Some do, including penicillin: “Antibiotics that cross the BBB tend to have certain physical characteristics including: small molecular size, being lipophilic,

Some do, including penicillin: “Antibiotics that cross the BBB tend to have certain physical characteristics including: small molecular size, being lipophilic, binding to fatty molecules on cell membranes, low plasma protein binding and other specialized characteristics“ http://lymemd.blogspot.com/2013/03/blood-brain-barrier.html?m=1 http://lymemd.blogspot.com/2013/03/blood-brain-barrier.html?...