Transporters: Importance in Drug Absorption, Distribution, and Removal

There is an increasing appreciation of the role that transport proteins play in the absorption, distribution, and elimination of a wide variety of drugs in clinical use. These transporters can be divided into efflux transporters belonging to the ATP-binding cassette (ABC) family and solute carrier (SLC) family members that mediate the influx or bidirectional movement of drugs across the cell membrane. Their coordinated expression and activities at the basolateral and apical side of transporting epithelia are significant determinants of drug disposition, drug drug interactions, and variability in drug response and toxicity. This chapter focuses on the major SLC and ABC drug transporters expressed in intestine, liver, and kidney, with special emphasis on their distribution, mode of action, and drug substrate specificity.