Population pharmacokinetics of erlotinib in Japanese patients with advanced non-small cell lung cancer.

What Is Known And Objective: This study aimed to elucidate the pharmacokinetics of erlotinib in Japanese patients with advanced non-small cell lung cancer (NSCLC) and to investigate the relationship between erlotinib exposure and the occurrence of interstitial lung disease (ILD)-like events.

Methods: Population pharmacokinetics analysis was performed using nonlinear mixed-effects modelling software (NONMEM) based on 348 plasma samples from 97 patients obtained in two phase II clinical studies. Individual empirical Bayesian estimates (EBEs) of apparent oral clearance (CL/F) and Cmax were compared between the patients who developed and did not develop ILD-like events.

Diurnal variation in P-glycoprotein-mediated transport and cerebrospinal fluid turnover in the brain.

Nearly all bodily processes exhibit circadian rhythmicity. As a consequence, the pharmacokinetic and pharmacodynamic properties of a drug may also vary with time of day. The objective of this study was to investigate diurnal variation in processes that regulate drug concentrations in the brain, focusing on P-glycoprotein (P-gp).