FHI - June 3, 1996

Microbicide Research Seeks "Safer Sex" -- June 3, 1996

RESEARCH TRIANGLE PARK, NC - Polysaccharides, buffer gels and a variety of plant and animal extracts are among promising candidates scientists are examining in a search for microbicides, a new class of chemical barriers that would protect people against sexually transmitted diseases (STDs).

Microbicides may also offer women better options for "safer sex," since these products would likely resemble the variety of existing spermicides women now use for contraception. Correct and consistent use of the latex condom is currently recommended as the best way of reducing the risk of AIDS and other STDs, but many women are unable to convince their partners to use condoms.

Ideal microbicides would be highly effective against a range of STDs, including HIV, the virus that causes AIDS. They would also be capable of being formulated with or without contraceptive properties, allowing women to become pregnant while being protected against disease. Existing spermicides, including the widely used nonoxynol-9 (N-9), offer some protection against such bacterial STDs as gonorrhea and chlamydia, but their effect on viral STDs, such as HIV, is uncertain.

"Because of the uncertainties about N-9, and the desire to have a microbicide without spermicidal [contraceptive] properties, developmental research is under way to discover new microbicides," Dr. Willard Cates Jr., FHI's corporate director of medical affairs, writes in an editorial in the current issue of Network, Family Health International's quarterly bulletin on reproductive health. Dr. Cates argues that people at high risk of STDs should be encouraged to used latex condoms consistently and correctly as their best defense against disease, while research and development efforts should focus on developing microbicides and other new barrier methods and should also examine whether formulations of N-9 or other existing spermicides can be used effectively for disease prevention.

Microbicide research cited in the magazine includes the following:

At the University of Pittsburgh, safety and efficacy trials will soon begin on microbicides containing lactobacilli, bacteria that occur naturally in the vagina. Lactobacilli produce hydrogen peroxide, which may prevent the spread of infections. The research will follow 900 women using lactobacilli suppositories for one year.
The New York-based Population Council is conducting safety trials among women using microbicides containing polysaccharides, substances that occur naturally in the human body that coat cells and connective tissue. Shown in laboratory studies to inhibit HIV, these polysaccharides may offer a microbicide that could coat the lining of the vagina with a film that repels HIV and HIV-infected cells.
Several organizations, including FHI, are working together to evaluate a buffer gel that would protect against HIV and other STDs. Similar to some of the gel agents found in shampoos and soaps, these products would maintain the level of acidity in the vagina, even in the presence of semen, which normally neutralizes the vagina's acidity. Many types of enveloped viruses, including HIV, are incapacitated by acidity.
Plant extracts, including cottonseed oil and a tropical tree called neem, are being investigated by the Brazil-based South to South Cooperation in Reproductive Health. Neem, for example, has been shown to have microbicidal properties.
Other substances under study include synthetic protegrins, small proteins found in white blood cells that have been shown to inactivate HIV and other STD organisms; C31G, a substance in mouthwash that is microbicidal; N-docosanol, an alcohol that blocks some enveloped viruses; squalamine, a steroid-based compound that may be effective against bacterial and viral STDs; and a modified version of beta-lactoglobulin, a protein found in the dairy product called whey.

The current issue of Network provides an overview of all barrier methods, the only contraceptives that protect against STDs. Other articles explore the need for consistent and correct use of barrier methods in order for them to be most effective, the role communication between partners can play in achieving better contraception and safer sex, and an article on STD protection steps that can be taken after intercourse.

A chart on the six types of barrier methods compares contraceptive effectiveness, effect on STDs and health concerns. The chart includes instructions on the correct use of the six methods: male condom, female condom, spermicides, diaphragm, sponge and cervical cap.

See Also:

Microbicide Research Seeks "Safer Sex" -- June 3, 1996