title: Low-level, progestogen-releasing vaginal contraceptive devices.
abstract: Silicone rubber vaginal contraceptive devices of four different formulations, which release predetermined, controlled doses of three progestogens at four distinct levels, were designed and fabricated, and tested in 90-day clinical trials. Data obtained with 70 of the devices indicated that in vivo release rates (microgram/day +/- S.D.) for the formulations were: progesterone, 1400 +/- 30; norethindrone (two levels), 49.4 +/- 2.4, 196 +/- 21; d-norgestrel, 21.6 +/- 1.4. Clinical studies with these devices indicate that the women usually ovulate (with the exception of the high-dose norethindrone-releasing devices) while sperm penetration of the cervix was inhibited by all four fromulations, most consistently by the norgestrel-releasing devices.
mesh_terms: D003273:Contraceptive Devices; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D009640:Norethindrone / Q000008:administration & dosage; D009644:Norgestrel / Q000008:administration & dosage; D011309:Preservation, Biological; D011374:Progesterone / Q000008:administration & dosage; D011372:Progestins / Q000008:administration & dosage*
chemical_list: D011372:Progestins; D009644:Norgestrel; D011374:Progesterone; D009640:Norethindrone