Rapid Quantification of Ceftobiprole in Human Plasma and Cerebrospinal Fluid by LC-MS/MS and Its Application in...

Ceftobiprole is a fifth-generation beta-cephalosporin with high inter-individual pharmacokinetic variability in critically ill patients. However, data on its pharmacokinetics and central nervous system (CNS) penetration are limited. This study developed and validated a rapid LC-MS/MS method for quantifying ceftobiprole in human plasma and CSF. Sample preparation involved protein precipitation of 50 µL aliquots. Analysis used gradient elution on an ACQUITY UPLC^® HSS T3 column (2.1 × 100 mm, 1.8 µm) with 0.2% formic acid and acetonitrile and was detected by positive ion electrospray, achieving a 3.5 min run time. The method was linear from 0.100 to 25.0 mg/L in plasma and 0.0500 to 15.0 mg/L in CSF. Intra- and inter-run precision and accuracy were within ±15% at all quality control levels. All validation parameters, including selectivity, matrix effects, recovery, and stability under various conditions, met acceptance criteria. Potential interference from the prodrug ceftobiprole medocaril was evaluated and found to be negligible. The method was successfully applied to samples from three patients, revealing a CSF penetration range of 11.9% to 36.5%. This validated LC-MS/MS method enables simple and rapid quantification of ceftobiprole in plasma and cerebrospinal fluid, filling the gap in data on its CNS penetration and supporting routine drug concentration monitoring in critically ill patients.