Tracheobronchial Deposition Research Articles

While a number of studies have considered the dynamics of ambient or environmental particles in the respiratory tract, far fewer have evaluated the transport and deposition of pharmaceutical aerosols from inhalers in the mouth-throat (MT) and tracheobronchial (TB) airways. The objective of this study was to develop a new stochastic individual path (SIP) modeling approach for simulating the MT and TB deposition of a pharmaceutical aerosol from a dry powder inhaler and to evaluate the effects of transient vs. steady state conditions and sampling of the airways. In the SIP approach, representative models of the MT and upper TB geometries are considered through the third respiratory bifurcation (B3; approximately lobar bronchi). Stochastic individual paths are then evaluated extending from B4 to the terminal bronchioles (B15) in which one branch of each bifurcation is continued and one is not. Three SIP geometries were considered extending into the lower right lung lobe through the end of the conducting airways. A commonly prescribed dry powder inhaler (DPI) was connected to the MT geometry and the deposition of drug mass from a realistic polydisperse pharmaceutical aerosol was evaluated. Predictions of deposited drug mass in the MT and upper TB geometries were found to be in good agreement with concurrent experimental results. Transient inhalation was shown to influence the deposition of particles in the MT and upper TB airways through B3, where the Womersley number is greater than 1. In contrast, transient conditions were found to have little influence on deposition in the TB region starting with B4, where steady state simulations provided a good representation of total, regional, bifurcation-averaged, and localized deposition. Furthermore, a single SIP model was shown to characterize both regional and highly localized deposition within a lung lobe assuming mean airway dimensions. The resulting SIP model provides a highly efficient method to simulate the regional and local deposition of pharmaceutical aerosols throughout the conducting airways. In comparison with performing fully transient simulations of all branches in the regions considered, the SIP modeling approach reduces computational effort by a factor of approximately 3×10 5 while predicting regional and local deposition values to within approximately 5%.

Inhalation of airborne material poses a potential health risk to various subpopulations one of which is children. Little is known about the fate of particles in the respiratory tracts of children. Modeling efforts have been limited due largely to the lack of adequate information on lung geometry during growth. Lung morphometry measurements in children and adults between 3 months and 21 years of age were used to create 5-lobe lung geometries. Each lobe had a dichotomous, symmetric branching structure and was structurally different from the other lobes. The lung geometries were used in a multiple-path particle deposition model to calculate particle deposition fractions in different regions, lobes and airway generations of the lungs. Simulated breathing patterns were representative of resting breathing. Age-dependent, semi-empirical expressions of particles losses in the nasal airways, which were based on fits to the available experimental measurements, showed larger nasal deposition in adults than in children. Predicted tracheobronchial deposition patterns were similar among different ages for a given particle size. In the alveolar region, the predicted deposition fraction varied with age such that a clear trend could not be identified. Deposition fraction in a lobe was proportional to the volume of air going to that lobe. Deposition fractions in the lower left and right lobes were similar but higher than those in the other lobes for a given particle diameter. Lobar deposition fraction adjusted for lobar lung volume or lung deposition fraction adjusted for lung volume was found to be a unique property for an individual and presented a means for age-dependent deposition comparisons. The adjusted tracheobronchial and pulmonary deposition fractions were greatest for infants and decreased with age. A similar trend was also observed for deposition fraction per unit area as a function of airway generation. The distribution of particle deposition fraction per unit surface area varied with particle size for an individual, with ultrafine particles being more uniformly distributed throughout the lungs and coarse particles depositing primarily in the first few tracheobronchial airways. The trend of particle deposition with age indicates that children, particularly infants, may be at a greater health risk from exposure to airborne particulate matter and noxious materials all other conditions being equal. The age-dependent predicted deposition fraction pattern per unit area of different size particles has implications in the calculation of inhaled reference concentrations as well as site-specific delivery of drugs and other therapeutic compounds to the lungs of patients.

Tracheobronchial Deposition Research Articles

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Particulate matter deposition in the human respiratory system: A health risk assessment at a technical university

In Vitro Estimation of Tracheobronchial and Alveolar Doses Using Filters

Using Filters to Estimate Regional Lung Deposition with Dry Powder Inhalers

Combined in Vitro-in Silico Approach to Predict Deposition and Pharmacokinetics of Budesonide Dry Powder Inhalers.

Development of a filter that mimics tracheobronchial deposition of respirable aerosols in humans

Application of a One-Dimensional Computational Model for the Prediction of Deposition from a Dry Powder Inhaler.

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Development of a stochastic individual path (SIP) model for predicting the tracheobronchial deposition of pharmaceutical aerosols: Effects of transient inhalation and sampling the airways

A semi-empirical model of aerosol deposition in the human respiratory tract for mouth inhalation.

CFD Simulation of Aerosol Deposition in an Anatomically Based Human Large–Medium Airway Model

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Characterization of Regional and Local Deposition of Inhaled Aerosol Drugs in the Respiratory System by Computational Fluid and Particle Dynamics Methods

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Tracheobronchial Deposition Research Articles

Related Topics

Articles published on Tracheobronchial Deposition

Particulate matter deposition in the human respiratory system: A health risk assessment at a technical university

In Vitro Estimation of Tracheobronchial and Alveolar Doses Using Filters

Using Filters to Estimate Regional Lung Deposition with Dry Powder Inhalers

Combined in Vitro-in Silico Approach to Predict Deposition and Pharmacokinetics of Budesonide Dry Powder Inhalers.

Development of a filter that mimics tracheobronchial deposition of respirable aerosols in humans

Application of a One-Dimensional Computational Model for the Prediction of Deposition from a Dry Powder Inhaler.

Key considerations on nebulization of antimicrobial agents to mechanically ventilated patients

Characterization of particle emission from laser printers

Calcifediol-loaded liposomes for local treatment of pulmonary bacterial infections

Deposition of particles in the alveolar airways: Inhalation and breath-hold with pharmaceutical aerosols

Development of a new technique for the efficient delivery of aerosolized medications to infants on mechanical ventilation.

Removal of sedimentation decreases relative deposition of coarse particles in the lung periphery

L’amylose bronchopulmonaire : à propos de quatre cas

Tracheobronchial and alveolar dose of submicrometer particles for different population age groups in Italy

Development of a stochastic individual path (SIP) model for predicting the tracheobronchial deposition of pharmaceutical aerosols: Effects of transient inhalation and sampling the airways

A semi-empirical model of aerosol deposition in the human respiratory tract for mouth inhalation.

CFD Simulation of Aerosol Deposition in an Anatomically Based Human Large–Medium Airway Model

Amyloses et dépôts immunoglobuliniques non amyloïdes pulmonaires

Characterization of Regional and Local Deposition of Inhaled Aerosol Drugs in the Respiratory System by Computational Fluid and Particle Dynamics Methods

Modeling Age-Related Particle Deposition in Humans