The use of computational approaches in inhaler development

Area of Science:

• Multiphase flow simulations in pharmaceutical engineering.
• Computational modeling for drug delivery systems.

Background:

• Computational Fluid Dynamics (CFD) and Discrete Element Modelling (DEM) are crucial for optimizing inhaled drug delivery devices.
• Existing CFD models effectively simulate airflow, turbulence, and particle/droplet dynamics, benefiting from advanced commercial software.
• Discrete Element Modelling (DEM) offers insights into particle agglomerate break-up during inhalation, but faces computational challenges.

Purpose of the Study:

• To review the application of CFD and DEM in inhaled drug delivery research.
• To highlight the capabilities and limitations of current CFD and DEM methodologies.
• To identify future directions for integrated CFD-DEM simulations in this field.

Main Methods:

• Review of existing literature on CFD simulations for airflow patterns, turbulence, and particle transport in inhalers.
• Analysis of DEM studies focusing on particle agglomerate break-up mechanisms due to wall interactions and flow shear.
• Discussion of the computational costs and particle simulation limitations associated with DEM.

Main Results:

• CFD is routinely used in device design for predicting airflow and particle behavior, supported by sophisticated commercial software.
• DEM enables detailed modeling of particle break-up but is currently restricted to fundamental studies due to high computational demands.
• The number of particles simulated by DEM is significantly lower than that in typical inhaled formulations.

Conclusions:

• CFD is a well-established tool for inhaled drug delivery device design and simulation.
• DEM provides valuable fundamental insights into particle break-up but is computationally expensive for large-scale simulations.
• Future advancements in computational power will enable integrated CFD-DEM simulations to tackle complex issues in particle break-up and dispersion.