Brain delivery of peptides and proteins

Therapeutic proteins and peptides have been identified as showing great promise for the treatment of brain cancers and neurodegenerative diseases. However, their delivery to their intended site of action from the blood is hampered by the presence of the blood-brain barrier (BBB), a vital element in the regulation of the internal environment of the brain and the spinal cord. Peptides generally do not cross the BBB because these highly polar compounds are not lipid-soluble, and because most circulating peptides do not have access to specialized, BBB receptor-mediated transport systems. Over the past three decades, research has led to a better understanding of the transport mechanisms at the BBB, and to the development of several strategies for improving the delivery of peptides/proteins to the central nervous system (CNS).