Numerical assessment of respiratory airway exposure risks to diesel exhaust particles

Dong, Jingliang; Tian, Lin; Ahmadi, Goodarz

doi:10.1007/s42757-019-0005-2

Cited by 16 publications

(6 citation statements)

References 25 publications

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“…To reveal the relevance of the present rat central lung airway model to human airways, a preliminary comparison was made between the DEF distribution in the present rat model and a human lung airway model reported in our recent work [ 40 ]. In that study, an extended human respiratory airway model was built, including both upper and lower respiratory airway compartments, and the human airway model was exposed to accumulation mode particles in the size range of 100 nm to 3.0 µm.…”

Section: Discussionmentioning

confidence: 99%

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Inhalation Exposure Analysis of Lung-Inhalable Particles in an Approximate Rat Central Airway

Dong

Tian

et al. 2019

IJERPH

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Rats have been widely used as surrogates for evaluating the adverse health effects of inhaled airborne particulate matter. This paper presents a computational fluid and particle dynamics (CFPD) study of particle transport and deposition in an approximate rat central airway model. The geometric model was constructed based on magnetic resonance (MR) imaging data sourced from previous study. Lung-inhalable particles covering a diameter range from 20 nm to 1.0 µm were passively released into the trachea, and the Lagrangian particle tracking approach was used to predict individual particle trajectories. Overall, regional and local deposition patterns in the central airway were analyzed in detail. A preliminary interspecies data comparison was made between present rat models and previously published human data. Results showed deposition “hot spots” were mainly concentrated at airway bifurcation apexes, and a gravitational effect should also be considered for inertia particles when using a rat as a laboratory animal. While for humans, this may not happen as the standing posture is completely different. Lastly, the preliminary interspecies data comparison confirms the deposition similarity in terms of deposition enhancement factors, which is a weighted deposition concentration parameter. This interspecies comparison confirms feasibility of extrapolating surrogate rat deposition data to humans using existing data extrapolation approach, which mostly relies on bulk anatomical differences as dose adjustment factors.

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Section: Discussionmentioning

confidence: 99%

“… DEF contours of a human lower respiratory airway following exposure of 100 nm and 3 µm particles at flow rate of 18 L/min. Results were reproduced from [ 40 ]. …”

Section: Figurementioning

confidence: 99%

Inhalation Exposure Analysis of Lung-Inhalable Particles in an Approximate Rat Central Airway

Dong

Tian

et al. 2019

IJERPH

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“…We calculate this using the number of particles deposited within a fixed distance (1 mm, area A conc = π (1 mm) 2 ) of the central point of each wall face. This distance was based on that used by Dong et al (2019). Other studies have used much narrower radii (Longest et al, 2006; Xi et al, 2012), but using this wider radius can account for particle translocation during the time between deposition and absorption.…”

Section: Methodsmentioning

confidence: 99%

Image-based modelling of inhaler deposition during respiratory exacerbation

Williams

Kolehmainen

Cunningham

et al. 2020

Preprint

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For many of the one billion sufferers of respiratory diseases worldwide, managing their disease with inhalers improves their ability to breathe. Poor disease management and rising pollution can trigger exacerbations which require urgent relief. Higher drug deposition in the throat instead of the lungs limits the impact on patient symptoms. To optimise delivery to the lung, patient-specific computational studies of aerosol inhalation can be used. However in many studies, inhalation modelling does not represent an exacerbation, where the patient's breath is much faster and shorter. Here we compare differences in deposition of inhaler particles in the airways of a healthy male, female lung cancer and child cystic fibrosis patient. We aimed to evaluate deposition differences during an exacerbation with image-based healthy and diseased patient models. We found that during an exacerbation, particles progressing to the lower airways were distributed similarly to those inhaled during healthy breathing, but fewer in quantity. Throat deposits were halved in the healthy patient compared to the diseased patients under extreme inhalation, due to changes in the detailed shape of the throat. Our results identify that the modelled upper airway must be patient-specific, and an exacerbating profile tested for optimal measurement of reliever inhaler deposition.

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“…Nasal drug delivery has been recognised as a reliable alternative to parenteral routes since the richly vascularized nasal mucosa provides an effective route for drug absorption [1,2]. Compared with traditional antibiotics and surgical interventions, nasal drug delivery offers safer treatment for localised nasal conditions such as rhinosinusitis, and delivery to the systemic circulation [3][4][5] and central nervous system [6][7][8]. However, limited knowledge of regional nasal deposition patterns [9,10] and variations in the physico-chemical properties of the formulation make it difficult to predict bioequivalence of nasal spray drugs, which poses a challenge for regulators to assess the safety and efficacy of the products [3,11].…”

Section: Introductionmentioning

confidence: 99%

Prediction of nasal spray drug absorption influenced by mucociliary clearance

et al. 2021

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Evaluation of nasal spray drug absorption has been challenging because deposited particles are consistently transported away by mucociliary clearance during diffusing through the mucus layer. This study developed a novel approach combining Computational Fluid Dynamics (CFD) techniques with a 1-D mucus diffusion model to better predict nasal spray drug absorption. This integrated CFD-diffusion approach comprised a preliminary simulation of nasal airflow, spray particle injection, followed by analysis of mucociliary clearance and drug solute diffusion through the mucus layer. The spray particle deposition distribution was validated experimentally and numerically, and the mucus velocity field was validated by comparing with previous studies. Total and regional drug absorption for solute radius in the range of 1 − 110nm were investigated. The total drug absorption contributed by the spray particle deposition was calculated. The absorption contribution from particles that deposited on the anterior region was found to increase significantly as the solute radius became larger (diffusion became slower). This was because the particles were consistently moved out of the anterior region, and the delayed absorption ensured more solute to be absorbed by the posterior regions covered with respiratory epithelium. Future improvements in the spray drug absorption model were discussed. The results of this study are aimed at working towards a CFD-based integrated model for evaluating nasal spray bioequivalence.

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Numerical assessment of respiratory airway exposure risks to diesel exhaust particles

Cited by 16 publications

References 25 publications

Inhalation Exposure Analysis of Lung-Inhalable Particles in an Approximate Rat Central Airway

Inhalation Exposure Analysis of Lung-Inhalable Particles in an Approximate Rat Central Airway

Image-based modelling of inhaler deposition during respiratory exacerbation

Prediction of nasal spray drug absorption influenced by mucociliary clearance

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