Primary hepatocytes display a precipitous decline in phenotypic functions when cultured in a sandwich of extracellular matrix proteins (i.e. collagen, Matrigel). We describe the use of HepatoPac™ as a tool to screen for genotype-specific and clinically-relevant drug disposition. Several hepatotoxins (i.e. Trazodone, Isoniazid, Imipramine, etc.) are investigated under both acute and chronic dosing regimens and show concordance with pre-clinical and clinical findings. Since metabolism is an important determinant to the overall disposition of drugs and the profile of metabolites can have an impact on efficacy and safety, the utility of HepatoPac for prediction of compound clearance and generation of human metabolites was also evaluated. Transporter assays (uptake and efflux) and long-term drug-drug interaction studies (i.e. enzyme induction and inhibition) are also explored.