ampicillin n 1: semisynthetic penicillin (trade names Principen and Polycillin and SK-Ampicillin) [syn: {ampicillin}, {Principen}, {Polycillin}, {SK-Ampicillin}]
ampicillin \ampicillin\ n. 1. a semisynthetic penicillin which can be considered as the common benzylpenicillin containing an amino group at the alpha benzyl position. Note: 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(-)-[alpha]-aminobenzylpenicillin. [WordNet 1.5]