Scientists levitate liquid in order to develop better pharmaceuticals
September 16, 2012
In a new development which on first glance resembles a storyline plucked from the pages of Harry Potter, researchers at the U.S. Department of Energy’s (DOE) Argonne National Laboratory, Illinois, have adopted a system of levitation in order to more effectively develop pharmaceuticals - no magic wand required.
At the molecular level, pharmaceutical structures can be placed into one of two categories: amorphous or crystalline. Amorphous drugs have a higher bioavailability than their counterpart, which means they require a smaller dose of drug to lend the same benefits, while potentially resulting in fewer harmful side effects. Unfortunately, due to the difficulty of producing amorphous pharmaceuticals, most drugs on the market are crystalline.
“One of the biggest challenges when it comes to drug development is in reducing the amount of the drug needed to attain the therapeutic benefit, whatever it is,” explained Argonne X-ray physicist Chris Benmore, who led the study.
The inherent difficulties of moving pharmaceuticals from liquid solution into an amorphous state presented the researchers with a major headache: if the pharmaceutical solution evaporates while it is in contact with part of a vessel, it is far more likely to solidify in its crystalline form. “It’s almost as if these substances want to find a way to become crystalline,” said Benmore. To overcome this problem, the scientist utilized an acoustic levitator - a piece of equipment originally developed for NASA to simulate microgravity conditions.
The acoustic levitator uses two small speakers, one placed above the other, to generate sound waves at frequencies which reside slightly above the audible range: roughly 22 kilohertz. When correctly aligned, they create two sets of sound waves which perfectly interfere with each other, producing a phenomenon known as a standing wave. Because the pressure from the sound waves is sufficient to cancel the effect of gravity, very light objects are able to levitate when placed at key points within the wave.
At present, only small quantities of a drug can be “amorphized” using the levitating technique. However, the researchers see that the acoustic levitator as a powerful tool for understanding the conditions which make for the best amorphous preparation.
The Argonne National Laboratory researchers have already investigated over a dozen different pharmaceuticals using the technique, and the laboratory’s Technology Development and Commercialization Division is currently pursuing a patent for the method.
The short video below shows the acoustic levitator in action.
Source: Argonne National Laboratory
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