G. Petitjean, Fabrice Aman-Pommier, F. Coudoré
Nov 22, 2019
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Biomedical chromatography : BMC
Abstract
Temocillin is a β-lactamase-resistant penicillin used for the treatment of multiple drug-resistant Gram-negative bacteria. To maximize efficacy and avoid adverse effects, dose regimen had to be quickly adjusted to the clinical situations. This necessitated to develop a rapid, reliable and accurate analytical method. Temocillin and the stable isotopically labeled internal standard ([13 C6 ]-amoxicillin) were extracted from either serum or cerebrospinal fluid by a turbulent flow liquid chromatographic method and eluted onto a octadecyl-silica phase with polar endcapping. Mass spectrometry was conducted using exact mass determination method by an electrospray positive ionization high-resolution mass spectrometry. The LLOQ and ULOQ of the present method were determined to be 0.4 and 200 μg/mL for both serum and CSF samples, respectively. The total analysis time was less than 7 minutes. The recovery range from 87.7 to 120.8 %. Intra- and inter-day precision and trueness were tested at four concentration levels: 0.4, 8, 40 and 160 μg/mL. Values were 6.33 ±1.53%, 8.8 ±1.3%, 8.8 ±0.36% and 2.1 ±0.76%, 5.0 ± 0.54%, 9.9 ±1.0%, 5.8 ±1.6 and 0.1 ±1.1%, for inter-day and intra-day analysis, respectively. Temocillin was found to be stable under all relevant laboratory conditions. The method was cross-validated with a microbiological assay. This method is suitable for accurate measurement of temocillin concentration in small volumes of serum or CSF. Thanks to the on-line extraction procedure, the overall analytical time is compatible with high-throughput analysis for clinical application.