This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharmacokinetics, Subject name: Pharmacology
[{'content': 'All of the following have poor penetration in brain and eyes except \nSelect and explain. \nA. Glycopyrrolate, B. Pilocarpine, C. Tiotropium bromide, D. Isopropamide', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Glycopyrrolate, Tiotropium bromide, Isopropamide are Atropine substitute Quaternary compounds. These compounds are lipid insoluble and therefore have poor penetration in brain and eyes. Glycopyrrolate blocks the peripheral muscarinic side effects(caused by increased Ach levels) without causing unwanted central anticholinergic effects. Pilocarpine and Arecoline being teiary aminesare readily absorbed and can cross the blood-brain barrier.', 'role': 'assistant'}]