Steroid antifertility agents. Ionic complexes of basic derivatives for prolonged action

Ethynylestradiol 3-dimethylaminopropionate (1), norethindrone 3-(O-dimethylaminopropyl)oxime (syn and anti isomers, 2a and 2b), and testosterone 3-(O-dimethylaminopropyl)oxime (3) have been prepared and converted to zinc and aluminum tannate complexes as potentially long-acting prodrug forms of the parent steroids. The basic derivatives and the complexes showed the appropriate hormonal activities although they were less active in acute tests than the respective parents. The complexes of 1 showed prolonged activities and, in particular, the zinc tannate showed a prolonged duration of antifertility activity in the rat on subcutaneous administration in an aluminum monostearate gel.