Antinociceptive effect of 3-(4-fluorophenyl)-5-trifluoromethyl-1H-1-tosylpyrazole. A Celecoxib structural analog in models of pathological pain.

Pain is the most common complaint in the medical field and the identification of novel compounds that can effectively treat painful states without causing side effects remains a major challenge in biomedical research. The aim of the present study is to investigate the antinociceptive effect of 3-(4-fluorophenyl)-5-trifluoromethyl-1H-1-tosylpyrazole (FTosPz) in models of pathological pain in mice and compare these effects with those produced by Celecoxib. FTosPz (100-500 μmol/kg) or Celecoxib (26-260 μmol/kg) was administrated orally. The administration of either FTosPz or Celecoxib reduced the hyperalgesia but not the edema or leukocyte infiltration that was caused by Complete Freund's Adjuvant (CFA), used as an arthritis model. Oral administration of both FTosPz and Celecoxib also attenuated the postoperative hyperalgesia as well as the hyperalgesia caused by partial sciatic nerve ligation, used as a neuropathic pain model. FTosPz and Celecoxib produced antinociceptive effects without altering the locomotor activity of animals. Furthermore, FTosPz neither altered AST/ALT enzyme activity nor the urea/creatinine levels. Still, the FTosPz did not alter the COX-1 and COX-2 enzyme activities. Thus, FTosPz is an interesting prototype for the development of novel analgesic drugs.