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

Abstract

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 cotrimoxazole. The liquid chromatography assay is based upon use of a column with a pentafluorophenyl-propyl modified and multiendcapped stationary phase and the coupling to electrospray ionization with a single quadrupole detector. The performances of both assays with multilevel 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 cotrimoxazole 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.

Monitoring of cefepime in urine by micellar electrokinetic capillary chromatography with ultraviolet detection and liquid chromatography coupled to mass spectrometry

“…Intra‐ and interday drug level repeatability was found to be ≤5.9 and ≤8.6%, respectively. These data compare well with those reported for the MEKC assay to monitor cefepime levels in serum und plasma .…”

“…The cefepime results of urine and serum analyses are presented in Table . Cefepime serum levels were in the expected range, according to our previous experience with TDM . Cefepime urine levels showed a broad range of results, depending on renal function, dosing and excreted urinary volume.…”

“…In the used assay format, internal standard and cefepime were detected around 8.8 and 10.7 min, respectively (Figure ), and the current was about 24 μA, values that are comparable to those under the assay conditions for serum and plasma . Electropherograms obtained with a blank urine fortified with the internal standard and a calibrator urine comprising 60 μg/mL cefepime and the internal standard are presented in panels A and B, respectively, of Figure .…”

“…patients receiving a large number of drugs), however, interferences with the detection of cefepime were often observed (Figure D). Removal of hydrophobic compounds with dichloromethane, as was described for the elimination of sulfamethoxazole in sera of patients that received co‐trimoxazole , did not provide a mean for an interference‐free detection of urinary cefepime in these samples. For selected of these samples, cefepime levels could be estimated by urine dilution and addition of a known amount of cefepime.…”

Separation and simultaneous determination of seven bioactive components in Tripterygium wilfordii Hook. F. and Tripterygium preparations by micellar electrokinetic capillary chromatography

“…Since the introduction of MEKC technique by Terabe et al. in 1982, it has been widely used in different analytical fields . The very high variability of BGE, including the possibility to add different surfactants and organic modifiers, makes MEKC an effective tool for the separation of a broad range of compounds .…”