Biomedical engineering researchers at The University of Texas at
Austin report development of a gel-like material that could help
speed the long-awaited arrival of insulin that can be taken in a
pill by mouth, rather than with injections. The study appears in
the April 14 issue of the American Chemical Society's Biomacromolecules,
a monthly journal.
In the report, Nicholas A. Peppas, professor of chemical engineering,
biomedical engineering and
pharmaceutics at the university, and
colleagues point out acid
in the stomach destroys insulin, preventing its administration by
mouth. Many different research groups worldwide are searching for
ways to overcome that obstacle. However, an ideal material for safe,
effective oral delivery remains elusive.
The new study describes a promising candidate in the form of a
polymer hydrogel that responds to changes in pH levels. This hydrogel
has been modified by the addition of wheat germ agglutinin tethers,
or anchors, that allow it to interact with the lining of the upper
small intestine. In laboratory tests, the gel-like substance containing
insulin expands in the acidic environment of the stomach and protects
the drug from destruction by stomach acids. Upon exposure to the
alkaline environment of the small intestine, the site of insulin
absorption, the polymer shrinks and releases insulin. The addition
of wheat germ agglutinin, a type of sticky plant sugar, allows the
polymer to stick to the small intestine for prolonged periods. This
improves the duration of insulin absorption, the researchers say. — from the
American Chemical Society
