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EN
In this work, a simple and rapid high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method was developed and validated to carry out the simultaneous measurement of busulfan (BU) and phenytoin (PHT) in the plasma of children. In this method, plasma sample could be prepared by one-step protein precipitation using 1 mL of methanol/water (1:1, v/v). After centrifugation (14,500 rpm, 5 min, 4 °C), 10 μL of the supernatant was injected into a Hypersil Gold C18 column (150 × 2.1 mm, 5 μm, Thermo Fisher Scientific) for separation by gradient elution. Quantification was carried out using multiple reactions monitoring (MRM) under positive scan mode. In the method verification, the calibration curves of BU and PHT showed satisfactory linearity (r > 0.99) at the concentration ranging from 0.02 to 20 μg mL⁻¹. The accuracy and precision were tested at four concentration levels (including the LLOQ level) with the relative error (RE) ranging from −0.80% to 11.45% and coefficient of variation (CV) between 0.93% and 7.74%. There was no pronounced matrix effect to interfere with the quantitative analysis. Compared to determine BU and PHT using two individual methods, less pre-treatment process, labor and blood sample volume are required in this proposed method. Finally, this method was successfully applied to the therapeutic drug monitoring of BU and PHT for children underwent hematological stem cell transplantation.
EN
Schizonepeta tenuifolia Briq. (ST) has been used as an aromatic exterior-releasing medicine in clinical practice for thousands of years in China. Previous researches have revealed both volatile oil (STVO) and aqueous extract (STAE) from ST showed significant pharmacological activities, such as anti-virus, anti-inflammation, anti-oxidation, and immunoregulation. However, the influence between each other was still unknown. The purpose of this study was to compare the pharmacokinetic profiles of three main flavonoids (luteoloside, apigetrin, and hesperidin) in STAE to illustrate the influence of STVO. A liquid chromatography-tandem mass spectrometry (HPLC-MS) method was established to quantitatively analyze the three absorbed ingredients in the plasma of healthy rats. Biological samples were analyzed on an Agilent Eclipse Plus C18 column (3.0 mm × 150 mm, 3.5 μm) with gradient mobile phase (containing 0.2% formic acid and acetonitrile) at a flow rate of 0.8 mL/min. All the analytes and quercitrin (IS) were investigated with an electrospray ionization source (ESI) using multiple-reaction monitoring (MRM) in negative ionization mode. In addition, this quantitative method showed good linearities (r ≥ 0.9995) and the lower limits of quantification were 0.590–1.19 ng/mL. The intra- and inter-day precisions ranged 3.47–10.45% and 4.29–11.28% for the three analytes. The mean extraction recoveries were in the range of 77.41–109.79% and the average matrix effects were within 83.41–112.67%. The validated method has been fully applied to compare the pharmacokinetic parameters of the three flavonoid glycosides in rat plasma after oral administration of STAE and STAE+STVO. In comparison of luteoloside, apigetrin, and hesperidin in STAE group, it was found that different degree of increasing existed for the time to reach the maximum concentration (T max), elimination half-life time (T 1/2), the area under the concentration curves (AUC0→t and AUC0→∞) and the maximum concentrations (C max) in STAE+STVO group. As can be seen from above results, STVO could improve the absorption and bioavailability of the three analytes. These findings would provide some active and strong basis of safe clinical application for ST and further exploitation for STVO from the perspective of drug–drug interaction.
EN
A sensitive and rapid method using HPLC-MS/MS was developed for the determination of Wight glucocorticoids residues in chicken muscle simultaneously by Turbo Flow. The eight glucocorticoids were prednisone, prednisolone, hydrocortisone, methylprednisolone, dexamethasone, betamethasone, beclomethasone and fludrocortisones. Samples were extracted with ethyl acetate and on-line cleaned up through a Turbo Flow solid-phase extraction column without time-consuming pretreatment before HPLC-MS/MS analysis. Sample pretreatment conditions, Turbo Flow conditions and mass spectra parameters were optimized and obtained eight glucocorticoids calibration curves. These curves showed good linearity over the concentration from 0.2 mg/kg to 50 mg/kg with an average recovery from 71.63% to 117.36%. This method could be applied on real samples and provided simple, rapid, sensitive and highly selective analysis, which made it feasible to be adopted in food inspection organizations or carry out quantitative analysis for other banned substance.
EN
A rapid and sensitive High-Performance Liquid Chromatography-tandem Mass Spectrometry (HPLC/MS/MS) method for determining apremilast in beagle dog plasma and urine samples was developed and validated using clopidogrel as the internal standard (IS). Apremilast was extracted from the plasma and urine samples by liquid–liquid extraction using methyl tert-butyl ether. Chromatographic separation was performed using a C8 column with gradient elution and a mobile phase containing methanol and 0.1% formic acid. Quantification was achieved in multiple reaction monitoring (MRM) mode with a transition of m/z 461.3→178.2 for apremilast and m/z 322.2→184.1 for clopidogrel (IS). This method was validated regarding its specificity, linearity, precision, accuracy, and stability. The lower limit of quantification (LLOQ) for this method was 5 ng/mL, and the calibration curve was linear over 5–1,000 ng/mL. The intra- and inter-run coefficients of variance (CV) of aprelimast in plasma samples were less than 12.92% and 10.64%, respectively, while in urine samples, the CV were less than 11.84% and 10.20%, respectively. The samples were stable under the tested conditions. This method was successfully applied to a pharmacokinetic study in beagle dogs following oral administration of 10 mg of apremilast.
EN
Ixeris dentata (Thunb. ex Thunb.) Nakai (Asteraceae), a well-known edible vegetable in Asia, contains various bioactive secondary metabolites, including sesquiterpene lactones. In this study, a high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) method has been developed and validated for simultaneous determination of seven sesquiterpene lactone glucosides isolated from the roots of I. dentata. In addition, these compounds were evaluated in terms of their antiviral activities against coxsackievirus B3 (CVB3) and human enterovirus 71 (EV71). The developed method was validated in terms of linearity (R2 > 0.9996), precision (RSD < 2.24%), accuracy (96.30–102.77%), and stability (RSD < 1.94%) and successfully applied to the quantitation of the I. dentata root samples collected from six different regions of Korea. The content of sesquiterpene lactone glucosides varied significantly based on the region. For the antiviral activities, guaianolides with an ester group at C-8 (compounds 6 and 7) showed the most potent activities against CBV3, while germacranolide (compound 5) showed the most consistent antiviral activity against both CVB3 and EV71. The method was validated to be simple and reliable to simultaneously determine seven putative bioactive sesquiterpene lactone glucosides, the substantial chemotaxonomic markers, in I. dentata root samples
EN
The aim of this study was to develop and validate a HPLC-MS/MS assay to determine the lutein concentration in plasma samples of human and SD rats. Organic solvent was used for lutein extraction. The extract was injected into a HPLC-MS/MS system. Reversed phase chromatography was performed on a C18 column in gradient mode. Lutein and internal standard (phenytoin sodium) were identified in atmospheric pressure chemical ionization mode using ion transitions of m/z 567.5>549.4 and 205.2>110.8, respectively. The lutein quantification assay was linear over concentrations ranging from 4 to 500 ng/mL. The lower limit of quantification was 4 ng/mL with satisfactory precision and accuracy. The assay presented acceptable intra and inter-batch precision (RSD%) and accuracy (RE%) <8.16% in SD rat plasma and <12.80% in human plasma. The extraction recovery ranged from 50.94 to 60.90% in SD rat plasma and 68.73% in human plasma. The matrix effect for lutein was acceptable and had minimal influence on the results. The method was then applied to determine the lutein concentrations in human plasma after a single oral dose of 20mg lutein. The method described is rapid, selective, sensitive and reproducible. This method can be used for both pharmacokinetic studies and therapeutic drug monitoring purposes.
EN
A new, sensitive, and selective high-performance liquid chromatography-tandem mass spectrometric method (HPLC-MS/MS) has been developed for the quantification of six flavonoids (sophoricoside, genistin, genistein, rutin, quercetin, and kaempferol) in rat bile and urine. The sample pretreatment was simple by liquid-liquid extraction. Sulfamethalazole was used as internal standard (IS). During method development, the effect of extraction volume, mobile phase composition, column temperature, and injection volume were varied to optimize sensitivity and achieve a run time as short as possible. Chromatographic separation was accomplished on a C18 column with a simple linear gradient elution within 9 min. Full validation of the assay was in accordance with the requirement of the validation of the method in vivo and implemented including specificity, linearity, accuracy, precision, recovery, and matrix effect. This is the first report on determination of the major flavones in rat bile and urine after oral administration of Fructus Sophorae extract. The method has been used successfully in excretion studies of six major flavonoids in rat bile and urine.
EN
A selective and sensitive liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) method was developed and validated for analysis of xanthotoxol (1), xanthotoxin (2), isoimpinellin (3), bergapten (4), oxypeucedanin (5), imperatorin (6), cnidilin (7), and isoimperatorin (8) in rat bile and urine using pimpinellin as an internal standard (IS). An Agilent 1200 liquid chromatography system (Agilent Technologies, USA) equipped with a quaternary pump, an autosampler, and a column compartment was used for all analyses. Chromatographic separations were performed on a Sapphire C18 column (150 mm × 4.6 mm, 5 μm), and the column temperature was maintained at 30°C; the sample injection volume was 10 μL. The specificity, linearity, accuracy, precision, recovery, matrix effect, and several stabilities were validated for all analytes in the rat bile and urine samples. The method was successfully applied in monitoring the concentrations of eight coumarins in rat bile and urine after a single oral administration of Radix Angelicae Dahuricae extract with a dosage of 8.0 mL/kg. In the bile samples, the eight coumarins excreted completely in twenty-four hours. The average percentages of coumarins (1–8) excreted were 0.045%, 0.019%, 0.177%, 0.105%, 0.337%, 0.023%, 0.024%, 0.021%. In the urine samples, the eight coumarins excreted completely in seventy-two hours. The average percentages of coumarins (1–8) excreted were 1.78%, 0.095%, 0.130%, 0.292%, 0.082%, 0.008%, 0.005%, 0.004%. The method is robust and specific and it can successfully complete the requirements of the excretion study of the eight coumarins in Radix Angelicae Dahuricae.
EN
Structure, magnetic and optical properties of tetraphenylborate salt of 2,5-[1-methyl-4-[2-(4-hydroxyphenyl)ethenyl)]pyridinium]-hexane were performed for condensed phase by means of solution and solid-state conventional and linear-polarized IR-spectroscopy of oriented colloids in nematic host, UV-Vis and fluorescence methods, HPLC MS-MS tandem and ESI mass spectrometry, 1H-, 13C- and 1H-1H COSY NMR, TGV and DSC methods. Electronic structure and vibrational analysis were carried out by quantum chemical calculations at two levels of theory second-order Moller-Plesset perturbation theory (MP2) and density functional theory (DFT) using 6-31G* basis set. B3LYP method, which combines Becke's three-parameter non-local exchange functional with the correlation function of Lee, Yang and Parr, was applied.
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