Central nervous system diseases and the role of the blood-brain barrier in their treatment

The Neurodegenerative diseases, cancer and infections of the brain are becoming more prevalent in society as population become older. Nowadays, these diseases represent a major medical challenge, so neuroprotective therapeutics have the potential to play a key role in managing this growing global burden of long-term neurological care. Despite major advances in neuroscience, treatment for these diseases is still a challenging area due to the presence of the blood-brain barrier. Conventional therapeutics remain critically below levels of optimum therapeutic efficacy, since the blood-brain barrier ensures that many potential therapeutics cannot reach the central nervous system. Hence, the current challenge is to develop drug-delivery systems which ensure that drugs cross the blood brain barrier in a safe and effective manner. Robust methods to assess Central Nervous System permeation are therefore essential for drug discovery. Drug candidates can be successfully designed to cross the blood-brain barrier, but for those that can't cross it, a delivery system that facilitates the movement of drug candidate across the barrier may possibly enable this entry. In order to assess the drug capacity to cross the brain, animal models of neurological disorders are increasingly employed. This review focuses on the properties of the blood-brain barrier that restrict drug delivery to the brain as well as on some of the most hopeful strategies developed to study and enhance drug delivery across the blood-brain barrier.