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Nanofiber vs. HIV
SAN DIEGO—The American Association of Pharmaceutical Scientists (AAPS) signaled what could be a breakthrough in fighting human immunodeficiency virus (HIV) infection when it announced that its 2014 AAPS Annual Meeting and Exposition in November would feature a research presentation related to the development of a novel topical microbicide loaded with hyaluronic acid (HA) nanofibers that could potentially prevent transmission of HIV through the vaginal mucosa.
HIV, the AAPS notes, is an infectious virus that attacks T lymphocytes, and over time, HIV dramatically depletes the body’s T cell population, leaving the body defenseless against opportunistic pathogens. Estimates are that some 1.2 million people aged 13 years and older are living with HIV infection in the United States alone, including more than 180,000 who are unaware that they have the virus. To date, of course, there is no functional cure for HIV infection or the condition AIDS that results from it. Currently available anti- HIV drug delivery methods are formulated as gels and suppositories, the AAPS notes, but can lack appropriate vaginal retention, are prone to medicine leakage and may cause uncomfortable wetness.
To address these issues, Dr. Bi-Botti Youan and his colleagues at the University of Missouri–Kansas City School of Pharmacy developed an anti-HIV drug loaded onto a mucoadhesive hyaluronic acid (HA) nanofiber delivery system. The idea behind this delivery system is that it will offer a “triggered release” upon exposure to semen fluid during sexual intercourse, thus preventing HIV transmission through the vaginal mucosa.
As the AAPS describes the study conducted at the University of Missouri, the researchers used an electrospinning method to prepare the nanofibers loaded with tenofovir, a topical anti-HIV compound. Both semen enzyme-dependent nanofiber degradation and drug release were then measured using chemical and analytical assays. The cytotoxic effects of the nanofibers on human vaginal cells and on the Lactobacilli bacteria present in vaginal flora were also assessed.
“The success of vaginal drug delivery systems depends on the length of time that the drug- containing formulation remains at the site of administration,” according to Youan. “The mucoadhesive nanofibers developed in this study could be beneficial by causing much less discomfort and reducing the dosing frequency simultaneously due to their prolonged retention at the target site.”
As the AAPS notes, “The nanofiber-based formulation offers various potential advantages in vaginal drug delivery, including the ability to adapt delivery systems for different medical needs, with no leakage or messiness after their application. Furthermore, this technology could be beneficial in protecting drug molecules against enzymatic and other degradation that can occur in the body. Since human semen is the carrier of HIV virus transmission during male-to-female intercourse, a semen enzyme-triggered nanofiber delivery system as used in this study has the potential to inactivate or kill the HIV virus prior to exposure and penetration of the vaginal mucosa.”
The next step for Youan and his colleagues is to assess the safety and efficacy of the HA-based nanofiber templates, and they will conduct in- vivo studies using animal models to characterize the viral transmission, inhibition, potential biodistribution, pharmacokinetics, vaginal retention time, safety and immunological responses to the nanofibers.