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Positive Ion Electrospray Ionization (positive + ion_electrospray_ionization)
Selected AbstractsA validated liquid chromatographic/tandem mass spectrometric method for the determination of phencyclidine in microliter samples of rat serumJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 1 2005Howard P. Hendrickson Abstract A liquid chromatographic/tandem mass spectrometric method is described for the determination of phencyclidine (PCP) in small volumes of rat serum (e.g. 50 µl). Samples were extracted using a mixed-mode strong cation-exchange column and then separated isocratically using a narrow-bore (2.1 mm i.d.) 3 µm Hypersil phenyl column and a mobile phase consisting of an ammonium formate buffer (pH 2.7) with 60% (v/v) methanol. Detection was accomplished using positive ion electrospray ionization in the multiple reaction monitoring mode. Mass spectra were obtained and peaks were observed at an m/z (% abundance) of 244 (100), 159 (25), and 86 (89). Tandem mass spectra were also obtained from the m/z 244 precursor ion with peaks observed at m/z 159 (100), 86 (96), and 91 (11). Optimum serum PCP sensitivity and precision were obtained at a transition of m/z 244 , 159. Matrix-associated ion suppression did not significantly affect the accuracy (100,112%) or precision (CV ,8%) of the assay. The lower limit of quantitation was 1 ng ml,1 in 50 µl of serum. The method was used to study the serum pharmacokinetics of PCP in rats after an intravenous bolus dose of PCP. Copyright © 2004 John Wiley & Sons, Ltd. [source] Rapid quantification of levosulpiride in human plasma using RP-HPLC-MS/MS for pharmacokinetic and bioequivalence studyBIOMEDICAL CHROMATOGRAPHY, Issue 12 2009Jin-Hee Park Abstract A rapid and validated method for analysis of levosulpiride in human plasma using liquid chromatography coupled to tandem mass spectrometry was developed. Levosulpiride and tiapride (IS, internal standard) were extracted from alkalized plasma samples with ethylacetate and separation by RP-HPLC. Detection was performed by positive ion electrospray ionization in multiple-reaction monitoring mode, monitoring the transitions m/z 342.1 , m/z 112.2 and m/z 329.1 , m/z 213.2, for quantification of levosulpiride and IS, respectively. The standard calibration curves showed good linearity within the range of 2,200 ng/mL (r2 , 0.9990). The lower limit of quantitation was 2 ng/mL. The retention times of levosulpiride (0.63 min) and IS (0.66 min) presented a significant time saving benefit of the proposed method. No significant metabolic compounds were found to interfere with the analysis. This method offered good precision and accuracy and was successfully applied for the pharmacokinetic and bioequivalence study of a 25 mg of levosulpiride tablet in 24 healthy Korean volunteers. Copyright © 2009 John Wiley & Sons, Ltd. [source] Simultaneous determination and pharmacokinetic study of oxymatrine and matrine in beagle dog plasma after oral administration of Kushen formula granule, oxymatrine and matrine by LC-MS/MSBIOMEDICAL CHROMATOGRAPHY, Issue 8 2007Yiqi Wang Abstract A rapid, specific and sensitive LC-MS/MS method was developed for the determination of oxymatrine (OMT) and matrine (MT) in beagle dog plasma. The method was applied to study the pharmacokinetics of OMT and MT after oral administration of OMT, MT and Kushen formula granule (KFG) containing equivalent amounts of OMT and MT in a three-period crossover design. The analysis was carried out on an Acquity UPLCÔ BEH C18 column by linear gradient elution with 0.01% acetic acid,water,methanol as mobile phase. Detection was by positive ion electrospray ionization (ESI) mass spectrometry with multiple-reaction monitoring (MRM). Linear calibration curves were both obtained over the concentration range 15,2000 ng/mL, with a limit of quantification of 15 ng/mL. The matrix effect was minimized. The intra- and inter-day precisions (RSDs) were less than 12.4 and 14.7%, respectively, and the accuracy (RE) was from ,2.1 to 2.7%. The validated method was used to determine the concentration,time profiles of OMT and MT. The results indicated that the absorption of OMT and MT after oral administration of KFG was significantly greater than that after oral administration of pure components. Copyright © 2007 John Wiley & Sons, Ltd. [source] Amlodipine bioequivalence study: quantification by liquid chromatography coupled to tandem mass spectrometryBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 9 2001M. Carvalho Abstract Objective,To assess the bioequivalence of two amlodipine tablet formulations (Amlodipine® 5 mg tablet from Merck S.A. Indústrias Químicas, Brazil as test formulation and Norvasc® 5 mg tablet from Laboratórios Pfizer Ltd., Brazil as reference formulation) in 24 healthy volunteers of both sexes. Methods,The study was conducted using an open, randomized two-period crossover design with a 4-week washout interval. Plasma samples were obtained over a 144 h period. Plasma amlodipine concentrations were analyzed by combined liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS) with positive ion electrospray ionization using multiple reaction monitoring (MRM). From the amlodipine plasma concentration vs time curves, the following pharmacokinetic parameters were obtained: AUClast, AUC0,inf and Cmax. The statistical interval proposed was 80,125% according to the US Food and Drug Administration Agency. Results,The limit of quantification was 0.1 ng/ml for plasma amlodipine analysis. The geometric mean and the 90% confidence interval (CI) test/reference ratios were 101.2 (92.9,110.2%) for AUClast, 99.6 (91.5,108.4%) for AUC0,inf and 98.5 (89.0,109.1%) for Cmax. Conclusion,Since the 90% CI for AUClast, AUC0,inf and Cmax ratios were within in the 80,125% interval proposed by the US FDA, it was concluded that Amlodipine® 5 mg tablet (test formulation) was bioequivalent to Norvasc® 5 mg tablet, in terms of both rate and extent of absorption. Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||