Very soon it may be possible to gain protection from HIV infection by inserting a disappearing, medicated fabric a few minutes prior to having sex.
Bioengineers based at the University of Washington have discovered a potentially quicker method of delivering a topical drug which will protect women from contracting the HIV virus. The method they have devised spins the drug into the silk-like fibres which dissolve quickly when it comes into contact with moisture. It releases higher doses of the drug than what is obtained from using creams or gels.
The lead author of the study and doctoral student in bioengineering at UW, Cameron Ball, said this system could offer women a more effective, more discreet method of protection from HIV infection by inserting the drug-loaded material into the vagina prior to sex.
The team, led by assistant professor in bioengineering Kim Woodrow, previously discovered that cloth which has been spun electrically could dissolve to release the drugs. The new test results are based on that specific research, indicating that the materials are able to hold 10 times the concentration of medicine, compared to anti-HIV gels which are currently being developed.
In the US, oral pills are provided to those who are considered at risk of HIV infection, and topical medications, such as films and gels are in the early stages of development. The products should be placed inside the woman’s vagina prior to sexual intercourse, which allows the drug to dissolve and fuse into the surrounding tissue. The drugs, microbicides, have to be taken in a large dose to ensure effectiveness, minutes prior to sex.
However, the topical drugs have not been very successful during clinical trials. One of the reasons for this is that they are not easy to use. The drugs in film form take a minimum of 15 minutes to dissolve fully in the body and the volume has to be large enough to provide a full dosage, but small enough to not leak. This makes the microbicides extremely difficult to use.
Ball said that the effectiveness of a topical anti-HIV drug depends partially on quick release and high dosages. He said the team has achieved higher drug levels in the material used, which implies that the user will not need to insert a big amount of the fibres to deliver an adequate dosage.
The soft fibres were created by using a process called electrospinning. The process commenced by dissolving a polymer and combining it with a drug, maraviroc, and other agents used in pharmaceuticals that aid in allowing the material to become more water soluble and dissolve faster. Maraviroc is currently used to treat the symptoms of those who are already infected.
The substance was then charged with a high-voltage generator and pushed through a syringe. The charge on the surface of the substance makes it form a long string through the syringe where it spins and ultimately collects on an electrical surface. It takes around five minutes to make a palm-sized swatch of this fabric.
Due to the large surface area of the electrically spun fibres, the researchers were able to produce samples where 30% of the mass was made up of the drug itself. In topical gels, the drug makes up a mere 3% of its total mass.
The researchers were able to dissolve the drug in around six minutes, regardless of the drug mass in the fibre, simply by adjusting the fibre ingredients.
According to the researchers, the fibres could be rolled into a tampon applicator to make for easier insertion or shaped into a vaginal ring, similar to what is used for contraception. The material is able to hold different types of anti-HIV drugs and others are currently being tested for effectiveness.
The researchers are in the process of developing prototypes to allow for testing in animal models.
Image Credit: NIAID