instead of getting an injection. Unfortunately, many drugs, especially
those made from large proteins, cannot be given as a pill because they
get broken down in the stomach before they can be absorbed.
To help overcome that obstacle, researchers at MIT and Massachusetts
General Hospital (MGH) have devised a novel drug capsule coated with
tiny needles that can inject drugs directly into the lining of the
stomach after the capsule is swallowed. In animal studies, the team
found that the capsule delivered insulin more efficiently than
injection under the skin, and there were no harmful side effects as
the capsule passed through the digestive system.
"This could be a way that the patient can circumvent the need to have
an infusion or subcutaneous administration of a drug," says Giovanni
Traverso, a research fellow at MIT's Koch Institute for Integrative
Cancer Research, a gastroenterologist at MGH, and one of the lead
authors of the paper, which appears in the Journal of Pharmaceutical
Sciences.
Although the researchers tested their capsule with insulin, they
anticipate that it would be most useful for delivering
biopharmaceuticals such as antibodies, which are used to treat cancer
and autoimmune disorders like arthritis and Crohn's disease. This
class of drugs, known as "biologics," also includes vaccines,
recombinant DNA, and RNA.
"The large size of these biologic drugs makes them nonabsorbable. And
before they even would be absorbed, they're degraded in your GI tract
by acids and enzymes that just eat up the molecules and make them
inactive," says Carl Schoellhammer, a graduate student in chemical
engineering and a lead author of the paper.
Safe and effective delivery
Scientists have tried designing microparticles and nanoparticles that
can deliver biologics, but such particles are expensive to produce and
require a new version to be engineered for each drug.
Schoellhammer, Traverso, and their colleagues set out to design a
capsule that would serve as a platform for the delivery of a wide
range of therapeutics, prevent degradation of the drugs, and inject
the payload directly into the lining of the GI tract. Their prototype
acrylic capsule, 2 centimeters long and 1 centimeter in diameter,
includes a reservoir for the drug and is coated with hollow, stainless
steel needles about 5 millimeters long.
Previous studies of accidental ingestion of sharp objects in human
patients have suggested that it could be safe to swallow a capsule
coated with short needles. Because there are no pain receptors in the
GI tract, patients would not feel any pain from the drug injection.
To test whether this type of capsule could allow safe and effective
drug delivery, the researchers tested it in pigs, with insulin as the
drug payload. It took more than a week for the capsules to move
through the entire digestive tract, and the researchers found no
traces of tissue damage, supporting the potential safety of this novel
approach.
--Sciencedaily
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