434-02-6 FDA 0255 NSC19609 Pregn-4-ene-3,20-dione, 21-fluoro-11,17-dihydroxy-, (11.beta.)- Pregn-4-ene-3,20-dione, 21-fluoro-11.beta.,17-dihydroxy- Progesterone, 21-fluoro-11.beta.,17-dihydroxy-