Gastro intestinal tracking and gastric emptying of solid dosage forms in rats using X-ray imagining

The aim of this research was to study the gastrointestinal transit and gastric emptying of non-disintegrating solid dosage forms in rats using X-ray imaging. Commercial gelatin minicapsules were filled with barium sulfate and enterically coated using Eudragit S100. The capsules were administered orally to rats followed by a solution of iodine based contrast agent iopromide. Images were obtained using a standard X-ray camera and digital film processing. Capsules were followed through the GI tract from the stomach to the small intestine, cecum and large intestine and the capsule location could be easily identified. Gastric emptying of different sized capsules was studied. The effect of fasting and time of administration on gastric retention was also studied. It was found that shortened capsules of 3.5 and 4.8 mm length were emptied from the stomach whereas the commercial length 7.18 mm capsules were retained. Surprisingly, 2.5 h post administration more rats retained the capsules in the stomach in the fasted state than in the fed state. We found that X-ray imaging can be used for simple visualization and localization of solid dosage forms in rats in the fed state using shortened commercial minicapsules on rats.