Abstract
Blood-brain barrier(BBB) is formed by brain capillary endothelial cells. Because of highly developed tight junction between the adjacent cells, the cells act as diffusion barrier to isolate central nervous system from the blood circulation. To order to develop CNS acting drugs, the not only the Systemic eyposave but also permeability across the BBB needs to be optimized. Various transporters are expressed in the BBB, and facilitate the exchange of nutrients and metabolites between the CNS and blood. They are available as target molecule to improve the CNS penetration. In addition, P-gp and Bcrp actively extrude their substrate into the blood at the BBB, and thereby, limit the CNS penetration of drugs. Avoiding these transporters is another strategy to improve CNS penetration of drugs. Kinetic analysis suggests the expression of a transporter which facilitates the penetration of lipophilic cationic drugs, such as clonidine, diphenhydramine and D2 receptor antagonists in rodents and human BBB. These transporters are potentially target transporters to optimige drug deliver into the CNS. This manuscript summarized the current knowledge on the transporters expressed in the BBB.
