Pharmacological and toxicological studies of a new non-steroidal anti-inflammatory drug: KC-8973.

A benzophenone derivative, 4-butyl-2'-fluorobenzophenone (KC-8973), having anti-inflammatory effects has been studied pharmacologically and toxicologically. On the carrageenin-induced paw edema, KC-8973 had the most potent activity of the tested commercial non-steroidal anti-inflammatory drugs. KC-8973 had a moderate effect on bradykinin-induced capillary permeability and lesser effect on dextran-, egg white- and serotonin-induced paw edemas in rats, respectively. From the detailed studies of prophylactic and therapeutic effects on the adjuvant-induced arthritis in rats, it was demonstrated that KC-8973 has an immuno-suppressive activity in addition to an anti-inflammatory effect. KC-8973 had a local-analgesic and antipyretic effect on the rat paw edema induced by brewer's yeast. KC-8973 caused no undesirable side effect at pharmacologically effective dose in the 1-month sub-acute toxicological study.