Carrageenan-Based Nonoxynol-9 Spermicides for Prevention of Sexually Transmitted Infections

Abstract

Carrageenan-based nonoxynol-9 (N-9)-containing formulations were developed in response to the concern that over the counter (OTC) spermicides may not protect people from HIV infection and other sexually transmitted pathogens. The goal of this study was to compare the efficacy of carrageenan-based formulations to OTC spermicides in protecting mice from infection by herpes simplex virus 2 (HSV-2). Mice were challenged with vaginal inoculation of HSV-2 after pretreatment with test formulations. Carrageenan-based formulations were significantly more effective than currently marketed spermicides containing the same amount of N-9. Efficacy was demonstrated over a wide pH range. The carrageenan-based formulations could be autoclaved without losing antiviral activity and remained active in the vagina for several hours. We conclude that carrageenan-based N-9 formulations are likely to provide a more significant degree of protection against HSV-2 and other enveloped viruses than current OTC spermicides while providing comparable spermicidal activity.