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 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 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

Simultaneous determination of four cytochrome p450 probe drugs in rat plasma by a simple liquid chromatography–mass spectrometry method

A sensitive and simple liquid chromatography- mass spectrometry (LC-MS) method was developed and validated for determination of four cytochrome P450 probe drugs (phenacetin (CYP1A2), tolbutamide (CYP2C9), bupropion (CYP2B6) and omeprazole (CYP2C19) in rat plasma. Four cytochrome P450 probe drugs extracted from plasma samples by protein precipitation with acetonitrile and separation were carried out on Agilent Zorbax SB-C18 column (2.1 mm x 150 mm, 5 μm) at 30 °C, acetonitrile –0.1 % formic acid in water used as mobile phase with gradient elution. Electrospray ionization (ESI) source was applied and operated in positive ion mode, and selective ion monitoring (SIM) mode was used to quantify cytochrome P450 probe drugs. The method showed excellent intra-assay and inter-assay precision (relative standard deviation (RSD) and bias 0.99 over the range investigated (5-2000 ng/mL). Lower limits of quantification (LLOQs) were estimated to be 5 ng/mL. The method was successfully applied to determinate cytochrome P450 probe drugs in a pharmacokinetic study.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