Background: A number of prevention opportunities exist for the sexual transmission of HIV. Antiretroviral drugs are used for post-exposure prophylaxis (PEP) and treatment of the index case, and are currently being studied for pre-exposure prophylaxis (PrEP). In all cases, the challenge is to deliver the appropriate concentration of drug to the correct anatomic site for the proper duration to prevent HIV-infection while avoiding forcing resistance.

Conclusions: Understanding pharmacologic compartmentalization can inform clinical trials for optimal selection of drug, dose, and dosing frequency, and to provide biologic plausibility to the interpretation of such trials. In this presentation, current fluid, tissue, and cellular drug exposure data available for animals and humans in the settings of PrEP, PEP, and treatment of the index case will be reviewed, in addition to the challenges investigators face in generating such data.