1. This study assessed the value of a static in vitro human hepatocyte-murine stromal cell co-culture model to qualitatively and quantitatively predict human in vivo metabolic clearance pathways using 14C-labeled test compounds and compared these results to an in vitro suspended human hepatocyte model and the in vivo human 14C ADME studies. 2. Test compounds represented a diverse set of clearance pathways (Phase I and Phase II). Compounds were incubated for 4 h in suspended human hepatocytes and for 24 and 168 h in the human co-culture model. Multivariate analysis revealed that long-term (168 h) incubation of test compounds in the co-culture had reasonable quantitative prediction of the in vivo human clearance pathways as compared to the 4 h suspended hepatocytes or the 24 h co-culture incubation. 3. In vivo and in vitro disconnects were observed in cases where extra-hepatic metabolism or urinary excretion was observed in vivo. Differences in the relative percentages of Phase I and Phase II metabolites observed were likely due to microbial β-glucuronidase hydrolysis of conjugates and microflora mediated metabolism in the gut not present in the in vitro systems.
Keywords: 14C human; 14C-labeled compounds; hepatocyte-stromal cell co-culture; hepatocytes; metabolite prediction; metabolites.