1,956 research outputs found
Ethyl 5-methyl-4-oxo-3-phenyl-2-propylamino-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxylate
The title compound, C19H21N3O3S, was synthesized via the aza-Wittig reaction of functionalized iminophosphorane with phenyl isocyanate under mild conditions. In the molecule, the fused thienopyrimidine ring system is essentially planar, with a maximum deviation of 0.072 (2) Å, and makes a dihedral angle of 60.11 (9)° with the phenyl ring. An intramolecular C—H⋯O hydrogen bond is present. The crystal packing is stabilized by intermolecular N—H⋯O and C—H⋯O hydrogen bonds
Determination of dextromethorphan in rabbit plasma by LC-MS/MS and its application to pharmacokinetic study
A highly sensitive liquid chromatographic tandem mass spectrometric (LC-MS/MS) method for determination of dextromethorphan in rabbit plasma using triazolam as the internal standard (IS) was developed. Plasma samples were extracted with ethyl acetate and separated on a SB-C18 column with a mobile phase of acetonitrile-water 60:40 (v/v) at a flow of 0.3 mL/min. Detection is carried out by multiple reaction monitoring (MRM) on a ion-trap LC-MS/MS system with an electrospray ionization interface. The lower limit of quantification (LLOQ) was 1 ng/mL. After intravenous administration of a single dose of dextromethorphan 2 mg/kg, the main pharmacokinetic parameters were as follows: AUC0→t 636.13 ± 47.13 (ng/mL·h); CL 2.60 ± 0.24 (L/h), Cmax 874 ± 67.16 (ng/mL), Vz 1.58 ± 0.11 (L/kg), T1/2 2.41 ± 0.35 (h), MRT 1.26 ± 0.08 (h).Colegio de Farmacéuticos de la Provincia de Buenos Aire
Determination of dextromethorphan in rabbit plasma by LC-MS/MS and its application to pharmacokinetic study
A highly sensitive liquid chromatographic tandem mass spectrometric (LC-MS/MS) method for determination of dextromethorphan in rabbit plasma using triazolam as the internal standard (IS) was developed. Plasma samples were extracted with ethyl acetate and separated on a SB-C18 column with a mobile phase of acetonitrile-water 60:40 (v/v) at a flow of 0.3 mL/min. Detection is carried out by multiple reaction monitoring (MRM) on a ion-trap LC-MS/MS system with an electrospray ionization interface. The lower limit of quantification (LLOQ) was 1 ng/mL. After intravenous administration of a single dose of dextromethorphan 2 mg/kg, the main pharmacokinetic parameters were as follows: AUC0→t 636.13 ± 47.13 (ng/mL·h); CL 2.60 ± 0.24 (L/h), Cmax 874 ± 67.16 (ng/mL), Vz 1.58 ± 0.11 (L/kg), T1/2 2.41 ± 0.35 (h), MRT 1.26 ± 0.08 (h).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 tetramethylpyrazine in rat plasma by liquid chromatography/electrospray mass spectrometry
A sensitive and selective liquid chromatography/electrospray mass spectrometry (LC-ESIMS)
method for determination of tetramethylpyrazine in rat plasma was developed. After addition of
phenacetin as internal standard, protein precipitation by acetonitrile was used as sample preparation.
Chromatographic separation was achieved on a Zorbax SB-C18 (2.1 mm×150 mm, 5 µm) column with
(40:60, v/v) acetonitrile-water containing 0.1 % formic acid as mobile phase. Electrospray ionization (ESI)
source was applied and operated in positive ion mode; selected ion monitoring (SIM) mode was used to
quantify tetramethylpyrazine using target fragment ions m/z 136.9 for tetramethylpyrazine and m/z 179.8
for the IS. Calibration plots were linear over the range of 20-4000 ng/mL for tetramethylpyrazine in plasma.
Lower limit of quantitation (LLOQ) for tetramethylpyrazine was 20 ng/mL. Mean recovery of tetramethylpyrazine
from plasma was in the range 95.4-97.2 %. RSD of intra-day and inter-day precision were
less than 9 %, respectively. This method is simple, sensitive and fast enough to be used in pharmacokinetic
research for determination of tetramethylpyrazine in rat plasma.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 tetramethylpyrazine in rat plasma by liquid chromatography/electrospray mass spectrometry
A sensitive and selective liquid chromatography/electrospray mass spectrometry (LC-ESIMS)
method for determination of tetramethylpyrazine in rat plasma was developed. After addition of
phenacetin as internal standard, protein precipitation by acetonitrile was used as sample preparation.
Chromatographic separation was achieved on a Zorbax SB-C18 (2.1 mm×150 mm, 5 µm) column with
(40:60, v/v) acetonitrile-water containing 0.1 % formic acid as mobile phase. Electrospray ionization (ESI)
source was applied and operated in positive ion mode; selected ion monitoring (SIM) mode was used to
quantify tetramethylpyrazine using target fragment ions m/z 136.9 for tetramethylpyrazine and m/z 179.8
for the IS. Calibration plots were linear over the range of 20-4000 ng/mL for tetramethylpyrazine in plasma.
Lower limit of quantitation (LLOQ) for tetramethylpyrazine was 20 ng/mL. Mean recovery of tetramethylpyrazine
from plasma was in the range 95.4-97.2 %. RSD of intra-day and inter-day precision were
less than 9 %, respectively. This method is simple, sensitive and fast enough to be used in pharmacokinetic
research for determination of tetramethylpyrazine in rat plasma.Colegio de Farmacéuticos de la Provincia de Buenos Aire
Determination of tolbutamide and hydroxytolbutamide by LC–MS/MS in rat and its application to assessment of CYP2C9 activity
A sensitive and selective liquid chromatography–tandem mass spectrometry method (LC–MS/MS) for the determination of tolbutamide (TB) and its metabolite hydroxytolbutamide (HTB) in rat plasma was developed using carbamazepine as an internal standard. Chromatographic separation was performed by an Agilent Zorbax SB-C18 column (150 mmx2.1 mm, 3.5 μm), using the gradient elution of 0.1 % formic acid in water and acetonitrile. Calibration plots were linear over range of 5–1000 ng/mL for TB and 10–2000 ng/mL for HTB in rat plasma. The intra- and inter-day relative standard deviations of the assay were less than 10 % for both TB and HTB. The validated method is successfully used to analyze the influence of bupropion on cytochrome P450-mediated metabolism of TB. The biotransformation rates of TB administered either separately or both simultaneously were compared in this study. The results revealed that bupropion had no significant effect on TB hydroxylation.Colegio de Farmacéuticos de la Provincia de Buenos Aire
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