Magnetic marker monitoring of disintegrating capsules

Magnetic marker monitoring was studied for its applicability to investigate the in vivo fate and behavior of disintegrating magnetically marked dosage forms. As a model, hard gelatin capsules were filled with an effervescent mixture of lactose, ascorbic acid and sodium hydrogen carbonate containing 1.3 mg black iron oxide as a magnetic label. The accuracy of the localizati on procedure whilst calculating all parameters of the dipole in one fitting procedure was checked in phantom experiments where the capsules were moved in well-defined paths with respect to the measurement device. The calculat ed position coordinates of the capsules deviated between less than 2 mm up to 8 mm from the expected position values depending on the distance between the sensor area and the capsule's path. Further experiments on the in vitr o disintegration of the capsules showed that the value of the magnetic mome nt of the capsules can serve as a measure for their disintegration behavior . In vivo monitoring of the capsules was performed in eight experiments whe re a healthy volunteer swallowed each time one of the capsules. It was foun d that the in vivo disintegration behavior of the capsules corresponds well to their disintegration observed in water of about 37 degreesC. (C) 2001 E lsevier Science B.V. All rights reserved.