Vaccine-delivery patch
Researchers from Emory University and the Georgia Institute of Technology have developed a new vaccine-delivery patch that could allow persons without medical training to painlessly administer vaccines – while providing improved immunization against diseases such as influenza.
The vaccine-delivery patch consists of an array of 100 needles. Each needle is 650 microns in length. These needles are arranged on a water-soluble backing. Pressed into the skin, the microneedles quickly dissolve in bodily fluids, leaving only the water-soluble backing. The backing can be discarded because it no longer contains any sharps.
The microneedle arrays were made from a polymer material, poly-vinyl pyrrolidone, that has been shown to be safe for use in the body. Freeze-dried vaccine is mixed with the vinyl-pyrrolidone monomer before being placed into microneedle molds and polymerized at room temperature using ultraviolet light.
In their study, one group of mice received the influenza vaccine using traditional hypodermic needles injecting into muscle; another group received the vaccine through dissolving microneedles applied to the skin, while a control group had microneedle patches containing no vaccine applied to their skin. When infected with influenza virus 30 days later, both groups that had received the vaccine remained healthy while mice in the control group contracted the disease and died.
Three months after vaccination, the researchers also exposed a different group of immunized mice to flu virus and found that animals vaccinated with microneedles appeared to have a better “recall” response to the virus and thus were able to clear the virus from their lungs more effectively than those that received vaccine with hypodermic needles. At present the researchers are not clear as to why vaccine delivery with dissolving microneedles has shown to provide better protection.
According to the researchers, though the study examined only the administration of flu vaccine with the dissolving microneedles, the technique should be useful for other immunizations. If mass-produced, the microneedle patches are expected to cost about the same as conventional needle-and-syringe techniques, and may lower the overall cost of immunization programs by reducing personnel costs and waste disposal requirements.
One of the researchers, Mark Prausnitz, a professor in the Georgia Tech School of Chemical and Biomolecular Engineering, said “In this study, we have shown that a dissolving microneedle patch can vaccinate against influenza at least as well, and probably better than, a traditional hypodermic needle. The dissolving microneedle patch could open up many new doors for immunization programs by eliminating the need for trained personnel to carry out the vaccination. This approach could make a significant impact because it could enable self-administration as well as simplify vaccination programs in schools and assisted living facilities.”
Ioanna Skountzou, an Emory University assistant professor, said “Another advantage of these microneedles is that the vaccine is present as a dry formulation, which will enhance its stability during distribution and storage.”
Sean Sullivan, the study’s lead author from Georgia Tech. said “We envision people getting the patch in the mail or at a pharmacy and then self administering it at home. Because the microneedles on the patch dissolve away into the skin, there would be no dangerous sharp needles left over.”
However, to assure safety and effectiveness, clinical studies will have to be done before dissolving microneedles can be made widely available.
Other members of the researcfh team included Jeong-Woo Lee, Vladimir Zarnitsyn, Seong-O Choi and Niren Murthy from Georgia Tech, and Dimitrios Koutsonanos and Maria del Pilar Martin from Emory University.
Source: http://gtresearchnews.gatech.edu/dissolving-microneedles-patch/
July 19, 2010