Quick bioanalytical method of quantification and validation of sulbactam in plasma using high performance liquid chromatography

Therapeutic Drug Monitoring of High-dose Sulbactam in Pediatric Patients: Preliminary Data From a Prospective Observational Pharmacokinetic Study

BACKGROUND

Rates of carbapenem-resistant Acinetobacter baumannii are rising in Thailand. Although high-dose (HD) sulbactam is recommended for treating carbapenem-resistant A. baumannii infections, data on plasma sulbactam concentrations in children are limited. We aimed to evaluate plasma sulbactam concentrations and pharmacokinetic-pharmacodynamic (PK-PD) target achievement in pediatric patients.

METHODS

Prospective study data (January-November 2023) on children (1 month-18 years) who received sulbactam every 6-8 hours were analyzed. Mid-dosing ( Cmid , 50% f T) and trough ( Ctrough , 100% f T) concentrations were evaluated. PK-PD target achievement [50% f T > minimum inhibitory concentration (MIC), 100% f T > MIC] was evaluated using Clinical and Laboratory Standards Institute 2024 MIC cutoffs and MIC data of isolates of Acinetobacter calcoaceticus-baumannii complex from this study.

RESULTS

Thirty-five patients (median age 50 months) were categorized into standard-dose (SD) or HD groups. The geometric mean Cmid was higher in the HD (41.3 mg/L) versus SD (19.5 mg/L) groups ( P = 0.006). Among 101 isolates of Acinetobacter calcoaceticus-baumannii complex, the MIC50 and MIC90 (concentrations that inhibit 50% and 90% of isolates of the A. calcoaceticus-baumannii complex) were 16 and 128 mg/L, respectively. The HD group achieved Cmid >MIC50 in 87.5% of the patients compared with 63.6% in SD ( P = 0.17). Within the HD group, patients with augmented renal clearance (ARC) had lower Cmid (geometric mean 31.9 mg/L) compared with non-ARC (geometric mean 63.4 mg/L) ( P = 0.04).

CONCLUSIONS

HD sulbactam resulted in higher Cmid and PK-PD achievement. ARC significantly compromised plasma sulbactam concentration. HD sulbactam may be preferable for treating critically ill pediatric patients and those with ARC, especially during the empirical period.

Population Pharmacokinetics and Pharmacodynamics Modeling To Optimize Dosage Regimens of Sulbactam in Critically Ill Patients with Severe Sepsis Caused by Acinetobacter baumannii

Sulbactam is being considered as an alternative concomitant medication with other effective antibiotics for the treatment of multidrug-resistant (MDR) Acinetobacter baumannii infections. Pathophysiological changes in critically ill patients with severe sepsis, resulting in altered pharmacokinetic (PK) patterns for antibiotics, are important factors in determining therapeutic success. The aims of this study were (i) to examine the population PK parameters and (ii) to assess the probability of target attainment (PTA) for sulbactam in patients with severe sepsis caused by A. baumannii PK studies were carried out following administration of 2 g of sulbactam every 12 h on the 4th day of drug administration in 27 patients, and a Monte Carlo simulation was performed to determine the PTA of achieving 40% exposure time during which the plasma drug concentration remained above the MIC (T_>MIC) and 60% T_>MIC The central and peripheral volumes of distribution were 14.56 and 9.55 liters, respectively, and total clearances of sulbactam were 2.26 liters/h and 7.64 liters/h in patients aged >65 years and ≤65 years, respectively. The high PTAs (≥90%) for targets of 40% T_>MIC and 60% T_>MIC with a MIC of 4 μg/ml were observed when sulbactam was administered by a 4-h infusion of 1 g every 12 h and 1 g every 8 h, respectively. Sulbactam would be an alternative antibiotic option to coadminister with colistin for the treatment of infections caused by MDR A. baumannii However, for pathogens with MICs of >4 μg/ml, higher dosage regimens of sulbactam are required.

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.