The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Wolfgang Thormann - One of the best experts on this subject based on the ideXlab platform.
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monitoring of cefepime in urine by micellar electrokinetic Capillary Chromatography with ultraviolet detection and liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2018Co-Authors: Mirjam Kummer, Nela Sestakova, Regula Theurillat, Uyen Huynhdo, Andrea Endimiani, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in urine by micellar electrokinetic Capillary Chromatography with UV detection and liquid Chromatography coupled to mass spectrometry via electrospray ionization is described. For micellar electrokinetic Capillary Chromatography, sample preparation comprised urine dilution and dodecyl-sulfate protein precipitation at pH 4.5, whereas diluted urines were analyzed in the other assay. Both approaches provided suitable conditions for cefepime analysis in urines of healthy volunteers that were spiked with cefepime. Cefepime monitoring by micellar electrokinetic Capillary Chromatography in samples from patients taking multiple drugs were prone to interferences, whereas liquid Chromatography coupled to mass spectrometry provided clean chromatograms and thus selective detection of cefepime in all samples. The latter assay was used to measure urinary cefepime in a prospective pilot study and to assess cefepime stability in urines at 25, 4, -20 and -70°C. The data suggest that urinary cefepime is stable for at least 72 h at all tested temperatures.
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monitoring of cefepime in human serum and plasma by micellar electrokinetic Capillary Chromatography improvement of sample preparation and validation by liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2017Co-Authors: Nela Sestakova, Regula Theurillat, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in deproteinized human serum and plasma by micellar electrokinetic Capillary Chromatography and liquid Chromatography coupled to mass spectrometry in presence of other drugs is reported. For micellar electrokinetic Capillary Chromatography, sample preparation comprised dodecylsulfate protein precipitation at pH 4.5 using an increased buffer concentration compared to that of a previous assay and removal of hydrophobic compounds with dichloromethane. This provided robust conditions for cefepime analysis in the presence of sulfamethoxazole and thus enabled its determination in samples of patients that receive co-trimoxazole. The liquid Chromatography assay is based upon use of a column with a pentafluorophenyl-propyl modified and multi-endcapped stationary phase and the coupling to electrospray ionization with a single quadrupole detector. The performances of both assays with multi-level internal calibration were assessed with calibration and control samples and both assays were determined to be robust. Cefepime levels monitored by micellar electrokinetic Capillary Chromatography in samples from patients that were treated with cefepime only and with cefepime and co-trimoxazole were found to compare well with those obtained by liquid Chromatography coupled to mass spectrometry. Cefepime drug levels determined by micellar electrokinetic Capillary Chromatography could thereby be validated. This article is protected by copyright. All rights reserved
Parham Sendi - One of the best experts on this subject based on the ideXlab platform.
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monitoring of cefepime in urine by micellar electrokinetic Capillary Chromatography with ultraviolet detection and liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2018Co-Authors: Mirjam Kummer, Nela Sestakova, Regula Theurillat, Uyen Huynhdo, Andrea Endimiani, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in urine by micellar electrokinetic Capillary Chromatography with UV detection and liquid Chromatography coupled to mass spectrometry via electrospray ionization is described. For micellar electrokinetic Capillary Chromatography, sample preparation comprised urine dilution and dodecyl-sulfate protein precipitation at pH 4.5, whereas diluted urines were analyzed in the other assay. Both approaches provided suitable conditions for cefepime analysis in urines of healthy volunteers that were spiked with cefepime. Cefepime monitoring by micellar electrokinetic Capillary Chromatography in samples from patients taking multiple drugs were prone to interferences, whereas liquid Chromatography coupled to mass spectrometry provided clean chromatograms and thus selective detection of cefepime in all samples. The latter assay was used to measure urinary cefepime in a prospective pilot study and to assess cefepime stability in urines at 25, 4, -20 and -70°C. The data suggest that urinary cefepime is stable for at least 72 h at all tested temperatures.
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monitoring of cefepime in human serum and plasma by micellar electrokinetic Capillary Chromatography improvement of sample preparation and validation by liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2017Co-Authors: Nela Sestakova, Regula Theurillat, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in deproteinized human serum and plasma by micellar electrokinetic Capillary Chromatography and liquid Chromatography coupled to mass spectrometry in presence of other drugs is reported. For micellar electrokinetic Capillary Chromatography, sample preparation comprised dodecylsulfate protein precipitation at pH 4.5 using an increased buffer concentration compared to that of a previous assay and removal of hydrophobic compounds with dichloromethane. This provided robust conditions for cefepime analysis in the presence of sulfamethoxazole and thus enabled its determination in samples of patients that receive co-trimoxazole. The liquid Chromatography assay is based upon use of a column with a pentafluorophenyl-propyl modified and multi-endcapped stationary phase and the coupling to electrospray ionization with a single quadrupole detector. The performances of both assays with multi-level internal calibration were assessed with calibration and control samples and both assays were determined to be robust. Cefepime levels monitored by micellar electrokinetic Capillary Chromatography in samples from patients that were treated with cefepime only and with cefepime and co-trimoxazole were found to compare well with those obtained by liquid Chromatography coupled to mass spectrometry. Cefepime drug levels determined by micellar electrokinetic Capillary Chromatography could thereby be validated. This article is protected by copyright. All rights reserved
Nela Sestakova - One of the best experts on this subject based on the ideXlab platform.
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monitoring of cefepime in urine by micellar electrokinetic Capillary Chromatography with ultraviolet detection and liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2018Co-Authors: Mirjam Kummer, Nela Sestakova, Regula Theurillat, Uyen Huynhdo, Andrea Endimiani, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in urine by micellar electrokinetic Capillary Chromatography with UV detection and liquid Chromatography coupled to mass spectrometry via electrospray ionization is described. For micellar electrokinetic Capillary Chromatography, sample preparation comprised urine dilution and dodecyl-sulfate protein precipitation at pH 4.5, whereas diluted urines were analyzed in the other assay. Both approaches provided suitable conditions for cefepime analysis in urines of healthy volunteers that were spiked with cefepime. Cefepime monitoring by micellar electrokinetic Capillary Chromatography in samples from patients taking multiple drugs were prone to interferences, whereas liquid Chromatography coupled to mass spectrometry provided clean chromatograms and thus selective detection of cefepime in all samples. The latter assay was used to measure urinary cefepime in a prospective pilot study and to assess cefepime stability in urines at 25, 4, -20 and -70°C. The data suggest that urinary cefepime is stable for at least 72 h at all tested temperatures.
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monitoring of cefepime in human serum and plasma by micellar electrokinetic Capillary Chromatography improvement of sample preparation and validation by liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2017Co-Authors: Nela Sestakova, Regula Theurillat, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in deproteinized human serum and plasma by micellar electrokinetic Capillary Chromatography and liquid Chromatography coupled to mass spectrometry in presence of other drugs is reported. For micellar electrokinetic Capillary Chromatography, sample preparation comprised dodecylsulfate protein precipitation at pH 4.5 using an increased buffer concentration compared to that of a previous assay and removal of hydrophobic compounds with dichloromethane. This provided robust conditions for cefepime analysis in the presence of sulfamethoxazole and thus enabled its determination in samples of patients that receive co-trimoxazole. The liquid Chromatography assay is based upon use of a column with a pentafluorophenyl-propyl modified and multi-endcapped stationary phase and the coupling to electrospray ionization with a single quadrupole detector. The performances of both assays with multi-level internal calibration were assessed with calibration and control samples and both assays were determined to be robust. Cefepime levels monitored by micellar electrokinetic Capillary Chromatography in samples from patients that were treated with cefepime only and with cefepime and co-trimoxazole were found to compare well with those obtained by liquid Chromatography coupled to mass spectrometry. Cefepime drug levels determined by micellar electrokinetic Capillary Chromatography could thereby be validated. This article is protected by copyright. All rights reserved
Regula Theurillat - One of the best experts on this subject based on the ideXlab platform.
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monitoring of cefepime in urine by micellar electrokinetic Capillary Chromatography with ultraviolet detection and liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2018Co-Authors: Mirjam Kummer, Nela Sestakova, Regula Theurillat, Uyen Huynhdo, Andrea Endimiani, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in urine by micellar electrokinetic Capillary Chromatography with UV detection and liquid Chromatography coupled to mass spectrometry via electrospray ionization is described. For micellar electrokinetic Capillary Chromatography, sample preparation comprised urine dilution and dodecyl-sulfate protein precipitation at pH 4.5, whereas diluted urines were analyzed in the other assay. Both approaches provided suitable conditions for cefepime analysis in urines of healthy volunteers that were spiked with cefepime. Cefepime monitoring by micellar electrokinetic Capillary Chromatography in samples from patients taking multiple drugs were prone to interferences, whereas liquid Chromatography coupled to mass spectrometry provided clean chromatograms and thus selective detection of cefepime in all samples. The latter assay was used to measure urinary cefepime in a prospective pilot study and to assess cefepime stability in urines at 25, 4, -20 and -70°C. The data suggest that urinary cefepime is stable for at least 72 h at all tested temperatures.
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monitoring of cefepime in human serum and plasma by micellar electrokinetic Capillary Chromatography improvement of sample preparation and validation by liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2017Co-Authors: Nela Sestakova, Regula Theurillat, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in deproteinized human serum and plasma by micellar electrokinetic Capillary Chromatography and liquid Chromatography coupled to mass spectrometry in presence of other drugs is reported. For micellar electrokinetic Capillary Chromatography, sample preparation comprised dodecylsulfate protein precipitation at pH 4.5 using an increased buffer concentration compared to that of a previous assay and removal of hydrophobic compounds with dichloromethane. This provided robust conditions for cefepime analysis in the presence of sulfamethoxazole and thus enabled its determination in samples of patients that receive co-trimoxazole. The liquid Chromatography assay is based upon use of a column with a pentafluorophenyl-propyl modified and multi-endcapped stationary phase and the coupling to electrospray ionization with a single quadrupole detector. The performances of both assays with multi-level internal calibration were assessed with calibration and control samples and both assays were determined to be robust. Cefepime levels monitored by micellar electrokinetic Capillary Chromatography in samples from patients that were treated with cefepime only and with cefepime and co-trimoxazole were found to compare well with those obtained by liquid Chromatography coupled to mass spectrometry. Cefepime drug levels determined by micellar electrokinetic Capillary Chromatography could thereby be validated. This article is protected by copyright. All rights reserved
Árpád Gyéresi - One of the best experts on this subject based on the ideXlab platform.
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Principles of Micellar Electrokinetic Capillary Chromatography Applied in Pharmaceutical Analysis
Advanced pharmaceutical bulletin, 2013Co-Authors: Gabriel Hancu, Brigitta Simon, Aura Rusu, Eleonora Mircia, Árpád GyéresiAbstract:Since its introduction Capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic Capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic Capillary Chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of Capillary electrophoretic methods to neutral analytes. In micellar electrokinetic Capillary Chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic Capillary Chromatography, with particular attention to those relevant in pharmaceutical analysis.
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Separation of 1,4-benzodiazepine derivates by micellar elektrokinetic Capillary Chromatography
Acta pharmaceutica Hungarica, 2007Co-Authors: Gabriel Hancu, Árpád Gyéresi, Attila GáspárAbstract:Our aim was to develop a Capillary electrophoresis method for the separation of 1,4-benzodiazepine derivates. Benzodiazepines are hydrophobic substances, neutral from electrophoretic point of view, consequently the best method for their separation proved to be micellar elektrokinetic Capillary Chromatography (MECC). A fast and reliable method has been developed, for the 8 of the most frequently used benzodiazepine derivates, using a separation buffer composed of sodium tetraborate 25 mM (pH 9,3), SDS (50 mM) and methanol (at least 12 %) as an organic modifier. Beside the separation we also studied the analytical condition for the separation (i.e. the effects of buffer concentration, modifier concentration and buffer pH on the separation).
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Separation of 1,4-benzodiazepines by micellar elektrokinetic Capillary Chromatography.
Journal of Biochemical and Biophysical Methods, 2006Co-Authors: Gabriel Hancu, Attila Gáspár, Árpád GyéresiAbstract:In this work the applicability of micellar elektrokinetic Capillary Chromatography (MECC) for the determination of benzodiazepines (BZD) has been studied. The applied method was used for the simultaneous separation of 8 BZDs (alprazolam, bromazepam, chlordiazepoxide, diazepam, flunitrazepam, medazepam, oxazepam, nitrazepam), and also for the study of stability in acidic medium. A fast and reliable method has been developed; using a separation buffer composed of sodium tetraborate 25 mM (pH 9.5), SDS (50 mM) and methanol (at least 12%) as an organic modifier.
