[Pharmacologic profile of a new compound with antiinflammatory activity: 2-(4-dimethylvinylphenyl)propionic acid (Gx 258)].

: Gx 258, a new phenylalkanoic acid derivative, was shown in animal tests to possess potent antiinflammatory, analgesic and antipyretic activity. Its antiinflammatory activity was not mediated via the pituitary-adrenal axis, since it was also effective in adrenalectomized rats. Since large doses of Gx 258, 9-83 times greater than those showing antiinflammatory activity, were required to produce gastrointestinal lesions in rats, Gx 258 appears to have a very good therapeutic index. Its therapeutic index as an antiinflammatory and analgesic agent was 2.3-20.5 times greater than that of the parent compound ibuprofen. Gx 258, like ibuprofen, inhibited the biosynthesis of prostaglandins in vitro.