MIT's new oral capsule injects insulin through microneedles
For people with type 2 diabetes, regular insulin injections are a part of everyday life, but that's not the most comfortable routine. Plenty of work has gone into developing an insulin pill as a less invasive alternative, but that comes with its own challenges. Now, an MIT team has created a new design for a capsule that houses a microneedle made of insulin, which injects the hormone through the stomach lining.
Delivering insulin orally might sound simple enough, given how common pills are for many medicines. But the stomach is a hostile environment, and the harsh acids there can neutralize many drug compounds before they can get to work. Unsurprisingly, much of the work in developing insulin pills has gone into protective coatings that help it survive the journey until it can deliver the insulin payload.
But the MIT researchers have taken a different approach. A few years ago the team created a pill coated in tiny needles, which injected medicine into the intestinal lining as it passed through. Now the design has been refined so it only has one needle, which injects the drug into the wall of the stomach.
The new capsule is roughly the size of a blueberry and is made of a biodegradable polymer. The mechanical components inside are quite complex: There's a microneedle made of freeze-dried insulin, and a stainless steel spring coiled up and held back by a disk made of sugar. When the sugar dissolves in the stomach acid, the spring flicks out and pushes the microneedle into the stomach lining.
Once the tip of the needle is inserted, the insulin dissolves into the bloodstream at a consistent rate – in this test that took about an hour, but the rate can be tweaked by the researchers. After the payload has been delivered, the capsule then passes through the digestive system harmlessly.
To make sure the needle comes in contact with the stomach wall and stays there, the capsule has a high, steep dome so it will always roll and come to rest on the flat side, where the needle pops out from. This design, the team says, was inspired by the leopard tortoise, which has a similar-shaped shell that lets it get back on its feet if it ever finds itself on its back.
The team tested the capsule in pigs, and found that it was effective at delivering up to 5 milligrams of insulin into the animals' bloodstreams. This is on a level comparable to the amount in a regular insulin shot.
The researchers say the tests show that the method could be an effective alternative to self-injections for insulin, as well as other treatments delivered the same way.
"We are really hopeful that this new type of capsule could someday help diabetic patients and perhaps anyone who requires therapies that can now only be given by injection or infusion," says Robert Langer, senior author of the study.
As promising as the capsule seems, it's far from the only method in development. Other oral insulin delivery systems are in the works, including a pill from Oramed that is currently in Phase 2b trials. If that works, its relative simplicity compared to the MIT capsule could see it being favored. Either way, it looks like the daily insulin injection is on its way out.
The research was published in the journal Science, and the team describes the capsule in detail in the video below.