Agents and Actions

, Volume 12, Issue 5, pp 684–690 | Cite as

The analgesic and anti-inflammatory profile of (±)-5-benzoyl-1,2-dihydro-3H-pyrrolo[1,2a]pyrrole-1-carboxylic acid (RS-37619)

  • W. H. RooksII
  • A. J. Tomolonis
  • P. J. Maloney
  • M. B. Wallach
  • M. E. Schuler
Immunosuppression and Inflammation


RS-37619 showed highly potent analgesic activity when given p.o. in tests utilizing underlying inflammation. It inhibited phenylquinone-induced writhing in the mouse and rat (350 and 180×aspirin respectively) and the pain induced by flexing the adjuvant-inflamed rat paw (∼ 800×aspirin). The agent increased the pain threshold of compressed yeast-inflamed rat paws (3–10 ×naproxen). RS-37619 did not increase the pain threshold of the noninflamed paw and was inactive in the mouse hot plate test; therefore it is probably not a centrally acting or morphinelike agent. RS-37619 was also highly active p.o. in rat models of acute and chronic inflammation. It inhibited carrageenan-induced paw edema (36×phenylbutazone), cotton pellet-induced granuloma (≤1×indomethacin) and in an 18-day test, prevented the development of adjuvant-induced arthritis (∼2×naproxen). RS-37619 exhibited antiphlogistic activity in adrenalectomized rats. It did not have corticosteroid activity. When given p.o., RS-37619 lowered yeast-induced pyrexia (20×aspirin). Gastro-intestinal irritation was seen in the rat with doses ≥6.4 mg/kg/day p.o. The agent elicited mild CNS and cardiovascular activity only at doses far in excess of those required for analgesic and anti-inflammatory activity.


Naproxen Pain Threshold Phenylbutazone Underlying Inflammation Potent Analgesic Activity 


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Copyright information

© Birkhäuser Verlag 1982

Authors and Affiliations

  • W. H. RooksII
    • 1
  • A. J. Tomolonis
    • 1
  • P. J. Maloney
    • 1
  • M. B. Wallach
    • 1
  • M. E. Schuler
    • 1
  1. 1.Department of Bioassay and PharmacologySyntex (USA) Inc., Research DivisionPalo AltoUSA

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