Use of population pharmacokinetic modeling and monte carlo simulation to describe the pharmacodynamic profile of cefditoren in plasma and epithelial lining fluid

Thomas P Lodise Jr., Martina Kinzig, George Drusano, Ulrich Loos, Friedrich Vogel, Jurgen Bulitta, Markus Hinder, Fritz Sorgel

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23 Citations (Scopus)

Abstract

Cefditoren is a broad-spectrum, oral cephalosporin that is highly active against clinically relevant respiratory tract pathogens, including multidrug-resistant Streptococcus pneumoniae. This study described its pharmacodynamic profile in plasma and epithelial lining fluid (ELF). Plasma and ELF pharmacokinetic data were obtained from 24 patients under fasting conditions. Cefditoren and urea concentrations were determined in plasma and bronchoalveolar lavage fluid by liquid chromatography-tandem mass spectrometry. Concentration-time profiles in plasma and ELF were modeled using a model with three disposition compartments and first-order absorption, elimination, and transfer. Pharmacokinetic parameters were identified in a population pharmacokinetic analysis (big nonparametric adaptive grid with adaptive I?). Monte Carlo simulation (9,999 subjects) was performed with the ADAPT II program to estimate the probability of target attainment at which the free-cefditoren plasma concentrations (88 ) protein binding and total ELF concentrations exceeded the MIC for 33 of the dosing interval for 400 mg cefditoren given orally every 12 h. After the Bayesian step, the overall fits of the model to the data were good, and plots of predicted versus observed concentrations for plasma and ELF showed slopes and intercepts very close to the ideal values of 1.0 and 0.0, respectively. In the plasma probability of target attainment analysis, the probability of achieving a time for which free, or unbound, plasma concentration exceeds the MIC of the organism for 33 of the dosing interval was 0.06 mg/liter. Similar to plasma, the probability of achieving a time above the MIC of 33 was 0.06 mg/liter in ELF. Cefditoren was found to have a low probability of achieving a bacteriostatic effect against MICs of >0.06 mg/liter, which includes most S. pneumoniae isolates with intermediate susceptibility to penicillin, when given in the fasting state in both plasma and ELF.
Original languageEnglish
Pages (from-to)1945 - 1951
Number of pages7
JournalAntimicrobial Agents and Chemotherapy
Volume52
Issue number6
DOIs
Publication statusPublished - 2008

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