Characterization of the buccal and gastric transit of orally disintegrating tablets in humans using gamma scintigraphy.

The present study characterized the buccal cavity-emptying and gastric-emptying kinetics of orally disintegrating tablets (ODTs) in fasted humans using gamma scintigraphy. 111Indium-diethylenetriaminepentaacetic acid and technetium-99 m-labeled ion exchange resin were used as a model soluble drug and insoluble pellet-type drug, respectively, and housed in ODTs. These ODTs were then administered to human subjects with or without ingestion of water, after which scintigraphic images were collected in order to characterize the buccal and gastric transit of the radioactivity. The oral disintegration of the ODTs was extremely rapid, with a mean time of ≤1 min. The buccal emptying of the radioactivity was most rapid for the ODT with a water-soluble radiolabel; however, the ODTs with water-insoluble radiolabels showed buccal emptying with median half-times of ≤2.5 min. The ODT with the soluble radiolabel in subjects without water ingestion showed the most rapid gastric emptying compared with the ODTs with the insoluble radiolabels, the gastric-emptying time of which was highly variable. Further, water ingestion did not markedly affect the gastric-emptying time of the tablets with the water-soluble model drug. The observations in the present clinical study will help clarify the in vivo performance of ODTs in humans.