Population pharmacokinetics of clinafloxacin in healthy volunteers and patients with infections - Experience with heterogeneous pharmacokinetic data

Objective: Clinafloxacin is a new fluoroquinolone antibacterial with inhibitory activity against aerobic, anaerobic and atypical bacterial pathogens. The objectives of this study are to evaluate the pharmacokinetics of clinafloxacin in healthy volunteers and patients with infections and to describe our experience with mixed-effects modelling using heterogeneous pharmacokinetic data. Design and setting: Retrospective analysis of data from phase I to III trials. Patients and participants: 204 healthy volunteers and 221 patients with infections. Methods: Nonlinear mixed-effects modelling(MEM) was used to evaluate 3437 clinafloxacin plasma concentrations collected in 15 phase I to III trials. Models were developed separately for the healthy volunteers and patients, and then for the combined study population. Results: The phase I data were best described with a 2-compartment linear model with first-order absorption. The absorption lag-time and absorption rare constant were 0.24h and 1.17h(-1). respectively. The volumes of distribution were found to be nonlinear functions of body surface area. Estimated creatinine clearance was the most important covariate for systemic clearance (CL). Interoccasion variability (IOV) in CL was observed in the patients in the phase II trial. In the combined study population, the variability in CL was best described by a model including IOV and distinct variabilities for healthy volunteers and patients. Conclusion: MEM was useful for evaluating data collected during different phases of drug development for this new fluoroquinolone agent.