Determination of Total and Unbound Meropenem, Imipenem/Cilastatin, and Cefoperazone/Sulbactam in Human Plasma: Application for Therapeutic Drug Monitoring in Critically Ill Patients

Abstract

Background: Critically ill patients show several pathophysiological alterations that can complicate antibiotic dosing. Hence, there is a strong rationale to individualize anti-infective dosing in these patients by using therapeutic drug monitoring (TDM). The current study aimed to develop and validate a liquid chromatography-tandem mass spectrometry method for the simultaneous determination of total and unbound plasma concentrations of 3 commonly used antibiotics (meropenem, imipenem/cilastatin, and cefoperazone/sulbactam) in the treatment of infections in critically ill patients in China, which could be suitable for routine TDM in hospital laboratories. Methods: The unbound drug was separated from the bound drug by ultrafiltration. Simple protein precipitation was used for sample preparation. Meropenem, imipenem/cilastatin, cefoperazone/sulbactam, and their corresponding internal standards were then resolved using the Waters CORTECS C18 column. All the compounds were detected using electrospray ionization in the positive/negative ion-switching mode. Results: The calibration curves were linear for all compounds, with correlation coefficients (R 2) above 0.99 for total concentrations in human plasma and unbound concentrations in the plasma ultrafiltrate. For both total and unbound drugs, the relative errors and intra-assay/interassay relative standard deviations were below 15%. The limit of quantification was 0.05 mcg/mL for both total plasma concentrations and plasma ultrafiltrate concentrations of all compounds. Conclusions: The method was simple, rapid, and reliable and is currently being used to provide a TDM service to enhance the efficacious use of the 3 antibiotics.

Determination of free and total meropenem levels in human plasma and its application for the consistency evaluation of generic drugs

“…Meanwhile, post hoc LSD tests also showed significant differences among the six batches of plasma (Figure 4, P < 0.05; the data are presented in Table S1 [supporting information]). These results are consistent with of those from previous studies 11,27 (unbound fraction: 50.28-88.89% and 42-99%). The results showed PPB of 8.34 ± 5.85%, 6.57 ± 3.19%, 10.40 ± 8.31%, and 8.69 ± 6.05% for the four preparations.…”

“…Nonspecific binding was measured by comparing the peak areas of the analytes in samples with ultrafiltration to those in samples without ultrafiltration 11 . The average recoveries of meropenem with high, medium, and low concentration levels (40, 4, and 1.5 μg/ml) in PBS (pH 7.4) on the ultrafiltration membrane was 99.0%, 96.1%, and 106.5%, respectively.…”

“…Hydrophilic interaction chromatography (HILIC) is a variant of normal-phase separation. 11,24 The HILIC mode is particularly useful for separating polar compounds.…”

An Overview of the Protein Binding of Cephalosporins in Human Body Fluids: A Systematic Review

“…Even between studies of an individual cephalosporin, there is considerable variability. As can be seen in Table 1 , several cephalosporins are highly protein bound, such as cefonicid (mean 82%–98%, four studies) ( Dudley et al, 1986 ; Ackerman et al, 1988 ; Trang et al, 1989 ; Swanson et al, 1991 ) and cefoperazone in adults (mean 89%–92%, four studies) ( Lam et al, 1988 ; Kalman et al, 1992 ; Kan et al, 2020 ; Rao et al, 2020 ). Also, ceftriaxone is generally highly bound to proteins, although there is a large variability between studies.…”

Rapid and Simultaneous Analysis of Multiple Classes of Antimicrobial Drugs by Liquid Chromatography-Tandem Mass Spectrometry and Its Application to Routine Biomedical, Food, and Soil Analyses

“…A range of liquid chromatography–mass spectrometry (LC-MS)/MS methods are available for simultaneous estimation of various antibiotics in surface water, groundwater, , and plasma; − β-lactam antibiotics , and sulfonamides in environmental water and meat; , macrolides in food, biological, and environmental matrices; , cephalosporins in pork and beef muscle; , and tetracycline and sulfonamides in domestic wastewater. , However, there were no reports in the literature on simultaneous estimation of multiple classes of antibiotics in the human food chain and environment.…”