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
Which of the following drugs does not cross the blood placental barrier: 
Select and explain. 
A. Atropine, B. Glycopyrrolate, C. Physostigmine, D. Hyoscine hydrobromide.
B: Glycopyrrolate
Answer: B: Glycopyrrolate 
Explanation: Glycopyrrolate is a quaternary ammonium compound and is thus water-soluble and to penetrate BBB.