An UHPLC–MS/MS method for the simultaneous determination of ampicillin and sulbactam in human plasma and urine

Background: With few new antibiotics available and an increased prevalence of multidrug-resistant bacteria, optimizing the effectiveness of currently available antibiotics and minimizing the potential for emerging resistance, through PK characterization, is of paramount importance. Results: Inter- and intra-assay results for ampicillin were within 5% for accuracy and 7% for precision, and for sulbactam within 7% for accuracy and 7% for precision, for both plasma and urine. The plasma Cmax was 38.4 µg/ml for ampicillin and 19.0 µg/ml for sulbactam. The urine concentrations were 668 µg/ml for ampicillin and 438 µg/ml for sulbactam. Conclusion: An UHPLC–MS/MS method to simultaneously measure co-formulated ampicillin and sulbactam in plasma and urine, for use in a patient PK study, has been developed and validated.