Estimating inter-patient variability of dispersion in dry powder inhalers using CFD-DEM simulations

Benedict Benque, Johannes G. Khinast*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Drug delivery from a capsule-based dry powder inhaler depends on the inhaler's design, the drug's formulation, and the inhalation maneuver. The latter affects both the air flow and the capsule motion in the inhaler. It is well known that patient-to-patient variability is a major challenge in the design of new inhaler types. Modeling and simulation are important tools for understanding such systems, yet quite complex. Simulation studies of capsule-based dry powder inhalers have disregarded the transient nature of the inhalation process, adopting a constant flow rate through the inhaler instead. In addition, either no capsules, a capsule in a fixed position, or a capsule rotating at a constant rate have been considered. In this work, literature data for three inhalation flow profiles were incorporated into coupled simulations of the air flow and carrier particle motion through an Aerolizer® dry powder inhaler with a rotating capsule and compared to simulations at constant air flow rates. The results for the profile simulations indicated that the carrier powder experienced larger velocity fluctuations. Acceleration events were tracked as a measure of collision- and flow-induced dispersion. The majority of fast particle accelerations occurred when the particles collided with the swirl chamber walls. Of the two common particle dispersion metrics, only the peak particle force distribution appeared to be sensitive to the inhalation profiles, while the effect of the profiles on the cumulative impulse was small.

Original languageEnglish
Article number105574
JournalEuropean Journal of Pharmaceutical Sciences
Publication statusPublished - 1 Jan 2021


  • Dry powder inhaler
  • Inhalation profile
  • Computational fluid dynamics
  • Discrete element method
  • Carrier particle
  • Capsule motion

ASJC Scopus subject areas

  • Pharmaceutical Science

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