I believe there is an explosion of interest in membrane transporters, particularly those that influence the disposition of therapeutic agents. In the last five years, the knowledge base describing the various transport proteins has expanded exponentially, as has the appreciation for their role in drug absorption, distribution, metabolism, and excretion. The development of new therapeutic agents to treat diseases in the CNS has been hampered by poor delivery to the brain. This is in part due to efflux transporters in the barriers of the CNS. This review article helps outline the various classes of transporters in the CNS, and how they may impact drug therapy for such diseases as AIDS, cancer, Alzheimer's disease, and other neurodegenerative diseases.

This paper is a review of the current knowledge regarding how some active transport proteins in the barriers of the CNS could limit the effectiveness of drug therapy to the brain.

I became involved in drug transporter research because my laboratory is trying to find the physiological mechanisms that limit drug delivery to the brain. It was a natural extension to examine transporter biology as part of the search to use this mechanistic knowledge to improve therapy for CNS diseases.