Researchers have created dissolvable fibers that absorb anti-HIV drugs, which they say could be placed in a tampon applicator for insertion into the vagina minutes before sex, delivering the drugs to the user.
Image credit: University of Washington
More than 1.1 million Americans are living with HIV infection, and around 50,000 more people are infected every year. The infection is most commonly transmitted through sexual intercourse, meaning the race is on to find new methods of protection against the virus.
At present, those who are considered high-risk for HIV infection are prescribed daily pills called pre-exposure prophylaxis (PrEP) to protect against the virus.
But there have been advancements in topical HIV protection methods, mainly in the form of microbicides - gels or films containing HIV drugs than could be applied inside the vagina just before sex.
But the research team - led by Cameron Ball, a doctoral student in bioengineering at UW, and Kim Woodrow, an assistant professor of bioengineering - notes that such products have not performed well in clinical trials, mainly because women find them difficult to use.
They explain that in order for the gels to be effective just before sex, they must be applied in large doses, but leakage can occur if too much is applied. And the films, they say, can take at least 15 minutes to completely dissolve in the body.
But the team believes their new creation could offer much faster protection against HIV for women.
How were the dissolvable fibers created?
In a 2012 study published in PLOS One, the researchers first discovered that fibers created by electrospinning - a process that uses an electrical charge to pull tiny fibers from liquid - could be dissolved to release drugs.
In this latest study, recently published in the journal Antimicrobial Agents and Chemotherapy, the team finds that these fibers can hold concentrations of anti-HIV drugs 10 times higher than that of microbicides.
To create the fibers, the researchers dissolved a polymer - a large molecule - and combined it with a drug currently used to treat symptoms of HIV, called maraviroc. This created a substance syrupy in texture.
This substance was then electrically charged with a high-voltage generator before being passed through a syringe. The researchers explain that the electrical charge on the surface of the substance makes it form a long string from the syringe. This string then spins and accumulates on an electrically grounded surface.
Because maraviroc and other anti-HIV drugs are slow to absorb in the body, the researchers wanted to develop a method that speeds up the process, while still delivering high concentrations.
They explain that electrically spun fibers have large surface areas. Because of this, the researchers were able to develop sample fibers where almost 30% of their total mass was made up of the drug. By comparison, the researchers say that only around 3% of microbicides' mass consists of drugs.
The researchers then modified the ingredients in the fibers, allowing them to dissolve the drug in around 6 minutes, regardless of the drug concentration.
Commenting on their findings, Ball says:
"The effectiveness of an anti-HIV topical drug depends partially on high-enough dosages and quick release. We have achieved higher drug loading in our material such that you wouldn't need to insert a large amount of these fibers to deliver enough of the drug to be helpful."
Fibers could be incorporated with tampon applicator or vaginal ring
The researchers believe these fibers hold promise for faster HIV protection in women. They say they could be placed into a cardboard tampon applicator for easy insertion into the vagina, or even made into the shape of a vaginal ring just like those used for contraception.
"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," says Woodrow.
The team explains 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.
They note that the fibers can hold an array of anti-HIV drugs, and studies are currently underway to test their capabilities. Furthermore, the team are looking to create user-guided prototypes of the fibers and test their safety and effectiveness in animal models.
Earlier this year, Medical News Today reported on a study led by the Centers for Disease Control and Prevention (CDC), revealing the creation of a vaginal gel that could protect women against HIV hours after sex.