New hope raised for OTC antiviral lubricants
Three sexual lubricants destroy HIV in vitro
After the disastrous findings involving nonoxynol-9 and its use as an antiviral vaginal lubrication, clinicians may have been tempted to think there was very little possibility of finding a spermicide that could kill HIV-infected cells. However, the possibility of finding a safe and effective antiviral lubricant was given new life by a recently published study by researchers at the University of Texas Medical Branch (UTMB) at Galveston. Investigators found in test-tube experiments that three over-the-counter sexual lubricants inhibited HIV production by more than a thousandfold when studied in vitro.
"We screened 22 of these preparations, and using two to three criteria we brought it down to three from different companies that would have this protective effect," says Samuel Baron, MD, professor of microbiology/immunology at UTMB. "We mimicked an in vivo situation by using seminal fluid with HIV-infected cells in the fluid or HIV free virus," Baron explains.
By layering the lubricants on HIV-infected white blood cells, investigators were able to reduce viral output by more than 30 times. When the lubricants were mixed with HIV-infected cells, the viral output was reduced by more than one thousand times. The three lubricants found to meet all criteria also are in the Food and Drug Administration’s safest category for such products, Baron says.
Lesions permitted HIV transmission
The problem with the spermicide nonoxynol-9, which also showed potent antiviral capabilities in vitro, was that it irritated mucous membranes of the vagina and rectum. That caused lesions that permitted transmission of HIV from seminal fluid, which led to higher rates of HIV infection among one study’s participants who used the product, Baron says.
UTMB investigators theorized that if a product designed to be used in the vagina or anus during intercourse could be found that would not irritate skin, then perhaps it still could successfully block HIV transmission. "We needed a similarly highly active material against HIV without any of the irritating properties, so we did a simple study trying to identify all the lubricants that had various preservatives and surfactants and materials that make them slippery and potentially as potent as nonoxynol-9," Baron explains.
The lubricants, sold as Astroglide, Silken Secret, and Vagisil, significantly reduced viral output when mixed with HIV-infected cells, according to a study published in AIDS Research and Human Retroviruses on July 20, 2001. "Our report is to point out that there is a very high potential for these materials, which have already been tested and distributed throughout the world," Baron says. "They’re potentially very inexpensive and deserving of a field trial like the one nonoxynol-9 had, and we’re trying to arrange that with various government agencies, which isn’t easy."
The Texas researchers also have contacted international health organizations about the potential benefits of studying these products.
Poor nations could benefit greatly
Future published papers will address which of the three lubricants’ chemical components were potent against HIV. This information would enable poor nations to make the same products for a fraction of the current cost of supplying such products, Baron says. "No one is advocating avoiding condoms, because condoms are clearly the best way to go, but the addition of a lubricant which has additional supplemental activity would likely enhance the protection of condoms," Baron says.
Also, because the three lubricants found to have effective antiviral qualities can be purchased by anyone, and because they are considered by the FDA to be in the safest category of any lubricants sold in the United States, then there is ample reason for physicians to let patients know that, in addition to a condom, these three lubricants may provide protection against HIV transmission, Baron adds.
While a field trial still is needed to prove whether these lubricants will reduce HIV transmission among at-risk populations, it may not be necessary for at-risk individuals to wait until all studies are complete before adding the use of these products to their safer sex practices.