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papers from the latest issue:
Liquid chromatography-mass spectrometric determination of Losartan and its active metabolite on dried blood spots
19 June 2012,
16:45:38
Publication year:
2012
Source:Journal of Chromatography B
R. Nageswara Rao, S. Satyanarayana Raju, R. Mastan Vali, G.Girija Sankar
A simple and rapid quantitative bioanalytical liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for simultaneous determination of Losartan and its active metabolite, losartan carboxylic acid on rat dried blood spots was developed and validated as per regulatory guidelines. Losartan and its metabolite were extracted from dried blood spots using 50% aqueous methanol and separated on Waters XTerra® RP18 (250×4.6mm, 5μm) column using mobile phase composed of 40% acetonitrile and 60% aqueous ammonium acetate (10mM). The eluents were monitored using ESI tandem mass spectrometric detection with negative polarity in MRM mode using ion transitions m/z 421.2→179.0, m/z 435.3→157.0 and m/z 427.3→193.0 for losartan, losartan carboxylic acid and Irbesartan (internal standard) respectively. The method was validated over the linear range of 1-200ng/mL and 5-1000ng/mL with lower limits of quantification of 1.0ng/mL and 5.0ng/mL for losartan and losartan carboxylic acid respectively. Inter and intra-day precision and accuracy (Bias) were below 5.96% and between -2.8 and 1.5% respectively. The mean recoveries of the analytes from dried blood spots were between 89% and 97%. No significant carry over and matrix effects were observed. The stability of stock solution, whole blood, dried blood spot and processed samples were tested under different conditions and the results were found to be well within the acceptable limits. Additional validation parameters such as influence of hematocrit and spot volume were also evaluated and found to be well within the acceptable limits.
Source:Journal of Chromatography B
R. Nageswara Rao, S. Satyanarayana Raju, R. Mastan Vali, G.Girija Sankar
A simple and rapid quantitative bioanalytical liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for simultaneous determination of Losartan and its active metabolite, losartan carboxylic acid on rat dried blood spots was developed and validated as per regulatory guidelines. Losartan and its metabolite were extracted from dried blood spots using 50% aqueous methanol and separated on Waters XTerra® RP18 (250×4.6mm, 5μm) column using mobile phase composed of 40% acetonitrile and 60% aqueous ammonium acetate (10mM). The eluents were monitored using ESI tandem mass spectrometric detection with negative polarity in MRM mode using ion transitions m/z 421.2→179.0, m/z 435.3→157.0 and m/z 427.3→193.0 for losartan, losartan carboxylic acid and Irbesartan (internal standard) respectively. The method was validated over the linear range of 1-200ng/mL and 5-1000ng/mL with lower limits of quantification of 1.0ng/mL and 5.0ng/mL for losartan and losartan carboxylic acid respectively. Inter and intra-day precision and accuracy (Bias) were below 5.96% and between -2.8 and 1.5% respectively. The mean recoveries of the analytes from dried blood spots were between 89% and 97%. No significant carry over and matrix effects were observed. The stability of stock solution, whole blood, dried blood spot and processed samples were tested under different conditions and the results were found to be well within the acceptable limits. Additional validation parameters such as influence of hematocrit and spot volume were also evaluated and found to be well within the acceptable limits.
Highlights
► A simple isocratic LC-MS/MS method was developed and validated for losartan and its active metabolite ► First Dried blood spot report on Losartan and it active metabolite as sample collection technique. ► Stability of analytes on FTA cards was also studied. ► Good LC resolution was obtained between the analytes and IS.Development of simple and rapid LC-MS/MS method for determination of celecoxib in human plasma and its application to bioequivalence study
19 June 2012,
16:45:38
Publication year:
2012
Source:Journal of Chromatography B
Mi-Sun Park, Wang-Seob Shim, Sung-Vin Yim, Kyung-Tae Lee
A suitable liquid chromatography tandem mass spectrometry (LC-MS/MS) method to determine celecoxib in human plasma is needed for bioequivalence and pharmacokinetic studies of celecoxib preparations. The present study describes a simple, rapid, reproducible, and reliable LC-MS/MS method to determine celecoxib concentrations in human plasma. After one-step liquid-liquid extraction (LLE) using methyl tert-butyl ether (MTBE), celecoxib and atorvastatin (internal standard, IS) were eluted on a Luna HILIC column with an isocratic mobile phase, consisting of 10mM ammonium formate buffer (adjusted to pH 3.0 with formic acid): methanol (5: 95, v/v) at a flow rate of 0.2mL/min. The achieved lower limit of quantitation (LLOQ) was 10ng/mL (S/N >10) and the standard calibration curve for celecoxib was linear (correlation coefficients were >0.9995) over the studied concentration range (10–2000ng/mL). The inter- and intra- assay coefficients of variation ranged from 1.15% to 4.93% and 1.08% to 7.81%, respectively. The chromatographic run time for each plasma sample was <2min. The developed method was successfully applied to a bioequivalence study of celecoxib in healthy Korean male volunteers.
Source:Journal of Chromatography B
Mi-Sun Park, Wang-Seob Shim, Sung-Vin Yim, Kyung-Tae Lee
A suitable liquid chromatography tandem mass spectrometry (LC-MS/MS) method to determine celecoxib in human plasma is needed for bioequivalence and pharmacokinetic studies of celecoxib preparations. The present study describes a simple, rapid, reproducible, and reliable LC-MS/MS method to determine celecoxib concentrations in human plasma. After one-step liquid-liquid extraction (LLE) using methyl tert-butyl ether (MTBE), celecoxib and atorvastatin (internal standard, IS) were eluted on a Luna HILIC column with an isocratic mobile phase, consisting of 10mM ammonium formate buffer (adjusted to pH 3.0 with formic acid): methanol (5: 95, v/v) at a flow rate of 0.2mL/min. The achieved lower limit of quantitation (LLOQ) was 10ng/mL (S/N >10) and the standard calibration curve for celecoxib was linear (correlation coefficients were >0.9995) over the studied concentration range (10–2000ng/mL). The inter- and intra- assay coefficients of variation ranged from 1.15% to 4.93% and 1.08% to 7.81%, respectively. The chromatographic run time for each plasma sample was <2min. The developed method was successfully applied to a bioequivalence study of celecoxib in healthy Korean male volunteers.
Highlights
► Simple and rapid method to determine celecoxib in human plasma with a total running time of 2min for each sample. ► Validated for specificity, LLOQ, recovery, accuracy, precision, stability and linearity. ► Applied to analyze more than 1200 clinical samples by using the proposed method.Determination of 6-keto prostaglandin F1α and its metabolites in human plasma by LC-MS/MS
19 June 2012,
16:45:38
Publication year:
2012
Source:Journal of Chromatography B
Mark Enzler, Stefan Schipp, Laurent B. Nicolas, Jasper Dingemanse, Christoph Siethoff
An HPLC-MS/MS method was developed and validated for the quantification of 6-keto prostaglandin F1α, the stable hydrolysis product of prostacyclin, and its metabolites 2,3-dinor-6-keto prostaglandin F1α and 6,15-diketo-13,14-dihydro prostaglandin F1α in human plasma. For sample preparation, a solid phase extraction step was combined with a column switching approach for analytes enrichment and further sample clean-up of the processed sample. The assay was validated in the concentration range 50.0 to 5000pg/mL for 6-keto prostaglandin F1α and 6,15-diketo-13,14-dihydro prostaglandin F1α, and 100 to 10000pg/mL for 2,3-dinor-6-keto prostaglandin F1α. The inter-batch precision was better than 12.7 %, 9.2 %, and 9.4 % for 6-keto prostaglandin F1α, 2,3-dinor-6-keto prostaglandin F1α, and 6,15-diketo-13,14-dihydro prostaglandin F1α, respectively. The inter-batch accuracy was between 97.3 % and 100.8 % for 6-keto prostaglandin F1α, between 97.5 % and 103.0 % for 2,3-dinor-6-keto prostaglandin F1α, and between 92.0 % and 100.0 % for 6,15-diketo-13,14-dihydro prostaglandin F1α. Further it has been demonstrated that the analytes were stable in plasma for 20hours at room temperature, during three freeze-and-thaw cycles, for 96 days at -25°C storage temperature, and 50hours in the autosampler tray at room temperature.
Source:Journal of Chromatography B
Mark Enzler, Stefan Schipp, Laurent B. Nicolas, Jasper Dingemanse, Christoph Siethoff
An HPLC-MS/MS method was developed and validated for the quantification of 6-keto prostaglandin F1α, the stable hydrolysis product of prostacyclin, and its metabolites 2,3-dinor-6-keto prostaglandin F1α and 6,15-diketo-13,14-dihydro prostaglandin F1α in human plasma. For sample preparation, a solid phase extraction step was combined with a column switching approach for analytes enrichment and further sample clean-up of the processed sample. The assay was validated in the concentration range 50.0 to 5000pg/mL for 6-keto prostaglandin F1α and 6,15-diketo-13,14-dihydro prostaglandin F1α, and 100 to 10000pg/mL for 2,3-dinor-6-keto prostaglandin F1α. The inter-batch precision was better than 12.7 %, 9.2 %, and 9.4 % for 6-keto prostaglandin F1α, 2,3-dinor-6-keto prostaglandin F1α, and 6,15-diketo-13,14-dihydro prostaglandin F1α, respectively. The inter-batch accuracy was between 97.3 % and 100.8 % for 6-keto prostaglandin F1α, between 97.5 % and 103.0 % for 2,3-dinor-6-keto prostaglandin F1α, and between 92.0 % and 100.0 % for 6,15-diketo-13,14-dihydro prostaglandin F1α. Further it has been demonstrated that the analytes were stable in plasma for 20hours at room temperature, during three freeze-and-thaw cycles, for 96 days at -25°C storage temperature, and 50hours in the autosampler tray at room temperature.
Highlights
► A new HPLC-MS/MS method was developed and validated for the quantification. ► Improved selectivity in comparison to ligand-binding assays. ► First application to clinical trial samples obtained from a pharmacokinetic study.Matrix Effect Marker For Multianalyte Analysis By Lc-Ms/Ms In Biological Samples
19 June 2012,
16:45:38
Publication year:
2012
Source:Journal of Chromatography B
Eva Tudela, Gloria Muñoz, Jesús A. Muñoz-Guerra
Matrix effects (ion suppression/enhancement) are a well-observed phenomenon in analyses of biological matrices by high-performance liquid chromatography-mass spectrometry (LC-MS). However, few simple solutions for detecting and minimising these adverse effects have been described so far in multianalyte analysis, especially in the field of doping control. This study describes an exhaustive characterization of matrix effects in one hundred urine samples fortified with 41 analytes (glucocorticoids and diuretics). It introduces a novel marker to identify samples in which the reliability of the results is compromised because of acute ion suppression. This new strategy strengthens the rigor of the analysis for screening purposes. Once the matrix effect is identified, a selective sample preparation is introduced to minimise the adverse ion suppression effect. That selective extraction together with the use of a deuterated internal standard permits enhancing the ruggedness of the estimation of glucocorticoid concentration in urine.
Source:Journal of Chromatography B
Eva Tudela, Gloria Muñoz, Jesús A. Muñoz-Guerra
Matrix effects (ion suppression/enhancement) are a well-observed phenomenon in analyses of biological matrices by high-performance liquid chromatography-mass spectrometry (LC-MS). However, few simple solutions for detecting and minimising these adverse effects have been described so far in multianalyte analysis, especially in the field of doping control. This study describes an exhaustive characterization of matrix effects in one hundred urine samples fortified with 41 analytes (glucocorticoids and diuretics). It introduces a novel marker to identify samples in which the reliability of the results is compromised because of acute ion suppression. This new strategy strengthens the rigor of the analysis for screening purposes. Once the matrix effect is identified, a selective sample preparation is introduced to minimise the adverse ion suppression effect. That selective extraction together with the use of a deuterated internal standard permits enhancing the ruggedness of the estimation of glucocorticoid concentration in urine.
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