Pill coated with tiny needles can deliver drugs directly into the lining of the digestive tract
Researchers at Massachusetts Institute of Technology (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,' said 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 such as arthritis and Crohn’s disease.
For molecules that are particularly difficult to absorb, this would be a way of actually administering them at much higher efficiency
The team 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, 2cm in length and 1cm in diameter, includes a reservoir for the drug and is coated with hollow, stainless steel needles about 5mm long.
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.
They also found that the microneedles successfully injected insulin into the lining of the stomach, small intestine, and colon, causing the animals’ blood glucose levels to drop. This reduction in blood glucose was faster and larger than the drop seen when the same amount of glucose was given by subcutaneous injection.
'The kinetics are much better, and much faster-onset, than those seen with traditional under-the-skin administration,' says Traverso.
'For molecules that are particularly difficult to absorb, this would be a way of actually administering them at much higher efficiency.'
This approach could also be used to administer vaccines that normally have to be injected, the researchers say.
The research team now plans to modify the capsule so that contractions of the digestive tract would slowly squeeze the drug out of the capsule as it travels through the tract. They are also working on capsules with needles made of degradable polymers and sugar that would break off and become embedded in the gut lining, where they would slowly disintegrate and release the drug. This would further minimise any safety concerns.