%ampicillin%

n. 1. a semisynthetic penicillin which can be considered as the common benzylpenicillin containing an amino group at the alpha benzyl position. It is more active against certain gram-negative bacteria than is benzylpenicillin. It found wide use in treatment of bacterial infections, and has been sold under many trade names.
Syn. -- D(-)-α-aminobenzylpenicillin. [ WordNet 1.5 ]