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ShareAug. 4, 1999 — Writer: Aaron Hoover
Sources: Jim Talton, (352) 846-2730, jtalt@ufl.edu
Rajiv Singh, 392-1032, rsing@mse.ufl.edu
Guenther Hochhaus, 846-2727, hochhaus@cop.health.ufl.edu
GAINESVILLE, Fla. --- People who suffer from asthma won't have to breathe into inhalers repeatedly throughout the day -- or worry about harmful side effects of asthma drugs -- if a University of Florida-developed coating proves as successful in humans as it has in rats.
The coating, developed by team of researchers in UF's colleges of pharmacy and engineering, covers tiny drug particles contained in many asthma inhalers with a polymer 1,000 times thinner than a human hair. The coated drugs need several hours to dissolve, reducing the need for frequent inhaler use and minimizing unintended, potentially harmful, release of the drugs into the blood stream.
"Pharmacists prefer drugs that patients only have to take once a day, because they tend to forget to take them at times other than the morning or evening," said Guenther Hochhaus, a UF professor of pharmaceutics. "This drug coating not only makes that possible, it also appears to have significant impact on the lung with no systemic, or reduced systemic, effects."
The process was developed after professors and graduate students in pharmacy and materials science and engineering decided to put their expertise together to come up with better asthma drugs. The professors are Hochhaus and Rajiv Singh, a professor of materials science and engineering. The others are Jim Fitz-Gerald, a materials science and engineering doctoral student who graduated last year, and Jim Talton, a graduate student in pharmacy who will receive his doctorate this month. Research related to the project was funded in part by UF's Engineering Research Center for Particle Science and Technology.
Asthma afflicts 14.6 million people nationally and causes more than 5,600 deaths annually, according to the American Lung Association. The chronic disease is the most common in children, with about a third of all asthma patients under the age of 18.
Many asthma drugs now on the market are effective in alleviating the symptoms of the disease, which results from inflammation of the airways, Hochhaus said. But the drugs, known as glucocorticoids, are a form of steroid that can have serious side effects, including inhibiting growth in children, hypertension and suppression of the immune system.
The side effects don't result from the action of the drugs on the lung but rather from their absorption through the lung tissue into the blood stream, they said. So the researchers set out to create a coating that would eliminate or reduce the side effect.
The challenges were numerous. For one thing, the coating had to be nontoxic. For another, it had to dissolve in four to six hours, or the lungs' natural cleaning process would move the drug particles from the lungs to the throat, where they would be ingested. The coating also would have to cover each microscopic particle evenly.
The researchers solved the puzzle through modifying a technique called pulsed laser deposition that Singh helped pioneer about a decade ago. Singh, a world expert on the technique who has authored some 150 papers about it, said it is used to make extremely thin coatings on flat surfaces in semiconductor processing. He and the others modified it to shoot a biodegradable polymer with a very high energy laser beam into a chamber containing suspended drug particles. The entire process takes less than an hour.
"The material basically evaporates," Singh said. "It shoots out like a little jet in a shock wave and coats the drug particles."
Talton said the polymer-coated drugs performed well in laboratory tests as well as in testing in rats. Although the polymer coating will require extensive testing in humans before it is approved for the marketplace, it is similar to the material used in dissolvable sutures for closing internal wounds, Talton said. He said he is confident the coating will prove benign, and the coated drugs could reach the market in well under a decade.
"We've done cell cultures and testing in rats, and this coating is fine," he said.
The researchers have applied for several patents on the technology, Talton said. They also have formed a company, Gainesville-based Nanocoat Technologies, and will seek to further develop and license the technology, he said.
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