This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'Which of the following drugs does not cross the blood placental barrier: \nSelect and explain. \nA. Atropine, B. Glycopyrrolate, C. Physostigmine, D. Hyoscine hydrobromide.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Glycopyrrolate is a quaternary ammonium compound and is thus water-soluble and to penetrate BBB.', 'role': 'assistant'}]