A quantitative approach to hepatic clearance prediction of metabolism by aldehyde oxidase using custom pooled hepatocytes.

ABSTRACT

We describe the usability of human pooled hepatocytes for non-CYP metabolism evaluation and an in vivo-in vitro correlation analysis for aldehyde oxidase (AO) substrate compounds using pooled hepatocytes. By comparing intrinsic clearance values of 18 compounds primarily metabolized by AO, UDP-glucuronosyltransferase, carbonyl/aldo-keto reductase, flavin-containing monooxygenase, and monoamineoxidase in individual hepatocytes and pooled hepatocytes from the same individual donors, intrinsic clearance in the pooled hepatocytes was ± 30% of the average clearance value in individuals for 15 of 18 compounds, suggesting that pooled hepatocytes maintained the average activity of the individual hepatocytes. Although the results of an in vivo-in vitro correlation analysis for AO substrate compounds showed a trend toward under-prediction, the underestimation ratios for all AO substrates were nevertheless comparable (7.2- to 14.9-fold), suggesting that hepatic clearance prediction for these compounds can be quantified using empirical scaling. These observations enabled us to obtain specific pooled hepatocytes that showed the expected non-CYP enzyme activities by pre-characterization and to quantify hepatic clearance prediction for AO compounds using an empirical scaling factor.