This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
Which of the following drugs cannot cross the blood placental barrier 
Select and explain. 
A. Atropine, B. Glycopyrolate, C. Physostigmine, D. Hyoscine hydro bromide
B: Glycopyrolate
Answer: B: Glycopyrolate 
Explanation: Refer kDT 7/e p116 Glycopyrrolate is a quaternary ammonium compound and is this water soluble and unable to penetrate blood brain barrier