Smart pills eliminate the need for invasive procedures: wireless communication allows the transmission of real-time information; advances in batteries and on-board memory make them useful for long-term sensing from within the body. In the long term, smart pills are expected to be an integral component of remote patient monitoring and telemedicine.
The term “smart pills” refers to miniature electronic devices that are shaped and designed in the mold of pharmaceutical capsules but perform highly advanced functions such as sensing, imaging and drug delivery. They may include biosensors or image, pH or chemical sensors. Once they are swallowed, they travel along the gastrointestinal tract to capture information that is otherwise difficult to obtain, and then are easily eliminated from the system. Their classification as ingestible sensors makes them distinct from implantable or wearable sensors.
The U.S. Centers for Disease Control and Prevention estimates that gastrointestinal diseases affect between 60 and 70 million Americans every year. This translates into tens of millions of endoscopy procedures. Millions of colonoscopy procedures are also performed to diagnose or screen for colorectal cancers. Conventional, rigid scopes used for these procedures are uncomfortable for patients and may cause internal bruising or lead to infection because of reuse on different patients. Smart pills eliminate the need for invasive procedures: wireless communication allows the transmission of real-time information; advances in batteries and on-board memory make them useful for long-term sensing from within the body. The key application areas of smart pills are discussed below.
Diagnostic Imaging
Smart pills have revolutionized the diagnosis of gastrointestinal disorders and could replace conventional diagnostic techniques such as endoscopy. Traditionally, an endoscopy probe is inserted into a patient’s esophagus, and subsequently the upper and lower gastrointestinal tract, for diagnostic purposes. There is a risk of perforation or tearing of the esophageal lining, and the patient faces discomfort during and after the procedure. A smart pill or wireless capsule endoscopy (WCE), however, can easily be swallowed and maneuvered to capture images, and requires minimal patient preparation, such as sedation. The built-in sensors allow the measurement of all fluids and gases in the gut, giving the physician a multidimensional picture of the human body.
Minnesota-based Medtronic offers a U.S. Food and Drug Administration (FDA)-cleared smart pill called PillCam COLON, which provides clear visualization of the colon and is complementary to colonoscopy. It is an alternative for patients who refuse invasive colon exams, have bleeding or sedation risks or inflammatory bowel disease, or have had a previous incomplete colonoscopy. PillCam COLON allows more people to get screened for colorectal cancer with a minimally invasive, radiation-free option. The research focus for WCEs is on effective localization, steering and control of capsules. Device development relies on leveraging applied science and technologies for better system performance, rather than completely reengineering the pill.
Vital Sign Monitoring
Core body temperature, local pH and internal pressure are important indicators of patient well-being. While a thermometer can give an accurate reading during regular checkups, the monitoring of professionals in high-intensity situations requires a more accurate inner body temperature sensor. An ingestible chemical sensor can record acidity and pH levels along the gastrointestinal tract to screen for ulcers or tumors. Sensors also can be built into medications to track compliance.
Proteus Digital Health (Redwood City, Calif.) offers an FDA-approved microchip—an ingestible pill that tracks medication-taking behavior and how the body is responding to medicine. Through the company’s Digital Health Feedback System, the sensor monitors blood flow, body temperature and other vital signs for people with heart problems, schizophrenia or Alzheimer’s disease.
A similar pill from HQ Inc. (Palmetto, Fla.) called the CorTemp Ingestible Core Body Temperature Sensor transmits real-time body temperature. Firefighters, football players, soldiers and astronauts use it to ensure that they do not overheat in high temperatures. HQ Inc. is working on a consumer version, to be available in 2018, that would wirelessly communicate to a smartphone app.
The focus of research is perfecting wireless charging and communications to make the monitoring process longer, more convenient and more effective. Aerospace and defense organizations are trying to develop low-power, wireless pH sensors.
Targeted Drug Delivery
Medication can be ineffective if the drug payload is not delivered at its intended place and time. Since an oral medication travels through a broad pH spectrum, the pill encapsulation could dissolve at the wrong time. However, a smart pill with environmental sensors, a feedback algorithm and a drug release mechanism can give rise to smart drug delivery systems. This can ensure optimal drug delivery and prevent accidental overdose.
Recent developments include biosensor-equipped smart pills that sense the appropriate environment and location to release pharmacological agents. Medimetrics (Eindhoven, Netherlands) has developed a pill called IntelliCap with drug reservoir, pH and temperature sensors that release drugs to a defined region of the gastrointestinal tract. This device is CE marked and is in early stages of clinical trials for FDA approval. Recently, Google announced its intent to invest and innovate in this space.
What’s the Future?
The miniaturization of electronic components has been crucial to smart pill design. As cloud computing and wireless communication platforms are integrated into the health care system, the use of smart pills for monitoring vital signs and medication compliance is likely to increase. In the long term, smart pills are expected to be an integral component of remote patient monitoring and telemedicine. As the call for noninvasive point-of-care testing increases, smart pills will become mainstream devices.
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