A rapid and sensitive method for quantitative determination of paclitaxel in rat plasmawas developed and validated by using ultra-performance liquid chromatography-tandemmass spectrometry (UPLC-MS/MS). Docetaxel was u...A rapid and sensitive method for quantitative determination of paclitaxel in rat plasmawas developed and validated by using ultra-performance liquid chromatography-tandemmass spectrometry (UPLC-MS/MS). Docetaxel was used as an internal standard anddiethyl ether was the liquideliquid extraction agent. Multiple reaction monitoring (MRM)mode via positive electrospray ionization (ESI) was applied to detect paclitaxel and IS at thetransitions m/z 854 / 286 and m/z 808.48 / 527.3, respectively. This method covered alinearity range from 5 to 5000 ng/ml, with the total run time of 3.0 min. In summary, a highthroughout UPLC-MS/MS method was successfully developed to measure paclitaxel in ratplasma and was applied to pharmacokinetic study after intravenous administration ofpaclitaxel.展开更多
A simple, rapid and sensitive LC-MS/MS method was developed to quantify erlotinib and its active metabolite, OSI-420, simultaneously in BALB/c nude mice plasma. Erlotinib, OSI-420 and propranolol （internal standard）...A simple, rapid and sensitive LC-MS/MS method was developed to quantify erlotinib and its active metabolite, OSI-420, simultaneously in BALB/c nude mice plasma. Erlotinib, OSI-420 and propranolol （internal standard） were extracted from nude mice plasma samples by liquid-liquid extraction. Separation was achieved on a reversed phase ClS column with a mobile phase of acetonitrile-water （35：65, v/v） containing 5 mM ammonium formate （pH = 3.0）. All compounds were monitored by mass spectrometry with electrospray positive ionization. The lower limit of quantification was 0.5 ng/mL for both erlotinib and OSI-420; accuracy was estimated by relative error, which was in the range from 0.07% to 8.00% for erlotinib and -2.83% to 6.67% for OSI-420; precision was validated by relative standard deviation, which was from 2.28% to 15.12% for erlotinib and from 1.96% to 11.50% for OSI-420. This method was applied to a pharmacokinetic study of BALB/c nude mice following oral administration of erlotinib at 12.5 mg/kg. A 2-compartment model was used to fit the pharmacokinetics of erlotinib and 1-compartment model for the pharmacokinetics of OSI-420. The ratio of the active metabolite to parent drug in mice was greater than previously reported in humans and probably reflects interspecies difference in the rate of conversion of erlotinib to OSI-420.展开更多
In the current study, we established and validated a simple and sensitive liquid chromatography-tandem mass spectrometric method for the determination of 21-hydroxy deflazacort in nude mice plasma, and such a method w...In the current study, we established and validated a simple and sensitive liquid chromatography-tandem mass spectrometric method for the determination of 21-hydroxy deflazacort in nude mice plasma, and such a method was applied to a pharmacokinetic study. Using betamethasone as the internal standard, the plasma samples were pre-treated by precipitation with acetonitrile and then analyzed on a reversed-phase C18 column （50 mm×2 mm, 5 μm） with a mobile phase consisting of acetonitrile and 4.0 mM ammonium formate （pH was adjusted to 3.5 with formic acid （40：60, v/v））. The analyte was detected by a triple quadrupole tandem mass spectrometer using electrospray, and multiple reaction monitoring was employed to select 21-hydroxy deflazacort at m/z 400.2/124.0 and betamethasone at m/z 393.3/147.0 in the positive ion mode. The calibration curves were linear （r〉0.99） over the range of 0.5~,00 ng/mL. The intra- and inter-day precisions and accuracies were 4.5%-10.1% and -1.7%-10.7% respectively. This method was successfully applied to a preclinical administered with a single oral dose of 4 mg/kg deflazacort, and its pharmacokinetic study of deflazacort on female nude mice pharmacokinetics was characterized by a two-compartment model with first-order absorption.展开更多
Trimethylamine-N-oxide(TMAO)has emerged as a potential biomarker for atherosclerosis and the development of cardiovascular diseases(CVDs).Although several clinical studies have shown striking associations of TMAO leve...Trimethylamine-N-oxide(TMAO)has emerged as a potential biomarker for atherosclerosis and the development of cardiovascular diseases(CVDs).Although several clinical studies have shown striking associations of TMAO levels with atherosclerosis and CVDs,TMAO determinations are not clinical routine yet.The current methodology relies on isotope-labeled internal standards,which adds to pre-analytical complexity and costs for the quantification of TMAO and its precursors carnitine,betaine or choline.Here,we report a liquid chromatography-tandem mass spectrometry based method that is fast(throughput up to 240 samples/day),consumes low sample volumes(e.g.,from a finger prick),and does not require isotope-labeled standards.We circumvented the analytical problem posed by the presence of endogenous TMAO and its precursors in human plasma by using an artificial plasma matrix for calibration.We cross-validated the results obtained using an artificial matrix with those using mouse plasma matrix and demonstrated that TMAO,carnitine,betaine and choline were accurately quantified in’reallife’human plasma samples from healthy volunteers,obtained either from a finger prick or from venous puncture.Additionally,we assessed the stability of samples stored at-20℃and room temperature.Whereas all metabolites were stable at-20℃,increasing concentrations of choline were determined when stored at room temperature.Our method will facilitate the establishment of TMAO as a routine clinical biomarker in hematology in order to assess the risk for CVDs development,or to monitor disease progression and intervention effects.展开更多
A highly sensitive liquid chromatography-tandem mass spectrometry（LC-MS/MS） method was developed for the determination of tadalafil（TAD） in human plasma. TAD and its deuterated internal standard（IS）, tadalafil-d...A highly sensitive liquid chromatography-tandem mass spectrometry（LC-MS/MS） method was developed for the determination of tadalafil（TAD） in human plasma. TAD and its deuterated internal standard（IS）, tadalafil-d3, were extracted from 200 mL plasma using Phenomenex Strata-X-C 33 m extraction cartridges. Chromatographic analysis was carried out on Synergi Hydro-RP C18（100 mm × 4.6 mm, 4 mm）column with a mobile phase consisting of methanol and 10 m M ammonium formate, p H 4.0（90：10, v/v）,delivered at a flow rate of 0.9 m L/min. Quantitation of the protonated analyte was done on a triple quadrupole mass spectrometer using multiple reaction monitoring via electrospray ionization. The precursor to product ions transitions monitored for TAD and TAD-d3 were m/z 390.3-268.2 and m/z393.1-271.2, respectively. The calibration curve was linear over the concentration range of 0.50–500 ng/m L with correlation coefficient, r2 Z 0.9994. Acceptable intra-batch and inter-batch precision（r3.7%） and accuracy（97.8% to 104.1%） were obtained at five concentration levels. The recovery of TAD from spiked plasma was highly precise and quantitative（98.95% to 100.61%）. Further, the effect of endogenous matrix components was minimal. TAD was found to be stable under different storage conditions in human plasma and also in whole blood samples. The validated method was successfully used to determine TAD plasma concentration in a bioequivalence study with 20 mg TAD tablets in 24 healthy volunteers. Method performance was evaluated by reanalyzing 115 study samples.展开更多
Benapenem is a new parenteral beta-lactam antibacterial with a broad antibacterial spectrum. In the present study, we developed and validated a simple, rapid and sensitive assay method using D6-benapenem as internal s...Benapenem is a new parenteral beta-lactam antibacterial with a broad antibacterial spectrum. In the present study, we developed and validated a simple, rapid and sensitive assay method using D6-benapenem as internal standard(IS) after one-step precipitation with methanol to determine benapenem in the plasma of infected mice. Separation was achieved on a reverse phase C18 column with a mobile phase composed of acetonitrile containing 0.2% formic acid–water(0.2% formic acid) and 10 mmol/L ammonium acetate in gradient elution mode. A triple quadrupole tandem mass spectrometer with electrospray ionization source was used as detector and operated by multiple reaction monitoring(MRM) in the positive ion mode. Calibration curves were linear(r>0.99) between 10 and 2000 ng/m L. The quantitative limit was 10 ng/m L, and the intra-and inter-precisions were <4.85% and <1.47%, respectively. The extraction recovery of benapenem and IS was 97.07%–107.09% and 92.47%–111.59%, respectively. The intra-and inter-accuracies were –9.70%– –11.00%, and the matrix effects of benapenem and IS were 85.68%–92.04% and 83.17%–92.04%, respectively. The method was successfully applied to the preclinical pharmacokinetic(PK) studies of benapenem. We also developed a two-compartment model to characterize the PK profiles of benapenem in infected mice, which could provide a better understanding of the PK properties of benapenem.展开更多
The quantitation of serum tocilizumab using liquid chromatography tandem-mass spectrometry(LC-MS/MS)method has not been widely applied in clinical settings because of its time-consuming and costly sample pretreatments...The quantitation of serum tocilizumab using liquid chromatography tandem-mass spectrometry(LC-MS/MS)method has not been widely applied in clinical settings because of its time-consuming and costly sample pretreatments.The present study aimed to develop a validated LC-MS/MS method for detecting serum tocilizumab by utilizing immobilized trypsin without an immunoglobulin G purification step and evaluate its applicability in the treatment of rheumatoid arthritis(RA)patients administered intravenously or subcutaneously with tocilizumab.The tocilizumab-derived signature peptide was deciphered using a nano-LC system coupled to a hybrid quadrupole-orbitrap mass spectrometer.The serum tocilizumab was rapidly digested by immobilized trypsin for 30 min.The chromatographic peak of the signature peptide and that of the internal standard were separated from the serum digests for a total run time of 15 min.The calibration curve of serum tocilizumab concentration was linear with a range of 2-200 μg/mL.The intra-and inter-day accuracy and relative standard deviation(RSD)were 90.7%-109.4%and<10%,respectively.The serum tocilizumab concentrations in the RA patients receiving intravenous and subcutaneous injections were 5.8-28.9 and 2.4-63.5 μg/mL,respectively.The serum tocilizumab concentrations using the current method positively correlated with those using the enzyme-linked immunosorbent assay,although a systematic error was observed between these methods.In conclusion,a validated LC-MS/MS method with minimal sample pretreatments for monitoring serum tocilizumab concentrations in RA patients was developed.展开更多
A sensitive and selective liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of rosuvastatin in human plasma using gliclazide as ...A sensitive and selective liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of rosuvastatin in human plasma using gliclazide as an internal standard (IS). Rosuvastatin and gliclazide in plasma were extracted with ethyl acetate, separated on a C18 reversed phase column, eluted with mobile phase of acetonitrile-methanoic acid (0.1%) (60:40, v/v), ionized by positive ion pneumatically assisted electrospray and detected in the multi-reaction monitoring mode using precursor → product ions of m/z 482.1 → 258.1 for rosuvastatin and m/z 324.2 → 127.2 for IS, respectively. The calibration curve was linear (r2 > 0.99, n = 5) over the concentration range of 0.1 - 60 ng/mL. The speci?city, matrix effect, recovery, sensitivity, linearity, accuracy, precision, and stabilities were validated for rosuvastatin in human plasma. In conclusion, the validation results showed that this method was sensitive, economical and less toxic and it can successfully ful?ll the requirement of bioequivalence study of rosuvastatin calcium tablets in Chinese healthy volunteers.展开更多
Nitrosamine impurities are potentially genotoxic which are considered under cohort of concern as per ICH M7 guidelines and need to be controlled at trace levels during quantification in drug substances and drug produc...Nitrosamine impurities are potentially genotoxic which are considered under cohort of concern as per ICH M7 guidelines and need to be controlled at trace levels during quantification in drug substances and drug products for safe human consumption. Recent regulatory requirements also suggest the need to have highly sensitive analytical methods for the accurate quantification of Nitrosamine impurities. In this paper we have presented simple, rapid and ultra-sensitive LC-MS/MS method for six potential genotoxic nitrosamine impurities: N-Nitroso dimethyl amine (NDMA), N-Nitroso diethyl amine (NDEA), N-Nitroso Ethyl Iso propylamine (NEIPA), N-Nitroso-N-methyl-4-aminobutyric acid (NMBA) N-Nitroso diisopropylamino (NDIPA) and N-Nitroso dibutyl amine (NDBA) with a LOQ of 0.004 ppm. Chromatographic separation is achieved using Zorbax SB C18 150 × 3.0 mm, 3.5 μ column with 0.1% formic acid in water as mobile phase A and 0.1% formic acid in methanol as mobile phase B at a flow rate of 0.3 ml/min using gradient mode of elution at a total run time of 18 minutes. Six nitrosamine impurities are successfully ionized and quantified in positive mode of atmospheric pressure chemical ionization (APCI) using multiple reaction monitoring (MRM). Method validation is performed as per ICH guidelines evaluating the limit of quantification and detection and found to give good S/N ratios with good linearity range of 0.002 - 2 ppm with regression coefficient >0.99 for all the six nitrosamine impurities. Method recoveries are established using three-step sample preparation protocol and are found to be satisfactory within 80% - 120%. The method can be used routinely applied for the detection of Nitrosamines in Telmisartan at a concentration of 1.5 ng/ml (0.03 ppm with respect to telmisartan concentration of 50 mg/ml).展开更多
A sensitive and selective liquid chromatography-tandem mass spectrometric（LC —MS/MS）method was established to determine 2-oxo-clopidogrel,a crucial intermediate metabolite in human plasma.A chromatographic separati...A sensitive and selective liquid chromatography-tandem mass spectrometric（LC —MS/MS）method was established to determine 2-oxo-clopidogrel,a crucial intermediate metabolite in human plasma.A chromatographic separation was performed on a Sapphire C_（18） column following a liquid-liquid extraction sample preparation with methyl t-butyl ether.Detection was carried out on a triple quadrupole mass spectrometer operated in multiple reaction monitoring（MRM） with an electrospray ionization（ESI）mode.The method was validated in terms of specificity,accuracy,precision and limit of quantification.The calibration curves ranged from 0.50 to 50.0 ng/mL with good linearity.The stability was fully validated with addition of 1,4-dithio-DL-threitol（DTT） into the plasma sample prior to and in the preparation procedure.The validated method was proved to be suitable for use in pharmacokinetic study after single oral administration of 75 mg clopidogrel tablets in human subjects,which could make contribution to intensive study of the clinical drug-drug interactions of clopidogrel and individual treatment.展开更多
Here we have presented a sensitive and selective LC-MS/MS method for the quantification of tyrphostin A9, which is a selective inhibitor for platelet derived growth factor receptor tyrosine kinase and has been investi...Here we have presented a sensitive and selective LC-MS/MS method for the quantification of tyrphostin A9, which is a selective inhibitor for platelet derived growth factor receptor tyrosine kinase and has been investigated in vitro as a potent oxidative phosphorylation uncoupler. The murine analytical method was developed for three biological matrices: cell culture media, 3T3-L1 cell lysate, and murine plasma. For each matrix the limit of detection and the limit of quantification were found to be 0.5 ng/mL and 1.0 ng/ mL, respectively. The range of standard curve for each matrix was 1.0-100 ng/mL, linearity was >0.99, and the precision and accuracy were within 20%. 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoic acid was found to be the most suitable internal standard. The validated LC-MS/MS method was used to investigate stability and in vitro pharmacokinetics of tyrphostin A9. It was found that tyrphostin A9 is susceptible to hydrolysis, and the degradation product was identified as 3,5-di-tert-butyl-4- hydroxybenzaldehyde. Tyrphostin A9 was not stable in biological matrices, and the rate of its degradation in murine plasma was faster than that in cell culture media. In vitro pharmacokinetic studies revealed that tyrphostin A9 concentrations in the cell culture media declined in a bi-exponential manner and the concentrations inside the adipocytes remained constant, suggesting tyrphostin A9 has an intracellular binding site and is retained within the cell. The LC-MS/MS method presented here paves the way for further quantitative investigations involving tyrphostin A9.展开更多
A rapid and sensitive liquid chromatography-tandem mass chromatography (LC-MS/MS) method has been developed and validated for simultaneous determination of catalpol and harpagide in rat plasma. The samples were extrac...A rapid and sensitive liquid chromatography-tandem mass chromatography (LC-MS/MS) method has been developed and validated for simultaneous determination of catalpol and harpagide in rat plasma. The samples were extracted by one-step protein precipitation and separated on a SunFireTM C18 column (100 mm × 2.1 mm, 3.5 μm;Waters) using acetonitrile-10 mM ammonium formate as mobile phase at a flow rate 0.3 mL/min in gradient mode. The analytes were detected without interference in Multiple Reaction Monitoring (MRM) mode with negative electrospray ionization. Linear responses were obtained for catalpol ranging from 20 to 5000 ng/mL and harpagide ranging from 10 to 2500 ng/mL. Coefficients of correlation (r) for the calibration curves were more than 0.99 for both analytes. Intra- and inter-day accuracy and precision were within the acceptable limits of less than 15.0% at all concentrations. The quantitation method was successfully applied for simultaneous estimation of catalpol and harpagide after oral administration of Zeng Ye Decoction.展开更多
In Korea and China,ilaprazole is a widely used proton pump inhibitor in the treatment of gastric ulcers.In this study,a specific and sensitive LC-MS/MS method has been developed and validated for the quantification of...In Korea and China,ilaprazole is a widely used proton pump inhibitor in the treatment of gastric ulcers.In this study,a specific and sensitive LC-MS/MS method has been developed and validated for the quantification of ilaprazole enantiomers in the rat plasma,using R-lansoprazole as the internal standard.The enantioseparation was achieved on a CHIRALPAK AS-RH column(4.6 mm×150 mm,i.d.5 mm),with a mobile phase composed of 10 m M ammonium acetate aqueous solution and acetonitrile(60:40,V/V),at a flow-rate of 0.5 m L/min.The method was validated over the concentration range of 0.5 e300 ng/m L for both,R-and S-ilaprazole.The lower limit of quantification was 0.5 ng/m L for both enantiomers.The relative standard deviation(RSD)of intra-and inter-day precision of R-ilaprazole and S-ilaprazole was less than 10.9%,and the relative error accuracy(RE)ranged fromà0.5%e2.0%.Finally,the method was successfully evaluated in rats in a stereoselective pharmacokinetic study of the ilaprazole racemate.展开更多
A rapid and sensitive liquid chromatography-tandem mass spectrometry method（LC-MS/MS）was developed and validated for the quantification of fexofenadine in human plasma,to conduct comparative bioavailability studies....A rapid and sensitive liquid chromatography-tandem mass spectrometry method（LC-MS/MS）was developed and validated for the quantification of fexofenadine in human plasma,to conduct comparative bioavailability studies.Human plasma was extracted with a mixture of dichloromethane-diethyl ether（volume ratio 2∶3）in a basic environment and the extract was separated on a C18 column with a mobile phase consisting of acetonitrile-methanol-10 mmol/L ammonium acetate（volume ratio 45∶45∶10）.The analytes were detected via electrospray ionization（ESI）tandem mass spectrometry in the multiple-reaction-monitoring（MRM）mode.The linearity was within a range of 1-1000 ng/mL.The intra-and inter-day precision were〈4.1% and〈4.8%,respectively,and the accuracy was in the range of 95.0%-105%.The method was applied to the quantification of fexofenadine human plasma from 20 healthy male Chinese volunteers,according to a single dose,randomized,two-way crossover design with a two-week washout period.The mean values of major pharmacokinetic parameters of ρmax,AUC0-48,AUC0-∞,tmax,and t1/2 were determined from the plasma concentration.The analysis of variance（ANOVA）did not show any significant difference between the two products of fexofenadine and 90% confidence intervals fell within the acceptable range for bioequivalence.展开更多
Simvastatin （SIM） is a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor widely used in hyperlipidemia therapy. SIM has recently been studied for its anticancer activity at doses higher than those used for t...Simvastatin （SIM） is a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor widely used in hyperlipidemia therapy. SIM has recently been studied for its anticancer activity at doses higher than those used for the hyperlipidemia therapy. This prompted us to study the pharmacokinetics of high-dose SIM in cancer patients. For this purpose, an LC-MS/MS method was developed to measure SIM and its acid form （SIMA） in plasma and peripheral blood mononuclear cells （PBMCs） obtained from patients. Chromatographic analyte separation was carried out on a reverse-phase column using 75：25 （% v/v） acetonitrile：ammonium acetate （0.1 M, pH 5.0） mobile phase. Detection was performed on a triple quadrupole mass spectrometer, equipped with a turbo ion spray source and operated in positive ionization mode. The assay was linear over a range 2.5-500 ng/mL for SIM and 5-500 ng/mL for SIMA in plasma and 2.5-250 ng/mL for SIM and 5-250 ng/mL for SIMA in cell lysate. Recovery was 〉 58% for SIM and 〉 75% for SIMA in both plasma and cell lysate. SIM and SIMA were stable in plasma, cell lysate and the reconstitution solution. This method was successfully applied for the determination of SIM and SIMA in plasma and PBMCs samples collected in the pharmacokinetic study of high-dose SIM in cancer patients.展开更多
A simple and reliable high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for the determination of colistin A and colistin B in human plasma was developed and validated. Clarithromycin was...A simple and reliable high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for the determination of colistin A and colistin B in human plasma was developed and validated. Clarithromycin was used as an internal standard (IS). Plasma extraction was performed using C-18 cartridges and methanol containing 0.1% formic acid. Analysis was performed using Atlantis dC18 (2.1 × 100 mm, 3 μm) column at room temperature and a mobile phase of 0.2% formic acid in acetonitrile and water (50:50, v:v), delivered at a flow rate of 0.2 ml/minute. Eluent was detected in the positive ion mode using electrospray ionization at the following transitions of mass to charge (m/z): colistin A, 585.6 → 101.4;colistin B, 578.7 → 101.3;and IS, 748.6 → 158.4. No interference by components of blank plasma or commonly used drugs was observed. The relationship between colistin A colistin B concentrations and their corresponding peak height ratios to the IS was linear over the range of 0.05 - 10 μg/ml. Inter-day coefficient of variation and bias were, respectively, ≤11.5% and <span style="white-space:nowrap;">−</span>3.0 to 6.0 for colistin A and ≤9.9 and <span style="white-space:nowrap;">−</span>4.7 to 3.0 for colistin B. Mean extraction recovery of colistin A, colistin B, and the IS were 97%, 94%, and 97%, respectively. The method was applied to assess the stability of colistin A and colistin B in processed samples (24 hr. at room temperature, 48 hours at <span style="white-space:nowrap;">−</span>20<span style="white-space:nowrap;">°</span>C) and unprocessed samples (24 hr. at room temperature, 8 weeks at <span style="white-space:nowrap;">−</span>20<span style="white-space:nowrap;">°</span>C) and after three cycles of freeze and thaw found to be ≥87%.展开更多
A highly sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the de-termination of imperatorin and isoimperatorin in rat plasma using psoralen as internal standard. Analyses w...A highly sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the de-termination of imperatorin and isoimperatorin in rat plasma using psoralen as internal standard. Analyses were performed on a Shimadzu HPLC system using a Shimadzu C18 column eluted with a mobile phase of methanol-water (25:75), containing 0.1% formic acid at a flow rate of 0.4 ml/min. The detection was performed by positive ion elec-trospray ionization in multiple reactions monitoring mode, monitoring the transitions m/z 203→147 and m/z 203→159 for imperatorin and isoimperatorin, respectively. The method was validated over the concentration range of 2.5 -1000.0 ng/mL for imperatorin and isoimperatorin. The limits of detection and quantification were 1.0 and 3.0 ng/mL, repectively for both analytes. The intra-day and inter-day accuracy and precision of the assay were less than 10.9%. This method has been applied successfully to a pharmacokinetic study involving the intragastric administration of extract of Angelicae Dahuricae Radix to rats.展开更多
A simple, rapid, specific and precise liquid chromatography—tandem mass spectrophotometric (LC-MS/MS) method was developed and validated for the quantification of chiral separated R-bicalutamide from S-bicalutamide, ...A simple, rapid, specific and precise liquid chromatography—tandem mass spectrophotometric (LC-MS/MS) method was developed and validated for the quantification of chiral separated R-bicalutamide from S-bicalutamide, in human plasma. Topiramate (TPM) was used as internal standard, added to plasma sample prior to extraction using t-butyl methyl ether (TBME). Chromatographic separation was achieved on CHIRALPAK AD-RH column (150 mm×4.6 mm, 5 μm) with acteonitrile: 0.1% formic acid Buffer (50:50 v/v) as an isocratic mobile phase with a flow rate of 1.0 mL·min-1. Quantitation was performed by transition of 429.0 → 255.0 (m/z) for R-bicalutamide and 338.1 → 77.8 (m/z) for topiramate. The lower limit of quantitation was 20 ng·mL-1with a 100 μL plasma sample. The concentrations of eight working standards showed linearity between 20 to 3200 ng·mL-1(r2≥ 0.9990). Chromatographic separation was achieved within 6 min, compared to the 15 min of previous methods. The average extraction recoveries of 3 quality control concentrations were 98.56% for R-bicalutamide and 92.42% for topiramate. The coefficient of variation was ≤15% for intra- and inter-batch assays. Therefore a rapid, specific and sensitive LC-MS/MS method for the quantification of R-bicalutamide in human plasma was developed and validated can be used in the bioequivalence study of this drug.展开更多
A simple, rapid, and highly sensitive LC-MS/MS method has been developed for the simultaneous and trace level quantification of underivatized boronic acids in lumacaftor active pharmaceutical ingredient. Chromatograph...A simple, rapid, and highly sensitive LC-MS/MS method has been developed for the simultaneous and trace level quantification of underivatized boronic acids in lumacaftor active pharmaceutical ingredient. Chromatographic separation of boronic acids and lumacaftor achieved using Agilent Poroshell HPH C18 150<span> </span><span>×</span><span> </span><span>4.6</span><span> </span><span>mm 2.7</span><span> </span><span>μ column with 0.1% ammonia in water as mobile phase A and 100%</span><span> </span><span>acetonitrile as mobile phase B at a flow rate of 0.25</span><span> </span><span>ml/min. Gradient elution</span><span> was</span><span> used with a total method run time of 14</span><span> </span><span>minutes. Boronic acids were successfully ionized and quantified without derivatization using electrospray ionization in negative mode using tandem quadrupole mass spectrometry in multiple reactions monitoring mode. Method validation </span><span>was </span><span>performed as per ICH guidelines with good linearity over the concentration range of 0.05 ppm to 5 ppm of Lumacaftor test concentration for both the boronic acids with a correlation coefficient of >0.99.</span><span> </span><span>Recoveries were found good at different concentration levels and within the range of 80</span><span>% </span><span>-</span><span> </span><span>120%.</span><span> </span><span>The developed method can be successfully used for the routine quantification of boronic acids at a concentration level of 20</span><span> </span><span>ng/ml (1</span><span> </span><span>ppm with respect to 20</span><span> </span><span>mg/ml lumacaftor).</span>展开更多
Pomalidomide is an immunomodulatory agent (IMiD) that has been approved by the US Food and Drug Administration (FDA) for clinical treatment of patients with multiple myeloma.In this work,we developed a sensitive and v...Pomalidomide is an immunomodulatory agent (IMiD) that has been approved by the US Food and Drug Administration (FDA) for clinical treatment of patients with multiple myeloma.In this work,we developed a sensitive and validated LC-MS/MS method for high-throughput determination of pomalidomide over the range of 1.006-100.6 ng/mL(R^(2)=0.9991) in human plasma and pharmacokinetic studies.A liquid-liquid extraction method using ethyl acetate was applied to extract pomalidomide and afatinib (as an internal standard,IS) from human plasma.Chromatographic separation was performed on a Hedera ODS column (150 mm×2.1 mm,5μm) with security guard C18 column (4 mm×2.0 mm) at 40℃.Methanol and 10 mmol/L aqueous solution of ammonium acetate containing 0.1%formic acid were used as a gradient elution mobile phase,and the flow rate was 0.4 mL/min.A triple quadruple tandem mass spectrometer using multiplex reaction monitoring mode (MRM) with electrospray ionization (ESI) positive ionization was employed.The precursor to product ion transitions for the quantitative analysis of pomalidomide and the IS were m/z 274.2→163.1 and m/z 486.1→371.1,respectively.This established method has been validated according to regulatory guideline,and the results were all within the acceptance criteria.The validated LC-MS/MS method was successfully applied to analyze samples obtained from clinical pharmacokinetics study after oral administration of pomalidomide (4 mg) capsules in human.展开更多
基金This work was financially supported from the National Nature Science Foundation of China(No.81173008)from the National Basic Research Program of China(973 Program)No.2009CB930300+1 种基金from Project for Excellent Talents of Liaoning Province(No.LR20110028)from Program for New Century Excellent Talents in University(No.NCET-12-1015).
文摘A rapid and sensitive method for quantitative determination of paclitaxel in rat plasmawas developed and validated by using ultra-performance liquid chromatography-tandemmass spectrometry (UPLC-MS/MS). Docetaxel was used as an internal standard anddiethyl ether was the liquideliquid extraction agent. Multiple reaction monitoring (MRM)mode via positive electrospray ionization (ESI) was applied to detect paclitaxel and IS at thetransitions m/z 854 / 286 and m/z 808.48 / 527.3, respectively. This method covered alinearity range from 5 to 5000 ng/ml, with the total run time of 3.0 min. In summary, a highthroughout UPLC-MS/MS method was successfully developed to measure paclitaxel in ratplasma and was applied to pharmacokinetic study after intravenous administration ofpaclitaxel.
基金National Integrity Innovational Technology Platform of New Drug and Development (Grant No. 2009ZX09301-010)Innovation Team of Ministry of Education (Grant No. BMU20110263)
文摘A simple, rapid and sensitive LC-MS/MS method was developed to quantify erlotinib and its active metabolite, OSI-420, simultaneously in BALB/c nude mice plasma. Erlotinib, OSI-420 and propranolol （internal standard） were extracted from nude mice plasma samples by liquid-liquid extraction. Separation was achieved on a reversed phase ClS column with a mobile phase of acetonitrile-water （35：65, v/v） containing 5 mM ammonium formate （pH = 3.0）. All compounds were monitored by mass spectrometry with electrospray positive ionization. The lower limit of quantification was 0.5 ng/mL for both erlotinib and OSI-420; accuracy was estimated by relative error, which was in the range from 0.07% to 8.00% for erlotinib and -2.83% to 6.67% for OSI-420; precision was validated by relative standard deviation, which was from 2.28% to 15.12% for erlotinib and from 1.96% to 11.50% for OSI-420. This method was applied to a pharmacokinetic study of BALB/c nude mice following oral administration of erlotinib at 12.5 mg/kg. A 2-compartment model was used to fit the pharmacokinetics of erlotinib and 1-compartment model for the pharmacokinetics of OSI-420. The ratio of the active metabolite to parent drug in mice was greater than previously reported in humans and probably reflects interspecies difference in the rate of conversion of erlotinib to OSI-420.
基金National Natural Science Foundation of China(NSFC,Grant No.81673500)
文摘In the current study, we established and validated a simple and sensitive liquid chromatography-tandem mass spectrometric method for the determination of 21-hydroxy deflazacort in nude mice plasma, and such a method was applied to a pharmacokinetic study. Using betamethasone as the internal standard, the plasma samples were pre-treated by precipitation with acetonitrile and then analyzed on a reversed-phase C18 column （50 mm×2 mm, 5 μm） with a mobile phase consisting of acetonitrile and 4.0 mM ammonium formate （pH was adjusted to 3.5 with formic acid （40：60, v/v））. The analyte was detected by a triple quadrupole tandem mass spectrometer using electrospray, and multiple reaction monitoring was employed to select 21-hydroxy deflazacort at m/z 400.2/124.0 and betamethasone at m/z 393.3/147.0 in the positive ion mode. The calibration curves were linear （r〉0.99） over the range of 0.5~,00 ng/mL. The intra- and inter-day precisions and accuracies were 4.5%-10.1% and -1.7%-10.7% respectively. This method was successfully applied to a preclinical administered with a single oral dose of 4 mg/kg deflazacort, and its pharmacokinetic study of deflazacort on female nude mice pharmacokinetics was characterized by a two-compartment model with first-order absorption.
基金support from the German Centre for Infection Research(DZIF,TTU 09.710)supported by the Helmholtz Association’s Initiative on Aging and Metabolic Programming(AMPro)。
文摘Trimethylamine-N-oxide(TMAO)has emerged as a potential biomarker for atherosclerosis and the development of cardiovascular diseases(CVDs).Although several clinical studies have shown striking associations of TMAO levels with atherosclerosis and CVDs,TMAO determinations are not clinical routine yet.The current methodology relies on isotope-labeled internal standards,which adds to pre-analytical complexity and costs for the quantification of TMAO and its precursors carnitine,betaine or choline.Here,we report a liquid chromatography-tandem mass spectrometry based method that is fast(throughput up to 240 samples/day),consumes low sample volumes(e.g.,from a finger prick),and does not require isotope-labeled standards.We circumvented the analytical problem posed by the presence of endogenous TMAO and its precursors in human plasma by using an artificial plasma matrix for calibration.We cross-validated the results obtained using an artificial matrix with those using mouse plasma matrix and demonstrated that TMAO,carnitine,betaine and choline were accurately quantified in’reallife’human plasma samples from healthy volunteers,obtained either from a finger prick or from venous puncture.Additionally,we assessed the stability of samples stored at-20℃and room temperature.Whereas all metabolites were stable at-20℃,increasing concentrations of choline were determined when stored at room temperature.Our method will facilitate the establishment of TMAO as a routine clinical biomarker in hematology in order to assess the risk for CVDs development,or to monitor disease progression and intervention effects.
文摘A highly sensitive liquid chromatography-tandem mass spectrometry（LC-MS/MS） method was developed for the determination of tadalafil（TAD） in human plasma. TAD and its deuterated internal standard（IS）, tadalafil-d3, were extracted from 200 mL plasma using Phenomenex Strata-X-C 33 m extraction cartridges. Chromatographic analysis was carried out on Synergi Hydro-RP C18（100 mm × 4.6 mm, 4 mm）column with a mobile phase consisting of methanol and 10 m M ammonium formate, p H 4.0（90：10, v/v）,delivered at a flow rate of 0.9 m L/min. Quantitation of the protonated analyte was done on a triple quadrupole mass spectrometer using multiple reaction monitoring via electrospray ionization. The precursor to product ions transitions monitored for TAD and TAD-d3 were m/z 390.3-268.2 and m/z393.1-271.2, respectively. The calibration curve was linear over the concentration range of 0.50–500 ng/m L with correlation coefficient, r2 Z 0.9994. Acceptable intra-batch and inter-batch precision（r3.7%） and accuracy（97.8% to 104.1%） were obtained at five concentration levels. The recovery of TAD from spiked plasma was highly precise and quantitative（98.95% to 100.61%）. Further, the effect of endogenous matrix components was minimal. TAD was found to be stable under different storage conditions in human plasma and also in whole blood samples. The validated method was successfully used to determine TAD plasma concentration in a bioequivalence study with 20 mg TAD tablets in 24 healthy volunteers. Method performance was evaluated by reanalyzing 115 study samples.
基金National Natural Science Foundation of China(Grant No.81803614)
文摘Benapenem is a new parenteral beta-lactam antibacterial with a broad antibacterial spectrum. In the present study, we developed and validated a simple, rapid and sensitive assay method using D6-benapenem as internal standard(IS) after one-step precipitation with methanol to determine benapenem in the plasma of infected mice. Separation was achieved on a reverse phase C18 column with a mobile phase composed of acetonitrile containing 0.2% formic acid–water(0.2% formic acid) and 10 mmol/L ammonium acetate in gradient elution mode. A triple quadrupole tandem mass spectrometer with electrospray ionization source was used as detector and operated by multiple reaction monitoring(MRM) in the positive ion mode. Calibration curves were linear(r>0.99) between 10 and 2000 ng/m L. The quantitative limit was 10 ng/m L, and the intra-and inter-precisions were <4.85% and <1.47%, respectively. The extraction recovery of benapenem and IS was 97.07%–107.09% and 92.47%–111.59%, respectively. The intra-and inter-accuracies were –9.70%– –11.00%, and the matrix effects of benapenem and IS were 85.68%–92.04% and 83.17%–92.04%, respectively. The method was successfully applied to the preclinical pharmacokinetic(PK) studies of benapenem. We also developed a two-compartment model to characterize the PK profiles of benapenem in infected mice, which could provide a better understanding of the PK properties of benapenem.
基金supported by the Japan Society for the Promotion of Science KAKENHI(Grant No.:JP19H00349).
文摘The quantitation of serum tocilizumab using liquid chromatography tandem-mass spectrometry(LC-MS/MS)method has not been widely applied in clinical settings because of its time-consuming and costly sample pretreatments.The present study aimed to develop a validated LC-MS/MS method for detecting serum tocilizumab by utilizing immobilized trypsin without an immunoglobulin G purification step and evaluate its applicability in the treatment of rheumatoid arthritis(RA)patients administered intravenously or subcutaneously with tocilizumab.The tocilizumab-derived signature peptide was deciphered using a nano-LC system coupled to a hybrid quadrupole-orbitrap mass spectrometer.The serum tocilizumab was rapidly digested by immobilized trypsin for 30 min.The chromatographic peak of the signature peptide and that of the internal standard were separated from the serum digests for a total run time of 15 min.The calibration curve of serum tocilizumab concentration was linear with a range of 2-200 μg/mL.The intra-and inter-day accuracy and relative standard deviation(RSD)were 90.7%-109.4%and<10%,respectively.The serum tocilizumab concentrations in the RA patients receiving intravenous and subcutaneous injections were 5.8-28.9 and 2.4-63.5 μg/mL,respectively.The serum tocilizumab concentrations using the current method positively correlated with those using the enzyme-linked immunosorbent assay,although a systematic error was observed between these methods.In conclusion,a validated LC-MS/MS method with minimal sample pretreatments for monitoring serum tocilizumab concentrations in RA patients was developed.
文摘A sensitive and selective liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of rosuvastatin in human plasma using gliclazide as an internal standard (IS). Rosuvastatin and gliclazide in plasma were extracted with ethyl acetate, separated on a C18 reversed phase column, eluted with mobile phase of acetonitrile-methanoic acid (0.1%) (60:40, v/v), ionized by positive ion pneumatically assisted electrospray and detected in the multi-reaction monitoring mode using precursor → product ions of m/z 482.1 → 258.1 for rosuvastatin and m/z 324.2 → 127.2 for IS, respectively. The calibration curve was linear (r2 > 0.99, n = 5) over the concentration range of 0.1 - 60 ng/mL. The speci?city, matrix effect, recovery, sensitivity, linearity, accuracy, precision, and stabilities were validated for rosuvastatin in human plasma. In conclusion, the validation results showed that this method was sensitive, economical and less toxic and it can successfully ful?ll the requirement of bioequivalence study of rosuvastatin calcium tablets in Chinese healthy volunteers.
文摘Nitrosamine impurities are potentially genotoxic which are considered under cohort of concern as per ICH M7 guidelines and need to be controlled at trace levels during quantification in drug substances and drug products for safe human consumption. Recent regulatory requirements also suggest the need to have highly sensitive analytical methods for the accurate quantification of Nitrosamine impurities. In this paper we have presented simple, rapid and ultra-sensitive LC-MS/MS method for six potential genotoxic nitrosamine impurities: N-Nitroso dimethyl amine (NDMA), N-Nitroso diethyl amine (NDEA), N-Nitroso Ethyl Iso propylamine (NEIPA), N-Nitroso-N-methyl-4-aminobutyric acid (NMBA) N-Nitroso diisopropylamino (NDIPA) and N-Nitroso dibutyl amine (NDBA) with a LOQ of 0.004 ppm. Chromatographic separation is achieved using Zorbax SB C18 150 × 3.0 mm, 3.5 μ column with 0.1% formic acid in water as mobile phase A and 0.1% formic acid in methanol as mobile phase B at a flow rate of 0.3 ml/min using gradient mode of elution at a total run time of 18 minutes. Six nitrosamine impurities are successfully ionized and quantified in positive mode of atmospheric pressure chemical ionization (APCI) using multiple reaction monitoring (MRM). Method validation is performed as per ICH guidelines evaluating the limit of quantification and detection and found to give good S/N ratios with good linearity range of 0.002 - 2 ppm with regression coefficient >0.99 for all the six nitrosamine impurities. Method recoveries are established using three-step sample preparation protocol and are found to be satisfactory within 80% - 120%. The method can be used routinely applied for the detection of Nitrosamines in Telmisartan at a concentration of 1.5 ng/ml (0.03 ppm with respect to telmisartan concentration of 50 mg/ml).
文摘A sensitive and selective liquid chromatography-tandem mass spectrometric（LC —MS/MS）method was established to determine 2-oxo-clopidogrel,a crucial intermediate metabolite in human plasma.A chromatographic separation was performed on a Sapphire C_（18） column following a liquid-liquid extraction sample preparation with methyl t-butyl ether.Detection was carried out on a triple quadrupole mass spectrometer operated in multiple reaction monitoring（MRM） with an electrospray ionization（ESI）mode.The method was validated in terms of specificity,accuracy,precision and limit of quantification.The calibration curves ranged from 0.50 to 50.0 ng/mL with good linearity.The stability was fully validated with addition of 1,4-dithio-DL-threitol（DTT） into the plasma sample prior to and in the preparation procedure.The validated method was proved to be suitable for use in pharmacokinetic study after single oral administration of 75 mg clopidogrel tablets in human subjects,which could make contribution to intensive study of the clinical drug-drug interactions of clopidogrel and individual treatment.
基金supported by NIH grant GM114179 and AI138195 to D.K.S.the Centre for Protein Therapeutics at University at BuffaloDonald F. and Edna G. Bishop Scholarship Foundation for their continued support
文摘Here we have presented a sensitive and selective LC-MS/MS method for the quantification of tyrphostin A9, which is a selective inhibitor for platelet derived growth factor receptor tyrosine kinase and has been investigated in vitro as a potent oxidative phosphorylation uncoupler. The murine analytical method was developed for three biological matrices: cell culture media, 3T3-L1 cell lysate, and murine plasma. For each matrix the limit of detection and the limit of quantification were found to be 0.5 ng/mL and 1.0 ng/ mL, respectively. The range of standard curve for each matrix was 1.0-100 ng/mL, linearity was >0.99, and the precision and accuracy were within 20%. 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoic acid was found to be the most suitable internal standard. The validated LC-MS/MS method was used to investigate stability and in vitro pharmacokinetics of tyrphostin A9. It was found that tyrphostin A9 is susceptible to hydrolysis, and the degradation product was identified as 3,5-di-tert-butyl-4- hydroxybenzaldehyde. Tyrphostin A9 was not stable in biological matrices, and the rate of its degradation in murine plasma was faster than that in cell culture media. In vitro pharmacokinetic studies revealed that tyrphostin A9 concentrations in the cell culture media declined in a bi-exponential manner and the concentrations inside the adipocytes remained constant, suggesting tyrphostin A9 has an intracellular binding site and is retained within the cell. The LC-MS/MS method presented here paves the way for further quantitative investigations involving tyrphostin A9.
文摘A rapid and sensitive liquid chromatography-tandem mass chromatography (LC-MS/MS) method has been developed and validated for simultaneous determination of catalpol and harpagide in rat plasma. The samples were extracted by one-step protein precipitation and separated on a SunFireTM C18 column (100 mm × 2.1 mm, 3.5 μm;Waters) using acetonitrile-10 mM ammonium formate as mobile phase at a flow rate 0.3 mL/min in gradient mode. The analytes were detected without interference in Multiple Reaction Monitoring (MRM) mode with negative electrospray ionization. Linear responses were obtained for catalpol ranging from 20 to 5000 ng/mL and harpagide ranging from 10 to 2500 ng/mL. Coefficients of correlation (r) for the calibration curves were more than 0.99 for both analytes. Intra- and inter-day accuracy and precision were within the acceptable limits of less than 15.0% at all concentrations. The quantitation method was successfully applied for simultaneous estimation of catalpol and harpagide after oral administration of Zeng Ye Decoction.
基金the National Key Research and Development Program of China(2017YFC0908600)the National Natural Science Foundation of China(81773817)+1 种基金the National Key R&D Program of China(No.2017YFE0102200)the Fundamental Research Funds for the Central Universities(2017XZZX011-04)。
文摘In Korea and China,ilaprazole is a widely used proton pump inhibitor in the treatment of gastric ulcers.In this study,a specific and sensitive LC-MS/MS method has been developed and validated for the quantification of ilaprazole enantiomers in the rat plasma,using R-lansoprazole as the internal standard.The enantioseparation was achieved on a CHIRALPAK AS-RH column(4.6 mm×150 mm,i.d.5 mm),with a mobile phase composed of 10 m M ammonium acetate aqueous solution and acetonitrile(60:40,V/V),at a flow-rate of 0.5 m L/min.The method was validated over the concentration range of 0.5 e300 ng/m L for both,R-and S-ilaprazole.The lower limit of quantification was 0.5 ng/m L for both enantiomers.The relative standard deviation(RSD)of intra-and inter-day precision of R-ilaprazole and S-ilaprazole was less than 10.9%,and the relative error accuracy(RE)ranged fromà0.5%e2.0%.Finally,the method was successfully evaluated in rats in a stereoselective pharmacokinetic study of the ilaprazole racemate.
文摘A rapid and sensitive liquid chromatography-tandem mass spectrometry method（LC-MS/MS）was developed and validated for the quantification of fexofenadine in human plasma,to conduct comparative bioavailability studies.Human plasma was extracted with a mixture of dichloromethane-diethyl ether（volume ratio 2∶3）in a basic environment and the extract was separated on a C18 column with a mobile phase consisting of acetonitrile-methanol-10 mmol/L ammonium acetate（volume ratio 45∶45∶10）.The analytes were detected via electrospray ionization（ESI）tandem mass spectrometry in the multiple-reaction-monitoring（MRM）mode.The linearity was within a range of 1-1000 ng/mL.The intra-and inter-day precision were〈4.1% and〈4.8%,respectively,and the accuracy was in the range of 95.0%-105%.The method was applied to the quantification of fexofenadine human plasma from 20 healthy male Chinese volunteers,according to a single dose,randomized,two-way crossover design with a two-week washout period.The mean values of major pharmacokinetic parameters of ρmax,AUC0-48,AUC0-∞,tmax,and t1/2 were determined from the plasma concentration.The analysis of variance（ANOVA）did not show any significant difference between the two products of fexofenadine and 90% confidence intervals fell within the acceptable range for bioequivalence.
文摘Simvastatin （SIM） is a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor widely used in hyperlipidemia therapy. SIM has recently been studied for its anticancer activity at doses higher than those used for the hyperlipidemia therapy. This prompted us to study the pharmacokinetics of high-dose SIM in cancer patients. For this purpose, an LC-MS/MS method was developed to measure SIM and its acid form （SIMA） in plasma and peripheral blood mononuclear cells （PBMCs） obtained from patients. Chromatographic analyte separation was carried out on a reverse-phase column using 75：25 （% v/v） acetonitrile：ammonium acetate （0.1 M, pH 5.0） mobile phase. Detection was performed on a triple quadrupole mass spectrometer, equipped with a turbo ion spray source and operated in positive ionization mode. The assay was linear over a range 2.5-500 ng/mL for SIM and 5-500 ng/mL for SIMA in plasma and 2.5-250 ng/mL for SIM and 5-250 ng/mL for SIMA in cell lysate. Recovery was 〉 58% for SIM and 〉 75% for SIMA in both plasma and cell lysate. SIM and SIMA were stable in plasma, cell lysate and the reconstitution solution. This method was successfully applied for the determination of SIM and SIMA in plasma and PBMCs samples collected in the pharmacokinetic study of high-dose SIM in cancer patients.
文摘A simple and reliable high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for the determination of colistin A and colistin B in human plasma was developed and validated. Clarithromycin was used as an internal standard (IS). Plasma extraction was performed using C-18 cartridges and methanol containing 0.1% formic acid. Analysis was performed using Atlantis dC18 (2.1 × 100 mm, 3 μm) column at room temperature and a mobile phase of 0.2% formic acid in acetonitrile and water (50:50, v:v), delivered at a flow rate of 0.2 ml/minute. Eluent was detected in the positive ion mode using electrospray ionization at the following transitions of mass to charge (m/z): colistin A, 585.6 → 101.4;colistin B, 578.7 → 101.3;and IS, 748.6 → 158.4. No interference by components of blank plasma or commonly used drugs was observed. The relationship between colistin A colistin B concentrations and their corresponding peak height ratios to the IS was linear over the range of 0.05 - 10 μg/ml. Inter-day coefficient of variation and bias were, respectively, ≤11.5% and <span style="white-space:nowrap;">−</span>3.0 to 6.0 for colistin A and ≤9.9 and <span style="white-space:nowrap;">−</span>4.7 to 3.0 for colistin B. Mean extraction recovery of colistin A, colistin B, and the IS were 97%, 94%, and 97%, respectively. The method was applied to assess the stability of colistin A and colistin B in processed samples (24 hr. at room temperature, 48 hours at <span style="white-space:nowrap;">−</span>20<span style="white-space:nowrap;">°</span>C) and unprocessed samples (24 hr. at room temperature, 8 weeks at <span style="white-space:nowrap;">−</span>20<span style="white-space:nowrap;">°</span>C) and after three cycles of freeze and thaw found to be ≥87%.
文摘A highly sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the de-termination of imperatorin and isoimperatorin in rat plasma using psoralen as internal standard. Analyses were performed on a Shimadzu HPLC system using a Shimadzu C18 column eluted with a mobile phase of methanol-water (25:75), containing 0.1% formic acid at a flow rate of 0.4 ml/min. The detection was performed by positive ion elec-trospray ionization in multiple reactions monitoring mode, monitoring the transitions m/z 203→147 and m/z 203→159 for imperatorin and isoimperatorin, respectively. The method was validated over the concentration range of 2.5 -1000.0 ng/mL for imperatorin and isoimperatorin. The limits of detection and quantification were 1.0 and 3.0 ng/mL, repectively for both analytes. The intra-day and inter-day accuracy and precision of the assay were less than 10.9%. This method has been applied successfully to a pharmacokinetic study involving the intragastric administration of extract of Angelicae Dahuricae Radix to rats.
文摘A simple, rapid, specific and precise liquid chromatography—tandem mass spectrophotometric (LC-MS/MS) method was developed and validated for the quantification of chiral separated R-bicalutamide from S-bicalutamide, in human plasma. Topiramate (TPM) was used as internal standard, added to plasma sample prior to extraction using t-butyl methyl ether (TBME). Chromatographic separation was achieved on CHIRALPAK AD-RH column (150 mm×4.6 mm, 5 μm) with acteonitrile: 0.1% formic acid Buffer (50:50 v/v) as an isocratic mobile phase with a flow rate of 1.0 mL·min-1. Quantitation was performed by transition of 429.0 → 255.0 (m/z) for R-bicalutamide and 338.1 → 77.8 (m/z) for topiramate. The lower limit of quantitation was 20 ng·mL-1with a 100 μL plasma sample. The concentrations of eight working standards showed linearity between 20 to 3200 ng·mL-1(r2≥ 0.9990). Chromatographic separation was achieved within 6 min, compared to the 15 min of previous methods. The average extraction recoveries of 3 quality control concentrations were 98.56% for R-bicalutamide and 92.42% for topiramate. The coefficient of variation was ≤15% for intra- and inter-batch assays. Therefore a rapid, specific and sensitive LC-MS/MS method for the quantification of R-bicalutamide in human plasma was developed and validated can be used in the bioequivalence study of this drug.
文摘A simple, rapid, and highly sensitive LC-MS/MS method has been developed for the simultaneous and trace level quantification of underivatized boronic acids in lumacaftor active pharmaceutical ingredient. Chromatographic separation of boronic acids and lumacaftor achieved using Agilent Poroshell HPH C18 150<span> </span><span>×</span><span> </span><span>4.6</span><span> </span><span>mm 2.7</span><span> </span><span>μ column with 0.1% ammonia in water as mobile phase A and 100%</span><span> </span><span>acetonitrile as mobile phase B at a flow rate of 0.25</span><span> </span><span>ml/min. Gradient elution</span><span> was</span><span> used with a total method run time of 14</span><span> </span><span>minutes. Boronic acids were successfully ionized and quantified without derivatization using electrospray ionization in negative mode using tandem quadrupole mass spectrometry in multiple reactions monitoring mode. Method validation </span><span>was </span><span>performed as per ICH guidelines with good linearity over the concentration range of 0.05 ppm to 5 ppm of Lumacaftor test concentration for both the boronic acids with a correlation coefficient of >0.99.</span><span> </span><span>Recoveries were found good at different concentration levels and within the range of 80</span><span>% </span><span>-</span><span> </span><span>120%.</span><span> </span><span>The developed method can be successfully used for the routine quantification of boronic acids at a concentration level of 20</span><span> </span><span>ng/ml (1</span><span> </span><span>ppm with respect to 20</span><span> </span><span>mg/ml lumacaftor).</span>
基金financial support from National Natural Science Foundation of China (No.81603072)。
文摘Pomalidomide is an immunomodulatory agent (IMiD) that has been approved by the US Food and Drug Administration (FDA) for clinical treatment of patients with multiple myeloma.In this work,we developed a sensitive and validated LC-MS/MS method for high-throughput determination of pomalidomide over the range of 1.006-100.6 ng/mL(R^(2)=0.9991) in human plasma and pharmacokinetic studies.A liquid-liquid extraction method using ethyl acetate was applied to extract pomalidomide and afatinib (as an internal standard,IS) from human plasma.Chromatographic separation was performed on a Hedera ODS column (150 mm×2.1 mm,5μm) with security guard C18 column (4 mm×2.0 mm) at 40℃.Methanol and 10 mmol/L aqueous solution of ammonium acetate containing 0.1%formic acid were used as a gradient elution mobile phase,and the flow rate was 0.4 mL/min.A triple quadruple tandem mass spectrometer using multiplex reaction monitoring mode (MRM) with electrospray ionization (ESI) positive ionization was employed.The precursor to product ion transitions for the quantitative analysis of pomalidomide and the IS were m/z 274.2→163.1 and m/z 486.1→371.1,respectively.This established method has been validated according to regulatory guideline,and the results were all within the acceptance criteria.The validated LC-MS/MS method was successfully applied to analyze samples obtained from clinical pharmacokinetics study after oral administration of pomalidomide (4 mg) capsules in human.
