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12 Aug, 2014 23:03

Bioengineers develop dissolvable anti-HIV ‘tampon’

Bioengineers develop dissolvable anti-HIV ‘tampon’

Women may have a new ‘knight in shining armor’ in the search for protection against HIV: A team of bioengineers are developing a dissolvable ‘tampon’ that delivers HIV-preventing medication minutes before having sex.

Currently, women must rely on men wearing condoms to protect themselves from the virus. But there is a stigma against using condoms ‒ men say rubbers decrease their pleasure too much ‒ that often leaves women with the choice between not having intercourse and unprotected sex.

But now researchers at the University of Washington have published a preliminary study that uses fibers created by electrospinning ‒ a process that uses an electrical charge to pull tiny fibers from liquid ‒ in which they dissolve a polymer that contains a drug currently used to treat symptoms of HIV ‒ maraviroc ‒ directly into the walls of the vagina. The team explained that, when the fibers combine with moisture, they quickly hydrate and dissolve to create a gel. During sex, the gel would spread around the vagina, deliver the anti-HIV drug and protect against HIV.These fibers could be incorporated into a tampon-like applicator or a vaginal ring (similar to the NuvaRing, which delivers localized birth control hormones).

The product could be a leap forward in topically applied HIV protection methods, according to Medical News Today. Current advancements in microbicides have focused on gels or films containing HIV drugs that could be applied inside the vagina just before sex. But the research team points out those drugs haven’t done well in clinical trials because women find them difficult to use.

Topical microbicides require high drug doses for maximum efficacy. “The goal of achieving a high antiretroviral dose is complicated by the need to simultaneously retain the dose and quickly release drug compounds into the tissue,” the UW bioengineers said in their abstract.

“For drugs with limited solubility in vaginal gels, increasing the gel volume to increase the dose can result in leakage,” the team added. “While solid dosage forms like films and tablets increase retention, they often require more than 15 minutes to fully dissolve, potentially increasing the risk of inducing epithelial abrasions during sex.”

Studies in South Africa have already shown that using microbicide gels as PrEP, or pre-exposure prophylaxis, can reduce HIV transmission by about 54 percent, Healthline reported. The advantage of the tampon-like applicator is that the fibers retain a large amount of microbicides, yet dissolve quickly without leaking. The UW researchers were able to develop sample fibers where almost 30 percent of their total mass was made up of the drug. By comparison, the researchers say that only around 3 percent of current microbicides' mass consists of drugs.

"We envision a product that could dissolve, pretty much instantaneously, into a gel and then spread around the vagina during sex," Cameron Ball, lead author on the paper and a doctoral student in bioengineering at UW, told The Huffington Post.

"We want something that dissolves quickly so that people can say, 'Hey, I wasn't planning on it, but I'm going to have sex in five minutes so I need to use this product, and I want it to be completely dissolved before that’," he added.

Ball and his team are still looking for funding to continue their research. Their next step is to test the product on rabbits for safety and effectiveness, he told Healthline. The use of maraviroc saves them some time, as the drug has been approved by the US Food and Drug Administration. The polymer fibers are also widely used by the pharmaceutical industry already.

"It would probably take five years to get into a clinical study phase, with humans, and then depending on how that goes, it would probably take up to another five years before these types of things might be seen on the shelf of a local Walgreens or CVS," Ball told The Huffington Post.

But once that happens, he believes gynecologists and patients will quickly adopt the product. “Everyone gets excited when they hold it,” Ball told Healthline.

The eventual goal is to develop a tampon that would prevent against HIV, herpes and pregnancy. “This could prove especially useful in developing countries, where women may not have easy access to other kinds of birth control,” Healthline reported.

They are also working on a version of their product for rectal use, Ball said.

"We think the fiber platform technology has the capability of being developed into multifunctional medical fabrics that address, simultaneously, challenges related to biological efficacy and user preferences," Kim Woodrow, an assistant professor of bioengineering and an author of the study, told Medical News Today.