When a patient takes medicine, it is usually absorbed in the stomach and small intestine before making it into the large intestine. This makes it difficult to treat illnesses originating in the large intestine, such as Crohn’s disease and irritable bowels syndrome. To deliver drugs to the large intestine, researchers at Purdue University developed a “smart” capsule roughly the size of a 000-size gel capsule.
The capsule contains two sealed compartments, one that holds powdered drugs and one that contains electronic controls. A capacitor inside the capsule powers the electronics and gets charged before the capsule is given to the patient. As the capsule makes its way to the large intestines, a 12-hour trip, it comes close to the patient’s waist as well as a magnet worn on the patient’s belt. The magnet activates a switch that releases a spring-loaded door and the drug is released. If the timing is right, the drug should be released just before the capsule reaches the ileocecal valve, where the small and large intestines meet.
To test the prototype, engineers sent it through a fluidic model that mimics the gastrointestinal tract. The model recreates the GI tract’s changing acidity and peristalsis, the constriction and relaxation of the intestine's muscles that create wavelike movements and push things along.
