Establishment of the Relay Method for Low Turnover Compounds in Hepatocyte Stability Assays

In vitro assays using liver subcellular fractions or suspended hepatocytes for characterizing the metabolism of drug candidates play an important role in the lead optimization stages. However, conventional in vitro assays have limitations in their ability to predict clearance for low turnover (slowly metabolized) drug molecules. In this study, two in vitro methods, one using suspended cryopreserved hepatocytes (routine method) and a relay of sequential incubations with suspended cryopreserved hepatocytes (relay method) have been developed. We validated the relay method with 7 commercial compounds . The data were in good agreement with those reported in the literature. The in vitro in vivo correlation (IVIVC) analysis of low turnover compounds showed that almost all the compounds were within 3-fold of unity.