Course, Nicola Jane; (1992) Gastrointestinal transit of tablets of different size and density. Doctoral thesis (Ph.D.), University College London.

Text Gastrointestinal_transit_of_ta.pdf Download (11MB)

Abstract

The non-invasive technique of gamma scintigraphy has been employed to investigate the gastrointestinal transit of tablets (size 3.2-12.0mm, density 1.38-3.70g/cm3). In Study 1 an ion-exchange resin was incorporated and the tablets radiolabelled with technetium-99m or indium-111. Eight healthy fasted male volunteers participated in the study, receiving the 3.2mm tablets as multiple units or the 6.6mm tablets as single units. Dual radionuclide imaging was performed, enabling 2 densities of tablets to be administered concurrently at each tablet size. Three volunteers also repeated the 3.2mm tablet study in the fed state. In Study 2 Neutron Activation was employed to radiolabel the tablets by incorporating a small amount of stable nuclide in the formulation and bombarding with neutrons. Tablets of 12.0mm, radiolabelled with barium-139 or erbium-171, were administered to another 8 healthy male volunteers, in the fed or fasted states. A large inter individual variability was observed in the gastric emptying of all tablets. In the fasted state the mean gastric emptying time was lower and the variability between subjects less, as the size of the tablet was increased from 3.2mm to 12.0mm. The trend was reversed for the fed state. For the 3.2mm tablets the gastric emptying process was significantly prolonged in the fed and fasted states if the density was increased from 1.38g/cm3 to 2.86g/cm3. An increase in gastric residence time was observed for a density of 3.7 0g/cm3 when compared to 1.50g/cm3, at a tablet size of 12.0mm, in the fasted state only. No effect of density was observed with the 6.6mm tablets. The lag time at the ileo-caecal junction increased with increasing tablet size but no period of stasis was observed for the 3.2mm tablets. The results have important implications in the design of oral controlled release dosage forms and drug delivery to the gastrointestinal tract.

Download activity - last month

Export as XMLJSONCSV

Download activity - last 12 months

Export as CSVXMLJSON

Downloads by country - last 12 months

Export as CSVJSONXML

Archive Staff Only

View Item