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Andrew PorterfieldAndrew Porterfield has a master’s degree in biotechnology management from the University of Maryland and has worked as a marketing communications consultant for many biotechnology and pharmaceutical firms.

Ingestible sensors—tiny computers contained in a digestive-system friendly shell—have been around for years. Several National Football League (NFL) teams adopted ingestibles to measure core body temperatures and prevent heatstroke among their players. The League’s interest was spurred largely by the 2001 death of Minnesota Vikings offensive tackle Korey Stringer from heatstroke complications.

Football - LinebackersToday, the NFL and major college teams have adopted the technology. In addition, ingestibles are now being tested for medical purposes, undergoing experiments on their ability to measure medication adherence and even for delivery of certain drugs.

But the ingestible monitor didn’t start with football. It actually was developed by NASA, working with Johns Hopkins University Applied Physics Laboratory in the 1980s, to create a device that could measure body temperatures in space, where heat exhaustion is just as much a problem as it is for a 300-pound football player in humid August heat. Now available commercially (and approved by the FDA), the CorTemp Ingestible Core Body Thermometer pill sends a signal to a data recorder of an athlete’s body temperature for 18 to 30 hours.

A typical ingestible can be quite tiny, ranging just a few millimeters in width and length. Underneath a silicon or other coating that’s able to take on (and be tolerated by) the digestive system, a typical ingestible contains miniaturized circuits on chips, wireless transmitters, sensors, and batteries. Signals from the sensor can be read by a receiver placed on the person’s body, or even a hand-held remote device. Today, ingestible sensors are being tested for their ability to determine whether a patient is taking his or her prescribed medications:

  • A team based in Switzerland tested an ingestible sensor made by Proteus Digital Health among kidney transplant patients, to measure the sensor’s capacity to determine if patients were taking their immunosuppressant and other required medication. The team’s study found that patients could tolerate the device’s presence in their intestines, and that the device accurately detected the ingestion of a test compound.
  • A US-based team also using a Proteus device found that ingestible sensors (and a wearable receiver on the body) could record each ingestion of anti-tuberculosis drugs. Testing the device with 30 patients (who took 1,080 doses during the study), the device was shown to be 95% accurate in its ability to detect these ingestions. The device, then, would be an improvement over current direct observations of dosing, which haven’t prevented dangerous lapses in tuberculosis therapy.
  • Ingestibles are making their way into mental health, too. Not only did patients with schizophrenia and bipolar disorder tolerate an ingestible sensor during a study, but most of them found the sensor system easy to use and reported liking the digital reminders to take their medicine. The device accurately measured the patient’s drug dosage adherence rate (which came to just around 70%), indicating the value of the sensor not just for detecting dosages but also for patient acceptance of the technology.

While adherence monitoring is an important application, ingestibles also could be useful in actually delivering drugs. A Dutch team reported using an ingestible capsule that contained a drug reservoir, as well as sensors for pH and body temperature, a microchip and wireless transceiver, motor, and batteries. While the pH data determined where the capsule was located in the test volunteers, the motor could be triggered to dispense the drug. Data transmission was over 95% accurate, and expulsion of the experimental drug was largely successful.

Ingestible capsules could probably fulfill a wide variety of medicinal functions. Perhaps someday the devices will be able to detect real-time fat and cholesterol loads from chicken wings, nachos, and other Super Bowl snacks!