Copper chelates of antirheumatic and anti-inflammatory agents: their superoxide dismutase-like activity and stability.

An in vitro assay is described which simultaneously tests for the superoxide dismutase-like activity of low-molecular-weight copper chelates and their stability in the presence of excess EDTA. The EDTA is introduced to simulate the competitive endogenous ligands a copper-chelating drug will encounter in plasma and other body fluids. Under the conditions of the assay, antirheumatic drugs of the D-penicillamine type are clearly distinguished both from nonsteroidal anti-inflammatories and from some drugs which chelate copper but lack antirheumatic activity.