Single and multiple exposure tolerance study of polystyrene sulfonate gel: a phase I safety and colposcopy study.

Objectives: To evaluate symptoms and signs of genital irritation, vaginal leakage and acceptability of polystyrene sulfonate (PSS), which is being studied as a vaginal contraceptive and microbicide.

Methods: Forty-nine women applied 2.5 mL of either 5% PSS, 10% PSS, PSS vehicle, or Conceptrol (a marketed spermicidal product containing 4% nonoxynol-9) for 6 consecutive days.

Results: All women completed the study except one in the Conceptrol group who experienced vaginal symptoms after her first use and was discontinued. After both the first use and after all uses, irritation was seen among more women in the Conceptrol group than in the PSS groups, reaching statistical significance with regard to any evidence of irritation, signs of irritation and product-related irritation. There were no adverse events that were serious, unexpected and related to product use in any group. The 5% concentration of PSS may be preferable in terms of leakage and acceptability.

Conclusion: The results suggest that PSS has a safety profile comparable to that of the marketed nonoxynol-9 product, Conceptrol, and appears to be associated with less genital irritation.