The blood-brain barrier is not a "barrier" for many drugs.
Fenstermacher
J D
JD
Department of Neurological Surgery, State University of New York, Stony Brook 11794-8122.
D000818:Animals; D001812:Blood-Brain Barrier; D004058:Diffusion; D006801:Humans; D010539:Permeability; D010599:Pharmacokinetics; D012995:Solubility