3D Rod Array Dry Powder Inhaler for High Fine Particle Fraction
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Solution Overview
Problem
Conventional dry powder inhalers (DPIs) face challenges in efficiently delivering medicines to the lungs due to cohesive particles smaller than 5 μm, which result in low lung deposition and high extrathoracic deposition, leading to side effects and medication waste.
Innovation Solution
The use of a 3D rod array system combined with an external air pressure source and optimized capsule motion, along with submicrometer combination particle formulations incorporating drugs, hygroscopic excipients, and surface active agents, to enhance aerosol dispersion and deaggregation, achieving a high fine particle fraction and reduced mass median aerodynamic diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If particles are micronized to produce smaller particles for improved lung deposition, then the fine particle fraction increases, but particle cohesion increases making dispersion difficult
Solution Approach 1:
The invention divides the powder formulation into two distinct size populations: fine particles (submicrometer, 0.1-1 μm) for lung deposition and larger carrier particles (5-50 μm) for dispersion. The fine particles are segmented from the carrier particles through controlled aggregation during formulation, allowing each population to perform its specific function independently - the fine particles provide high FPF while the carrier particles provide ease of dispersion
Solution Approach 2:
The invention creates a composite powder formulation consisting of fine drug particles aggregated with larger carrier particles. This composite structure combines the advantages of both size populations: the fine particles enable high fine particle fraction (FPF > 50%) while the carrier particles provide sufficient aerodynamic diameter for effective dispersion in the inhaler device. The composite particles are designed with specific drug-to-carrier ratios to optimize both dispersion and lung deposition
2Device complexity
If conventional DPI designs are used, then device simplicity is maintained, but aerosol dispersion efficiency is low resulting in high extrathoracic deposition
Solution Approach 1:
The invention introduces a three-dimensional array of rods within the inhaler flow passage, transforming the conventional two-dimensional flow path into a three-dimensional dispersion structure. The rod array creates multiple flow paths and turbulence zones that enhance particle deaggregation and dispersion without significantly increasing device complexity. This dimensional enhancement allows efficient lung delivery (reducing extrathoracic deposition) while maintaining a relatively simple device structure
3Device complexity
If patient-generated airflow is used, then device simplicity is maintained, but sufficient flow cannot be generated for high quality aerosol in certain scenarios
Solution Approach 1:
The invention introduces an external air source as an intermediary to assist patient-generated airflow in producing sufficient and consistent aerosol quality. The external air source provides supplemental flow to ensure adequate aerosolization, particularly in scenarios where patient inspiratory flow is insufficient (nasal delivery, mechanical ventilation, children, infants). This intermediary approach maintains reliability of aerosol quality without requiring complete redesign of the airflow generation system
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
This approach significantly increases the fine particle fraction and decreases the mass median aerodynamic diameter of aerosols, improving lung delivery efficiency and reducing extrathoracic deposition, resulting in higher drug deposition in the lungs and lower side effects.
Implementation Method 1
The 3D array can be used to increase turbulence and improve the FPF and MMAD of an aerosol
Implementation Method 2
generation of a high fine particle aerosol using a 3D rod array for particle deaggregation with an external air pressure source
Data Source
AI summary
A dry powder inhaler (DPI) device has a flow passage with a three-dimensional (3D) rod array. The rod array includes multiple rows each having multiple unidirectional rods. The rows are spaced apart along a primary direction of air flow and are staggered. A viewing window to the capsule chamber allows viewing of the capsule's position within the chamber which provides visual feedback of inhalation flow rate to the user during inhalation. The capsule chamber may orient the capsule parallel to a primary direction of air flow or perpendicular to a primary direction of air flow and provide capsule motion in a plane which is perpendicular to the primary direction of air flow.