Population pharmacokinetics of intravenous levofloxacin 500 mg/day dosage in infected patients.

The purpose of this study was to explore the population pharmacokinetic features of levofloxacin in Chinese infected patients. A total of 27 Chinese adult infected patients were treated with intravenous levofloxacin (500 mg/day). In total, 49 plasma samples of levofloxacin were collected immediately after intravenous dripping and before administration on the 3rd, 4th or 5th day. A nonlinear mixed effect model was used to model the population pharmacokinetic (PK) behavior of levofloxacin. The final population pharmacokinetic models were validated using the bootstrap method. Some covariates, including demographic characteristics and hematological and biological indicators, were analyzed. A structural model was developed based on a one-compartment model with intravenous infusion and first-order elimination. The typical population values for pharmacokinetic parameters of apparent clearance (CL) and apparent distribution volume (V) were 5.84 L/h and 43.3L, respectively. The inter-individual variabilities of CL and V were 7.75% and 6.4%, respectively, while the intra-individual variability of observed concentrations was 0.06 microg/mL. The covariates of age and AST influenced the CL and V values determined by the final model. The present study developed population pharmacokinetic models for levofloxacin in infected Chinese patients. The results detailed here could provide a reference for individualized levofloxacin therapy in the clinical setting.