[Establishment of a population pharmacokinetic model for linezolid in neonates with sepsis].

Objectives: To establish the pharmacokinetic model of linezolid in neonates, and to optimize the administration regimen.
Methods: A prospective study was conducted among 64 neonates with sepsis who received linezolid as anti-infective therapy, and liquid chromatography-tandem mass spectrometry was used to measure the plasma concentration of the drug. Clinical data were collected, and nonlinear mixed effects modeling was used to establish a population pharmacokinetic (PPK) model. Monte Carlo simulation and evaluation was performed for the optimal administration regimen of children with different features.
Results: The pharmacokinetic properties of linezolid in neonates could be described by a single-compartment model with primary elimination, and the population typical values for apparent volume of distribution and clearance rate were 0.79 L and 0.34 L/h, respectively. The results of goodness of fit, visualization verification, and the Bootstrap method showed that the model was robust with reliable results of parameter estimation and prediction. Monte Carlo simulation results showed that the optimal administration regimen for linezolid in neonates was as follows: 6 mg/kg, q8h, at 28 weeks of gestational age (GA); 8 mg/kg, q8h, at 32 weeks of GA; 9 mg/kg, q8h, at 34-37 weeks of GA; 11 mg/kg, q8h, at 40 weeks of GA.
Conclusions: The PPK model established in this study can provide a reference for individual administration of linezolid in neonates. GA and body weight at the time of administration are significant influencing factors for the clearance rate of linezolid in neonates.