A ‘Microneedle’ Pill You Can Swallow Could Replace Insulin Shots

The pill passes through the stomach into the small intestine, where it opens to painlessly inject drugs into the bloodstream

X-ray images at top left show the drug-delivery capsule in the intestine, before and after the arms expand. At right, the arms are unfolded to reveal the microneedles. (Image courtesy of the researchers)
smithsonian.com

Nobody likes getting shots. But most of us only have to face needles occasionally, for a seasonal flu vaccine or routine blood test. People with some forms of diabetes, on the other hand, have to inject themselves with insulin two to four times a day just to stay alive.

A new kind of pill developed at MIT could change all that. The capsule is swallowed and passes through the stomach whole, then opens in the small intestine to reveal “microneedles” that attach to the intestine surface and deliver drugs to the bloodstream. This makes it possible to swallow protein drugs like insulin that would normally be destroyed by stomach acids.

“Needle administration of therapeutics can be painful, require training for correct administration, [and] be associated with needle stick injuries,” says Giovanni Traverso, a gastroenterologist and professor in MIT’s department of mechanical engineering, who helped lead the study recently published in the journal Nature Medicine.

There’s also a stigma associated with diseases that require injectable drugs, Traverso says, and this stigma can delay diagnosis. The pill would have none of these drawbacks.

The new capsule system passes through the acidic environment of the stomach unharmed thanks to a special polymer coating. As it enters the small intestine, the higher pH triggers a spring to push open the capsule, releasing a microneedle patch. The patch adheres to the intestinal walls and delivers drugs into the bloodstream via one-millimeter long needles. It then dissolves, passing harmlessly through the rest of the digestive tract. The small intestine is an ideal spot for drug delivery, since it has an enormous surface area—about the size of a tennis court—and lacks pain receptors.

The researchers have successfully delivered insulin to pigs using the microneedle capsules. The amount of insulin that reached the bloodstream was comparable to that of an injection. Working with the drug company Novo Nordisk, the team is continuing to test the system’s safety and efficacy in large animals, including dogs and pigs. They plan to move to human trials in the next two or three years.

The system “has the capacity to transform how we deliver peptides, proteins—including mono-clonal antibodies—and nucleic acids,” Traverso says. “This could change drug delivery science.”

The kind of protein drugs that could be transformed by the microneedle system include hormones, like those used in fertility treatments, antibodies, like those used to treat cancer and autoimmune disorders, enzymes used to treat genetic diseases, and many more.

“It’s a compelling paper,” says David Putnam, a professor of biomedical engineering and chemical and biomolecular engineering at Cornell University, who was not involved in the study, in a press release. “Delivering proteins is the holy grail of drug delivery. People have been trying to do it for decades.”

A diagnosis of diabetes or another life-altering illness will never be easy. But if the microneedle capsules are successful, it may be a bit less painful.

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