A hiSIEC-based Gut/Liver Microphysiological System for Assessing Oral Bioavailability Potential

Oral bioavailability (F) is determined by the combined effects of intestinal absorption, gut metabolism, and hepatic first-pass extraction. To better recapitulate these processes in vitro, we developed a gut–liver microphysiological system (MPS) on the CN-Bio Dual-Organ platform by integrating iPSC-derived small intestinal epithelial cells (hiSIECs) with primary human hepatocytes.

The hiSIEC monolayer exhibited robust barrier function (TEER 300–400 Ω·cm²), expressed major intestinal cell populations, and demonstrated physiologically relevant enzyme (CYP3A4, CES2) and transporter (P-gp, BCRP, PEPT1) activities, with improved in vitro–in vivo correlation compared with Caco-2 cells. Both intestinal and hepatic components maintained stable function throughout co-culture.

Using midazolam as a model compound, the system captured intestinal absorption, gut metabolism, and hepatic first-pass extraction, revealing distinct absorption–metabolism dynamics relative to conventional Caco-2 models. Collectively, this hiSIEC-based gut–liver MPS recapitulates the key determinants of oral bioavailability and represents a promising platform for predicting human F and supporting oral drug development.