Low-dose intravaginal estradiol delivery using a Silastic vaginal ring for estrogen replacement therapy in postmenopausal women: a review

Abstract

Objective: The aim of this study was to review the potential of the intravaginal ring to be an effective low-dose estrogen delivery system for the treatment of postmenopausal women. Methods The data were extracted from the literature using the computerized MEDLINE system. The soft and flexible ring (Estring®) is made of silicone rubber with a 55-mm outer diameter and 9.5-mm cross-sectional diameter, contains 2 mg 17β-estradiol in the core section with the release specification limit of 6.5-9.5 μg/24 h and maintains a continuous plasma estradiol concentration of 20-30 pmol/l for 3 months when inserted in women. Results: Comparative clinical trials have demonstrated that treatment with the intravaginal ring is excellent at alleviating subjective and objective symptoms of estrogen deficiency, restores vaginal mucosa, induces a high maturation index of mucosal cells and reduces vaginal pH to < 5.5 in postmenopausal women. No major side-effects or endometrial proliferation have been observed during treatment. The majority of patients prefer using the vaginal ring to other currently available vaginal steroid delivery systems. The sustained low-dose estrogen therapy is also found to improve the serum lipid profile in elderly women. Conclusion: It is suggested that the low-dose estradiol intravaginal ring is safe, effective and well accepted for the treatment of estrogen deficiency symptoms in postmenopausal women.