No abstract

The release of a radiolabelled marker from an orally administered osmotic pump device (Osmet) has been evaluated in-vivo in a group of 6 subjects, using the technique of gamma scintigraphy. The duration of residence of the pump in the stomach was greatly influenced by food intake. However, the release of the marker from the device was independent of food and position within the gastrointestinal tract. Furthermore, the material released from the osmotic pump was well distributed in the gastrointestinal tract. Good agreement between in-vitro and in-vivo release rates was obtained.

The gastric emptying of pellets and single units of different densities has been followed in healthy subjects using the technique of gamma scintigraphy. The gastric emptying of the light pellets was affected by their buoyancy in the upper part of the stomach. However, the mean gastric emptying rates of pellets and single units were not significantly affected by density. Floating or buoyant delivery systems may have little advantage over conventional systems. The presence of food in the stomach was found to be the major factor in determining the gastric emptying of single units.