TRANSPORTING THERAPEUTICS ACROSS THE BLOOD-BRAIN-BARRIER

In 1996, we are half-way through the Decade of the Brain, yet we still have few effective treatments for major disorders of the central nerv ous system. These include affective disorders, epilepsy, neurodegenera tive disorders, brain tumours, infections and HIV encephalopathy; suff erers far outnumber the morbidity of cancer or heart disease. Increase d understanding of the pharmacology of the brain and its blood supply, and methods for rational drug design, are leading to potential new dr ug therapies based on highly specific actions on particular target sit es, such as neurotransmitter receptors and uptake systems. These metho ds are capable of reducing the side effects that are common with more general treatments. However, all these treatments and potential treatm ents meet a formidable obstacle the blood-brain barrier. In this artic le, we review the properties of this barrier that complicate drug deli very to the brain, and some of the most hopeful strategies for overcom ing or bypassing the barrier in humans.