Chapter 5: Drug Transporters at the Blood–Brain Barrier

The blood–brain barrier (BBB) is an active cellular barrier that provides both a physical obstruction to the entry of molecules and, by the expression of drug transporters, a dynamic mechanism for affecting drug permeation to the brain. The barrier is formed by brain endothelial cells that express both influx and efflux transporters. This chapter details the basic structure and function of the BBB and choroid plexus, with both the challenges and the opportunities this presents for targeting and/or preventing the uptake of compounds to the brain.