Quantification of sulbactam and durlobactam in saline and human plasma via ultra-performance liquid chromatography tandem mass spectrometry.

Sulbactam-durlobactam is a combination β-lactam/β-lactamase inhibitor antibiotic approved in the United States for the treatment of adult patients with hospital-acquired and ventilator-associated bacterial pneumonia due to susceptible isolates of Acinetobacter baumannii-calcoaceticus complex. A liquid chromatography tandem mass spectrometry method for the quantification of sulbactam and durlobactam in human plasma and aqueous matrices has been developed and validated. The standard curves for each drug were linear over the range 0.5 to 50 μg/mL and use the isotopic analogs sulbactam-d5 and [13C2, 15N2]-durlobactam as internal standards for their respective analytes. This simple, reproducible method for the determination of sulbactam and durlobactam concentrations was developed with the intent to conduct future pharmacokinetic analyses and to guide clinical laboratories in the development of a therapeutic drug monitoring assay.