Increased COX-2 expression in human vaginal epithelial cells exposed to nonoxynol-9, a vaginal contraceptive microbicide that failed to protect women from HIV-1 infection.

Problem: Despite displaying virucidal activity in vitro, nonoxynol-9 (N-9), a vaginal contraceptive microbicide candidate, failed to reduce the rate of human immunodeficiency virus (HIV) transmission in clinical trials. With frequent use, it even increased the risk of HIV acquisition. Such outcome was postulated to be because of N-9-induced mucosal inflammation, which resulted in recruitment of HIV-target immune cells to the sites of virus entry.