Characterization of 5-[5-(4-chlorophenyl-2-furanyl)]dihydro-2(3H)-furanone as a nonsteroidal antiinflammatory drug.

5-[5-(4-Chlorophenyl-2-furanyl)]dihydro-2(3H)-furanone (F-1044), a nonsteroidal antiinflammatory drug related to orpanoxin, lacks the usual acid moiety of such agents. F-1044 had antiinflammatory activity equivalent to ibuprofen's and orpanoxin's in the carrageenin-induced paw edema model in normal and adrenalectomized rats. Antiinflammatory activity was also expressed in the guinea pig UV-induced erythema and rat established arthritis models. F-1044 was a more potent analgesic than ibuprofen and orpanoxin in the rat paw pressure assay. In contrast to the reference agents, F-1044 raised the pain threshold of both the yeast-injected and non-injected paws, suggesting a central component to its analgesic action. F-1044 was more potent than ibuprofen and orpanoxin in the rat brewer's yeast pyresis model. Based on its low activity in inhibiting bradykinin-induced bronchoconstriction in guinea pigs and low gastric irritation activity in rats. F-1044 appears to have a mechanisms of action that involves more than simple inhibition of prostaglandin synthesis. Thus F-1044 is a nonsteroidal antiinflammatory agent with unique chemical and pharmacological features.