The activity of candidate virucidal agents, low pH and genital secretions against HIV-1 in vitro.

The effect of low pH, normally present in the female genital tract, on HIV viability was examined. HIV is more acid stable than previously reported with no substantial reduction in infectivity occurring until pH levels are reduced below 4.5. The virucidal activity of 3 topical spermicides and chlorhexidine was assessed in vitro using previously established and newly modified assay systems. None of the agents tested had a selectivity index (SI) greater than 5.2. Semen and cervical secretions were assessed for their ability to inhibit HIV-1. While no virucidal effect was found in the latter, seminal fluid was found to have significant activity against HIV-1 and a SI of approximately 50.