Prostaglandin F2-alpha for induction of midterm abortion: a comparative study.

The action of prostaglandin F2alpha (PGF2-alpha) to induce midterm abortion in rabbits, rats, hamsters, and mice using different methods and routes of administration was studied. Administration of PGF-alpha in a Silastic-PVP implant was more effective than was the parenteral injection at the same dose levels. The efficacy of PGF2alpha was optimum when deposited locally in the uterine lumen as a Silastic-PVP implant, a condition comparable to a continuous intra-amniotic or extra-amniotic administration of PGF2alpha in women. It is possible that the insertion of a Silastic-PVP implant into the uterine lumen results in a continuous PGF2alpha release and a high local PGF2alpha concentration which minimizes such factors as dilution and the short half life displayed in the general circulation. PGF2alpha contained in a Silastic-PVP implant and inserted into the uterine lumen may effectively induce abortion with a comparatively lower dose than that necessary for parenteral routes of administration.