piroxicam and Arthritis

A series of 4-hydroxy-3-quinolinecarboxamides has been synthesized and evaluated by the oral route as antiinflammatory agents in carrageenin-induced foot edema and adjuvant-induced arthritis and as analgesic agents in the acetic acid induced writhing test. Among the most active molecules, some have shown both analgesic and acute antiinflammatory activities. Others, such as compounds 24, 37, and 52, were only powerful peripherally acting analgesics. Compound 52, being active at 1 mg/kg (ED50), is the most potent compound in the series. Some analogues, substituted in the 2-position by an alcohol, ester, or amine function, displayed potent antiarthritic activity in the same range as that of piroxicam and were also active in acute tests of inflammation and nociception. They inhibited the activity of both cyclooxygenase and 5-lipoxygenase at micromolar concentrations. Compound 102 (RU 43526) showed potent antiarthritic activity (adjuvant-induced arthritis, ED50 = 0.7 mg/kg, po) and gastrointestinal tolerance (ED100 greater than 250 mg/kg, po) and thus it is presently undergoing an extensive pharmacological evaluation.

Topics: Amides; Analgesia; Animals; Anti-Inflammatory Agents; Arthritis; Arthritis, Experimental; Carrageenan; Cattle; Chemical Phenomena; Chemistry; Cyclooxygenase Inhibitors; Edema; Female; Hydroxyquinolines; Lipoxygenase Inhibitors; Male; Mice; Pain Measurement; Rats; Rats, Inbred Lew; Rats, Inbred Strains; Structure-Activity Relationship

A novel class of antiinflammatory drugs, which are substituted derivatives of the fused tricyclic system 6-hydroxypyrimido[2,1-f]purine-2,4,8(1H,3H,9H)-trione, is described. Synthetic procedures and structure determination with the assistance of X-ray crystallography are discussed. Semiempirical molecular orbital calculations are used to investigate the relative stability of the possible isomers and tautomers of the title compounds. A biological profile of the class, and of several of the more potent analogues, in several antiinflammatory models, including the adjuvant-induced arthritis and the collagen II models, is defined. Several members of the class are shown to possess extremely low ulcerogenic effects in spite of exhibiting cyclooxygenase inhibition. A preliminary bioavailability study of two of the lead structures is presented. The compounds 6-72 appear to constitute a class of drugs that shows interesting potential antiarthritic activity and also exhibits an activity profile different from that of the standard classical NSAI drugs, as determined by a comparison of the profile of this class of drug with that of several standard agents. Certain findings from toxicological studies have precluded the further development of compounds within this group, although related structural types are being investigated.

Topics: Animals; Anti-Inflammatory Agents; Arthritis; Biological Availability; Cyclooxygenase Inhibitors; Gastrointestinal Diseases; Male; Purines; Pyrimidines; Rats; Rats, Inbred Strains; Structure-Activity Relationship; Ulcer