Naproxen sodium (Anaprox) is a COX inhibitor for COX-1 and COX-2 with analgesic and antipyretic properties.

COX-2:5.2 μM, COX-1:8.7 μM

In rat models of carrageenan-induced arthritis and attenuation of pain perception (IC50=27 μM) as well as yeast-induced fever (IC50=40 μM), Naproxen exhibits inhibitory effects. Additionally, in rats, Naproxen suppresses the production of PGE2 (IC50=12.8 μM) and TXB2 (IC50=5.9 μM) triggered by lipopolysaccharides.

In HCA-7 colon cancer cells (IC50=1.45 mM), high concentrations of Naproxen induce apoptosis. Within cells, Naproxen inhibits COX-1 (IC50=2.2 μg/mL) and COX-2 (IC50=1.3 μg/mL).

COX-1 and COX-2 activities in intact cells: For the determination of COX-1 and COX-2 inhibition, bovine aortic endothelial cells (BAEC) are incubated for 30 minutes with Naproxen (0.1 ng/mL to 1 mg/mL), and cultured J774.2 macrophages are treated with endotoxin at 1 μg/mL for 12 hours to induce COX-2 followed by incubated for 30 minutes with Naproxen (0.1 ng/mL to 1 mg/mL), respectively. Arachidonic acid (30 μM) is then added, and the cells are incubated for a further 15 minutes at 37 °C. The medium is then removed, and radioimmunoassay is used to measure the formation of 6-keto-PGF1α, PGE2, thromboxane B2, or PGF2α for the assessment of IC50 for COX-1 and COX-2.

Cells are exposed to Naproxen for 24 and 48 hours, respectively. At the end of incubation, cells are harvested by trypsinization, stained with trypan blue solution (0.04% wt/vol) and counted in a Neubauer haemocytometer chamber for the determination of cell viability.(Only for Reference)