Determination of bupropion hydrochloride in rat plasma by LC-MS/MS and Its application to pharmacokinetic study

A selective and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for quantitation of bupropion hydrochloride in rat plasma using triazolam as an internal standard. Chromatographic separation was achieved on a SB-C18 column at 30 °C, with 50: 50 (v/v) acetonitrile-0.1 % formic acid in water as mobile phase. The flow rate was 0.3 mL/min. The determination of bupropion was performed in MRM mode, m/z 239.9 → 183.7 for bupropion and m/z 343.0 → 308.0 for triazolam (IS) and positive ion electrospray ionization interface. Calibration curve was linear over range of 1.2 to 480 ng/mL. The intra- and inter-run relative standard deviations of the assay were less than 10 %. The mean absolute recoveries determined at the concentrations of 2.4, 48 and 360 ng/mLwere 91.00%, 92.06%, 91.71%, respectively. The validated method is successfully used to analyze the drug in samples of rat plasma for pharmacokinetic study.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Determination of bupropion hydrochloride in rat plasma by LC-MS/MS and Its application to pharmacokinetic study

A selective and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for quantitation of bupropion hydrochloride in rat plasma using triazolam as an internal standard. Chromatographic separation was achieved on a SB-C18 column at 30 °C, with 50: 50 (v/v) acetonitrile-0.1 % formic acid in water as mobile phase. The flow rate was 0.3 mL/min. The determination of bupropion was performed in MRM mode, m/z 239.9 → 183.7 for bupropion and m/z 343.0 → 308.0 for triazolam (IS) and positive ion electrospray ionization interface. Calibration curve was linear over range of 1.2 to 480 ng/mL. The intra- and inter-run relative standard deviations of the assay were less than 10 %. The mean absolute recoveries determined at the concentrations of 2.4, 48 and 360 ng/mLwere 91.00%, 92.06%, 91.71%, respectively. The validated method is successfully used to analyze the drug in samples of rat plasma for pharmacokinetic study.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Discovery of a pair density wave state in a monolayer high-Tc iron-based superconductor

The pair density wave (PDW) is an extraordinary superconducting state where Cooper pairs carry nonzero momentum. It can emerge when the full condensation of zero momentum Cooper pairs is frustrated. Evidence for the existence of intrinsic PDW order in high-temperature (high-Tc) cuprate superconductors and kagome superconductors has emerged recently. However, the PDW order in iron-based high-Tc superconductors has not been observed experimentally. Here, using scanning tunneling microscopy/spectroscopy, we report the discovery of the PDW state in monolayer iron-based high-Tc Fe(Te,Se) films grown on SrTiO3(001) substrates. The PDW state with a period of {\lambda}~3.6a_Fe (a_Fe is the distance between neighboring Fe atoms) is observed at the domain walls by the spatial electronic modulations of the local density of states, superconducting gap, and the {\pi}-phase shift boundaries of the PDW around the dislocations of the intertwined charge density wave order. The discovery of the PDW state in the monolayer Fe(Te,Se) film provides a low-dimensional platform to study the interplay between the correlated electronic states and unconventional Cooper pairing in high-Tc superconductors

Development and Validation of Liquid Chromatography-Mass Spectrometry Method for Determination of Febuxostat in Rat Plasma and its Application

A selective liquid chromatography-mass spectrometry (LC–MS) method for determination of febuxostat in rat plasma was developed and validated. After addition of midazolam as internal standard (IS), protein precipitation by acetonitrile was used as sample preparation, and chromatography involved Agilent SB-C18 column (2.1 x150 mm, 5 μm) using 0.1% formic acid in water and acetonitrile as a mobile phase with gradient elution. Detection involved positive ion mode electrospray ionization (ESI), and selective ion monitoring (SIM) mode was used for quantification of target fragment ions m/z 317 for febuxostat and m/z 326 for midazolam (internal standard, IS). The assay was linear over the range of 10-2000 ng/mL for febuxostat, with a lower limit of quantitation (LLOQ) of 10 ng/mL for febuxostat. Intra- and inter-day RSDs were less than 15% and the accuracies were in the range of 93.8-111.9% for febuxostat. This developed method was successfully applied to determinate of febuxostat in rat plasma for pharmacokinetic study.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Determination of bupropion hydrochloride in rat plasma by LC-MS/MS and Its application to pharmacokinetic study

A selective and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for quantitation of bupropion hydrochloride in rat plasma using triazolam as an internal standard. Chromatographic separation was achieved on a SB-C18 column at 30 °C, with 50: 50 (v/v) acetonitrile-0.1 % formic acid in water as mobile phase. The flow rate was 0.3 mL/min. The determination of bupropion was performed in MRM mode, m/z 239.9 → 183.7 for bupropion and m/z 343.0 → 308.0 for triazolam (IS) and positive ion electrospray ionization interface. Calibration curve was linear over range of 1.2 to 480 ng/mL. The intra- and inter-run relative standard deviations of the assay were less than 10 %. The mean absolute recoveries determined at the concentrations of 2.4, 48 and 360 ng/mLwere 91.00%, 92.06%, 91.71%, respectively. The validated method is successfully used to analyze the drug in samples of rat plasma for pharmacokinetic study.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Determination of dezocine in rabbit plasma by liquid chromatography-mass spectrometry and its application

A sensitive and selective liquid chromatography-mass spectrometry (LC–MS) method for determination of dezocine in rabbit plasma was developed and validated. After addition of diazepam as internal standard (IS), liquid–liquid extraction (LLE) was used for sample preparation, and chromatography involved Agilent SB-C18 column (2.1 mmx50 mm, 3.5 um) using 0.1 % formic acid in water and acetonitrile as a mobile phase with gradient elution. Detection involved positive ion mode electrospray ionization (ESI), and selective ion monitoring (SIM) mode was used for quantification of target fragment ions m/z 245.8 for dezocine and m/z 284.8 for diazepam (internal standard, IS). The assay was linear over the range of 5–500 ng/mL for dezocine, with a lower limit of quantitation (LLOQ) of 5 ng/mL for dezocine. Intra- and inter-day precisions were less than 13 % and the accuracies were in the range of 93.1-105.2 % for dezocine. This developed method was successfully applied for the determination of dezocine in rabbit plasma for pharmacokinetic study.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Determination of sulpiride in rabbit plasma by LC-ESI-MS and its application to a pharmacokinetic study

A sensitive and selective liquid chromatography-mass spectrometry (LC-MS) method for determination of sulpiride in rabbit plasma was developed and validated. The analyte and internal standard (IS) were extracted from plasma by liquid-liquid extraction using ethyl acetate, and chromatography involved Agilent Extend-C18 column (2.1 mm x 50 mm, 3.5 μm) using 0.2 % formic acid in water and acetonitrile (60: 40, v/v) as a mobile phase. Detection involved positive ion mode electrospray ionization (ESI), and selective ion monitoring (SIM) mode was used for quantification of target fragmentions m/z 342.0 for sulpiride and m/z 294.8 for estazolam (internal standard, IS). The assay was linear over the range of 10-2000 ng/mL for sulpiride, with a lower limit of quantitation (LLOQ) of 10 ng/mL for sulpiride. Intraand inter-day precisions were less than 12 % and the accuracies were in the range of 94.1-108.7 % for sulpiride. This developed method was successfully applied for the determination of sulpiride in rabbit plasma for pharmacokinetic study.Colegio de Farmacéuticos de la Provincia de Buenos Aire

A simple LC-ESI-MS method for the determination of norvancomycin in rat plasma and application to pharmacokinetic study

A simple and sensitive LC-ESI-MS method for determination of norvancomycin in plasma was developed and validated over the concentration range of 20-2,000 ng/mL. After addition of vancomycin as internal standard (IS), protein precipitation with 5 % trichloroacetic acid was employed for the sample preparation. Chromatographic separation was performed on a Zorbax SB-C18 (100 mm×2.1 mm, 3.5 μm) column with 10:90 (v/v) acetonitrile-0.1 % formic acid as mobile phase. The MS data acquisition was accomplished by selective ions monitoring (SIM) mode with positive electrospray ionization (ESI) interface. The limit of quantification (LOQ) was 20 ng/mL. For inter-day and intra-day tests, the precision (RSD) for the entire validation was less than 12 %. The developed method was successfully applied to pharmacokinetic studies of norvancomycin in rats following single intravenous administration dose of 10 mg/Kg.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Determination of meropenem in rabbit plasma by LC-MS/MS

A sensitive and selective liquid chromatography tandem mass spectrometry (LC–MS/MS) method for determination of meropenem in rabbit plasma was developed. After addition of triazolam as internal standard (IS), protein precipitation by acetonitrile was used in sample preparation. Chromatographic separation was achieved on a Restek Allure (TM) PFP Propyl (2.1 mm × 100 mm, 5 μm) column with acetonitrile-0.1 % formic acid as mobile phase with gradient elution. Electrospray ionization (ESI) source was applied and operated in positive ion mode; multiple reaction monitoring (MRM) mode was used to quantification using target fragment ions m/z 384.1 → 339.9 for meropenem and m/z 342.7 → 307.8 for the IS. Calibration plots were linear over the range of 0.1-40 μg/mL for meropenem in plasma. Lower limit of quantification (LLOQ) for meropenem was 0.1 μg/mL. Mean recovery of meropenem from plasma was in the range 85.6 %-96.5 %. CV of intra-day and inter-day precision were both less than 15 %. This method is simple and sensitive enough to be used in pharmacokinetic research for determination of meropenem in rabbit plasma.Colegio de Farmacéuticos de la Provincia de Buenos Aire