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Three-dimensional DEM-CFD analysis of air-flow-induced detachment of API particles from carrier particles in dry powder inhalers.

Yang J, Wu CY, Adams M - Acta Pharm Sin B (2014)

Bottom Line: Hence, an understanding of these mechanisms is critical for the development of DPIs.A carrier-based agglomerate is initially formed and then dispersed in a uniformed air flow.It is also shown that the cumulative Weibull distribution function can be used to describe the DPI performance, which is governed by the ratio of the fluid drag force to the pull-off force.

View Article: PubMed Central - PubMed

Affiliation: School of Chemical Engineering, University of Birmingham, Birmingham B15 2TT, UK ; Department of Chemical and Process Engineering, University of Surrey, Guildford GU2 7XH, UK.

ABSTRACT
Air flow and particle-particle/wall impacts are considered as two primary dispersion mechanisms for dry powder inhalers (DPIs). Hence, an understanding of these mechanisms is critical for the development of DPIs. In this study, a coupled DEM-CFD (discrete element method-computational fluid dynamics) is employed to investigate the influence of air flow on the dispersion performance of the carrier-based DPI formulations. A carrier-based agglomerate is initially formed and then dispersed in a uniformed air flow. It is found that air flow can drag API particles away from the carrier and those in the downstream air flow regions are prone to be dispersed. Furthermore, the influence of the air velocity and work of adhesion are also examined. It is shown that the dispersion number (i.e., the number of API particles detached from the carrier) increases with increasing air velocity, and decreases with increasing the work of adhesion, indicating that the DPI performance is controlled by the balance of the removal and adhesive forces. It is also shown that the cumulative Weibull distribution function can be used to describe the DPI performance, which is governed by the ratio of the fluid drag force to the pull-off force.

No MeSH data available.


Related in: MedlinePlus

The variation of the dispersion ratio with the fluid drag force and the pull-off force for a range of carrier radii.
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f0035: The variation of the dispersion ratio with the fluid drag force and the pull-off force for a range of carrier radii.

Mentions: The detachment process is governed by the removal force (e.g., fluid drag force) and the adhesive force (e.g., inter-particle force), and the dispersion performance is the result of the balance of these two forces. The variations of the dispersion ratio, Φ, with the fluid drag force (Eq. (7)) and the pull-off force (Eq. (3)) are shown in Fig. 7a and b, respectively. For each carrier size, cases with four air velocities and four works of adhesion, as shown in Table 1, are systematically simulated. It can be seen from Fig. 7a that for a specific fluid drag force, the dispersion ratio varies as the works of adhesion are different, indicating that the detachment process is not governed by the fluid drag force only. In addition, the variation range of dispersion ratio increases with increasing drag force, suggesting that API particles are more easily removed by high-speed flow. Similarly, it is clearly seen from Fig. 7b that for a specific pull-off force, the dispersion ratio varies with different air velocities. The variation range of the dispersion ratio decreases with increasing pull-off force, indicating that API particles are more difficult to be removed with strong adhesion. However, for either of the two figures, the data cannot superimpose into a master curve, which indicates that there is no direct correlation between the dispersion ratio and the removal force or the adhesive force.


Three-dimensional DEM-CFD analysis of air-flow-induced detachment of API particles from carrier particles in dry powder inhalers.

Yang J, Wu CY, Adams M - Acta Pharm Sin B (2014)

The variation of the dispersion ratio with the fluid drag force and the pull-off force for a range of carrier radii.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4590728&req=5

f0035: The variation of the dispersion ratio with the fluid drag force and the pull-off force for a range of carrier radii.
Mentions: The detachment process is governed by the removal force (e.g., fluid drag force) and the adhesive force (e.g., inter-particle force), and the dispersion performance is the result of the balance of these two forces. The variations of the dispersion ratio, Φ, with the fluid drag force (Eq. (7)) and the pull-off force (Eq. (3)) are shown in Fig. 7a and b, respectively. For each carrier size, cases with four air velocities and four works of adhesion, as shown in Table 1, are systematically simulated. It can be seen from Fig. 7a that for a specific fluid drag force, the dispersion ratio varies as the works of adhesion are different, indicating that the detachment process is not governed by the fluid drag force only. In addition, the variation range of dispersion ratio increases with increasing drag force, suggesting that API particles are more easily removed by high-speed flow. Similarly, it is clearly seen from Fig. 7b that for a specific pull-off force, the dispersion ratio varies with different air velocities. The variation range of the dispersion ratio decreases with increasing pull-off force, indicating that API particles are more difficult to be removed with strong adhesion. However, for either of the two figures, the data cannot superimpose into a master curve, which indicates that there is no direct correlation between the dispersion ratio and the removal force or the adhesive force.

Bottom Line: Hence, an understanding of these mechanisms is critical for the development of DPIs.A carrier-based agglomerate is initially formed and then dispersed in a uniformed air flow.It is also shown that the cumulative Weibull distribution function can be used to describe the DPI performance, which is governed by the ratio of the fluid drag force to the pull-off force.

View Article: PubMed Central - PubMed

Affiliation: School of Chemical Engineering, University of Birmingham, Birmingham B15 2TT, UK ; Department of Chemical and Process Engineering, University of Surrey, Guildford GU2 7XH, UK.

ABSTRACT
Air flow and particle-particle/wall impacts are considered as two primary dispersion mechanisms for dry powder inhalers (DPIs). Hence, an understanding of these mechanisms is critical for the development of DPIs. In this study, a coupled DEM-CFD (discrete element method-computational fluid dynamics) is employed to investigate the influence of air flow on the dispersion performance of the carrier-based DPI formulations. A carrier-based agglomerate is initially formed and then dispersed in a uniformed air flow. It is found that air flow can drag API particles away from the carrier and those in the downstream air flow regions are prone to be dispersed. Furthermore, the influence of the air velocity and work of adhesion are also examined. It is shown that the dispersion number (i.e., the number of API particles detached from the carrier) increases with increasing air velocity, and decreases with increasing the work of adhesion, indicating that the DPI performance is controlled by the balance of the removal and adhesive forces. It is also shown that the cumulative Weibull distribution function can be used to describe the DPI performance, which is governed by the ratio of the fluid drag force to the pull-off force.

No MeSH data available.


Related in: MedlinePlus