BY JOSEPH GUSTAITIS | FEBRUARY 17, 2023
It was exactly 100 years ago that two Canadian physicians shared the Nobel Prize In Medicine for the discovery of insulin. Since then it has proven to be a wonder drug. Before it, a diagnosis of diabetes was essentially a death sentence. Today, diabetes patients can live for many decades.
But there’s a catch. The standard way of administering insulin is through injections under the skin (or infusions via insulin pump) and many people just don’t like the process, which can bring along with it side effects such as injection pain, needle phobia, small areas of fat loss (lipodystrophy), an excess of insulin in the blood (hyperinsulinemia). One of the main problems for health care providers who treat diabetes is that some patients may not keep to their injection schedule because of needle phobia, pain, or the way in which an injection regimen impacts on their lives.
The obvious solution to the drawbacks of injected insulin would be a pill — an oral medication. The main obstacle to the development of one, however, has been that the acids in the stomach destroy insulin before it can enter the bloodstream through the small intestine and the colon. Other chemicals, like pepsin in the stomach and trypsin in the duodenum, also damage or destroy insulin.
Oral insulin progress
In a paper just published in the American Chemical Society’s journal ACS Nano, however, a team of scientists from several research facilities in China report that they have developed what they called “a mini-tablet system based on self-propelled micromotors” for the oral administration of insulin. Yingfeng Tu, Fei Peng, Kun Liu, and colleagues began the process by electrostatically coating tiny particles of magnesium with a solution containing insulin and liposomes, which are small spherical pouches that are able to encapsulate drugs for delivery in the body.
They then mixed these particles with baking soda and formed them into mini-tablets about 3 millimeters long (about one-tenth of an inch). They then coated the tablets with a starch solution that protected them on their journey through the acidic environment of the stomach and into the small intestines. During this journey the tiny magnesium particles reacted with water, which caused the release of hydrogen gas bubbles. These bubbles acted as “micromotors” that drove the insulin into the lining of the colon, where it was absorbed into the bloodstream. The starch coating, according to the researchers, had “colonic degradation capability” (meaning it was able to break down in the environment of the colon).
Insulin pills found to lower blood sugar in rats
When the research team tested their tablets on rats, they observed that the rodents’ blood sugar levels were substantially reduced for more than five hours. In addition, the blood sugar levels achieved by the micromotor-based tablets were almost as low as those achieved by injected insulin. A lot of work remains to be done to make the technology available for humans, but the researchers wrote, “Our micromotor based mini-tablet system can not only broaden the biomedical applications of emerging self-propelled micromotors but also offer an appealing strategy for oral administration of biomacromolecular drugs represented by insulin.”
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