Estradiol absorption from vaginal tablets in postmenopausal women

Area of Science:

• Reproductive Endocrinology
• Pharmacokinetics
• Gynecology

Background:

• Atrophic vaginitis is a common condition in postmenopausal women.
• Estrogen therapy is a standard treatment, but systemic absorption and side effects are concerns.

Purpose of the Study:

• To evaluate the absorption of estradiol (E2) from two low-dose vaginal tablet formulations (25 mcg and 10 mcg).
• To compare the efficacy of these two doses in treating postmenopausal women with atrophic vaginitis.

Main Methods:

• A double-masked, randomized, parallel-group study involving 58 postmenopausal women.
• Participants received either 25 mcg or 10 mcg of 17 beta-estradiol (E2) vaginal tablets for 12 weeks.
• Serum E2 and FSH levels, along with vaginal maturation values, were measured.

Main Results:

• After 12 weeks, the 25 mcg group showed higher E2 absorption (AUC, Cmax, Cav) than the 10 mcg group.
• A high percentage of women in both groups (74% in 25 mcg, 96% in 10 mcg) exhibited low systemic E2 absorption (AUC < 500 pg/mL).
• FSH levels remained below 35 mIU/mL in most women receiving 25 mcg E2.

Conclusions:

• Vaginal administration of 17 beta-E2 at 25 mcg or 10 mcg resulted in low systemic estrogen absorption.
• These low doses did not produce systemic effects commonly associated with hormone replacement therapy.
• Consistent absorption patterns and no E2 accumulation were observed after 12 weeks of treatment for atrophic vaginitis.