Ketorolac tromethamine salt (Ketorolac tris salt) non-selective inhibits the enzymes cyclooxygenase 1 (COX-1) and COX-2with anti-inflammatory, analgesic, and antipyretic activities.

COX-2:20 nM, COX-1:20 nM

In models of acetic acid-induced writhing (ID50=0.24 mg/kg), carrageenan-induced hyperalgesia in the paw (ID50=0.29 mg/kg), and carrageenan-induced rat paw edema (ID50=0.08 mg/kg), (R,S)-Ketorolac has demonstrated efficacy.

Ketorolac inhibits prostaglandin synthesis in HEL cells (COX-1) (IC50=0.025 μM) and LPS-stimulated Mono Mac 6 cells (COX-2) (IC50=0.039 μM). In human osteoblasts (hOB), Ketorolac dose-dependently suppresses thymidine incorporation and proliferation at the G0/G1 phase, blocking cell cycle progression.

Inhibition of Prostaglandin Formation: Recombinant COX-1 and COX-2 from rat (rCOX) and human (hCOX) expressed in a baculovirus system are purified and reconstituted with 2 mM phenol and 1 μM hematin. Then the cyclooxygenase activity is measured using a radiometric assay, and the specific activity of the final enzyme preparations used is between 20,000 and 35,000 units. Ketorolac (2 -15 μL) are diluted in DMSO and preincubated with the appropriate recombinant COX (3 -15 ng) at a final concentration of 0.01 to 1000 μM in a reaction mixture (150 μL) containing 50 mM Tris-HCl buffer (pH 7.9), 2 mM EDTA, 10% glycerol, 2 mM phenol, and 1 μM hematin for 10 minutes. The reaction is initiated by addition of [14C]arachidonic acid (50–60 mCi/mmol in a final concentration of 20 μM) and is terminated 45 seconds later by the addition of 100 μL of 0.2 N HCl and 750 μL of distilled water. The total reaction volume is then applied to a 1 mL C18 Sep-pak column that has previously been washed with 2 mL of methanol followed by 5 mL of deionized water. Oxygenated products are eluted with 3 mL of a mixture of acetonitrile/water/acetic acid (50:50:0.1, v/v/v) and quantified by liquid scintillation spectroscopy.

Human osteoblasts cells are exposed to Ketorolac for 24 hours. Thymidine incorporation is assessed by the TopCount Microplate Scintillation and Luminescence Counters through adding [3H]-thymidine to cultures 4 hours prior to harvesting. Cell cycle distribution is determined by using propidium iodide in flow cytometer, and cell apoptosis or necrosis is detected using the Annexin V-FITC Apoptosis Detection Kit. (Only for Reference)