The blood brain barrier are formed by endothelial cells of the brain capillaries, restricts access to brain cells of blood-borne compounds and facilitates nutrients essential for normal metabolism to reach brain cells. This is a very tight regulation that results in the inability of small and large therapeutic compounds to cross the BBB.
Lipidic systems can be considered to be the most promising carrier for drug delivery to the brain. Carbohydrates and amino acids are able to cross the BBB.
P-glycoprotein plays a role in the protection of the organism against toxic xenobiotics (drug, pesticide or carcinogen), by