TY - JOUR T1 - <strong>Comparison of In Vitro to In Vivo Extrapolation Approaches for Predicting Transporter-Mediated Hepatic Uptake Clearance Using Suspended Rat Hepatocytes</strong> JF - Drug Metabolism and Disposition JO - Drug Metab Dispos DO - 10.1124/dmd.120.000064 SP - DMD-AR-2020-000064 AU - Na Li AU - Akshay Badrinarayanan AU - Xingwen Li AU - John Roberts AU - Mike Hayashi AU - Manpreet Virk AU - Anshul Gupta Y1 - 2020/01/01 UR - http://dmd.aspetjournals.org/content/early/2020/08/05/dmd.120.000064.abstract N2 - 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 (PSu,inf) and intrinsic metabolic CL (CLint,met) corrected by unbound hepatocytes to media partition coefficient (Kpuu). Kpuu was determined by temperature method (Temp Kpuu,ss), homogenization method (Hom Kpuu,ss), and initial rate method (Kpuu,V0). In addition, impact of albumin (BSA) on each of these methods was investigated. Twelve compounds, which are known substrates of organic anion-transporting polypeptides (OATP) representing diverse chemical matter, were selected for these studies. As expected, CLint,met alone significantly underestimated hepatic CL for all the test compounds. Overall, predicted hepatic CL using PSu,inf with BSA, Hom Kpuu,ss with BSA and Temp Kpuu,ss showed the most robust correlation with in vivo rat hepatic CL. Adding BSA improved hepatic CL prediction for selected compounds when using PSu,inf and Hom Kpuu,ss methods, with minimal impact on Temp Kpuu,ss and Kpuu,V0 methods. None of the IVIVE approaches required empirical scaling factor. These results suggest that supplementing rat hepatocyte suspension with BSA may be essential in discovery research for novel chemical matters to improve CL prediction. Significance Statement The current investigation demonstrates that hepatocyte uptake assay supplemented with 4% BSA is a valuable tool for estimating unbound hepatic uptake CL and Kpuu. Based upon extended clearance concept, direct extrapolation from these in vitro parameters significantly improved the overall prediction of hepatic CL for OATP substrates in rat. This study provides a practical IVIVE strategy for predicting transporter-mediated hepatic CL in early drug discovery. ER -