Abstract
Therapeutic effect of etofenamate gel (5% etofenamate), applied topically, on traumatic edema and mode of its anti-edema action were investigated in rats. Plasma flufenamic acid levels were 5.73 and 0.173μg/ml 2.5 h after oral administration of etofenamate (diethylene glycol ester of flufenamic acid, 8.5 mg/kg) and after topical application of etofenamate gel (33 mg/paw) equipotent to the oral etofenamate, respectively. Etofenamate gel (25 mg/paw) showed a significant therapeutic effect against traumatic edema of the hind paw, when the gel was applied to the inflamed paw 2 h after bruising but not to the non-inflamed paw. Vehicle gel lacked the activity. Etofenamate gel (25 mg/paw) inhibited both the early and delayed phases of hind paw edema produced by the mixed phlogistics (histamine, serotonin, kaolin, carrageenin), but vehicle gel inhibited only the early phase mediated by histamine and serotonin. Hind paw edema induced by carrageenin (1 mg) was potentiated by the concomitant administration of arachidonic acid (100μg) or PGE2 (1μg). Etofenamate gel (25 mg/paw) did not modify the edema produced by the combination of carrageenin and PGE2, but reduced the arachidonic acid potentiation of carrageenin-induced edema. Vehicle gel did not reduce the edema. From these results, it was suggested that etofenamate gel, applied topically, produced locally therapeutic activity against traumatic edema, and mode of its antiedema action was discussed.
