Modulation of drug transporters at the blood-brain barrier.

A major challenge in the management of diseases of the central nervous system is the limited penetration of drugs into the brain. The structures responsible are the capillaries of the brain, whose endothelial cells form the so-called blood-brain barrier. Understanding the cellular and molecular structure as well as integrated function of this barrier is a prerequisite for successful drug delivery to the brain. Here we briefly review current knowledge about the active transport proteins (ABC and organic anion transporters) which function at the blood-brain barrier. We describe novel approaches to (1). modulate carrier protein function, and (2). circumvent the transporter-based carrier by targeted site-specific drug delivery systems, such as immunoliposome and nanoparticulate systems.