/MS method was developed and validated for the determination of levamisole in human plasma. The assay was based on liquid-liquid extraction of analytes from human plasma with ethyl ether. Chromatographic separation was carried on an Agilent HC-C(8) column (150 mm × 4.6 mm, 5 μm) at 40°C, with a mobile phase consisting of acetonitrile-10 mM ammonium acetate (70:30, v/v), a flow rate of 0.5 mL/min and a total run time of 6 min. Detection and quantification were performed by mass spectrometry in the multiple reaction monitoring mode with positive electrospray ionization m/z at 205.1→178.2 for levamisole, and m/z 296.1→264.1 for mebendazole (internal standard). The assay was linear over a concentration range of 0.1-30 ng/mL with a lower limit of quantification of 0.1 ng/mL. The coefficient of variation of the assay precision was less than 8.5%. The assay was successfully used to analyze human plasma samples in a pharmacokinetic study where levamisole was administered as a liniment.
    No preview · Article · Feb 2011 · Journal of chromatography. B, Analytical technologies in the biomedical and life sciences
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    ABSTRACT: Safflower is a popular Traditional Chinese Medicine (TCM) to invigorate the blood and dispel 'blood stasis', which arises from poor blood circulation. The differences of pharmacokinetic properties between normal and blood stasis syndrome rats were seldom reported. The present study was conducted to evaluate the pharmacokinetics of hydroxysafflower yellow A (HSYA) following oral administration of hydroxysafflower yellow A and safflower extract with approximately the same dose of HSYA 100mg/kg in both normal and acute blood stasis rats. The animals were orally administered with HYSA monomer and safflower extract. The blood samples were collected according to the time schedule. The concentrations of HSYA in rat plasma were determined by HPLC. Various pharmacokinetic parameters were estimated from the plasma concentration versus time data using non-compartmental methods. It was found that AUC(0-t), C(max), Vd and CL of HSYA in both HSYA monomer and safflower extract in acute blood stasis rats were with significant difference (P<0.05) comparing with that in normal rats. The results indicated that HSYA was with high uptake and eliminated slowly in the animals with blood stasis syndrome, suggesting that the rate and extent of drug metabolism was altered in acute blood stasis animals.
    No preview · Article · Mar 2010 · Journal of ethnopharmacology