X-ray Imaging for Gastrointestinal Tracking of Microscale Oral Drug Delivery Devices

Rolf Bech Kjeldsen*, Maja Nørgaard Kristensen, Carsten Gundlach, Lasse Højlund Eklund Thamdrup, Anette Müllertz, Thomas Rades, Line Hagner Nielsen, Kinga Zór, Anja Boisen

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review


Microscale devices are promising tools to overcome specific challenges within oral drug delivery. Despite the availability of advanced high-quality imaging techniques, visualization and tracking of microscale devices in the gastrointestinal (GI) tract is still a challenge. This work explores the possibilities of applying planar X-ray imaging and computed tomography (CT) scanning for visualization and tracking of microscale devices in the GI tract of rats. Microcontainers (MCs) are an example of microscale devices that have shown great potential as an oral drug delivery system. Barium sulfate (BaSO4) loaded into the cavity of the MCs increases their overall X-ray contrast, which allows them to be easily tracked. The BaSO4-loaded MCs are quantitatively tracked throughout the entire GI tract of rats by planar X-ray imaging and visualized in 3D by CT scanning. The majority of the BaSO4-loaded MCs are observed to retain in the stomach for 0.5-2 h, enter the cecum after 3-4 h, and leave the cecum and colon 8-10 h post-administration. The imaging approaches can be adopted and used with other types of microscale devices when investigating GI behavior in, for example, preclinical trials and potential clinical studies.

Original languageEnglish
JournalACS Biomaterials Science and Engineering
Issue number6
Pages (from-to)2538-2547
Publication statusPublished - 2021

Bibliographical note

Funding Information:
The authors would like to acknowledge the Danish National Research Foundation (DNRF122) and Villum Fonden (Grant no. 9301) for Intelligent Drug Delivery and Sensing Using microcontainers and Nanomechanics (IDUN). Additionally, the animal facility at Department of Pharmacy at University of Copenhagen and the 3D Imaging Center at the Technical University of Denmark are acknowledged.

Publisher Copyright:
© 2021 American Chemical Society.


  • Barium sulfate
  • Computed tomography scanning
  • Gastrointestinal transit
  • Microcontainers
  • Planar X-ray imaging


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