Intestinal efflux transporters and drug absorption

BACKGROUND: The intestinal epithelial membrane expresses ATP-binding cassette (ABC) transporters such as P-glycoprotein (P-gp), multi-drug resistance-associated proteins (MRPs) and breast cancer resistance protein (BCRP), in addition to various solute carrier (SLC) transporters. These ABC transporters affect the oral bioavailability of their substrate drugs. OBJECTIVE: To review the contribution of ABC efflux transporters such as P-gp, MRP2, MRP3, and BCRP in the intestinal absorption of substrate drugs. METHODS: Discussion was made by focusing on the site-specific expression and function of these ABC transporters, and the solubility and permeability of their substrate compounds. RESULTS/CONCLUSION: The increase in the solubility and permeability of orally administered drugs could be the key to escape barrier function of ABC transporters, especially P-gp.