TY - JOUR T1 - A Novel Relay Method for Determining Low-Clearance Values JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 1860 LP - 1865 DO - 10.1124/dmd.112.046425 VL - 40 IS - 9 AU - Li Di AU - Patrick Trapa AU - R. Scott Obach AU - Karen Atkinson AU - Yi-An Bi AU - Angela C. Wolford AU - Beijing Tan AU - Thomas S. McDonald AU - Yurong Lai AU - Larry M. Tremaine Y1 - 2012/09/01 UR - http://dmd.aspetjournals.org/content/40/9/1860.abstract N2 - A novel relay method has been developed using cryopreserved human hepatocytes to measure intrinsic clearance of low-clearance compounds. The relay method involved transferring the supernatant from hepatocyte incubations to freshly thawed hepatocytes at the end of the 4-h incubation to prolong the exposure time to active enzymes in hepatocytes. An accumulative incubation time of 20 h or longer in hepatoctyes can be achieved using the method. The relay method was validated using seven commercial drugs (diazepam, disopyramide, theophylline, timolol, tolbutamide, S-warfarin, and zolmitriptan) that were metabolized by various cytochrome P450s with low human in vivo intrinsic clearance at approximately 2 to 15 ml · min−1 · kg−1. The results showed that the relay method produced excellent predictions of human in vivo clearance. The difference between in vitro and in vivo intrinsic clearance was within 2-fold for most compounds, which is similar to the standard prediction accuracy for moderate to high clearance compounds using hepatocytes. The relay method is a straightforward, relatively low cost, and easy-to-use new tool to address the challenges of low clearance in drug discovery and development. ER -