Given what you know about the capillaries of the brain what

Given what you know about the capillaries of the brain, what special feature must be incorporated into drugs designed to exert their effects in the brain, and how might this feature be achieved?

Solution

The whole brain tissue is enveloped by a lipid layer called blood-brain barrier (BBB). The endothelial cells of brain are connected together by tight junctions, which form a barrier between the vasculature and brain. If we remove this barrier, molecules can directly enter the brain, which causes brain damage.

Thus, the function of BBB is to restrict the entry of various substances into the brain and thus provides protection against toxins.

This is because, BBB is a selective lipophilic barrier that only allow certain molecules by binding to the surface endothelial receptors. If this barrier is absent or damaged, some of the toxic substances may enter into the brain by crossing this undeveloped BBB and alter the brain functions.

Thus, to make the drugs to pass through the BBB, they must be lipophilic in nature.