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

ObjectivesConstruction 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 MethodsIntravaginal 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.ResultsThe 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.ConclusionThe data indicate that the rings described here can be developed for intravaginal delivery of nonhormonal contraceptives and/or anti-HIV agents.