Original research article Postcoital testing after the use of a bio-adhesive acid buffering gel (ACIDFORM) and a 2% nonoxynol-9 product Eliana Amaral a, * , Antero Perdiga ˜o b , Maria Helena Souza b , Christine Mauck c , Donald Waller d , Lourens Zaneveld e , Anibal Fau ´ ndes a,b a Department of Obstetrics and Gynecology, UNICAMP, Caixa Postal 6181, Campinas, SP CEP: 13.084-971, Brazil b Centro de Pesquisas Materno-Infantis de Campinas/CEMICAMP, P.O. Box 6181, 13084-971, Brazil c CONRAD, Arlington, VA, USA d University of Illinois, Chicago, IL, USA e Rush University, Chicago, IL, USA Received 6 February 2004; revised 10 May 2004; accepted 9 June 2004 Abstract ACIDFORM is a gel already shown to be safe in vaginal use during six consecutive days through colposcopic observation. A randomized, blinded, crossover study was carried out to compare the spermicidal effect of ACIDFORM to that of a commercial 2% nonoxynol-9 (N-9) product. Twenty sexually active, sterilized women, aged 19–45 years, with regular cycles, normal gynecological exam, no previous sexually transmitted infection (STI) and stable partner willing to undergo four postcoital tests (PCTs) at midcycle during four different menstrual cycles, were enrolled in the study. Known allergy to N-9 or ACIDFORM, oligospermic partner, chronic diseases, use of hormones, previous treatment for STI or presence of STI at screening tests were criteria for exclusion. ACIDFORM or N-9 product administered 0 – 30 min precoitus or ACIDFORM given 8 – 10 h precoitus significantly reduced the mean number of progressively motile sperm compared to control cycles (0.19, 0.07, 0.75 vs. 17.94, respectively, p b .05, Wilcoxon test). All treated cycles had five or fewer progressively motile sperm in midcycle cervical mucus, confirming in vivo the spermicidal effect of ACIDFORM previously observed in vitro and in animal models. D 2004 Elsevier Inc. All rights reserved. Keywords: ACIDFORM; Nonoxynol-9; Postcoital test; Spermicide; Microbicide; Randomized trial 1. Introduction Studies have been undertaken to develop chemical substances that can be applied to the vagina or rectum for the primary prevention of sexually transmitted infections (STIs) including HIV, and which also have a spermicidal effect [1–5]. Nonoxynol-9 (N-9) was the natural candidate, but its performance as a spermicidal, bactericidal and virucidal agent has been disappointing [6–9]. Recent metaanalysis including over to 5000 women showed no risk reduction for HIV, gonorrhea, chlamydia, trichomoni- asis, bacterial vaginosis (BV) and candidiasis when N-9 was used as prophylaxis [10]. In addition, studies also have shown that N-9 causes irritation to the vaginal and cervical epithelium, particularly after frequent use [10 –13]. Other compounds based their spermicidal effect on their capacity to maintain an acidic pH of the vagina [14]. Spermatozoa are completely immobilized at pH 5.0 and below, but partial immobilization already occurs between pH 5.0 and 6.0 [15–18]. After becoming immobilized by acidification, spermatozoa can regain motility when pH is restored to normal [19]. An acidic pH is also effective against HIV and herpes simplex in vitro [20 –22]. It inhibits the appearance of chlamydia inclusions in McCoy cell cultures [23] and causes inactivation of gonococci [24], Gardnerella and various BV- associated organisms [25], as well as Treponema pallidum and Haemophilus ducreyi in culture [26,27]. In preliminary studies using the mouse model, BufferGel, an acidic vaginal gel, was reported to be completely protective against rectal and vaginal herpes infections and was reported to provide significant protection against skin transmission of papilloma virus (CRPV) [28]. 0010-7824/$ – see front matter D 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.contraception.2004.06.007 * Corresponding author. Tel.: +55 19 3289 2856; fax: +55 19 3289 2440. E-mail address: elianaa@unicamp.br (E. Amaral). Contraception 70 (2004) 492 – 497