Capsule antennas for medication compliance monitoring

Reports from the Tufts Center for the Study of Drug Development (CSDD) indicate that the average cost to develop a drug in the US is $802 million per drug, of which the clinical trial phase is one of the costliest. During clinical trials, it is important to know with certainty a patient´s compliance to a medication regimen, because without it, the results cannot be interpreted accurately. Small antennas printed directly onto the surface of standard capsules can potentially serve as a cost-effective method of validating medication compliance via electronic detection of a swallowed pill in the digestive tract. In this paper, electrically small capsule antennas made of biocompatible silver inks are experimentally evaluated. The antenna performance inside the human stomach is analyzed using the finite difference time domain (FDTD) method. The radiated field intensity inside and outside the torso or gut area is determined for FCC regulated medical and Industrial-Scientific-Medical (ISM) bands, including the 402 to 405 MHz for Medical Implant Communications Service (MICS), 608 to 614 MHz for Wireless Medical Telemetry Service (WMTS), and the 902-928 MHz ISM frequency band.