Development of vaginal rings for sustained release of nonhormonal contraceptives and anti-HIV agents

Abstract

Objectives: Construction of vaginal rings to deliver nonhormonal contraceptives and 3'-azido-3'-deoxythymidine (AZT) as an anti-HIV agent and determination of their daily release and efficacy in vitro.

Materials and methods: Intravaginal rings of 0.5-0.7 cm rim and 5-5.5 cm in diameter were cast in the molds. The rings were composed of biosoluble acacia gum or nonbiodegradable hydrogel of 2-hydroxyethyl methacrylate (HEMA) and sodium methacrylate (SMA) [P(HEMA-co-SMA)]. The rings were impregnated with nonhormonal contraceptives such as ferrous gluconate to cause spermiostasis, l-ascorbic acid to increase the viscosity of the cervical mucus, and pharmalytes of pH 4-5 or AZT.

Results: The daily release rate of nonhormonal contraceptives as well as AZT from the rings was efficacious in vitro. Cumulative effect of nonhormonal contraceptives showed complete spermiostasis within 30 s up to 10 and 28 days, respectively. Daily release of AZT from both rings was also likely to be efficacious to inhibit HIV proliferation in vitro for 10 and 28 days, respectively.

Conclusion: The data indicate that the rings described here can be developed for intravaginal delivery of nonhormonal contraceptives and/or anti-HIV agents.