The HUREL micro liver coculture system is a robust and reliable method for human in vivo clearance prediction and metabolite detection of slowly metabolized drugs.  The coculture system has similar phase I and phase II enzyme activity as freshly thawed hepatocytes for at least 10 days, which enables a range of in vitro studies to predict the human in vivo situation. The confidence of the in vivo clearance prediction can further be increased by including at least two preclinical species, normally rat and dogs (HUREL Rat, HUREL Dog.)  Prediction of induction, drug-drug interaction, metabolites, drug transport, and toxicity could all be improved in a system with polarized human hepatocytes that maintains enzyme activity at a high level. The system has been thoroughly validated by many companies such as AstraZeneca through: Use of HUREL Human Coculture System for Prediction of Intrinsic Clearance and Metabolite Formation for Slowly Metabolized Compounds