| Abstract: | The analgesic effect of topically applied pranoprofen-gel (1% and 3%) was investigated in comparison with indomethacin-gel in experimental animals. Applied topically, 1% and 3% pranoprofen-gel inhibited the inflammatory pain induced by Randall and Selitto's method and the pain response (abnormal gait) of concanavalin A-induced arthritis in rats dose-dependently. Furthermore, in antigen (methylated bovine serum albumin)-induced arthritis in rats, pranoprofen-gel had a concentration and application-dependent therapeutic effect on knee joint swelling and the pain response. Pranoprofen-gel had a stronger analgesic effect than indomethacin-gel in these experimental models. Both drugs inhibited the flexor reflexes of the hind limb induced by injecting bradykinin (BK) in combination with arachidonic acid into the common iliac artery of the spinal rat, but failed to do so with BK combined with prostaglandin E2 (PGE2). Moreover, pranoprofen-gel inhibited the BK-induced increase in the firing rate of the saphenous nerve of the spinal cat. These results show that pranoprofen-gel, applied topically, permeates well from the skin to the nociceptor site, relieving the hyperalgesia caused by PGs-induced sensitization of pain receptors by inhibiting their production. As a topical anti-inflammatory and analgesic agent, pranoprofen-gel is at least as effective as indomethacin-gel, so that it should have good clinical potential. |
