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QC Samples (qc + sample)
Selected AbstractsDetermination of carbocysteine in human plasma by liquid chromatography/tandem mass spectrometry employing precolumn derivatizationRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 3 2003Xiaoyan Chen A sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed to determine carbocysteine in human plasma using 2-pyridylacetic acid as the internal standard (IS). The method employed derivatization with 10 M hydrochloric acid/methanol, which significantly improved the ionization efficiency of carbocysteine. After methanol-induced protein precipitation of plasma samples, carbocysteine and the IS were derivatized and subjected to LC/MS/MS analysis using atmospheric pressure chemical ionization. The method has a lower limit of quantitation of 20 ng/mL for a 0.2-mL plasma aliquot. The intra- and inter-day precision (RSD), calculated from quality control (QC) samples, was less than 7%. The accuracy, determined using QC samples, was within ±,1%. The method offered increased sensitivity, selectivity and speed of analysis over existing methods. The method was utilized to support clinical pharmacokinetic studies of carbocysteine in volunteers following oral administration. Copyright © 2002 John Wiley & Sons, Ltd. [source] Validation of a simple HPLC method for DRF-4848, a novel COX-2 inhibitor suitable for pharmacokinetic application in rats,BIOMEDICAL CHROMATOGRAPHY, Issue 12 2006Raja Reddy Kallem Abstract For pharmacokinetic and toxicokinetic purpose a simple HPLC-UV method has been developed and validated for the estimation of DRF-4848, a novel COX-2 inhibitor in rat plasma. A liquid,liquid extraction was used to extract DRF-4848 and internal standard (IS, DRF-4367) from rat plasma. The analysis was performed on a C18 column with UV detection at 285 nm. The isocratic mobile phase, 0.01 m potassium dihydrogen ortho phosphate (pH 3.2) and acetonitrile (50:50, v/v) was run at a flow rate of 1 mL/min. The retention times of DRF-4848 and IS were 6.8 and 11.2 min, respectively. Absolute recovery for analyte and IS was >80% from rat plasma. A linear response was observed over a concentration range 0.1,20 mg/mL. The lower limit of quantification (LLOQ) of DRF-4848 was 0.1 mg/mL. The inter- and intra-day precisions in the measurement of quality control (QC) samples, 0.1, 0.3, 8.0 and 15.0 mg/mL, were in the range 1.74,8.70% relative standard deviation (RSD) and 0.75,8.43% RSD, respectively. Accuracy in the measurement of QC samples was in the range 93.29,116.51% of the nominal values. Analyte and IS were stable in the battery of stability studies viz., benchtop, autosampler, long-term and freeze/thaw cycles. Copyright © 2006 John Wiley & Sons, Ltd. [source] Development and validation of a sensitive ELISA for quantitation of Grastim® (rhG-CSF) in rat plasma: application to a pharmacokinetic study,BIOMEDICAL CHROMATOGRAPHY, Issue 9 2006Chandrasekar Nirmala Abstract Grastim® is bacterially produced recombinant counterpart of human granulocyte colony stimulating factor (G-CSF). It has biological activity similar to that of endogenous G-CSF. In the present work a sensitive, accurate, precise and enzyme-linked immunosorbent assay (ELISA) for the quantitation of G-CSF in rat plasma was developed and validated. The ELISA method employed a technique in which anti-human-G-CSF was adsorbed onto 96-well maxisorp plates and used to capture the G-CSF in rat plasma samples. The captured G-CSF was then detected using streptavidin-HRP amplification system. Absolute recovery was >90% from rat plasma. The validation includes assessments of method accuracy and precision, range of reliable response, lower limit of quantitation (LLOQ), storage stability (30 days) in rat plasma and assay specificity. The standard curve for G-CSF was linear (R2 > 0.996) in the concentration range 4.88,625 pg/mL. The LLOQ was established at 4.88 pg/mL. The inter- and intra-day precisions in the measurement of quality control (QC) samples, 15, 250 and 500 pg/mL, were in the range 3.00,8.66% relative standard deviation (RSD) and 1.03,4.69% RSD, respectively. Accuracy in the measurement of QC samples was in the range 87.28,110.79% of the nominal values. The assay shows dilutional linearity and specificity. Stability of G-CSF was established for 30 days at ,80°C and through three freeze,thaw cycles. The validated assay was successfully employed for the assessment of pharmacokinetic disposition of G-CSF in rats. Copyright © 2006 John Wiley & Sons, Ltd. [source] HPLC method for determination of DRF-4367 in rat plasma: validation and its application to pharmacokinetics in Wistar rats,BIOMEDICAL CHROMATOGRAPHY, Issue 8 2004Ramesh Mullangi Abstract A speci,c, accurate, precise and reproducible high-performance liquid chromatography (HPLC) method was developed for the estimation of DRF-4367, a novel cyclooxygenase-2 inhibitor in rat plasma. The assay procedure involved simple liquid/liquid extraction of DRF-4367 and internal standard (IS, celecoxib) from plasma into dichloromethane. The organic layer was separated and evaporated under a gentle stream of nitrogen at 40°C. The residue was reconstituted in the mobile phase and injected onto a Kromasil KR 100-5C18 column (4.6 × 250 mm, 5 µm). The mobile phase consisting of 0.01 m potassium dihydrogen ortho -phosphate (pH 3.2) and acetonitrile (40:60, v/v) was used at a ,ow rate of 1.0 mL/min. The eluate was monitored using an UV detector set at 247 nm. The ratio of peak area of analyte to IS was used for quanti,cation of plasma samples. Nominal retention times of DRF-4367 and IS were 6.6 and 11.2 min, respectively. The standard curve for DRF-4367 was linear (r2 > 0.999) in the concentration range 0.1,20 µg/mL. Absolute recovery was >86% from rat plasma for both analyte and IS. The lower limit of quanti,cation of DRF-4367 was 0.1 µg/mL. The inter- and intra-day precisions in the measurement of quality control samples, 0.1, 0.3, 8.0 and 15.0 µg/mL, were in the range 6.93,9.34% relative standard deviation (RSD) and 0.48,6.59% RSD, respectively. Accuracy in the measurement of QC samples was in the range 91.24,109.36% of the nominal values. Analyte and IS were stable in the battery of stability studies, viz. benchtop, autosampler and freeze,thaw cycles. Stability of DRF-4367 was established for 1 month at ,80°C. The application of the assay to a pharmacokinetic study in rats is described. Copyright © 2004 John Wiley & Sons, Ltd. [source] Simultaneous determination of chlorpheniramine and pseudoephedrine in human plasma by liquid chromatography,tandem mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 4 2004Xiaoyan Chen Abstract A sensitive and speci,c procedure for simultaneous quantitation of chlorpheniramine and pseudoephedrine in human plasma has been developed and validated. Analytes were extracted from plasma samples by liquid,liquid extraction, separated on a Diamonsil C18 column (250 × 4.6 mm i.d.) and detected by tandem mass spectrometry with an atmospheric pressure chemical ionization interface. Diphenhydramine was used as the internal standard. The method has a lower limit of quantitation of 0.2 and 2.0 ng/mL for chlorpheniramine and pseudoephedrine, respectively. The intra- and inter-day relative standard deviation, calculated from quality control (QC) samples were below 4.3% for chlorpheniramine and below 9.5% for pseudoephedrine. The inter-day relative error as determined from QC samples was within 4.7% for each analyte. The overall extraction recoveries of chlorpheniramine and pseudoephedrine were 77 and 61% on average, respectively. The method was successfully applied to pharmaockinetic study of chlorpheniramine and pseudoephedrine in volunteers receiving formulations containing 4 mg of chlorpheniramine maleate and 60 mg of pseudoephedrine hydrochloride. Copyright © 2004 John Wiley & Sons, Ltd. [source] High performance liquid chromatographic,mass spectrometric assay for the quantitation of BMS-204352 in dog K3EDTA plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 3 2002Ming Yao A high performance liquid chromatographic-mass spectrometric (LC/MS) assay was developed and validated for the determination of BMS-204352 in dog K3EDTA plasma. A 0.5,mL aliquot of control plasma was spiked with BMS-204352 and internal standard (IS) and buffered with 1,mL of 5,mM ammonium acetate. The mixture was then extracted with 3,mL of toluene. After separation and evaporation of the organic phase to dryness using nitrogen at 40°C, the residue was reconstituted in the mobile phase and 25,µL of the sample were injected onto a Hypersil C18 column (2,×,50,mm; 3,µm) at a flow rate of 0.5,mL/min. The mobile phase was consisted of two solvent mixtures (A and B). Solvent A was composed of 5,mM ammonium acetate and 0.1% triethylamine in 75:25 v/v water:methanol, pH adjusted to 5.5 with glacial acetic acid, and solvent B was 5,mM ammonium acetate in methanol. A linear gradient system was used to elute the analytes. The mass spectrometer was programmed to admit the de-protonated molecules at m/z 352.7 (IS) and m/z 357.9 (BMS-204352). Standard curves of BMS-204352 were linear (r2,,,0.998) over the concentration range of 0.5,1000,ng/mL. The mean predicted quality control (QC) concentrations deviated less than 5.1% from the corresponding nominal values (ie 4, 80, 400 and 2000,ng/mL); the within- and between-assay precision of the assay were within 5.5% relative standard deviation. Stability of BMS-204352 was confirmed after at least three freeze/thaw cycles and BMS-204532 was stable in dog plasma when stored frozen at or below ,20°C for at least 16 weeks in spiked QC samples and for at least 4 1/2 weeks for in vivo study samples. BMS-204352 and IS were stable in the injection solvent at room temperature for at least 24,h. The assay was applied to delineate the pharmacokinetic disposition of BMS-204352 in dogs following a single intravenous dose administration. In conclusion, the assay is accurate, precise, specific, sensitive and reproducible for the pharmacokinetic analysis of BMS-204532 in dog plasma. Copyright © 2002 John Wiley & Sons, Ltd. [source] | ||||||||||