NCIt definition : The sodium salt form of pirbenicillin, a broad-spectrum semisynthetic penicillin with
antibacterial activity. Pirbenicillin binds to and inactivates the penicillin binding
proteins (PBPs) located inside the bacterial cell wall. Inactivation of PBPs interferes
with the cross-linkage of peptidoglycan chains necessary for bacterial cell wall strength
and rigidity. This interrupts bacterial cell wall synthesis and results in the weakening
of the bacterial cell wall, eventually causing cell lysis.;