Many drugs can’t be taken orally because they are broken down in the gastrointestinal tract before they can take effect. Insulin, for example, which diabetes patients have to inject daily. Engineers from the Massachusetts Institute of Technology (MIT have designed a new drug capsule that can carry insulin or other protein drugs and protect them from the gastrointestinal tract.
When the capsule reaches the small intestine, it breaks down to reveal dissolvable 1-millimeter-long microneedles that attach to the intestinal wall and release drugs into the bloodstream.
Giovanni Traverso, one of the study’s lead authors, said: “A lot of this work is motivated by the recognition that both patients and health care providers prefer the oral route of administration over the injectable one.”
Most drugs are absorbed through the small intestine, Traverso says, in part because of its extremely large surface area (250 square meters, or about the size of a tennis court). His team previously developed several novel strategies for oral delivery of drugs that usually have to be injected. Those efforts include a pill coated with many tiny needles, as well as star-shaped structures that unfold and can remain in the stomach from days to weeks while releasing drugs.
In tests carried out on pigs, the researchers showed that this capsule could load a comparable amount of insulin to that of an injection, enabling fast uptake into the bloodstream after the release of microneedles. To allow their capsule to reach the small intestine and perform these micro-injections, the researchers coated it with a polymer that can survive the acidic environment of the stomach. The tests showed that the capsules could deliver doses of insulin effectively and generate an immediate blood-glucose-lowering response. They also showed that no blockages formed in the intestine and the arms were excreted safely after applying the microneedle patches.
Robert Langer, Institute Professor at MIT, said: “We are really 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.”