Simultaneous quantification of linezolid and pretomanid in BALB/c mice plasma using a validated LC-MS/MS method: Application to pharmacokinetic and lung distribution studies

Abstract A sensitive and selective LC–MS/MS method was developed and validated for the simultaneous quantification of pretomanid and linezolid in BALB/c mouse plasma and lung tissue in accordance with ICH M10 bioanalytical guidelines. Chromatographic separation was achieved on a C18 column with gradient elution using methanol and 0.1% formic acid in water. The method demonstrated linearity ( r 2 > 0.995), accuracy, precision, and recovery within the validated range of 10–20,000 ng mL −1 , without significant matrix effect. Stability under various storage and handling conditions was also confirmed. The validated assay was successfully applied to a pharmacokinetic study using a sparse sampling design, demonstrating reliable quantification of both analytes in plasma and lung tissue and confirming the applicability of the method to preclinical bioanalysis. The developed method provides a robust and validated analytical platform for the simultaneous determination of co-administered anti-tuberculosis agents and is suitable for future pharmacokinetic and tissue distribution studies in preclinical models.