Aim: To optimize clinical efficacy and reduce the drug-exposure-related toxicity of linezolid, whose concentrations show wide inter-variabilities, a simple and reliable quantitative assay for therapeutic drug monitoring is necessary. Results: A UHPLC-MS/MS assay has been established for determination of linezolid in human plasma and fully validated according to the US FDA guidelines. After a simple, isotope-dilluted precipitation with methanol, the analytes were separated by a straightforward isocratic mode and the MS/MS was conducted under the ESI+ mode fitted with SRM. The calibration curves proved acceptable linearity in the range of 0.1-30.0 µg/ml. Conclusion: The present assay is currently used in routine clinical practice, being applied to therapeutic drug monitoring and helps to optimize individual dosing regimens and manage adverse effects in ICU patients.
Keywords: LC–MS/MS; TDM; linezolid; therapeutic drug monitoring.