LC–MS/MS method for simultaneous quantification of antibiotics in dialysis effluent and human serum for routine therapeutic drug monitoring

protein precipitation, and quantification was performed using LC-MS/MS, utilizing a gradient of aqueous (water, acetonitrile, formic acid) and organic (acetonitrile, 2-propanol) phases, with a total run time of 6.5 min. The method employed identical calibration and quality control sets for both serum and effluent. Calibration curves were linear across compound-specific ranges. The method met the validation criteria, showing reproducibility with CV ≤ 10.6%, a mean recovery of 102.2% in serum and 99.1% in effluent, and an accuracy ranging from 94.7% to 98.9% in serum and 99.5% to 103.0% in effluent. Carry-over effects observed for levofloxacin and piperacillin and compounds' stability were effectively managed through proper sample handling procedures. The developed method confirms its suitability for routine clinical application, providing a reliable tool for antibiotics TDM in critically ill patients. Additionally, measuring drug concentrations in CRRT effluent offers valuable insights into drug clearance and pharmacokinetics, which could ultimately lead to better patient management and more tailored, effective treatments in the future.