Shaoyu Zhang

Tianjin University, Tianjin, Tianjin Shi, China

Are you Shaoyu Zhang?

Claim your profile

Publications (4)7.38 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A rapid and sensitive liquid chromatography-tandem mass spectrometric method (LC-MS/MS) for the determination of bromotetrandrine in rat plasma has been developed and applied to pharmacokinetic study in Sprague-Dawley (SD) rats after a single oral administration. Sample preparation involves a liquid-liquid extraction with n-hexane-dichlormethane (65:35, containing 1% 2-propanol isopropyl alcohol, v/v). Bromotetrandrine and brodimoprim (internal standard, IS) were well separated by LC with a Dikma C18 column using methanol-ammonium formate aqueous solution (20 mm) containing 0.5% formic acid (60:40, v/v) as mobile phase. Detection was performed on a triple quadrupole mass spectrometer in multiple reaction monitoring mode. The ionization was optimized using ESI+ and selectivity was achieved using MS/MS analysis, m/z 703.0 --> 461.0 and m/z 339.0 --> 281.0 for bromotetrandrine and IS, respectively. The present method exhibited good linearity over the concentration range of 20-5000 ng/mL for bromotetrandrine in rat plasma with a lower limit of quantification of 20 ng/mL. The intra- and inter-day precisions were 2.8-7.5% and 3.2-8.1%, and the intra- and inter-day accuracy ranged from -4.8 to 8.2% and -5.6 to 6.2%, respectively. The method was successfully applied to a pharmacokinetic study after a single oral administration to SD rats with bromotetrandrine of 50 mg/kg.
    Biomedical Chromatography 03/2009; 23(6):623-9. · 1.95 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Aim Biqi capsulae is a new drug made and refined according to morden pharmaceutical preparation theory. It is for the treatment of rheumatic arthritis, rhermatoid arthritis, cervical spondylopathy, scapulohumeral periarthritis and so on. Biqi capsulae has the advantages of good and rapid healing efficacy and excellent pain relieveing effect. Methods This study is aimed to investigate and evaluate the scientificalness and safety of Biqi capsulae prescription compatibility on cytochrome P450 (CYP450). A new "Cocktail" had been established, including probes of phenacetin, tolbutamide, mephenytoin, dextromephen and midazolam. A LC-MS/MS analytical method had been established to determine the above 5 probes and their corresponding metabolites. Results This study determined the in vitro inhibitory effects of Biqi capsulae extract, active constituents of Semen strychni (brucine and strychnine), brucine and strychnine combined with active constituents of Radix Glycyrrhiza uralensis (glycyrrhetic acid and glycyrrhetinic acid) on CYP1A2, 2C9, 2C19, 2D6 and 3A4. Conclusion The results showed that brucine and strychnine had no in vitro inhibitory effect on 5 CYPs. It is possible that groups of brucine and strychnine combined with glycyrrhetic acid and glycyrrhetinic acid had in vitro inhibitory effects on CYP2C9 and CYP2C19.
    Asian Journal of Pharmacodynamics and Pharmacokinetics. 01/2009; 9:277-283.
  • [Show abstract] [Hide abstract]
    ABSTRACT: A rapid and sensitive liquid chromatography-tandem mass spectrometric method (LC/MS/MS) for the determination of tetrandrine in rat plasma has been developed, fully validated and successfully applied to pharmacokinetic study in Sprague-Dawley (SD) rats after a single oral administration. Sample preparation involves a liquid-liquid extraction with n-hexane-dichlormethane (65:35, containing 1% 2-propanol isopropyl alcohol, v/v). Tetrandrine and brodimoprim (internal standard) were well separated by LC with a Dikma C(18) column using acetonitrile-methanol-ammonium formate aqueous solution (20mM) containing 0.3% formic acid (20:30:50, v/v/v) as mobile phase. Detection was performed on a triple quadrupole mass spectrometer in multiple reaction monitoring mode. The ionization was optimized using ESI(+) and selectivity was achieved using MS/MS analysis, m/z 623.0-->381.0 and m/z 339.0-->281.0 for tetrandrine and I.S., respectively. The present method exhibited good linearity over the concentration range of 5-2,000 ng/mL for tetrandrine in rat plasma with a lower limit of quantification of 5 ng/mL. The intra- and inter-day precision were 2.0-9.2% and 4.5-9.4%, and the intra- and inter-day accuracy ranged from -7.6 to 10.3% and -6.0 to 5.3%, respectively. No endogenous compounds were found to interfere with the analysis, and tetrandrine was stable during the whole assay period. The method was successfully applied to a pharmacokinetic study after an intragastric administration (i.g.) of tetrandrine to SD rats with a single dose of 50mg/kg. The results confirm that the assay is suitable for the pharmacokinetic study of tetrandrine.
    Journal of Pharmaceutical and Biomedical Analysis 11/2008; 48(3):974-9. · 2.95 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A reliable liquid chromatography/tandem mass spectrometry has been developed for simultaneous evaluation of the activities of five cytochrome P450s (CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A) in rat plasma and urine. The five-specific probe substrates/metabolites include phenacetin/paracetamol (CYP1A2), tolbutamide/4-hydroxytolbutamide and carboxytolbutamide (CYP2C9), mephenytoin/4'-hydroxymephenytoin (CYP2C19), dextromethorphan/dextrorphan (CYP2D6), and midazolam/1'-hydroxymidazolam (CYP3A). Internal standards were brodimoprim (for phenacetin, paracetamol, midazolam and 1'-hydroxymidazolam), ofloxacin (for 4'-hydroxymephenytoin, dextromethorphan and dextrorphan) and meloxicam (for tolbutamide, 4-hydroxytolbutamide and carboxytolbutamide). Sample preparation was conducted with solid-phase extraction using Oasis HLB cartridges. The chromatography was performed using a C(18) column with mobile phase consisting of methanol/0.1% formic acid in 20 mM ammonium formate (75:25). The triple-quadrupole mass spectrometric detection was operated in both positive mode (for phenacetin, paracetamol, midazolam, 1'-hydroxymidazolam, brodimoprim, 4'-hydroxymephenytoin, dextromethorphan, dextrorphan and ofloxacin) and negative mode (for tolbutamide, 4-hydroxytolbutamide, carboxytolbutamide and meloxicam). Multiple reaction monitoring mode was used for data acquisition. Calibration ranges in plasma were 2.5-2500 ng/mL for phenacetin, 2.5-2500 ng/mL for paracetamol, 5-500 ng/mL for midazolam, and 0.5-500 ng/mL for 1'-hydroxymidazolam. In urine calibration ranges were 5-1000 ng/mL for dextromethorphan, 0.05-10 microg/mL for dextrorphan and 4'-hydroxymephenytoin, 5-2000 ng/mL for tolbutamide, 0.05-20 microg/mL for 4-hydroxytolbutamide and 0.025-10 microg/mL for carboxytolbutamide. The intra- and inter-day precision were 4.3-12.4% and 1.5-14.8%, respectively for all of the above analytes. The intra- and inter-day accuracy ranged from -9.1 to 8.3% and -10 to 9.2%, respectively for all of the above analytes. The lower limits of quantification were 2.5 ng/mL for phenacetin and paracetamol, 5 ng/mL for midazolam, 0.5 ng/mL for 1'-hydroxymidazolam, 5 ng/mL for dextromethorphan, 50 ng/mL for dextrorphan and 4'-hydroxymephenytoin, 5 ng/mL for tolbutamide, 50 ng/mL for 4-hydroxytolbutamide and 25 ng/mL for carboxytolbutamide. All the analytes were evaluated for short-term (24 h, room temperature), long-term (3 months, -20 degrees C), three freeze-thaw cycles and autosampler (24 h, 4 degrees C) stability. The stability of urine samples was also prepared with and without beta-glucuronidase incubation (37 degrees C) and measured comparatively. No significant loss of the analytes was observed at any of the investigated conditions. The current method provides a robust and reliable analytical tool for the above five-probe drug cocktail, and has been successfully verified with known CYP inducers.
    Journal of Chromatography B 07/2008; 871(1):78-89. · 2.49 Impact Factor