classes of anti-retroviral drugs that attack HIV 1 at various points in the viral replication cycle could be useful additions to the microbicide development pipeline. The reduced genital tract of women constitutes Ibrutinib price an important site for HIV invasion. For that reason, prevention of natural infection will be a important landmark in minimizing the global AIDS epidemic. While male condoms are very effective at stopping vaginal human immunodeficiency virus transmission, girls are frequently not empowered to negotiate their use by their sexual partners or may object to their use due to sociocultural norms or the want to conceive. The most reliable long term method of HIV prevention is a vaccine, since it would confer protection, but a successful HIV 1 vaccine is unlikely to emerge in the near future. Hence, alternative strategies are urgently required to slow the spread of HIV. Systemic anti-viral preexposure prophylaxis and vaginally or rectally provided as preventive tools topical microbicides are getting increased attention. Thus far, polyanion external microbicides, pHbuffering, and only soap have completed testing in large scale clinical trials. With one recently described potential exception, none of those nonspecific microbicides has demonstrated a protective effect against vaginal HIV transmission. An increased risk of HIV transmission was indeed noted for the soap nonoxynol 9. These disappointing Endosymbiotic theory results have experienced two major effects on the microbicide industry. . First, efforts have increased to develop and standardize pre-clinical and animal testing types with high predictive power for medical microbicide efficacy. The effective use of these models in appropriate screening formulas must have the capability to screen out compounds such as cellulose sulfate before they enter stage II and III clinical trials. Second, the emphasis has shifted to materials with certain antiretroviral activity. Like, the reverse transcriptase inhibitors tenofovir, that is currently used to treat HIV infection, and dapivirine CX-4945 price are currently entering as prophylactic vaginal gel formulations in phase III efficacy trials and phase IIb screening. There are concerns, nevertheless, the usage of as microbicides RTIs might boost the spread of HIV 1 resistance. They include more HIV certain fusion and entry inhibitors some of which may have already demonstrated protection of macaques from transmission of simian human immunodeficiency virus as well as integrase inhibitors. Recently, enhanced animal models using humanized and macaques rats have now been developed which could become a part of a consistent go/no go decision algorithm for candidate microbicides under development. But, these animal models have drawbacks.