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 antibacterial drug is polar? 
Select and explain. 
A. Ampicillin, B. Penicillin G, C. Clavulanic acid, D. Cefepime
A: Ampicillin
Answer: A: Ampicillin 
Explanation: Ans. is 'a' i.e., Ampicillin Ampicillin: It is an ionized highly polar drug. In the duodenum it exes a zwitter ion effect and thus has a lower bioavailabilty. Though the oral absorption is incomplete it is adequate. It is an antibacterial drug acting both on gram positive and gram negative organisms. Main mode of excretion is by kidneys. It is paly excreted in bile and shows enterohepatic circulation.