Albumin-Mediated Uptake Improves Human Clearance Prediction for Hepatic Uptake Transporter Substrates Aiding a Mechanistic In Vitro-In Vivo Extrapolation (IVIVE) Strategy in Discovery Research.

This study focused on exploring various in vitro to in vivo extrapolation (IVIVE) approaches with the primary goal of improving human hepatic clearance (CL) prediction for OATP substrates. To that effect, the impact of albumin-mediated uptake in human hepatocytes was investigated. In vitro hepatic uptake assay using suspended human hepatocytes was performed with 16 selected OATP substrates to determine the uptake CL in the absence and presence of 4% BSA and unbound hepatocyte to media partition coefficient (Kp).

Comparison of In Vitro to In Vivo Extrapolation Approaches for Predicting Transporter-Mediated Hepatic Uptake Clearance Using Suspended Rat Hepatocytes.

Clearance (CL) prediction remains a significant challenge in drug discovery, especially when complex processes such as drug transporters are involved. The present work explores various in vitro to in vivo extrapolation (IVIVE) approaches to predict hepatic CL driven by uptake transporters in rat. Broadly, two different IVIVE methods using suspended rat hepatocytes were compared: initial uptake CL (PS) and intrinsic metabolic CL (CL) corrected by unbound hepatocytes to medium partition coefficient (Kp).

Enhanced detection and characterization of glutathione-trapped reactive metabolites by pseudo-MS(3) transition using a linear ion trap mass spectrometer.

We present a simple and label-free approach to characterize glutathione (GSH)-trapped reactive metabolites from a single LC-MS analysis employing a linear ion trap mass spectrometer. The GSH specific fragment anion m/z 272 was first generated from the nonselective in-source fragmentation of intact conjugates. GSH conjugates were then detected by selected reaction monitoring (SRM) of the anion pair m/z 272 → 179 or 210.

Simulation of clinical drug-drug interactions from hepatocyte CYP3A4 induction data and its potential utility in trial designs.

Rifampin and carbamazepine have been recommended in the U.S. Food and Drug Administration draft drug interaction guidance as CYP3A4 inducers for clinical drug-drug interaction (DDI) studies.

In vitro metabolism of the novel, highly selective oral angiogenesis inhibitor motesanib diphosphate in preclinical species and in humans.

Motesanib diphosphate is a novel, investigational, highly selective oral inhibitor of the receptor tyrosine kinases vascular endothelial growth factor receptors 1, 2, and 3, the platelet-derived growth factor receptor, and the stem cell factor receptor (Kit). The in vitro metabolic profiles of [(14)C]motesanib were examined by using microsomes and hepatocytes from preclinical species and humans. Several oxidative metabolites were observed and characterized by tandem mass spectrometry, nuclear magnetic resonance spectroscopy, and coinjection with authentic standards.

Modeling, prediction, and in vitro in vivo correlation of CYP3A4 induction.

CYP3A4 induction is not generally considered to be a concern for safety; however, serious therapeutic failures can occur with drugs whose exposure is lower as a result of more rapid metabolic clearance due to induction. Despite the potential therapeutic consequences of induction, little progress has been made in quantitative predictions of CYP3A4 induction-mediated drug-drug interactions (DDIs) from in vitro data. In the present study, predictive models have been developed to facilitate extrapolation of CYP3A4 induction measured in vitro to human clinical DDIs.