Development and clinical utility of an ultra performance liquid chromatography − tandem mass spectrometry assay for monitoring omadacycline and tigecycline in severe bacterial infections

Objective: We aimed to develop a rapid, simple, and precise ultra performance liquid chromatography − tandem mass spectrometry (UPLC-MS/MS) technique for simultaneous measurement of omadacycline (OMA) and tigecycline (TGC) in the bloodstream of individuals suffering from serious bacterial infections. Methods: All analytes were extracted using a 0.2 % formic acid–water dilution and acetonitrile plasma protein precipitation. The quantification was performed by electrospray ionization-triple quadrupole mass spectrometry with selected reaction monitoring and positive ion mode detection. Tetracycline was used as an internal standard in this experiment, with the mobile phase composed of water (with 0.1 % formic acid) and acetonitrile (using gradient elution) flowing at a rate of 0.35 ml/min, and the column temperature set at 30 °C. Each individual analysis was completed in under 3.5 min. Results: The method was validated based on FDA recommendations, including the assessment of extraction recovery (92.65–101.72 %) and matrix effects (86.22–91.12 %). The standard curve ranges for both OMA and TGC are 0.025 µg/mL to 2.5 µg/mL. The plasma samples were found to be consistent after undergoing three rounds of freezing and thawing at room temperature for 24 h, being placed in an automated sample injector for 24 h, and then frozen for 45 days. Clinical cases were used to demonstrate the application of the therapeutic drug monitoring (TDM) assay, showing how an analytical test can quickly provide information on antibiotic levels in patients and impact their treatment. Conclusion: Multiplex UPLC-MS/MS assays for the simultaneous measurement of plasma OMA and TGC concentrations are the ideal choice for clinically TDM applications.