HIGH-RESOLUTION MONITORING OF THE GASTROINTESTINAL TRANSIT OF A MAGNETICALLY MARKED CAPSULE

The purpose of this study was to demonstrate that it is possible to co ntinuously monitor the gastrointestinal transit of magnetically marked , solid, oral dosage forms with multichannel biomagnetic measuring equ ipment and by magnetic source imaging (MSI) methods. For the investiga tions presented, a sucrose pellet was coated with powdered magnetite ( Fe3O4) in poly(methyl methacrylate). Then, the pellet was enclosed in a capsule prepared from silicone rubber and magnetized to obtain a net magnetic dipole moment, After ingestion of the capsule, its magnetic field distribution over the abdomen was recorded for several time inte rvals with a 37-channel superconducting quantum interference device (S QUID) magnetometer. At each time point, the position of the capsule wi thin the gastrointestinal tract was calculated from the measured field distribution, assuming a magnetic dipole model. The data presented he re demonstrate that with this noninvasive method of magnetic marker mo nitoring it is possible to investigate the gastrointestinal transit of a solid oral dosage form with a temporal resolution in the order of m illiseconds and a spatial resolution within a range of millimeters.