Women someday could protect themselves against sexually transmitted infections by using a gel that uses nanoparticles to deliver drugs to the vaginal walls, a new study in mice suggests.

Researchers used the gel to deliver an anti-herpes drug to the mice and found that the technology tripled the level of protection that the drug normally provides against aherpes infection.

It's possible the gel's protection could be made to be long-lasting, so it could be applied hours before sexual intercourse, according to the study, which appears today (June 13) in the journal Science Translational Medicine.

If the gel is found fit for human use, the composition of the gel makes it likely that a woman could use it discreetly, without her partner noticing it, the researchers added.

To see just how much the nanoparticle delivery system improved a drug's effectiveness, the researchers purposefully chose an anti-herpes medication that was not particularly effective, and a strain of herpes virus that was remarkably infectious.

"We could protect animals fairly well, with a wimpy drug, against a strong herpes infection," said study researcher Justin Hanes, director of the Center for Nanomedicine at the John Hopkins School of Medicine.

The research has yet to be tried in people, and rodent studies often don't hold up in humans. Under ideal circumstances, clinical trials of the gel could be possible within a year or two, Hanes said.

The trick to developing the gel was making the particles small enough and slick enough to get through the mucus that coats the inside of the vagina. Hanes likened the problem to a bug trying to fly through a spider web.

"There could be a bug that's small enough to fit through a spider web, but that doesn't mean it will get through without getting stuck," he said. But with small, "non-sticky" nanoparticles, the drug was evenly applied across nearly 100 percent of the vaginal surface a feat given the vagina's complex, folding walls, Hanes said.

When they applied the anti-herpesdrug to mice, the researchers found that the drug's effectiveness in preventing herpes increased from 16 percent without the nanoparticles, to 53 percent with the nanoparticles.

Originally posted here:
STDs blocked by nano gel, study suggests