Inducing a Medical Castration With a GnRH Agonist While Simultaneously Replacing Physiologic Levels and Patterns of Human Sex Steroid Hormones Using an Ethylvinyl Acetate (EVA) Vaginal Ring Delivery System

3-Day Study (outpatient)

Healthy normal volunteers will participate in a 3-day outpatient study that will begin between days 1-7 of their menstrual cycle (i.e. early follicular phase). A negative urinary hCG will be obtained in these women prior to their starting the 3-day study. On the first day, subjects will have 4 baseline blood samples of 5mL each drawn at 20-minute intervals over an hour (Time = 0, +20, +40, +60). These will be pooled and will represent the pretreatment determination of gonadotropins and sex steroid levels. Thereafter, the individual vaginal rings to be tested will be inserted. Over the ensuing 3 days, subjects will have 3 blood draws per day (at approximately 8-9 AM, 12-1PM, and 4-5PM).

Serum levels of LH, FSH, E2, and P will be determined at the above time points for the next 3 days. A repeat CBC and LFT's will be done with the final blood draw. The only exceptions to this protocol will be those patients with the Sex Steroid Only rings in whom 75 ug/kg of a GnRH antagonist (Acyline IND# 58,448) will be administered subcutaneously every other day and upon subsequent onset of menses, subjects will return during day 3-6 for repeat LFT's and gonadotropins. This will ensure the return of normal liver function and hormonal levels.

A visual vaginal examination and colposcopy will be done at baseline and at the time of the removal of the ring. If lesions or abrasions are found at study termination, subjects will be followed until the lesions resolve. For the initial 3-day studies, daily visual inspection of the vaginal tissues will be conducted and findings recorded in a standardized manner.

The schedule of more intensive early sampling is selected to be certain that no rapid release of medication occurs from the rings during the earliest phase following their insertion. This will also document that we have, in fact, achieved a steady state of release of the ring's content in the circulation prior to expanding the duration of these studies to 14 days in the second portion of part A.