Which of the following antibacterial drug is polar?

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.