DEVELOPMENT OF A VAGINAL RING FOR ACHIEVING PHYSIOLOGIC LEVELS OF 17β-ESTRADI0L IN HYPOESTROGENIC WOMEN1

Abstract
The ability of polysiloxane vaginal rings containing 17.beta.-estradiol (E2) to deliver E2 into the systemic circulation at a steady state rate over long periods of time was evaluated in castrate and postmenopausal volunteers. Standard laminar designs, used to release contraceptive gestagens, deliver low levels of E2 (.apprx. 50 pg/ml) and only for 1 mo. With a modified design, E2 levels of 109-159 pg/ml were maintained for at least 3 mo., and circulating gonadotropins were suppressed to values approaching the premenopausal range. This homogeneous design provides for physiologic replacement of E2 as well as a practical research tool for studying chronic effects of E2 in human subjects.