An Army medical researcher at the Brooke Army Medical Center is reported to have developed a potential vaccine carrier that may be able to extend the shelf life of stockpiled vaccines.
The researcher will present his findings on Sunday at the Experimental Biology 2012 meeting in San Diego. U.S. Army Major Jean M. Muderhwa. Muderhwa created the solution, and says the microemulsion he has developed can act as a stable candidate for delivering antigens and preventing degradation for long periods of time.
The composition of the clear, isotropic liquid is a mixture of oil, water, glycerol, surfactants span 80 and tween 60, and also includes a protein that is commonly used in vaccines to boost the immune system's positive response to antigens.
"There is a synergy here," Muderhwa said. "What I found is a composition that is transparent, is liquid and that has been sitting there (on my shelf) for six months without degrading".
The composition, when compared to emulsions commonly found in creams applied topically, contains particles that are smaller than usual. It is this property that the researcher believes can contribute to prolonging the life of the vaccine carrier and prevent quick degradation -- with the promise of changing how we can stockpile essential vaccines in the future.
"If I were to make an emulsion (of oil and water), which is just a cream and white, that emulsion would separate within weeks," he said. "If you make a vaccine containing an emulsion, it's only (good for) probably a few months because the emulsion is not thermodynamically stable."
Due to the higher amount of molecules found in most emulsions, heightened surface tension results in components repelling each other until the composition degrades and fails. If the research proves promising, then vaccines could be stockpiled and preserved for longer -- the microemulsion would keep surface tension to a minimum -- therefore ensuring vaccine separation remains in prolonged stasis until it is required.
"There is a need (for new vaccine carriers like this) especially if we want to stockpile a vaccine.
The (U.S. Agency for International Development) and FDA are responsible for stocking, for example, the influenza vaccine in the case of epidemic. They have to deliver them as quickly as possible. So if you have a vaccine just sitting on the shelf for more than 10 or 20 years, you don't have to worry about its stability."
The researcher is hopeful that planned animal studies will show the full potential of the microemulsion, and it could potentially change how vaccines are preserved and stockpiled.
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