Pharmacological studies of a contraceptive drug anordrin.

A new oral contraceptive--Anordrin has been discovered. It is an A-Nor-steroid with some estrogenic activity and possessing a significant anti-fertility activity in mice, rats, rabbits, hamsters and dogs. In rats, AF-53, administrated repeatedly, led to sterility but did not alter mating behaviour, and the fertility of the animals recovered soon after cessation of the medication. In sub-minimal antifertility doses it has no teratogenic effect. Acute and chronic toxicity tests in animals showed that this drug did not cause any apparent abnormality in the blood picture, liver and renal functions, as well as in the histological examinations of organs. Experiments with 14C-labelled Anordrin showed that this drug could be absorbed rapidly but not completely in the gastrointestinal tract. The peak blood level was usually attained at 9 hours after administration. The drug excreted in the urine reached a maximum in 10--12 hours. Higher radio-activity was found in bile and gastrointestinal tract and was also excreted in large amounts in the feces. In clinical trials it is administrated only once post-coitally. The time for taking the drug is not limited by the menstrual cycle and it is unnecessary to be taken successively. Thus Anordrin is a convenient, safe and effective oral contraceptive drug.