[Anti-edema activity of a trans-cutaneous non-steroidal anti-inflammatory agent, etofenamate gel, in rats].

Local anti-inflammatory activity of etofenamate gel (5% etofenamate) was investigated in rats. Etofenamate gel (5--50 mg/paw) produced a dose related inhibition in the hind paw edema caused by carrageenin with a topical application to the inflamed paw, and its ED50-value was 33.0 mg/paw. A weak but significant inhibiton was seen with an application of 50 mg/paw to the non-inflamed paw, but not with 10 mg/paw. Anti-edema activity of oral etofenamate (ED50 = 8.49 mg/kg) was comparable to flufenamic acid. Against the hind paw edema caused by a mixture of kaolin and carrageenin, etofenamate gel showed a significant therapeutic activity with repeated application of 10--50 mg/paw to the inflamed paw, but not with 10 mg/paw to the non-inflamed paw. Etofenamate gel (50 mg/paw/day), applied topically to the inflamed hind paw of adjuvant rats, showed a significant therapeutic activity. The potency of oral etofenamate (4--8 mg/kg/day) in adjuvant rats was comparable to flufenamic acid. No gastrointestinal ulcer was produced by a topical application of etofenamate gel (up to 1,000 mg/rat) to the clipped skin, though oral etofenamate (40 mg/kg) produced the ulcer. From these results, it was suggested that etofenamate gel, applied to the skin of rats, showed local anti-edema activity approximately comparable to oral etofenamate, and the ratio of ulcerogenic effective to anti-edema dose of etofenamate gel was larger than that of oral etofenamate.