Researchers at MIT have developed a new drug capsule that consists of a robotic cap that allows the delivery of drugs to the gut without the need for injections
Presently, large protein drugs cannot be administered orally as these drugs cannot pass through the mucus barrier that lines the digestive tract. Hence, insulin and other biological drugs are injected or administered at the hospital. To avoid this, researchers have developed a unique drug capsule that consists of a robotic cap that spins and tunnels through the mucus barrier when it reaches the small intestine. This mechanism allows the drugs carried by the capsule to pass into cells lining the intestine. The researchers showed how they could implement this approach to deliver insulin as well as vancomycin, an antibiotic peptide that currently has to be injected.
“By displacing the mucus, we can maximize the dispersion of the drug within a local area and enhance the absorption of both small molecules and macromolecules,” says Giovanni Traverso, the Karl van Tassel Career Development Assistant Professor of Mechanical Engineering at MIT and a gastroenterologist at Brigham and Women’s Hospital.
Shriya Srinivasan, a research affiliate at MIT’s Koch Institute for Integrative Cancer Research and a junior fellow at the Society of Fellows at Harvard University, is the study’s lead author. “I thought that if we could tunnel through the mucus, then we could deposit the drug directly on the epithelium,” she says. “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.”
The “RoboCap” capsule is about the size of a multivitamin. It carries a drug payload in a small reservoir at one end and consists of the tunneling features in its main body and surface. The capsule is coated with gelatin that can be calibrated to dissolve at a specific pH. When the coating dissolves, the change in pH triggers a tiny motor inside the RoboCap capsule to start spinning. This motion helps the capsule to tunnel into the mucus and displace it. The capsule is also coated with small studs that brush mucus away similar to the action of a toothbrush. The spinning motion also helps to erode the compartment that carries the drug, which is gradually released into the digestive tract.
The researchers experimented with this capsule to deliver either insulin or vancomycin, a large peptide antibiotic that is used to treat a broad range of infections, including skin infections as well as infections affecting orthopedic implants. With the capsule, the researchers found that they could deliver 20 to 40 times more drugs than a similar capsule without the tunneling mechanism. Once the drug is released from the capsule, the capsule itself passes through the digestive tract on its own. The researchers found no sign of inflammation or irritation in the digestive tract after the capsule passed through, and they also observed that the mucus layer reforms within a few hours after being displaced by the capsule
The team envisions utilizing this drug capsule to target the stomach or colon by changing the pH at which the gelatin coating dissolves.
Click here for the Published Research Paper