The researchers have developed an oral capsule that can deliver insulin and other drugs, that usually have to be injected to the lining of the small intestine and release them for uptake into the bloodstream.
According to the study published in the journal ‘Nature Medicine’, many drugs, especially those made of proteins, cannot be taken orally because they are broken down in the gastrointestinal tract before they can take effect. One such example is insulin, which patients with diabetes have to inject daily or even more frequently. To solve this issue, the researchers at Massachusetts Institute of Technology (MIT), working with scientists from Danish pharmaceutical company Novo Nordisk, have designed a new drug capsule that can carry insulin or other protein drugs and protect them from the harsh environment of the gastrointestinal tract. It breaks down to reveal dissolvable microneedles that attach to the intestinal wall and release drug for uptake into the bloodstream.
Researchers showed that, in tests in pigs, this capsule could load a comparable amount of insulin to that of an injection, enabling fast uptake into the bloodstream after the microneedles were released.
“We are pleased with the latest results of the new oral delivery device our lab members have developed with our collaborators, and we look forward to hopefully seeing it help people with diabetes and others in the future,” said Robert Langer, a professor at MIT.
Earlier this year, they developed a blueberry-sized capsule containing a small needle made of compressed insulin. Upon reaching the stomach, the needle injects the drug into the stomach lining.
Most of the drugs are absorbed through the small intestine. According to Giovanni Traverso, an assistant professor at MIT, this is because of its extremely large surface area 250 square metres, or about the size of a tennis court. He noted that pain receptors are lacking in this part of the body, potentially enabling pain-free micro-injections in the small intestine for delivery of drugs like insulin. The researchers coated it with a polymer that can survive the acidic environment of the stomach, which has a pH of 1.5 to 3.5 to allow their capsule to reach the small intestine and perform these micro-injections. When the capsule reaches the small intestine, the higher pH triggers it to break open, and three folded arms inside the capsule spring open. Each arm contains patches of one-millimetre-long microneedles that can carry insulin or other drugs.
When the arms unfold open, the force of their release allows the tiny microneedles to just penetrate the topmost layer of the small intestine tissue. After insertion, the needles dissolve and release the drug.
The researchers have performed numerous safety tests on animal and human tissues to ensure that the penetration event allowed for drug delivery without causing a full-thickness perforation or any other serious adverse events.

Source: ET Healthworld, Times of India, Nature Medicine.