HomeNews Insulin pill could replace injections for diabetes
Insulin pill could replace injections for diabetes
Written by University of Texas at Austin
Thursday, 01 May 2008
Insulin pills to replace the injections necessary for those
suffering from diabetes appear closer to reality through new research by
chemical and biomedical engineers at The University of Texas at
Austin.
The breakthrough addresses the problem of
pills surviving stomach acids to later deposit their contents in the opposing
alkaline environment of the small intestine. The chemical answer: place the
insulin in a polymer hydrogel sensitive to these changes in pH levels, according
to Dr. Nicholas Peppas, professor of biomedical engineering, chemical
engineering and pharmaceutics at the university.
His newly developed gel
can quickly transport insulin through stomach acids and then actually linger in
the small intestine where insulin needs to be ingested.
When the insulin
travels through the stomach's acids, the insulin-loaded gel expands and protects
its precious contents. After safe passage to the small intestine's alkaline
surroundings, the pill not only shrinks and releases insulin, but attaches to
the intestinal wall so its contents releases for the extended period necessary
to maintain consistently healthy blood sugar levels.
Peppas, a National
Academy of Engineering member who has spent the past 10 years studying this
problem, revealed his discovery in the April 14 issue of the American Chemical
Society's monthly peer-reviewed journal, Biomacromolecules.
According
to the American Diabetes Association, 20.8 million children and adults in the
country, or 7 percent of the population, have diabetes and the number continues
to rise.
Previous work by Peppas had demonstrated the effectiveness of
the hydrogel barrier of molecules methylacrylic acid and polyethylene glycol
(PEG) linked to form a porous polymer network and securely hold insulin inside.
But once the insulin safely arrived at its destination, it passed too quickly
from the small intestine to provide sufficient insulin into the bloodstream.
Peppas' addition of a form of the popular health food, wheat germ
agglutinin, converted the hydrogel's stealth quality among stomach acids into a
lingering characteristic among the higher pH alkaline intestine.
"We
successfully increased the hydrogel's ability to attach to the upper intestinal
tract for 10 hours," Peppas said. "In that time, most insulin that is released
hopefully would pass into the intestinal wall and go into the blood."
