In an advance that could help ensure people are taking their medication on schedule, MIT engineers have designed a pill that can report when it has been swallowed.The new reporting system, which can be incorporated into existing pill capsules, contains a biodegradable radio frequency antenna. After it sends out the signal that the pill has been consumed, most components break down in the stomach while a tiny RF chip passes out of the body through the digestive tract.This type of system could be useful for monitoring transplant patients who need to take immunosuppressive drugs, or people with infections such as HIV or TB, who need treatment for an extended period of time, the researchers say.“The goal is to make sure that this helps people receive the therapy they need to help maximize their health,” says Giovanni Traverso, an associate professor of mechanical engineering at MIT, a gastroenterologist at Brigham and Women’s Hospital, and an associate member of the Broad Institute of MIT and Harvard.Traverso is the senior author of the new study, which appears today in Nature Communications. Mehmet Girayhan Say, an MIT research scientist, and Sean You, a former MIT postdoc, are the lead authors of the paper.A pill that communicatesPatients’ failure to take their medicine as prescribed is a major challenge that contributes to hundreds of thousands of preventable deaths and billions of dollars in health care costs annually.To make it easier for people to take their medication, Traverso’s lab has worked on delivery capsules that can remain in the digestive tract for days or weeks, releasing doses at predetermined times. However, this approach may not be compatible with all drugs.“We’ve developed systems that can stay in the body for a long time, and we know that those systems can improve adherence, but we also recognize that for certain medications, we can’t change the pill,” Traverso says. “The question becomes: What else can we do to help the person and help their health care providers ensure that they’re receiving the medication?”In their new study, the researchers focused on a strategy that would allow doctors to more closely monitor whether patients are taking their medication. Using radio frequency — a type of signal that can be easily detected from outside the body and is safe for humans — they designed a capsule that can communicate after the patient has swallowed it.There have been previous efforts to develop RF-based signaling devices for medication capsules, but those were all made from components that don’t break down easily in the body and would need to travel through the digestive system.To minimize the potential risk of any blockage of the GI tract, the MIT team decided to create an RF-based system that would be bioresorbable, meaning that it can be broken down and absorbed by the body. The antenna that sends out the RF signal is made from zinc, and it is embedded into a cellulose particle.“We chose these materials recognizing their very favorable safety profiles and also environmental compatibility,” Traverso says.The zinc-cellulose antenna is rolled up and placed inside a capsule along with the drug to be delivered. The outer layer of the capsule is made from gelatin coated with a layer of cellulose and either molybdenum or tungsten, which blocks any RF signal from being emitted.Once the capsule is swallowed, the coating breaks down, releasing the drug along with the RF antenna. The antenna can then pick up an RF signal sent from an external receiver and, working with a small RF chip, sends back a signal to confirm that the capsule was swallowed. This communication happens within 10 minutes of the pill being swallowed.The RF chip, which is about 400 by 400 micrometers, is an off-the-shelf chip that is not biodegradable and would need to be excreted through the digestive tract. All of the other components would break down in the stomach within a week.“The components are designed to break down over days using materials with well-established safety profiles, such as zinc and cellulose, which are already widely used in medicine,” Say says. “Our goal is to avoid long-term accumulation while enabling reliable confirmation that a pill was taken, and longer-term safety will continue to be evaluated as the technology moves toward clinical use.”Promoting adherenceTests in an animal model showed that the RF signal was successfully transmitted from inside the stomach and could be read by an external receiver at a distance up to 2 feet away. If developed for use in humans, the researchers envision designing a wearable device that could receive the signal and then transmit it to the patient’s health care team.The researchers now plan to do further preclinical studies and hope to soon test the system in humans. One patient population that could benefit greatly from this type of monitoring is people who have recently had organ transplants and need to take immunosuppressant drugs to make sure their body doesn’t reject the new organ.“We want to prioritize medications that, when non-adherence is present, could have a really detrimental effect for the individual,” Traverso says.Other populations that could benefit include people who have recently had a stent inserted and need to take medication to help prevent blockage of the stent, people with chronic infectious diseases such as tuberculosis, and people with neuropsychiatric disorders whose conditions may impair their ability to take their medication.The research was funded by Novo Nordisk, MIT’s Department of Mechanical Engineering, the Division of Gastroenterology at Brigham and Women’s Hospital, and the U.S. Advanced Research Projects Agency for Health (ARPA-H), which notes that the views and conclusions contained in this article are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the United States Government.
