Research Area: Infection Biological Activity: Oxacillin sodium monohydrate is an antibacterial agent and is a narrow spectrum beta-lactam antibiotic of the penicillin class. Oxacillin sodium monohydrate is a penicillinase-resistant β-lactam. Oxacillin sodium monohydrate is similar to methicillin, and has replaced methicillin in clinical use. [1][2]