A new way to avoid the needle
A cleverly designed capsule could make it possible to swallow insulin and other drugs that normally have to be injected.
Many drugs cannot be taken orally because they break down in the gastrointestinal tract before they can take effect. One example is insulin, which patients with diabetes have to inject at least daily.
In search of an alternative, MIT engineers and scientists from Novo Nordisk have designed a capsule that can protect such drugs until they reach the small intestine, where they are injected by dissolvable microneedles. Institute Professor Robert Langer, a member of the Koch Institute for Integrative Cancer Research, and Giovanni Traverso, an assistant professor of mechanical engineering and a gastroenterologist at Brigham and Women’s Hospital, led the research, which was published in Nature Medicine.
The two have developed several novel strategies for oral delivery of drugs that usually have to be injected. In this case, the capsule is coated with a polymer that can survive the acidic environment of the stomach, which has a pH of 1.5 to 3.5. When it reaches the small intestine—where drugs are typically absorbed—the higher pH (around 6) triggers it to open, releasing three folded arms containing patches of millimeter-long needles. When the arms unfold, the force of their release allows the needles to penetrate the intestinal wall, which lacks pain receptors. As the needles dissolve and release their drugs, the arms break apart so they won’t block the intestine. In tests in pigs, the researchers showed that the 30-millimeter-long capsules delivered standard doses of insulin effectively and safely.
They believe the system could have various uses. “We can deliver insulin, but we see applications for many other therapeutics and possibly vaccines,” Traverso says.
