Purity >99% by HPLC Heavy Metals: Less than 20 ppm . Cyclooxygenase inhibitor, may be selective for COX-3. It acts primarily in the CNS, increasing the pain threshold by inhibiting Cyclooxygenases (IC50 = 460 μM for COX-3 and > 1000 μM for COX-1 / COX-2). Analgesic agent displaying no antiinflammatory properties.