Pharmacological studies of a new non-steroidal antiinflammatory drug: 2-(5-ethylpyridin-2-yl)benzimidazole (KB-1043).

2-(5-Ethylpyridin-2-yl)benzimidazole (KB-1043) is a new benzimidazole derivative with marked antiinflammatory, analgesic and antipyretic properties. KB-1043 possesses potent inhibitory activities on the acute inflammatory edema induced by chemical and physical irritants in the hind paw of rats, but almost ineffective (similar to tiaramide) against adjuvant-induced polyarthritis in the rat. The antagonistic effects of KB-1043 on increased vascular permeability are more potent than those of phenylbutazone, and the analgesic effects of KB-1043 on the pain induced by chemical and mechanical stimulations were nearly equal to, or slightly less potent than, those of tiaramide and phenylbutazone. The fevers induced by brewer's yeast and polysaccharide from Pseudomonas fluorescens (T.T.G.) were lowered by KB-1043. THe ulcerogenic activity of KB-1043 was weaker than those of tiaramide and phenylbutazone. The therapeutic index of KB-1043 therefore is superior to those of tiaramide and phenylbutazone.