Simultaneous quantitation of tigecycline, meropenem, polymyxin B in plasma, and protein-binding analysis in HSCT patients

To develop a UPLC-MS/MS method for quantifying tigecycline (TIG), meropenem (MER), polymyxin B1 (PB1), and PB2 in human plasma, and analyze their unbound fractions and influencing factors in HSCT patients. Plasma samples from HSCT patients were analyzed using the developed UPLC-MS/MS technique. The method showed high accuracy, precision, and stability. Protein binding rates were 82.4% for TIG, 83.7%–79.3% for PB1, and 86.7%–82.6% for PB2, with lower binding at trough vs. peak concentrations. Preliminary analysis suggests that BMI and serum albumin may influence PB1/PB2 binding in CRE-infected HSCT patients though larger cohorts are needed for confirmation. (clinical trial registration # 2021–0938–01)