Colposcopic evaluation of a vaginal gel formulation of iota-carrageenan

Abstract

There is an urgent need to develop safe, effective, and acceptable vaginal products for the prevention of sexually transmitted infections. Preliminary in vitro results suggest that vaginal formulations of sulfated polysaccharides, including iota-carrageenan, have the potential to block mucosal transmission of human immunodeficiency virus (HIV). Twenty-five women in five sites participated in Phase I trials to evaluate the safety of a formulation containing iota-carrageenan (PC 213). The results of this study indicate that a 5 mL 2% gel formulation of iota-carrageenan is not associated with significant irritation of the female reproductive tract when administered once daily in the absence of sexual intercourse. Given the small number of participants in this initial study, careful observation for potential irritation must also be included in larger studies of this and other vaginal formulations.

PIP: Preliminary in vitro results suggest that vaginal formulations of sulfated polysaccharides have the potential to block mucosal HIV transmission. Reported in this paper are the results of a 1995 Phase I trial of the safety of a formulation containing 2% iota-carrageenan (PC 213). Enrolled were 25 women at 5 sites (Australia, Chile, Dominican Republic, Finland, and US). Study participants self-administered 5 ml of PC 213 gel intravaginally for 7 days, during which time they abstained from sexual intercourse. 18 women had completely normal colposcopic examinations both at baseline and at 1 week of follow-up. 3 of the 4 women who had signs of minor cervical irritation at baseline had normal exams after product use. Colposcopy indicated new cervical or vaginal lesions after PC 213 use in 3 women, but only 1 such case (cervical erythema) could be attributed to product use. Participants considered the product easy to apply, not messy, and easily disposable. Both the safety and acceptability of this preparation should be re-examined in larger populations and under conditions of use during sexual intercourse.