Jarkko Rautio

The blood–brain barrier (BBB) forms an interface between the circulating blood and the brain, and functions as a tremendously effective barrier for the delivery of potential neurotherapeutics into the brain parenchyma. Conversely, the BBB possesses various carrier-mediated transport systems for the uptake of small molecules, such as essential nutrients and vitamins. These transporters have become an attractive target for drug/prodrug design in an attempt to ferry drug molecules across the BBB. Central nervous system (CNS) drug delivery is often limited by poor brain penetration of the potential drug candidate. As a result of its unique barrier properties, the BBB poses a huge challenge for the delivery of potential neurotherapeutics into the brain parenchyma.1 It is estimated that only 2% of small-molecule drugs and ,0.1% of novel protein and peptide pharmaceuticals developed for CNS diseases reach therapeutic concentrations in the brain.2,3 Many of the pharmacologically active drugs tend to fail..