Development and Validation of a Volumetric Absorptive Microsampling- Liquid Chromatography Mass Spectrometry Method for the Analysis of Cefepime in Human Whole Blood: Application to Pediatric Pharmacokinetic Study

Cefepime is a fourth-generation cephalosporin antibiotic with an extended spectrum of activity against many Gram-positive and Gram-negative bacteria. There is a growing need to develop sensitive, small volume assays, along with less invasive sample collection to facilitate pediatric pharmacokinetic clinical trials and therapeutic drug monitoring. The volumetric absorptive microsampling (VAMS (TM)) approach provides an accurate and precise collection of a fixed volume of blood (10 mu L), reducing or eliminating the volumetric blood hematocrit assay-bias associated with the dried blood spotting technique. We developed a high-performance liquid chromatographic method with tandem mass spectrometry detection for quantification of cefepime. Sample extraction from VAMS (TM) devices, followed by reversed-phase chromatographic separation and selective detection using tandem mass spectrometry with a 4 min runtime per sample was employed. Standard curves were linear between 0.1-100 mu g/mL for cefepime. Intra- and inter-day accuracies were within 95.4-113% and precision (CV) was < 15 % based on a 3-day validation study. Recoveries ranged from 40.8 to 62.1% and the matrix effect was within 89.5-96.7% for cefepime. Cefepime was stable in human whole blood under assay conditions (3 h at room temperature, 24 h in autosampler post-extraction). Cefepime was also stable for at least 1 week (7 days) at 4 degrees C, 1 month (39 days) at -20 degrees C and 3 months (91 days) at -78 degrees C as dried microsamples. This assay provides an efficient quantitation of cefepime and was successfully implemented for the analysis of whole blood microsamples in a pediatric clinical trial. (C) 2019 Elsevier B.V. All rights reserved.