Which of the following drug do not cross the blood-brain barrier?: (A) Diacetyl monoxime, (B) Obidoximine, (C) Physostigmine, (D) Neostigmine
Answer is D. Neostigmine being a quaternary ammonium compound and highly polar cannot cross BBB.Pralidoxime which is used in OP poisoning also can&;t cross the BBB.Ref: Katzung 11th ed.Pg 121