Microbicides Fight AIDS

Duke researchers are addressing important unanswered questions about the effectiveness of proposed "topical microbicides" that when applied intravaginally would prevent sexually transmitted HIV viral infections.

Biomedical engineers will explore whether the virus-killing chemicals would reach the right tissues, adhere to them, and remain in place over time. Investigations into the biophysics of candidate topical microbicides are being led by David Katz in the Pratt School of Engineering. His laboratory's work is being supported by a new $2.3-million grant from the National Institutes of Health, as well as another $90,000 award from the American Foundation for AIDS Research.

Katz's microbicide research also is supported by grants from the Food and Drug Administration's Office of Women's Health and the Contraceptive Research and Development Program, the latter a nonprofit organization supported by the U.S. Agency for International Development, the Gates Foundation, and other sources. As part of the FDA grant, researchers from the FDA's Center for Drug Evaluation and Research are collaborating in the Duke studies.

There is need for such female-controlled prevention methods, says Katz, the Nello L. Teer Jr. Professor of Biomedical Engineering. The Centers for Disease Control estimates that between 120,000 and 160,000 adult and adolescent females in the United States now have AIDS-causing HIV infections, rates that have increased over the last decade. Most were infected by heterosexual exposure to HIV.

While researchers hope that women could someday shield themselves by applying such topical microbicides intravaginally, "objective, effective standards for evaluation of such proposed formulations do not yet exist," Katz says. His laboratory aims to address that deficit by developing a base of practical knowledge about candidate topical microbicides.

"Our methods also include theoretical applications of the laws of physics," says Katz, who is also a professor of obstetrics and gynecology at Duke Medical Center. "These mathematical exercises reveal particular relationships between properties of formulations and their deployment characteristics."

Human studies of microbicide formulations in the vagina are being conducted through a Duke Medical Center clinic, using an endoscope-like instrument built in Katz's lab. This instrument measures coating of the tissue surfaces, and detects bare spots of uncoated tissue that might be particularly vulnerable to infection, he says.