Nacubactam is broad-spectrum non-β-lactam antibiotic that is a β-lactamase inhibitor. It was developed by Meiji Seika Pharma (Tokyo, Japan). It can inhibit class A and C β-lactamases in vitro, and has minor class D activity. It is classified as a diazabicyclooctanone. Compared to avibactam, it has an additional aminoethoxy group attached to the carbamoyl side chain that is responsible for its antimicrobial activity. Nacubactam is soluble in DMSO.