Oxaprozin-d 5 is deuterium labeled Oxaprozin. Oxaprozin is an inhibitor of both COX-1 and COX-2 with IC50s of 2.2 μMand 36 μM for human platelet COX-1 and IL-1-stimulated human synovial cell COX-2 , respectively. Oxaprozin also inhibits the activation of NF-κB.