Drug delivery has been one of the toughest breakthroughs in medical science, and there remain several barriers, which include surviving acidic regions in the stomach, digestive enzymes, and above all, the mucus barrier that lines the digestive tract. Researchers at the Massachusetts Institute of Technology (MIT) have found a novel way.
They have developed a robotic pill that could be used to orally administer large protein drugs such as insulin that consist of proteins or nucleic acids and are at the moment only injectable. RoboCap developed by MIT, has a robotic cap that tunnels through the mucus barrier after reaching the small intestine and allows the drugs to pass into cells lining the intestine.
The details of the pill have been published in a paper in Science Robotics led by Shriya Srinivasan, a research affiliate at MITs Koch Institute for Integrative Cancer Research.
Researchers have demonstrated that the unique pills could be used to deliver insulin as well as vancomycin, an antibiotic peptide that currently has to be injected. The team designed the protective capsule to overcome the challenges faced inside the body by spinning and tunneling its way through.
I thought that if we could tunnel through the mucus, then we could deposit the drug directly on the epithelium. The idea is that you would ingest this capsule and the outer layer would dissolve in the digestive tract, exposing all these features that start to churn through the mucus and clear it, Shriya Srinivasan, said in a statement.
About the size of a multivitamin, the pill contains the drug in a small reservoir at one end and the spinning feature at the other. The capsule is coated with gelatin that can be tuned to dissolve at a specific pH.
What the RoboCap does is transiently displace the initial mucus barrier and then enhance absorption by maximizing the dispersion of the drug locally. By combining all of these elements, were really maximizing our capacity to provide the optimal situation for the drug to be absorbed, Giovanni Traverso, who has been working in the field said.
As the capsule dissolves, researchers said that the change in pH triggers a tiny motor inside the RoboCap capsule, which is coated with small studs to brush the mucus away, starts spinning. The spinning motion also helps to erode the compartment that carries the drug, which is gradually released into the digestive tract.
The team has tested the robotic pill on animals to deliver either insulin or vancomycin and found that they could deliver 20 to 40 times more drug than a similar capsule without the tunneling mechanism. Once the drug is released, the capsule passes through the digestive tract on its own, with no side effects noted so far.
The team is hopeful that it could also be used to target the stomach or colon by changing the pH at which the gelatin coating dissolves.
