Engineers at MIT have collaborated to develop a robotic drug delivery capsule that is specially designed to administer delicate protein drugs, such as insulin, through the wall of the intestine. Proteins are not suited for oral delivery, as they are typically destroyed by the low pH in the intestine and they can’t pass through the mucus layer that lines the gastrointestinal tract.
Protecting protein drugs from the acidic environment and providing a way to traverse this mucus layer is the goal behind this latest technology. The capsule can be loaded with the protein and then once swallowed it becomes activated by the low pH in the intestine. The capsule has a studded cap at one end that begins to spin, tunneling through the mucus until it reaches the epithelium and deposits its drug payload.
Patients with diabetes often require regular insulin injections. This is inconvenient and painful. An oral version of insulin would be very useful for such patients, but to date no-one has developed an effective means to achieve this. The acidic environment in the gut is particularly hostile for protein drugs, and the thick layer of mucus that is present in our intestines is a largely impenetrable barrier for intact proteins.
Enter the “RoboCap,” a robotic pill that can manually drill down through mucus in the gut to access the underlying epithelium, offering a means to deliver proteins orally. The capsule is approximately the size of a multivitamin, and it includes a reservoir at one end that contains the protein drug and a drilling mechanism at the other end. The spinning cap is powered by a small motor and it is studded to help brush away the mucus.
The entire capsule is covered in a gelatin coating that is broken down at a specific pH when it reaches the small intestine. This initiates the spinning cap to begin work, and once the capsule drills through the mucus layer and reaches the epithelium it releases the protein payload.
However, it is possible to fine-tune this gelatin coating so that it will break down at different pH levels, suggesting the system could be tailored to deliver drugs to other parts of the gastrotinestinal tract that have different levels of acidity, such as the stomach.
“What the RoboCap does is transiently displace the initial mucus barrier and then enhance absorption by maximizing the dispersion of the drug locally,” said Giovanni Traverso, one of the creators of the new robotic pill. “By combining all of these elements, we’re really maximizing our capacity to provide the optimal situation for the drug to be absorbed.”
Study in journal Science Robotics: RoboCap: Robotic mucus-clearing capsule for enhanced drug delivery in the gastrointestinal tract