6.alpha.,9-Difluoroprednisolone 6.alpha.,9.alpha.-Difluoroprednisolone 806-29-1 NSC77021 Pregna-1,4-diene-3,20-dione, 6,9-difluoro-11,17,21-trihydroxy-, (6.alpha.,11.beta.)- Pregna-1,4-diene-3,20-dione, 6.alpha.,9-difluoro-11.beta.,17,21-trihydroxy-