Antiinflammatory effects of some copper complexes.

Copper complexes of a range of ligands have been prepared and evaluated for antiinflammatory activity and irritancy after oral, subcutaneous, and local administration in rats and guinea pigs. The antiinflammatory activities were found to depend on the species used and the route of administration. When nonantiinflammatory ligands were used, the response was generally dose dependent. With D-penicillamine and when the ligands were themselves antiinflammatory in animal models of inflammation--as was the case with flufenamic acid, levamisole, aspirin, L-histidine, and 2-amino-2-thiazoline--differences in antiinflammatory activity were observed between the copper complexes and the free ligands. In some cases, the copper complexes were the more effective. There was a weak correlation between local (subplantar) irritation and the dose of copper but, for four compounds studied in more detail, the response in the local subplantar test and degree of antiinflammatory activity were not related, suggesting that the action of copper is not solely by a counterirritant mechanism. No obvious differences between the activities of copper(I) and copper(II) compounds were observed, suggesting that a common metabolite may be involved in the antiinflammatory action of copper.