Scientists are to begin trials to test how vaginal gels could be used by women to prevent the spread of HIV.

Currently the gels, known as microbicides, only contain one of two antiretrovirals (ARVs) – drugs which work against the virus.

For the first time a gel containing both ARVs will be trialled for internal application.

If the gels are found to be successful they could offer an effective method of protection for women who may not be able to get men they have sex with to use a condom, and could be especially important to people in developing countries where HIV is a major problem.

The 24 volunteers aged between 18 and 50 will be monitored to assess how safe the gel is, how long the active ingredients stay in the vagina and whether they are absorbed into the bloodstream, the research team said.

Laboratory-based culture tests on genital tract samples will also be undertaken to determine whether the ARVs would be capable of neutralising and blocking the replication of HIV in the cervical cell lining.

The two ARVs are known as Dapivirine and Darunavir. Dapivirine has been used in a previous successful clinical trial while Darunavir has been widely used as an oral tablet to treat people with the virus.

The research is being carried out by scientists at the University of York in conjunction with the York Clinical Research Facility.

Heather Hilliard, of the research team at the York Clinical Research Facility at York Hospital, said: “Throughout the world the most common way in which HIV spreads is through sexual intercourse between men and women.

“Although condoms are effective in preventing the transmission of HIV, it is not always possible for a woman to get her partner to agree to use them. Therefore, there is an urgent need for other methods of protection that can be used by women.”