Purdue University researchers, in findings to be discussed Aug. 26 during a national meeting of the American Chemical Society, have demonstrated that the method works in a chemical environment that mimics the stomach and upper small intestine.
The method might be used to treat insulin-dependent diabetes and other conditions for which medicines, such as insulin, currently cannot be administered orally because they are broken down in the acidic environment of the stomach.
To get around this complication, the engineers have made microscopic particles for drug delivery about a millionth of a meter in diameter, or roughly one-hundredth the width of a human hair. The particles protect medicines from the harsh environment of the stomach until they can be released in the intestines and absorbed into the blood.
In the most recent lab experiments, and in animal research, when the particles enter the less-acidic environment of the upper small intestine they expand and use chemical tethers to latch onto "mucosal" areas and cells that line the intestine.
The tethers serve two roles: They help prevent stomach enzymes from breaking down the particles. And once the particles enter the intestines, the tethers keep the particles anchored long enough for the medication to be released into the upper small intestine, where the medication is absorbed by capillaries into the blood.
"If we don't have these 'anchors' to stick in the upper small intestine and hold the particles for a little while, they will pass through and the medication will never release in the upper small intestine," said Nicholas A. Peppas, Purdue's Showalter Distinguished Professor of Chemical and Biomedical Engineering.
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Contact: Emil Venere
venere@purdue.edu
765-494-4709
Purdue University
26-Aug-2001