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.

PIP: 4 different formulations, which released predetermined, controlled doses of 3 progestogens at 4 distinct levels, were incorporated into newly designed and fabricated silicone rubber vaginal contraceptive devices. 90-day clinical trails tested in vivo release rates of 70 devices; the rates were: progesterone, 1400+ or -30 mcg/day; norethindrone (2 levels), 49.4+ or -2.4 and 196+ or -21 mcg/day; and d-norgestrel, 21.6+ or -1.4 mcg/day. Clinical studies with these devices indicated that the women usually ovulated (with the exception of the high-dose norethindrone-releasing device), whereas sperm penetration of the cervix was inhibited by all 4 formulations, most consistently by the norgestrel-releasing device. Data from a shelf-life study indicated that there were no significant differences between the amount of progestogen in freshly fabricated devices and that in devices stored at room temperature for 2 years.