Structure activity relationships of 4-substituted 1-acyl and 1,2-diacyl-1,2,4-triazolidine-3,5-diones as anti-inflammatory agents in rodents.

1-Acyl and 1,2-diacyl 1,2,4-triazolidine-3,5-diones proved to be potent anti-inflammatory agents in rodents at 8 or 20 mg/kg. They were effective against induced edema, pleurisy, and septic shock. Furthermore, these agents were potent in blocking the writhing reflex suggesting that they should be effective against local pain generated by inflammatory processes. These compounds were not lysosomal hydrolytic enzyme or proteolytic enzyme inhibitors in mouse liver, macrophages or human leukocytes. However, the agents were potent inhibitors of prostaglandin and leukotriene de novo synthesis and have potential in acting as free radical scavengers.