Development and validation of an UHPLC-MS/MS method for simultaneous quantification of Tazobactam, Meropenem, Vancomycin, Linezolid and Piperacillin in human plasma: Application in critically ill patients.

Antibiotic treatment for severe infections in critically ill patients might be challenging. The pathophysiological changes occurring in these patients can alter the pharmacokinetic profiles of antibiotics, resulting in ineffective or incorrect treatments, with potentially dangerous consequences. In this scenario, therapeutic drug monitoring is crucial for timely adjusting therapy and improving antibiotic effectiveness. In this study, we developed and validated an ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry method for simultaneous quantification of five antibiotics - Tazobactam, Meropenem, Vancomycin, Linezolid and Piperacillin - in human plasma. Detection was achieved using a triple-quadrupole mass spectrometer in multiple reaction monitoring mode, with chromatographic separation via a binary gradient elution in 10 min. Method validation following ICH M10 guidelines confirmed that a single-step protein precipitation efficiently extracted all five drugs, ensuring accurate and precise quantification without matrix interference. The method was then successfully applied to measure antibiotics concentrations in plasma from 64 critically ill patients admitted in intensive care unit and treated with one or more of these drugs simultaneously.