Antiinflammatory pyrazolones and pyrazolidones: a study of their inhibition of 5 beta-dihydrocortisone reduction in rat liver cytosol.

Seven pyrazolone and pyrazolidone derivates, some of them widely used as analgesic and anti-inflammatory drugs, were tested for the inhibitory property of the 3 alpha-hydroxysteroid dehydrogenase of rat liver cytosol. The data obtained clearly show that, among pyrazolone and pyrazolidone derivates, the correlation between IC50 and therapeutic potency is not always verified.