Vaginal rings delivery

Bachmann G. Estradiol-releasing vaginal ring delivery system for urogenital atrophy. Experience over the past decade. I Reprod Med 1998 43(ll) 991-8. 

Vaginal rings are circular, torus-shaped, drug delivery devices designed to prolong drug release after application. They measure approximately 5.5 cm in diameter with a circular cross section of 4—9 mm [6,12]. 

In conclusion, contraception therapies with vaginal rings present excellent efficacy with little risk of side effects and appear to be as effective as oral contraception and IUD, in terms of pregnancy prevention [42]. Moreover, rings are characterized by important benefits like ease of use, long-term schedule, and user-controlled application. These versatile drug delivery systems appear to be safe, effective, and acceptable. 

Johansson, E.D.B., and R. Sitruk-Ware. 2004. New delivery systems in contraception Vaginal rings. Am J Obstet Gynecol 190 S54. 

Nash, H. A., Brache, V., Alvarez-Sanchez, F., Jackanicz,T. M., and Harmon,T. M. (1997), Estradiol delivery by vaginal rings Potential for hormone replacement therapy, Maturitas, 26, 27-33. 

Vaginal controiled-delivery systems for IgG have been previously modeled in mice [43, 44]. The device was a flat disk, with IgG diffusing out of the face of the disk. To adapt this model for human use, the disk was replaced by a doughnut-shaped ring, with characteristics based on devices that have been used clinically. EVAc vaginal rings (54 mm) of different cross-sectional thickness (3, 3.5, or 4 mm) were acceptable in the majority of women tested (91%) [45] Similar rings have been used successfully in a number of clinical studies [46, 47],... 

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