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Dissolvable Fabric Loaded With Medicine Could Protect Women From HIV
Bioengineers at the University of Washington have discovered a potentially faster way to deliver a topical drug that protects women from being infected with the human immunodeficiency virus (HIV). Their method spins the drug into silk-like fibers that quickly dissolve when in contact with moisture, releasing higher doses of the drug than is possible with other topical materials, such as gels or creams.
“This could offer women a potentially more effective, discreet way to protect themselves from HIV infection by inserting the drug-loaded materials into the vagina before sex,” said lead author Cameron Ball, a UW doctoral student.
The new research was published in the August issue of Antimicrobial Agents and Chemotherapy.
The investigators had previously found that electrically spun cloth could be dissolved to release drugs. The new findings build on that research, showing that the fiber materials can hold 10 times the concentration of medicine as anti-HIV gels currently under development.
Oral pills are used in the U.S. for people who are considered at risk for HIV infection, and topical medications in the form of gels and films are just starting to be developed. These products would be placed inside the vagina before sexual intercourse, allowing the drug to dissolve and diffuse into the surrounding tissue. Called microbicides, the drugs must be given as a large dose to be effective minutes before sex.
These topical drugs haven’t done well in clinical trials, partly because they aren’t always easy for women to use. Drugs in film form take at least 15 minutes to fully dissolve in the body, and the volume of gels must be large enough to deliver a full dose but small enough to prevent leakage. These factors can make microbicides difficult for women to use before sex, the researchers said.
The UW team created the soft fibers using a process called electrospinning. First, a polymer is dissolved and combined with the HIV drug maraviroc (Selzentry, ViiV Healthcare) and other agents, which help a material to become more water soluble and to dissolve more quickly.
The syrupy substance is then charged with a high-voltage generator and passed through a syringe. The electric charge on the substance’s surface causes it to form a long string from the syringe, where it whips around — or spins — before collecting on an electrically grounded surface. A palm-sized swatch of the fabric takes about 5 minutes to make.
Anti-HIV drugs, such as maraviroc, can take a while to dissolve, so the researchers looked at different ingredients for the fiber that would allow the highest concentration of drug with the fastest-possible release in the body. Because the electrically spun fibers have a large surface area, the researchers were able to create samples in which nearly 30% of the mass was composed of the drug itself. In topical gels, the drug makes up only about 3% of the total mass.
By adjusting the ingredients in the fibers, the researchers were able to dissolve the drug in about 6 minutes, regardless of how much drug mass was in the fiber.
The investigators say that the soft, dissolving fibers could be rolled into a cardboard tampon applicator for insertion or built into the shape of a vaginal ring, similar to those used for contraception. The material can accommodate different anti-HIV drugs, and the team is testing several others for effectiveness.
“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,” said lead investigator Dr. Kim Woodrow.
The research was funded by the National Institutes of Health.
Source: University of Washington; July 30, 2014.