Poly(sodium 4-styrene sulfonate): Evaluation of a topical microbicide gel against herpes simplex virus type 2 and Chlamydia trachomatis infections in mice

Objective. To investigate the in vivo activity of poly(sodium 4-styrene sulfonate) (T-PSS) gel formulations as topical microbicides. Methods. The ability of the gel formulations to reduce the incidence of infection when applied prior to pathogen challenge was examined in mouse models of vaginal herpes simplex type 2 (HSV-2) and Chlamydia trachomatis infection, and rectal HSV-2 infection. Results. In the vaginal HSV-2 challenge studies, 10% T-PSS gel provided significant protection against infection, even when administered 60 min prior to virus challenge (P < 0.0001). Both 5% and 10% T-PSS gel formulations significantly reduced the incidence of upper genital tract C. trachomatis infection in animals treated up to 5 min before challenge (P < 0.001). However, no protection against C. trachomatis infection was seen in animals treated 30 min before challenge. In mice challenged rectally with HSV-2, both the 5% and 10% T-PSS gels significantly reduced infection at 20 s (P < 0.01 for both). However, only the 10% gel provided significant protection when administered 5 min before challenge (P < 0.01). Conclusions. T-PSS gel formulations have promising in vivo activity as topical microbicides.