Vaginal microbicides are topical gels or creams inserted into the vagina.
[2] The ideal vaginal microbicide would have the following characteristics: provide protection against infection not require application at the time of intercourse not harm the natural tissue[3] As of 2009[update], not harming natural tissue was the most troublesome aspect of development.
[4] Several unrelated chemical mechanisms have been proposed for vaginal microbicides treating HIV.
[1] PRO 2000, carrageenan, and cellulose sulphate have been studied as microbicides to block HIV binding.
[1] One example of a tenofovir study is CAPRISA 004 in 2010, finding its use reduced HIV infection risk by 39% overall.