Vaginal fluid simulant at pH 4.5, 5.5 or 6.5 has little effect on inhibition of HIV-1 by the compounds (a). Inhibition of HIV-1US657 by compound INP0149 is shown, and similar results were obtained with compounds INP0161, INP0341, and INP0400. Similarly, combined vaginal (pH 4.5) and semen (pH 7.7) simulants at a 1:1 vol/vol ratio (b) have little effect on compound activity. Horizontal dotted line indicates 50% virus inhibition.