This project will conduct a series of in vitro experimental and computational studies related to the vaginal and rectal distributions, and delivery of microbicide drugs, by prototype gels and suppositories. Results of these studies will be shared with Projects 1 - 5 of the parent Project, and related to results obtained in each of them. The goal of these studies is to evaluate the performances of the test microbicide products during several phases of prototype development, screening, and selection for further development. In particular, this project will provide specialized results and their interpretations that guide the optimal physical properties of the test gels and suppositories and volumes at which they are applied, to the vagina and to the rectum.