Characterization of EpiIntestinal Duodenum Microtissue as an In Vitro Model for Studying Intestinal Drug Permeability, Transport, and Metabolism.

PURPOSE: The intestinal absorption of compounds administered orally can be impacted by permeability, metabolism and uptake/efflux transport. This study aimed to characterize the EpiIntestinal duodenum microtissue developed from duodenum enterocytes and assess whether permeability, metabolism and transport could be simultaneously investigated in this model.

METHODS

Healthy human primary duodenum enterocytes were cultured on a permeable support. Their ability to predict drug absorption was evaluated using a set of drugs with known human absorption. Intestinal drug-metabolizing enzymes and transporters were assessed by analyzing their protein expression and functional activities using specific probe substrates and inhibitors.

RESULTS

The permeability (Papp) of the drug set showed a positive correlation with human % Fa. The expression and functional activities of P-gp, BCRP, MRPs (efflux ratio > 2), and PEPT1 were demonstrated in the microtissues. The functional activities of CYP3A4/5, CYP2C19, CYP2C8, UGT1A1 and SULT1B1 were also confirmed by the formations of probe substrate metabolites. In addition, the dominant effect of CYP3A4/5 over P-gp on the Papp of nicardipine was observed with a significant increase in permeability (Papp = 6.6 × 10-6 cm/s) following the addition of elacridar and ketoconazole compared to the control Papp of 2.8 × 10-6 cm/s and the Papp with elacridar at 3.7 × 10-6 cm/s.

CONCLUSIONS

These findings suggest that the EpiIntestinal duodenum microtissue can effectively replicate the complex interplay of permeability, metabolism, and transport in the gut, thereby improving the prediction of oral drug absorption.