Shampoo Ingredient Stops HIV
Sept. 19, 2000 (Toronto) -- A common toothpaste and shampoo ingredient may one day help control the spread of AIDS. The compound -- sodium lauryl sulfate (SLS) -- throws a monkey wrench into the machinery HIV, the virus that causes AIDS, uses to infect cells in the body. It offers hope for a cheap, effective way for women to protect themselves against HIV and other sexually transmitted diseases (STDs) when applied inside the vagina.
World health officials have long asked researchers to develop a safe, inexpensive way for women to protect themselves against HIV and STDs. In many parts of the world severely affected by AIDS, cultural barriers do not allow women to participate in sexual decision-making. "The issue is that women cannot always negotiate the use of condoms," biologist Jocelyne Piret, PhD, tells WebMD. "This would be a way for women to protect themselves."
Piret and co-workers at Laval University in Quebec City were experimenting with SLS as a way to use a herpes drug on the skin. "I saw that mice treated with SLS alone survived [herpes simplex virus] infection," she tells WebMD. "So I thought this might be something to decrease the infectivity of viruses."
In new experiments reported here at a meeting of infectious disease experts, Piret announced that SLS makes HIV noninfectious -- in the test tube.
The researchers have created an SLS formula they plan to test this fall in humans to see if it's safe. "The formulation is liquid at room temperature and becomes a gel at body temperature so it will stay in place," Piret says. "We have specially designed a syringe-like applicator to distribute the gel to the cervix and vagina."
Tests in rabbits show the SLS gel is safe when administered once a day for 14 days. "It causes mild irritation, but well within the range of acceptability," Piret says.
A major African study of the spermicide nonoxynol-9 -- which kills HIV very efficiently -- recently showed that the compound irritates the vagina. For women who used nonoxynol-9 every day, this irritation actually increased their risk of HIV infection.
Like nonoxynol-9, SLS is a detergent-like compound. There are differences -- which Piret and colleagues think will make SLS work better than nonoxynol-9. Others are not so sure. "I think SLS is very similar to nonoxynol-9, but not exactly the same," biochemist Hung Cong Vo, PhD, tells WebMD. Vo is developing a similar product for Viridae Clinical Sciences Inc.
Piret's team currently is evaluating the activity of SLS against other STDs, including chlamydia, gonorrhea, and syphilis. The researchers are also exploring the use of another, SLS-like substance used in soaps. Early studies suggest that it may have similar success, Piret says.