Anti-inflammatory effects of tretinoin (all-trans-retinoic acid) 0.1% and adapalene 0.1% in rats.

In this study, the anti-inflammatory effects of tretinoin (all-trans-retinoic acid) 0.1% cream and adapalene 0.1% gel were compared in rats to determine whether there was a difference between these agents. Thirty-six rats of either sex were divided into six groups (two control groups, and an etodolac, indomethacin, tretinoin and adapalene group) of six animals each. Each group was given different drugs or chemicals. The inhibitory activities of the drugs were determined on carrageenan-induced rat-paw oedema. The inhibition rate (53.48%) in the tretinoin group was found to be higher than adapalene and controls (P < 0.05). Adapalene was found to have an inhibition rate of 10.28%, and when compared with the other groups, was found to have no statistically significant anti-inflammatory activity. We conclude that tretinoin has a higher anti-inflammatory activity than adapalene and thus should be preferred for the treatment of inflammatory lesions.