|Researcher Shiyi Zhang with the ring-shaped device and the capsule within which it fits--Courtesy of MIT|
The gastrointestinal tract is notoriously difficult as a means for long-acting drug delivery--it expels its contents over a matter of hours, so getting any pill to stay in there longer than that is a challenge. To retain medication over a longer period, researchers at MIT and Massachusetts General Hospital have designed an expanding pill that can be easily swallowed but can remain in the stomach potentially for months without obstructing normal gastrointestinal function.
The scientists used an elastic ring that could be folded into a pill-sized polymer coating. When it enters the stomach, the polymer dissolves, leaving the ring to expand, unable to leave the stomach with the rest of the stomach contents but also, because of its shape, not obstructing the opening. In animal tests, the ring expanded within 15 minutes and remained in the stomach for up to 7 days. The ring is designed to break down naturally over time and pass through the rest of the gastrointestinal tract in small pieces, causing no harm to the intestines.
"One of the issues with any device in the GI tract is that there's the potential for an obstruction, which is a medical emergency potentially requiring surgical intervention," MGH researcher Giovanni Traverso said in a statement. "A material like this represents a real advance because it is both safe and stable in the stomach environment."
The team published its results in the journal Nature Materials.
Down the road, these pills could be used for a number of functions, including extended-release drug delivery for months after a single administration, bariatric devices for obesity or diagnostic devices to detect GI conditions.
MIT has entered an exclusive license agreement with the biotech Lyndra, which also works on oral drug delivery systems. MIT professor and entrepreneur Robert Langer founded Lyndra and is a co-author on the paper, which was led by MIT postdoc Shiyi Zhang.
"I'm delighted to see these new oral systems provide an opportunity that I've not seen previously," Langer said in a statement, "enabling patients to swallow a single pill that can then act for whatever length of time is desired."