Dissolution profile of theophylline modified release tablets, using a biorelevant Dynamic Colon Model (DCM)

Konstantinos Stamatopoulos, Hannah K. Batchelor, Mark. J.h. Simmons

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)
603 Downloads (Pure)


The human proximal colon has been considered a favourable site to deliver drugs for local and systemic treatments. However, modified dosage forms face a complex and dynamically changing colonic environment. Therefore, it has been realized that in addition to the use of biorelevant media, the hydrodynamics also need to be reproduced to create a powerful in vitro dissolution model to enable in vivo performance of the dosage forms to be predicted.

A novel biorelevant Dynamic Colon Model (DCM) has been developed which provides a realistic environment in terms of the architecture of the smooth muscle, the physical pressures and the motility patterns occurring in the proximal human colon. Measurements of pressure inside the DCM tube confirmed a direct association between the magnitude of the pressure signal with the occlusion rate of the membrane and the viscosity of the fluid.

The dissolution profile and the distribution of the highly soluble drug, theophylline, were assessed by collecting samples at different locations along the DCM tube. Differences in the release rates of the drug were observed which were affected by the sampling point location, the viscosity of the fluid and the mixing within the DCM tube. Images of the overall convective motion of the fluid inside the DCM tube obtained using Positron Emission Tomography enabled relation of the distribution of the tracer to likely areas of high and low concentrations of the theophylline drug.

This information provides improved understanding of how extensive phenomena such as supersaturation and precipitation of the drug may be during the passage of the dosage form through the proximal colon.
Original languageEnglish
Pages (from-to)9-17
JournalEuropean Journal of Pharmaceutics and Biopharmaceutics
Early online date13 Aug 2016
Publication statusPublished - Nov 2016


  • Theophylline
  • Biorelevant dissolution test
  • Extended release tablets
  • Proximal colon
  • In vitro model


Dive into the research topics of 'Dissolution profile of theophylline modified release tablets, using a biorelevant Dynamic Colon Model (DCM)'. Together they form a unique fingerprint.

Cite this