A UPLC-MS/MS method for simultaneous determination of eight special-grade antimicrobials in human plasma and application in TDM.

Linezolid, vancomycin, teicoplanin, tigecycline, imipenem, meropenem, voriconazole, and micafungin are eight special-grade antimicrobials commonly used for patients with severe infections. Changes in the pharmacodynamics and pharmacokinetics of critically ill patients severely affect the efficacy of antimicrobial drugs. Therefore, conventional or standard dosing regimens do not achieve satisfactory anti-infective effects. In the current study a simple and specific ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for simultaneously determining the concentrations of the above-mentioned eight antimicrobials in human plasma only 3 min after one-step magnetic solid phase extraction pre-treatment. Multiple-reaction monitoring and positive ion modes were used for detection. The calibration curves were established over a concentration range of 0.1-25.0 μg/mL for teicoplanin, linezolid, micafungin, voriconazole, imipenem, igecyclin, and meropenem, and 0.2-50.0 μg/mL for vancomycin; the coefficient of correlation was > 0.9971 for all the compounds. The inter- and intra-day coefficients of variation were < 6.88% at the lower limit of quantification and quality control (QC) levels (low concentration-QC, medium concentration-QC, and high-concentration QC). The UPLC-MS/MS method was successfully used for clinical therapeutic drug monitoring of linezolid, vancomycin, teicoplanin, tigecycline, imipenem, meropenem, voriconazole, and micafungin for critically ill patients.