Full-Scale DEM Simulation of Coupled Fluid and Dry-Coated Particle Flow in Swirl-Based Dry Powder Inhalers

Alfano, Francesca Orsola; Benassi, Andrea; Gaspari, Roberto; Renzo, Alberto Di; Maio, Francesco Paolo Di

doi:10.1021/acs.iecr.1c02864

Cited by 9 publications

(9 citation statements)

References 67 publications

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“…The approach for the dry powder coating of the carrier with API is described in Alfano et al [ 22 ]. The difference in the coating degree between Configuration A and B can be noticed in Figure 3 , which shows two coated carrier particles.…”

Section: Methodsmentioning

confidence: 99%

“…The difference in the coating degree between Configuration A and B can be noticed in Figure 3, which shows two coated carrier particles. The approach for the dry powder coating of the carrier with API is described in Alfano et al [22]. The difference in the coating degree between Configuration A and B can be noticed in Figure 3, which shows two coated carrier particles.…”

Section: Geometry and Powder Configurationsmentioning

confidence: 99%

“…In recent years, Discrete Element Method (DEM) modeling has emerged as a powerful simulation tool for studying the behavior of powders in inhalation devices [ 20 ]. Coupled DEM-CFD (Computational Fluid Dynamics) studies showed the detailed motion of particles from the initial dispersion in air through to the mouthpiece [ 21 , 22 , 23 , 24 , 25 ]. In the last decade, model formulations have been introduced to extend the particle-scale contact tracking capability of DEM with surface–surface charge transfer and physical electrostatic interaction models (see, e.g., [ 26 , 27 , 28 ]), allowing triboelectric charging phenomena at the particle scale to be studied [ 27 , 29 , 30 , 31 , 32 , 33 ].…”

Section: Introductionmentioning

confidence: 99%

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Discrete Element Method Evaluation of Triboelectric Charging Due to Powder Handling in the Capsule of a DPI

2023

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The generation and accumulation of an electrostatic charge from handling pharmaceutical powders is a well-known phenomenon, given the insulating nature of most APIs (Active Pharmaceutical Ingredients) and excipients. In capsule-based DPIs (Dry Powder Inhalers), the formulation is stored in a gelatine capsule placed in the inhaler just before inhalation. The action of capsule filling, as well as tumbling or vibration effects during the capsule life cycle, implies a consistent amount of particle–particle and particle–wall contacts. A significant contact-induced electrostatic charging can then take place, potentially affecting the inhaler’s efficiency. DEM (Discrete Element Method) simulations were performed on a carrier-based DPI formulation (salbutamol–lactose) to evaluate such effects. After performing a comparison with the experimental data on a carrier-only system under similar conditions, a detailed analysis was conducted on two carrier–API configurations with different API loadings per carrier particle. The charge acquired by the two solid phases was tracked in both the initial particle settling and the capsule shaking process. Alternating positive–negative charging was observed. Particle charging was then investigated in relation to the collision statistics, tracking the particle–particle and particle–wall events for the carrier and API. Finally, an analysis of the relative importance of electrostatic, cohesive/adhesive, and inertial forces allowed the importance of each term in determining the trajectory of the powder particles to be estimated.

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Section: Methodsmentioning

confidence: 99%

Section: Geometry and Powder Configurationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Discrete Element Method Evaluation of Triboelectric Charging Due to Powder Handling in the Capsule of a DPI

2023

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“…The Discrete Element Method (DEM), also in combination with computational fluid dynamics (CFD-DEM), is commonly utilized to model the behavior of granular materials, due to its versatility in dealing with very different flow regimes, packing density and dispersion of particle properties (Golshan et al, 2020;Kieckhefen et al, 2020). DEM has been successfully used to study the segregation of particles differing in size and density in fluidized beds (Di Renzo et al, 2011;Peng et al, 2016), the mixing of electrically charged API and carrier particles for inhalation in a vibrating container (Yang et al, 2015), the mixing of binary particle beds in a rotating drum (Huang and Nakagawa, 2023), the size segregation during powder spreading for additive manufacturing using laser powder bed fusion (Shaheen et al, 2021), the detachment of API from carrier particles in dry powder inhalers (Cui and Sommerfeld, 2015;Tong et al, 2017;Ariane et al, 2018;Alfano et al, 2021a;Alfano et al, 2022a;Alfano et al, 2022b).…”

Section: Introductionmentioning

confidence: 99%

A thick wall concept for robust treatment of contacts in DEM simulation of highly polydisperse particulate systems

Alfano,

Iozzi,

Di Maio

et al. 2024

Front. Chem. Eng.

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Modelling particulate systems with the Discrete Element Method (DEM) is an established practice, both in the representation and analysis of natural phenomena and in scale-up and optimization of industrial processes. Since the method allows tracking individual particles, each element can possess geometrical, physical, mechanical or chemical surface properties different from those of the other particles. One example is a polydisperse particulate system, i.e., characterized by a size distribution, opposed to the idealized monodisperse case. In conventional DEM, a softer particle stiffness is commonly adopted to reduce the computational time. It might happen that artificially soft particles, when colliding against a wall boundary, exhibit such large, unrealistic overlap that they “pass through” the wall and exit the domain. In the case of highly polydisperse systems, this often occurs when fine particles are pushed against the wall by coarse particles with masses several orders of magnitude larger. In the manuscript, a novel method is proposed, named thick wall, to allow the particles in contact with the walls to experience relatively large overlaps without ending up ejected out the domain. In particular, a careful way to calculate the particle-wall overlap and force unit vector can accommodate normal displacements larger than the maximum usually allowed, i.e., typically the particle radius, thereby preventing particles from being expelled from the domain. First, critical velocities for which single particles and pairs of fine/coarse particle escape the domain are analytically characterized using the linear and the Hertz models. The thick wall concept is then introduced and its effect on the maximum critical velocity is demonstrated with both contact models. Finally, application to pharmaceutical powder composed of carrier (coarse) and active pharmaceutical ingredient (API) (fine) particles in a shaken capsule prove this to be an example of vulnerability to the phenomenon of fine particle ejection and to significantly benefit from the thick wall modification.

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“…An interesting direction was proposed by Choi et al, 12 who used a multiscale model for controlling a pulping process. Other exciting results include the coupled fluid and particle flow simulation proposed by Alfano et al, 13 and its pharmaceutical application (dry powder inhalers).…”

mentioning

confidence: 99%

Virtual Issue: A Multiscale View on Molecular and Process Design

Baldea

2023

Ind. Eng. Chem. Res.

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Full-Scale DEM Simulation of Coupled Fluid and Dry-Coated Particle Flow in Swirl-Based Dry Powder Inhalers

Cited by 9 publications

References 67 publications

Discrete Element Method Evaluation of Triboelectric Charging Due to Powder Handling in the Capsule of a DPI

Discrete Element Method Evaluation of Triboelectric Charging Due to Powder Handling in the Capsule of a DPI

A thick wall concept for robust treatment of contacts in DEM simulation of highly polydisperse particulate systems

Virtual Issue: A Multiscale View on Molecular and Process Design

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