An Orally Effective Mammalian Antifertility Agent

Abstract

U-11555A (triethylamine, 2-[p-(6-methoxy-2-[p-methoxyphenyi]-inden-3-yl)-phenoxy] hydro-chloride) is an orally active antifertility agent in laboratory mammals. In rats, its efficacy is limited to the period of tubal transport of the zygote. Single oral doses, administered any time within 4 days of breeding, effectively inhibit pregnancy. After the zygote has reached the uterus U-11555A is ineffective as a pregnancy inhibition. At effective antifertility dosages, U-11555A does not exhibit significant progestational, antiprogestational, antigonadotropic, androgenic, or estrogenic activities. U-11555A inhibits the uterine and vaginal response to endogenous and exogenous estrogens.