Are Microneedles the Key to Oral Biologic Delivery?

The fact that biologic drugs are typically infused or injected poses numerous challenges, including discomfort for patients, instability under some storage conditions, and the generation of needle waste. Researchers have long sought a way to deliver biologics orally, and some teams have even reported progress toward the goal of delivering monoclonal antibodies in coated tablet forms. Now, researchers have reported in Nature Medicine that a luminal unfolding microneedle injector could be a feasible delivery device for delivering drugs like insulin.

The researchers, in a study funded by Novo Nordisk and the National Institutes of Health, developed a capsule that can carry insulin—and potentially other biologics—into the small intestine, where the capsule breaks down to reveal dissolvable microneedles on 3 folded arms. These needles attach to the intestinal wall and release the drug.

To allow the capsule to reach the small intestine, the researchers coated it with a polymer that can withstand stomach acidity until it reaches a pH of approximately 6.

Each of the arms, which are designed to break apart in order to reduce the risk of intestinal blockage, is covered with patches of 1 mm microneedles that are able to penetrate the topmost layer of the small intestine before they release the drug and dissolve.

In ex vivo human studies and in vivo swine studies, the capsule was demonstrated to load a comparable amount of insulin into test subjects as an injection would, allowing for fast uptake into the bloodstream; in the insulin tests, when the capsule was activated, the injector provided faster pharmacokinetic uptake than a subcutaneous injection over a 4-hour period.

In swine, no blockages formed in the intestine, and the capsule’s arms were safely excreted.

"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," said Robert Langer, ScD, the David H. Koch Institute Professor at the Massachusetts Institute of Technology (MIT) and a member of the Koch Institute for Integrative Cancer Research, in a statement.

Giovanni Traverso, PhD, assistant professor in MIT's Department of Mechanical Engineering and gastroenterologist at Brigham and Women's Hospital, added that "We can deliver insulin, but we see applications for many other therapeutics and possibly vaccines," Traverso says. "We're working very closely with our collaborators to identify the next steps and applications where we can have the greatest impact."

Reference

Abramson A, Caffarel-Salvador E, Soares V, et al. A luminal unfolding microneedle injector for oral delivery of macromolecules. Nat Med. 2019;25:1512-1518. doi: 10.1038/s41591-019-0598-9.