Progesterone dioxime, or progesterone 3,20-dioxime (P4-3,20-DO), also known as 3,20-di(hydroxyimino)pregn-4-en-3-one, is a progesterone derivative which was never marketed. It is a progestogen oxime â specifically, the C3 and C20 dioxime of the progestogen progesterone. Progesterone C3 and C20 oxime conjugates have been found to be water-soluble prodrugs of progesterone and pregnane neurosteroids.