Development and Structural-Activity Relationship of New Local Anti-inflammatory Steroid, Prednisolone Derivatives I. Binding Affinities to Rat Liver Glucocorticoid Receptor

ln order to develope anti-inflammatory glucocorticoids for local use without systemic side-effects, ester and amide derivatives of 20$\xi$-dihydroprednisolonic acid have been prepared. When binding affinities of these compounds to glucocorticoid receptor of rat liver cytosol were compared, all a-isomer at C-20 showed higher binding affinities than the corres¬ponding $\beta$-isomer. The size of the substituents at C-21 had significant influences on binding affinities, which were related with their lipophilicity.