Population pharmacokinetics of oxcarbazepine in Chinese epilepsy patients

Oxcarbazepine (OXC) is a common antiepileptic drugs. In this study, one hundred and eighty four epilepsy patients with 196 observations of oxcarbazepine's active metabolite, 10,11-dihydro-10-monohydroxy carbazepine (MHD) were collected prospectively from routine clinical monitoring. Nonlinear mixed effect modeling was employed to develop a population pharmacokinetic model of oxcarbazepine in Chinese patients with epilepsy to investigate the impact of gender, age, weight, co-medications and genetic polymorphisms of UGT2B7 c.802T>C, ABCC2 c.1249G>A, ABCC 23972C>T on pharmacokinetic characteristics of OXC. The population estimate of apparent clearance (CL/F) and apparent volume of distribution (V/F) was 1.84 L·h⁻¹ and 275 L, respectively. Gender and UGT2B7 c.802T>C affected the clearance rate of MHD significantly. The established model was:CL/F=1.84×0.848^UGT2B7×1.17^GENDER. Where the genotype of UGT2B7 c.802T>C was CC, UGT2B7=0, otherwise UGT2B7=1. When the patient was male, GENDER=1, otherwise GENDER=0. The final model was evaluated by normalized predictive distribution error (NPDE) and bootstrap method. The model was stable and reliable, which offers a powerful approach for rational use of OXC in epilepsy patients.