Respiratory System Model for Dry Powder Inhalation Aerodynamics
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Solution Overview
Problem
Current devices for characterizing aerodynamic behavior of dry powder inhalation in respiratory systems, such as Andersen Cascade Impactor and Next Generation Impactor, do not accurately simulate the human respiratory system, leading to discrepancies between in-vitro and in-vivo therapeutic effects and increased clinical risks due to differences in particle deposition conditions.
Innovation Solution
A simulation device comprising a constant temperature-and-humidity chamber, steam and vacuum generating device, and a respiratory system model with sticky coatings and multiple sample collectors with varying filter pore sizes, designed to mimic the human respiratory system and accurately collect particles of different sizes, reducing the gap between in-vitro and in-vivo data accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional devices like Andersen Cascade Impactor or Next Generation Impactor are used to characterize aerodynamic behavior, then device complexity is reduced and ease of manufacture is improved, but measurement precision and reliability are worsened due to inaccurate simulation of human respiratory system
Solution Approach 1:
The patent creates a physical copy of the human respiratory system model including oral cavity, pharynx, larynx, trachea, bronchi, and lungs with authentic anatomical structures and mucosal surfaces. This copying approach allows the device to replicate real human respiratory conditions, improving measurement precision while managing complexity through modular design of the respiratory tract components
Solution Approach 2:
The patent changes key parameters of the testing environment by controlling temperature (37±0.5℃) and humidity (45-55%) to match physiological conditions in the human respiratory system. This parameter adjustment ensures that aerodynamic behavior of dry powder inhalation is characterized under conditions that accurately reflect in-vivo situations, thereby improving measurement precision
2Measurement precision
If smooth stainless steel pipes are used for airway and throat representation, then ease of manufacture and cleaning are improved, but particle deposition accuracy is worsened due to particle adhesion differences from real respiratory mucosa
Solution Approach 1:
The patent employs composite material construction for the respiratory system model, combining rigid structural components (for maintaining anatomical shape) with flexible mucosal surface materials (for replicating particle adhesion characteristics). This composite approach allows accurate particle deposition measurement while managing manufacturing complexity through specialized material selection for different functional regions
Solution Approach 2:
The patent applies different material properties to different regions of the respiratory model - smooth surfaces in upper airways for low adhesion, and mucosal-like surfaces in lower airways for appropriate particle deposition. This local differentiation of surface properties accurately reflects real respiratory physiology while managing overall manufacturing feasibility
3Measurement precision
If right angle connection between airway and throat is used, then device complexity is reduced, but measurement precision is worsened due to deviation from real respiratory tract geometry
Solution Approach 1:
The patent replaces sharp right-angle connections with curved, anatomically accurate transitions between respiratory tract segments. The model incorporates natural bends and curves of the human respiratory system including the pharyngeal curve, laryngeal inlet, and bronchial bifurcations, which accurately represent airflow patterns and particle deposition sites while managing geometric complexity through standardized anatomical modeling
4Productivity
If vacuum pump is used for particle transport, then productivity and testing speed are improved, but measurement precision is worsened due to non-physiological particle movement conditions
Solution Approach 1:
The patent introduces a flow control system as an intermediary between the vacuum pump and the respiratory model. This intermediary component regulates and stabilizes the airflow rate to match physiological inhalation conditions, ensuring that particles are transported under realistic aerodynamic conditions while maintaining efficient testing throughput through controlled vacuum application
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The simulation device provides a more accurate characterization of dry powder inhalation aerodynamics, improving the correlation between in-vitro and in-vivo data and reducing clinical risks by simulating the human respiratory environment, thus enabling more precise comparison of generic and original medicines.
Implementation Method 1
a steam and vacuum generating device... The steam and vacuum generating device comprises a vacuum pump, a steamer and a temperature and humidity control valve
Implementation Method 2
The steam and vacuum generating device comprises a vacuum pump... the respiratory system model comprises an oral cavity receiver and sample collectors... connected with the steam and vacuum generating device
Implementation Method 3
inner walls of the respiratory system model are coated with coatings which become sticky after absorbing moisture
Implementation Method 4
The sample collectors include a first sample collector and a second sample collector, each of the collectors is provided with 8 collecting trays... filters with varying pore sizes
Data Source
AI summary
The present invention discloses a simulation device for characterizing aerodynamics of dry powder inhalation in respiratory system comprising: a constant temperature-and-humidity chamber, a steam and vacuum generating device and a respiratory system model arranged in the constant temperature and humidity chamber, and the constant temperature and humidity chamber and the respiratory system model are both connected with the steam and vacuum generating device; a temperature and humidity sensor is arranged in the constant temperature-and-humidity chamber and electrically connected with the steam and vacuum generating device; the respiratory system model comprises an oral cavity receiver and sample collectors, wherein inner walls of the respiratory system model are coated with a coating, the sample collectors includes a first sample collector and a second sample collector, each of the collectors is provided with 8 collecting trays.