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Biology

The Blood-Brain Barrier and Drug Delivery

Quick fact

About 98% of small-molecule drugs and nearly 100% of large-molecule biologics cannot cross the blood-brain barrier, making neurological drug development exceptionally challenging.

Why this is interesting

Your brain is shielded by a nearly impenetrable fortress—but that same fortress also blocks life-saving medicines. Why does the body protect itself so well, and yet cause so many treatment failures?