As new local antiinflammatory steroids, alkyl (or aryl) 20 $\xi$-dihydroprednisolonate have been synthesized adn evaluated for their antiinflammatory activity, systemic side effects, binding affinity to rat liver glucocorticoid receptor, and hydrolysis rate by serum. The results showed some of these compounds have significant antiinflammatory activity. Although they showed low antiinflammatory activity compared to the parent compound prednisolone, the systemic side effects was not expressed. Their binding affinity and hydrolysis rate in serum revealed usefull informations for new drug design. In this series, the compounds having 20 configuration showed higher antiinflammayory activity than theirn corresponding 20 isomers, although the 20 -isomer ahd higher receptor binding affinity. The increase of side chain at C-21 up to benzyl group favored the hydrolysis to the inactivecompounds, 20 -dihydroprednisolonic acid. Benzyl 20 -dihydroprednisolonate showed a promissing potential for new antiinflammatory steroids with reduced systemic side effects.