A pH-responsive polymer gel could create swallowable
devices, including capsules for ultra-long drug delivery.
(July 28, 2015) Medical
devices designed to reside in the stomach have a variety of applications,
including prolonged drug delivery, electronic monitoring, and weight-loss
intervention. However, these devices, often created with nondegradable elastic
polymers, bear an inherent risk of intestinal obstruction as a result of
accidental fracture or migration. As such, they are usually designed to remain
in the stomach for a limited time.
Now, researchers at MIT’s Koch Institute for Integrative
Cancer Research and Massachusetts General Hospital (MGH) have created a polymer
gel that overcomes this safety concern and could allow for the development of
long-acting devices that reside in the stomach, including orally delivered
capsules that can release drugs over a number of days, weeks, or potentially
months following a single administration.
This polymer is pH-responsive: It is stable in the acidic
stomach environment but dissolves in the small intestine’s near-neutral pH,
allowing for safe passage through the remainder of the gastrointestinal (GI)
tract. The material is also elastic, allowing for the compression and folding
of devices into easily ingestible capsules — meaning this polymer can be used
to create safe devices designed for extremely prolonged residence in the
stomach.
“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,” says Koch Institute research
affiliate Giovanni Traverso, also a gastroenterologist at MGH and an instructor
at Harvard Medical School. “A material like this represents a real advance
because it is both safe and stable in the stomach environment.”