NCIt definition : The sodium salt of a naphthydridine derivative of the broad spectrum, semisynthetic
ampicillin with antibacterial activity. Apalcillin specifically binds to and inactivates
penicillin-binding proteins (PBPs) located on the inner membrane of the bacterial
cell wall, thereby preventing the cross-linkage of peptidoglycans, which are critical
components of the bacterial cell wall. This leads to a weakening of the bacterial
cell wall, eventually causing bacterial cell lysis.;