Engineers at MIT have developed a pill that reports when it has been swallowed via a biodegradable antenna. The system is designed to work with existing medications and could help track adherence to drug regimens among high-risk patients. The corresponding study was published in Nature Communications.
Each year, poor adherence to medication contributes to hundreds of thousands of preventable deaths worldwide. To overcome this problem, in previous research, scientists developed drug delivery capsules that stay in the digestive system for extended periods to release medication at scheduled intervals.
"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,” study author Giovanni Traverso, an associate professor of mechanical engineering at MIT, said in a press release.
“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?” he added.
In the current study, Traverso and colleagues tried a different approach- to confirm whether or not the pill has been taken. To do so, they designed a system that included a tiny antenna made of zinc that emits a radio signal embedded within a cellulose particle. The cellulose-coated antenna was then rolled into a compact shape and placed inside the pill alongside the medication.
The pill capsule is made out of gelatin coated in cellulose and either molybdenum or tungsten, preventing radiofrequency from being emitted before the pill is swallowed. When swallowed, the coating dissolves, releasing the medication as well as the antenna.
At this point, the antenna receives a signal from the external readers and, via a small RF chip, confirms that the pill has been swallowed. The exchange takes place within 10 minutes. Unlike the antenna, the RF chip is not biodegradable; however is designed to pass safely through the digestive tract.
"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," said study author, Mehmet Girayhan Say, an MIT research scientist, in a press release.
"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,” he added.
The system successfully transmitted signals from inside the stomach to an external receiver up to two feet away in animal tests. If adapted for humans, the researchers imagine pairing the pill with a wearable device that could relay data to patients’ healthcare team.
The researchers are planning further preclinical studies and hope to begin testing the technology on people soon. Patients who have undergone organ transplantation are among those who could benefit most from the technology, as missing doses of immunosuppressive medication can quickly lead to organ rejection.
Sources: Science Daily, Nature Communications