Insulin tablets go one step further

For millions of people with diabetes, insulin is a life-saving medicine
.
However, unlike many other drugs, insulin cannot be easily delivered by swallowing the pill, and it needs to be injected
under the skin with a syringe or pump.
Researchers have been working on insulin pills, and now they deliver insulin to the colons
of rats with an oral pill powered by a chemical "micromotor.
"

People with diabetes have a hard time regulating their blood sugar levels because they produce little or no insulin
.
Synthetic insulin has been around for more than a hundred years, but it is usually administered
by injection or implanted pump.
People with diabetes usually inject insulin multiple times a day, so frequent injections can be painful, and as a result, some patients do not take the recommended dose
at the right time.

The oral form of this drug is ideal, but before it is absorbed by the intestines and enters the bloodstream, the harsh environment of the stomach breaks down and neutralizes the hormones
.
Previous attempts to protect hormones from stomach acid by oral micro- or nanocarriers, but relied on passive diffusion of insulin into the cells lining the colon, which was not very effective
.
A better approach might be to actively move drugs through the body, such as a recently reported robotic capsule that delivers cargo
by burrowing into the thick mucosal layer of the small intestine.
Yingfeng Tu, Fei Peng, Liu Kun and colleagues hope to achieve a similar effect with their insulin minisheets, which feature tiny chemical "micromotors" that safely and efficiently deliver insulin to the colon.

To make the tablets, the researchers covered magnesium particles with a layer of insulin-containing solution and a layer of liposomes
.
They then mixed these pellets with baking soda, pressed into micro-tablets about 3 mm long, and then covered
them with an esterified starch solution.
Starch protects the tablets from stomach acid, allowing them to reach the colon
intact.
When they break down, the magnesium particles react with the water to create bubbles of hydrogen that act like micromotors that push insulin towards the colonic mucosa for absorption
.
The team also tested their mini-tablets on mice and found that they significantly lowered the animals' blood sugar levels for more than 5 hours
.
In fact, they can maintain glucose levels
that are almost as low as injectable insulin.
While more work needs to be done, the researchers say it's a concrete step
toward creating more oral formulations of traditional injectable drugs.