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Human Plasma Samples (human + plasma_sample)
Selected AbstractsOxidation of carotenoids by heat and tobacco smokeBIOFACTORS, Issue 1 2004John S. Hurst Abstract The stability to autoxidation of the polar carotenoids, lutein and zeaxanthin, was compared to that of the less polar carotenoids, ,-carotene and lycopene at physiologically or pathophysiologically relevant concentrations of 2 and 6 ,M, after exposure to heat or cigarette smoke. Three methodological approaches were used: 1) Carotenoids dissolved in solvents with different polarities were incubated at 37 and 80°C for different times. 2) Human plasma samples were subjected to the same temperature conditions. 3) Methanolic carotenoid solutions and plasma were also exposed to whole tobacco smoke from 1,5 unfiltered cigarettes. The concentrations of individual carotenoids in different solvents were determined spectrophotometrically. Carotenoids from plasma were extracted and analyzed using high performance liquid chromatography. Carotenoids were generally more stable at 37 than at 80°C. In methanol and dichloromethane the thermal degradation of ,-carotene and lycopene was faster than that of lutein and zeaxanthin. However, in tetrahydrofuran ,-carotene and zeaxanthin degraded faster than lycopene and lutein. Plasma carotenoid levels at 37°C did not change, but decreased at 80°C. The decrease of ,-carotene and lycopene levels was higher than those for lutein and zeaxanthin. Also in the tobacco smoke experiments the highest autoxidation rates were found for ,-carotene and lycopene at 2 ,M, but at 6 ,M lutein and zeaxanthin depleted to the same extent as ,-carotene. These data support our previous studies suggesting that oxidative stress degrade ,-carotene and lycopene faster than lutein and zeaxanthin. The only exception was the thermal degradation of carotenoids solubilized in tetrahydrofuran, which favors faster breakdown of ,-carotene and zeaxanthin. [source] Development of capillary zone electrophoresis-electrospray ionization-mass spectrometry for the determination of lamotrigine in human plasmaELECTROPHORESIS, Issue 13 2004Jack Zheng Abstract A method of coupling capillary zone electrophoresis (CZE) with electrospray ionization-mass spectrometry (ESI-MS) detection has been developed for monitoring an antiepileptic drug, lamotrigine (LTG) in human plasma. The CZE-MS was developed in three stages: (i) CZE separation and ESI-MS detection of LTG and tyramine (TRM, internal standard) were simultaneously optimized by studying the influence of CZE background electrolyte (BGE) pH, BGE ionic strength, and nebulizer pressure of the MS sprayer; (ii) sheath liquid parameters, such as pH, ionic strength, organic modifier content, and flow rate of the sheath liquid, were systematically varied under optimum CZE-MS conditions developed in the first stage; (iii) MS sprayer chamber parameters (drying gas temperature and drying gas flow rate) were varied for the best MS detection of LTG. The developed assay was finally applied for the determination of LTG in plasma samples. The linear range of LTG in plasma sample assay was between 0.1,5.0 ,g/mL with a limit of detection as low as 0.05 ,g/mL and run time less than 6 min. Finally, the concentration-time profile of LTG in human plasma sample was found to correlate well when CZE-ESI-MS was compared to a more established method of high-performance liquid chromatography with ultraviolet detection. [source] Determination of a novel paclitaxel derivative (NPD-103) in human plasma by ultra-performance liquid chromatography,tandem mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 5 2009Shuang-Qing Zhang Abstract A sensitive and specific ultra-performance liquid chromatography,tandem mass spectrometry (UPLC-MS-MS) method for quantification of a newly developed anticancer agent NPD-103 has been established. An aliquot of human plasma sample (200 µL) was spiked with 13C-labeled paclitaxel (internal standard) and extracted with 1.3 mL of tert -butyl methyl ether. NPD-103 was quantitated on a C18 column with methanol,0.1% formic acid (75:25, v/v) as mobile phase using UPLC-MS-MS operating in positive electrospray ionization mode with a total run time of 3.0 min. For NPD-103 at the concentrations of 1.0, 5.0 and 10.0 µg/mL in human plasma, the absolute extraction recoveries were 95.58, 102.43 and 97.77%, respectively. The linear quantification range of the method was 0.1,20.0 µg/mL in human plasma with linear correlation coefficients greater than 0.999. The intra- and inter-day accuracy for NPD-103 at 1.0, 5.0 and 10.0 µg/mL levels in human plasma fell into the ranges of 95.29,100.00% and 91.04,94.21%, and the intra- and inter-day precisions were in the ranges of 8.96,11.79% and 7.25,10.63%, respectively. This assay is applied to determination of half-life of NPD-103 in human plasma. Copyright © 2008 John Wiley & Sons, Ltd. [source] Development and validation of a high-sensitivity liquid chromatography/tandem mass spectrometry (LC/MS/MS) method with chemical derivatization for the determination of ethinyl estradiol in human plasma,BIOMEDICAL CHROMATOGRAPHY, Issue 7 2004Wilson Z. Shou Abstract An ultra-sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the analysis of oral contraceptive ethinyl estradiol (EE) was developed and validated over the curve range of 2.5,500 pg/mL using 1 mL of human plasma sample. Ethinyl estradiol and the internal standard, ethinyl estradiol tetra-deuterated (EE-d4), were extracted from the plasma matrix with methyl t -butyl ether, derivatized with dansyl chloride and then back-extracted into hexane. The hexane phase was evaporated to dryness, reconstituted and injected onto the LC/MS/MS system. The chromatographic separation was achieved on a Luna C18 column (50 × 2 mm, 5 µm) with an isocratic mobile phase of 20:80 (v/v) water:acetonitrile with 1% formic acid. The of,ine derivatization procedure introduced the easily ionizable tertiary amine function group to EE. This greatly improved analyte sensitivity in electrospray ionization and enabled us to achieve the desired lower limit of quantitation at 2.5 pg/mL. This high sensitivity method can be used for therapeutic drug monitoring or supporting bio-equivalence and drug,drug interaction studies in human subjects. Copyright © 2004 John Wiley & Sons, Ltd. [source] Quantitative analysis of EO9 (apaziquone) and its metabolite EO5a in human plasma by high-performance liquid chromatography under basic conditions coupled to electrospray tandem mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 10 2006Liia D. Vainchtein A sensitive and specific LC-MS/MS assay for the quantitative determination of EO9 and its metabolite EO5a is presented. A 200-µl human plasma aliquot was spiked with a mixture of deuterated internal standards EO9- d3 and EO5a- d4 and extracted with 1.25 ml ethyl acetate. Dried extracts were reconstituted in 0.1 M ammonium acetate,methanol (7 : 3, v/v) and 25 µl-volumes were injected into the HPLC system. Separation was achieved on a 150 × 2.1 mm C18 column using an alkaline eluent (1 mM ammonium hydroxide,methanol (gradient system)). Detection was performed by positive ion electrospray followed by tandem mass spectrometry. The assay quantifies a range from 5 to 2500 ng/ml for EO9 and from 10 to 2500 ng/ml EO5a using 200 µl of human plasma samples. Validation results demonstrate that EO9 and EO5a concentrations can be accurately and precisely quantified in human plasma. This assay will be used to support clinical pharmacologic studies with EO9. Copyright © 2006 John Wiley & Sons, Ltd. [source] Rapid simultaneous determination of codeine and morphine in plasma using LC-ESI-MS/MS: Application to a clinical pharmacokinetic studyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 2 2009Qiongfeng Liao Abstract A rapid and sensitive high-performance LC-MS/MS method was developed and validated for the simultaneous quantification of codeine and its metabolite morphine in human plasma using donepezil as an internal standard (IS). Following a single liquid-liquid extraction with ethyl acetate, the analytes were separated using an isocratic mobile phase on a C18 column and analyzed by MS/MS in the selected reaction monitoring mode using the respective [M+H]+ ions, mass-to-charge ratio (m/z) 300/165 for codeine, m/z 286/165 for morphine and m/z 380/91 for IS. The method exhibited a linear dynamic range of 0.2,100/0.5,250 ng/mL for codeine/morphine in human plasma, respectively. The lower LOQs were 0.2 and 0.5 ng/mL for codeine and its metabolite morphine using 0.5 mL of human plasma. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 2.0 min for each sample made it possible to analyze more than 300 human plasma samples per day. The validated LC-MS/MS method was applied to a pharmacokinetic study in which healthy Chinese volunteers each received a single oral dose of 30 mg codeine phosphate. [source] Urea-based two-dimensional electrophoresis of beta-amyloid peptides in human plasma: Evidence for novel A, speciesPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 20 2007Juan Manuel Maler Abstract The detailed analysis of ,-amyloid (A,) peptides in human plasma is still hampered by the limited sensitivity of available mass spectrometric methods and the lack of appropiate ELISAs to measure A, peptides other than A,1,38, A,1,40, and A,1,42. By combining high-yield A, immuno precipitation (IP), IEF, and urea-based A,-SDS-PAGE-immunoblot, at least 30 A,-immunoreactive spots were detected in human plasma samples as small as 1.6,mL. This approach clearly resolved A, peptides A,1,40, A,1-42, A,1-37, A,1-38, A,1-39, the N-truncated A,2,40, A,2,42, and, for the first time, also A,1,41. Relative quantification indicated that A,1,40 and A,1,42 accounted for less than 60% of the total amount of A, peptides in plasma. All other A, peptides appear to be either C-terminally or N-terminally truncated forms or as yet uncharacterized A, species which migrated as trains of spots with distinct pIs. The A, pattern found in cerebrospinal fluid (CSF) was substantially less complex. This sensitive method (2-D A,-WIB) might help clarifying the origin of distinct A, species from different tissues, cell types, or intracellular pools as well as their amyloidogenicity. It might further help identifying plasma A, species suitable as biomarkers for the diagnosis of Alzheimer's disease (AD). [source] Impact of the storage temperature on human plasma proteomic analysis: Implications for the use of human plasma collections in researchPROTEOMICS - CLINICAL APPLICATIONS, Issue 8-9 2010María Insenser Abstract Purpose: To analyze the impact of storage temperature on the 2D-DIGE profile of human plasma. Experimental design: 2D-DIGE and MS were used to identify the differences in the proteomic profiles of aliquots of eight human plasma samples stored at either ,30 or ,80°C for 18 months. Results: After the depletion of albumin and IgG, 2D-DIGE identified four spots significantly and reproducibly increased, and five spots that were decreased, in samples stored at ,30°C compared with those stored at ,80°C. These nine spots were manually excised, digested in-gel and analyzed by MALDI-TOF/TOF. MASCOT database search using the PMF spectra allowed the identification of the proteins present in eight of the nine spots. All the spots corresponded to the complement C3 precursor protein. Conclusions and clinical relevance: Our present results indicate that plasma collections stored at ,30°C, and not only those stored at ,80°C, may be used for 2D-DIGE analyses of albumin- and IgG-depleted human plasma without loosing the essential information about highly abundant proteins. This finding expands the applicability of 2D-DIGE to the study of human disease by permitting the analysis of human plasma samples stored at temperatures between ,30 and ,80°C. [source] Quantification of alkylresorcinols in human plasma by liquid chromatography/tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 5 2010Alastair B. Ross Alkylresorcinols (AR) are of interest as biomarkers of wholegrain wheat and rye intake in epidemiological studies and are currently mainly measured by gas chromatography/mass spectrometry (GC/MS) after labour-intensive sample preparation including liquid-liquid extraction, solid-phase extraction (SPE) and chemical derivatization. This manuscript describes and validates an alternative approach based on normal-phase liquid chromatography/tandem mass spectrometry for the quantification of alkylresorcinols in human plasma. The method requires neither SPE nor chemical derivatization and has a shortened run time compared to GC/MS. Normal- and reversed-phase columns and various mobile phases were evaluated with and without previous SPE of the samples. Normal-phase chromatography allowed separation of AR from the interfering triacylglycerols, diacylglycerols and sterols and enabled detection of AR even without SPE of the samples. The described method has instrumental lower limits of detection in the 25,75 pg range, and lower limits of quantification in the 75,250 pg range. Pooled human plasma and 2H4 -nonadecylresorcinol (internal standard) was applied to calibrate the method in the 20,12,000,nM range. The overall method showed intra-batch precision of 8.6% and an averaged accuracy of 100.2%. Applications for diverse human plasma samples are presented and are compared with the results determined by GC/MS. Based on the presented data; this method requiring less sample preparation is suggested for further evaluation as an alternative to GC/MS for analysis of biomarkers of wholegrain wheat and rye intake in epidemiological studies. Copyright © 2010 John Wiley & Sons, Ltd. [source] Simultaneous determination of ten antihistamine drugs in human plasma using pipette tip solid-phase extraction and gas chromatography/mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 4 2006Chika Hasegawa Ten antihistamine drugs, diphenhydramine, orphenadrine, chlorpheniramine, diphenylpyraline, triprolidine, promethazine, homochlorcyclizine, cyproheptadine, cloperastine and clemastine, have been found to be extractable from human plasma samples using MonoTip C18 tips, inside which C18 -bonded monolithic silica gel was fixed. Human plasma (0.1,mL) containing the ten antihistamines was mixed with 0.4,mL of distilled water and 25,µL of a 1,M potassium phosphate buffer (pH 8.0). After centrifugation of the mixture, the supernatant fraction was extracted to the C18 phase of the tip by 25 repeated aspirating/dispensing cycles using a manual micropipettor. The analytes retained on the C18 phase were then eluted with methanol by five repeated aspirating/dispensing cycles. The eluate was injected into a gas chromatography (GC) injector without evaporation and reconstitution steps, and was detected by a mass spectrometer with selected ion monitoring in the positive-ion electron impact mode. The separation of the ten drugs from each other and from impurities was generally satisfactory using a DB-1MS column (30,m,×,0.32,mm i.d., film thickness 0.25,µm). The recoveries of the ten antihistamines spiked into plasma were 73.8,105%. The regression equations for the ten antihistamines showed excellent linearity with detection limits of 0.02,5.0,ng/0.1,mL. The within-day and day-to-day coefficients of variation for plasma were not greater than 9.9%. The data obtained from determination of diphenhydramine and chlorpheniramine in human plasma after oral administration of the drugs are also presented. Copyright © 2006 John Wiley & Sons, Ltd. [source] Quantitative assay of plasma homocysteine thiolactone by gas chromatography/mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 4 2003Parham Daneshvar Enzymatic cyclization of homocysteine forms a reactive thiolactone that may play an important role in its cardiovascular toxicity, but reliable quantitation of the free thiolactone metabolite in physiological fluids has not been reported. We have therefore used a highly selective gas chromatography/mass spectrometry (GC/MS) technique combined with the sensitivity of negative chemical ionization (NCI) to develop a quantitative method for the detection of homocysteine thiolactone (HcyTL) in plasma. To improve accutacy the deuterated isomer d4 -HcyTL was synthesized and added to plasma as internal standard. The plasma was then treated with silica solid-phase extraction and derivatized with heptafluorobutyric anhydride. The derivative was analyzed by GC/MS in NCI mode with methane as the reagent gas and quantified by analyzing for the HcyTL ion [M, HF] and its d4 -HcyTL counterpart in single-ion monitoring mode. The calibration curve showed a dynamic linear range up to 40 nmol/L. Within-day precision (n,=,20, nominal concentration 5.2 nmol/L) was 0.96% and between-day precision was 3.9%, with a detection limit of 1.7 nmol/L and quantification limit of 5.2 nmol/L. Two human plasma samples had HcyTL concentrations of 18 and 25 nmol/L. This facile method for quantitation of homocysteine thiolactone opens the way for more detailed clinical studies of its potential role in homocysteine-induced arteriosclerosis and vaso-occlusive disease. Copyright © 2003 John Wiley & Sons, Ltd. [source] Liquid chromatography tandem mass spectrometry method for determination of bisoprolol in human plasma using d5-bisoprolol as the internal standardBIOMEDICAL CHROMATOGRAPHY, Issue 6 2010Gang-yi Liu Abstract A simple, reliable and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) protocol was developed and validated for quantification of bisoprolol in human plasma. The sample was pretreated with a simple procedure of protein precipitation and an isotope-labeled d5-bisoprolol was used as internal standard. The chromatographic separation was performed on a Capcell Pak C18 MG III column (100,mm × 2.0,mm, 5,µm). The protonated ion of the analyte was detected in positive ionization by multiple reaction monitoring mode. The mass transition pairs of m/z 326.3 , 116.3 and m/z 331.3 , 121.3 were used to detect bisoprolol and the internal standard, respectively. Linearity, accuracy, precision, recovery, matrix effect, dilution test and stability were evaluated during method validation over the range of 0.5,100,ng/mL. The validated method was successfully applied to analyze human plasma samples in a bisoprolol bioavailability study. Copyright © 2009 John Wiley & Sons, Ltd. [source] Simultaneous quantification of a non-nucleoside reverse transcriptase inhibitor efavirenz, a nucleoside reverse transcriptase inhibitor emtricitabine and a nucleotide reverse transcriptase inhibitor tenofovir in plasma by liquid chromatography positive ion electrospray tandem mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 4 2009Ramakrishna Nirogi Abstract A high-performance liquid chromatography/positive ion electrospray tandem mass spectrometry method for the simultaneous quantification of efavirenz, emtricitabine and tenofovir was developed and validated with 100 µL human plasma. Following solid-phase extraction, the analytes were separated using a gradient mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M + H]+ ions, m/z 316 to 168 for efavirenz, m/z 248,130 for emtricitabine and m/z 288,176 for tenofovir, m/z 482,258 for rosuvastatin (IS), m/z 260,116 for propranolol (IS). The method exhibited a 100-fold linear dynamic range for all the three analytes in human plasma (20,2000, 2,200 and 20,2000 ng/mL for efavirenz, emtricitabine and tenofovir respectively). The lower limit of quantification was 2 ng/mL for emtricitabine and 20 ng/mL for both efavirenz and tenofovir with a relative standard deviation of less than 11%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. The total chromatographic run time of 4 min for each sample made it possible to analyze more than 250 human plasma samples per day. The method is precise and sensitive enough for its intended purpose. The method is also successfully applied to quantify efavirenz, emtricitabine and tenofovir concentrations in a rodent pharmacokinetic study. Copyright © 2008 John Wiley & Sons, Ltd. [source] Sensitive liquid chromatography tandem mass spectrometry method for the quantification of sitagliptin, a DPP-4 inhibitor, in human plasma using liquid,liquid extractionBIOMEDICAL CHROMATOGRAPHY, Issue 2 2008Ramakrishna Nirogi Abstract A sensitive high-performance liquid chromatography,positive ion electrospray tandem mass spectrometry method was developed and validated for the quantification of sitagliptin, a DPP-4 inhibitor, in human plasma. Following liquid,liquid extraction, the analytes were separated using an isocratic mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M + H]+ ions, m/z 408,235 for sitagliptin and m/z 310,148 for the internal standard. The assay exhibited a linear dynamic range of 0.1,250 ng/mL for sitagliptin in human plasma. The lower limit of quantification was 0.1 ng/mL with a relative standard deviation of less than 6%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 2.0 min for each sample made it possible to analyze more than 300 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic studies. Copyright © 2007 John Wiley & Sons, Ltd. [source] A validated HPLC method with electrochemical detection for simultaneous assay of 5-aminosalicylic acid and its metabolite in human plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 5 2005Giancarlo Palumbo Abstract A high-performance liquid chromatographic method was developed, validated and applied to the simultaneous determination of 5-aminosalicylic acid (5-ASA) and its acetylated metabolite (acetyl-5-ASA) in human plasma. The method involves liquid,liquid extraction with methanol followed by isocratic reversed-phase chromatography on a Kromasil KR100 C18 column with electrochemical detection. The recovery, selectivity, linearity, precision and accuracy of the method were evaluated from spiked human plasma samples. The effects of mobile phase composition, buffer concentration, mobile phase pH and concentration of organic modi,ers on retention of 5-ASA, acetyl 5-ASA and internal standard were investigated. Limits' of detection were 5 ng/mL for 5-ASA and 10 ng/mL for acetyl-5-ASA, respectively. The method can be used for supporting therapeutical drug monitoring and pharmacokinetic studies. Copyright © 2004 John Wiley & Sons, Ltd. [source] Simultaneous determination of estramustine phosphate and its four metabolites in human plasma by liquid chromatography,ionspray mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 5 2004M. Breda Abstract A sensitive and selective method, using liquid chromatography,ionspray mass spectrometry, was developed and validated for the simultaneous determination of Estracyt (estramustine phosphate) and its four metabolites, estramustine, estromustine, estrone and estradiol, in human plasma. Deuterated internal standards were available for all analytes. The ,ve compounds were extracted from plasma by protein precipitation with acetonitrile. The chromatographic separation was performed using a Zorbax SB C18, (150 × 4.6 mm i.d., 5 µm) reversed-phase column under gradient conditions with a mobile phase containing 2 mm ammonium acetate buffer (pH 6.8) and acetonitrile. MS detection was by electrospray ionization with multiple reaction monitoring in the positive ion mode for estramustine phosphate, estromustine and estramustine, and in the negative ion mode for estrone and estradiol. The limit of quantitation was 10 ng/mL for estramustine phosphate, 3 ng/mL for estromustine, estramustine and estrone and 30 ng/mL for estradiol. Linearity was veri,ed from these LLOQs up to about 4000 ng/mL for the parent drug and 2000 ng/mL for the metabolites. Inter-day precision and accuracy values were all less than 15%. This assay was applied successfully to the routine analysis of human plasma samples collected in cancer patients administered estramustine phosphate intravenously. Copyright © 2003 John Wiley & Sons, Ltd. [source] A high-performance liquid chromatography method using ultraviolet detection for the quantitation of flavopiridol from human plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 6 2002Suoping Zhai Flavopiridol is an inhibitor of cyclin-dependent kinase, a key regulator of cell cycle, and is currently under clinical trials. We developed and validated an HPLC assay method for the quantitation of flavopiridol in human plasma samples. The sample preparation consisted of protein precipitation with acetonitrile. Separation was accomplished on a C18 column and a C18 precolumn insert utilizing a gradient profile consisting of ammonium acetate and methanol. Ultraviolet detection was set at 268,nm for flavopiridol and 323,nm for umbelliferone, the internal standard. The method was validated over flavopiridol concentration range of 0.025,3.0,µg/mL using 250,µL of plasma. The assay was linear over this concentration range with a coefficient of variation less than 10% for inter- and intra-assay. The retention times were around 6.2,min for umbelliferone and 9.8,min for flavopiridol. The recoveries of flavopiridol and umbelliferone were 88.6,±,1.0% and 97.1,±,3.7%, respectively. This method is suitable for quantifying flavopiridol in plasma samples and further characterizing the clinical pharmacology of this compound. Copyright © 2002 John Wiley & Sons, Ltd. [source] | |||||||||||||