Biological profile of 2-[4-(2-N-piperidinoethoxy) phenyl]-3-phenyl (2H) benzo (b) pyran--a potent antiimplantation agent in rat.

Compound CDRI-85/287: 2-[4-(2-N-piperidinoethoxy) phenyl]-3-phenyl (2H) benzo (b) pyran has been identified as a potent antiimplantation agent in rat. A single oral dose (2.5 mg/kg body weight) of the compound administered on days 1, 2 or 3 of pregnancy or multiple dosing (0.05 mg/kg daily) on days 5-7 postcoitum effectively prevented pregnancy. When administered on days 5-7 postcoitum, it failed to interrupt pregnancy even at 20 mg/kg dose. The compound is a potent antiestrogen, with very weak uterotrophic activity; it does not induce vaginal cornification in immature ovariectomised rat. Also, it is devoid of progestational, antiprogestational, androgenic, antiandrogenic and antigonadotrophic activities. The results suggest that the compound exerts its antiimplantation acivity in rat by virtue of its antiestrogenic activity [corrected].