RESUMO
A sensitive and simple high-performance liquid chromatographic tandem mass spectrometric (LC-MS/MS) method for the determination of verapamil and norverapamil in human plasma was established and utilized in a pharmacokinetic study in healthy patients. Protein was precipitated by methanol in plasma samples, and the analytes and internal standard were separated on an Agilent Zorbax Eclipse C18 column (50 mm×4.6 mm, 5 μm) with a gradient procedure using methanol-acetonitrile (50∶50) as the organic phase and 0.1% formic acid - 5% acetonitrile - 10 mmol·L-1 ammonium formate solution as the mobile phase at flow rate of 0.5 mL·min-1. Electrospray ionization (ESI) and multiple reaction monitoring (MRM) detection modes were used for quantitative detection of verapamil, norverapamil and verapamil-d6 (IS). In the mode of multiple reaction monitoring of positive-ions, the monitoring ion pairs of verapamil, norverapamil and the verapamil-d6 were m/z 445.0→165.2, m/z 441.0→165.2 and m/z 461.1→165.2, respectively. The quantitative lower limit (LLOQ) for the determination of verapamil and norverapamil concentrations in human plasma can reach 0.1 ng·mL-1 in this assay. The calibration curve concentration ranged from 0.1 to 50 ng·mL-1 with high linearity (r2 > 0.997). The matrix effect of verapamil and norverapamil was 99.2%-100% and 101%-102%, respectively. The recovery of verapamil and norverapamil was 86.8%-95.9% and 87.4%-94.8%, respectively. This method has good specificity and high sensitivity. The determination of the verapamil and norverapamil was not subject to the matrix effect and stable extraction recovery was achieved in this assay. This method could be used to determine the concentration of verapamil and norverapamil in human plasma and suitable for human pharmacokinetic studies after approved by ethics committee.
RESUMO
A LC-MS/MS method for quantification of norfloxacin in human plasma had been developed. This method was applied to the pharmacokinetics study of norfloxacin in the human. The plasma sample was precipitated by methanol and ciprofloxacin was used as the internal standard (IS). Chromatographic separation was performed on a Symmetry® C18 column(100 mm×4.6 mm, 5 μm). Mobile phase contains 0.3% formic acid and 5% methanol in deionized water at a flow rate of 0.45 mL·min-1. Norfloxacin and ciprofloxacin (IS) were ionized with an ESI source and operated in positive ion mode. The detected ions were m/z 320.3→302.1 (norfloxacin), m/z 332.3→314.1 (ciprofloxacin). This LC-MS/MS method yielded a linearity over the range of 10-1 000 ng·mL-1 with the lower limit of quantitation (LLOQ) of 10 ng·mL-1. The intra and inter-assay precisions (RSD%) were within the range of 2.64%-7.23% and the accuracy (RE%) was less than ±5.00%. The pharmacokinetic parameters tmax, Cmax, AUC0-t, and t1/2 were 1.28±0.364 h, 627±171 ng·mL-1, 2 938±850 h·ng·mL-1, and 6.01±1.36 h, respectively. This LC-MS /MS method was proven simple, sensitive, rapid and suitable for pharmacokinetics study of norfloxacin in the human and Approved by the Medical Ethics Committee of Liuzhou Workers' Hospital.
RESUMO
A pre-column derivatization method combined with UHPLC-MS/MS was developed for the simultaneous determination of salidroside and tyrosol in Beagle dog plasma. After protein precipitation by acetonitrile, the liquid supernatant was treated with dansyl chloride under dark conditions at 60℃ for 30 min, and then, the sample solution was extracted using methyl tertiary butyl ether. The multiple reaction monitoring in positive ion mode was used for MS detection of the tested analytes with the specific ion transitions of m/z 534.2→372.0 for salidroside derivative, m/z 372.0→171.0 for tyrosol derivative and m/z 506.0→171.0 for arbutin derivative. The chromatograph separation was achieved on an ACQUITY UPLC® BEH C18 column (100 mm×2.1 mm, 1.7 μm) with a gradient mobile phase consisting of acetonitrile (0.1% formic acid)-water (10% acetonitrile, 0.1% formic acid) for 9 min. The assay showed a good linearity over the range of 0.02/0.1-20/10 μmol·L-1 with a lower limit of quantitation of 0.02 and 0.1 μmol·L-1 for salidroside and tyrosol in dog plasma, respectively. The intra-and inter-day precisions were all less than 8.68%, and the accuracy was within ±11.4%. The established method with a high sensitivity, good specificity and reliability was appropriate for simultaneous determination of salidroside and tyrosol in dog plasma and successfully applied to a pharmacokinetic study after intragastric administration of salidroside to Beagle dogs.
RESUMO
<p><b>OBJECTIVE</b>To reveal the relationship among congenital Toxoplasma gondii (T. gondii) infection, T lymphocyte cell subsets in umbilical cord blood and pregnancy outcome.</p><p><b>METHODS</b>784 umbilical cord blood samples were collected and information of pregnancy outcomes was collected in a hospital of Hefei city, Anhui province during March 2009 to May 2010. T. gondii IgM antibodies in the sera were detected by ELISA. For all neonates infected with T. gondii and 10 healthy neonates, T lymphocyte cell subsets were detected by flow cytometry.</p><p><b>RESULTS</b>According to the detection results of T. gondii IgM antibodies, 784 neonates were divided into infection group (21 neonates) and control group (763 neonates). The body weight and 1 min Apgar score of infection group were (3116.4 ± 352.6) g and (8.21 ± 1.26) points, respectively, which were statistically lower than control group ((3220.1 ± 242.3) g and (8.77 ± 1.61) points, respectively) (P < 0.01). The proportion of adverse pregnancy outcome of infection group was 19.0% (4/21), which was statistically greater than control group (4.8%, 37/763) (P < 0.01). The percentage of CD(3)(+) T lymphocyte cells in umbilical cord blood in infection group with and without adverse pregnancy outcomes were (64.51 ± 5.27)% and (64.32 ± 4.56)%, respectively, which were statistically lower than control group ((69.32 ± 4.32)%) (P < 0.01). The ratio value of CD(4)(+)/CD(8)(+) in infection group with, without adverse pregnancy outcomes and control group are 1.39 ± 0.24, 1.64 ± 0.28 and 2.34 ± 0.46, respectively, which showed statistical difference between any 2 groups (P < 0.01).</p><p><b>CONCLUSION</b>T. gondii infection leads to adverse pregnancy outcomes and disorder of cellular immunity while T lymphocyte cell subsets are closely associated with adverse pregnancy outcome.</p>