Dry Powder Inhaler With Two-Stage Deagglomeration
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Solution Overview
Problem
Conventional dry powder inhalers face challenges in achieving an appropriate balance between fine particle fraction (FPF), resistance, and drug hold-up, with existing deagglomerators being inefficient and leading to unwanted side effects such as increased resistance and adhesion to internal surfaces.
Innovation Solution
A dry powder inhalation device featuring a primary deagglomeration structure in the form of a baffle and a secondary deagglomeration structure as a tortuous passage, which together cause disruption to the airflow to effectively deagglomerate powdered medicament, enhancing FPF without excessive resistance or drug hold-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If increased resistance is applied in the dry powder inhaler, then the fine particle fraction (FPF) is improved, but the patient experiences unpleasant breathing resistance and potential respiratory distress
Solution Approach 1:
The deagglomeration process is divided into two distinct stages: a first deagglomeration structure (mesh) that performs initial particle separation, and a second deagglomeration structure (tortuous passage) that provides further particle size reduction. This segmentation allows each structure to be optimized for its specific function while maintaining overall balance between FPF and breathing resistance.
Solution Approach 2:
The second deagglomeration structure introduces a tortuous passage with multiple bends, adding spatial complexity to the airflow path. This dimensional change creates extended shear and collision zones without simply increasing linear resistance, enabling effective deagglomeration while maintaining acceptable breathing comfort.
2Ease of manufacture
If conventional mesh deagglomerators are used, then the device is simple and cheap to manufacture, but the deagglomeration efficiency is insufficient
Solution Approach 1:
The deagglomeration function is segmented into two structures: a simple mesh for initial separation and a tortuous passage for enhanced particle breakdown. This segmentation maintains manufacturing simplicity of individual components while achieving superior overall deagglomeration efficiency through their combined action.
Solution Approach 2:
Two different deagglomeration mechanisms (mesh filtration and tortuous passage shear/collision) are merged into a single inhalation system. The mesh provides first-stage deagglomeration while the tortuous passage delivers second-stage refinement, combining the advantages of both approaches for improved efficiency.
3Productivity
If helical mouthpiece deagglomeration systems are used, then particle deagglomeration is achieved through wall collisions, but drug hold-up increases due to surface adhesion
Solution Approach 1:
The harmful wall collision mechanism is extracted and replaced by a tortuous passage geometry that achieves deagglomeration through extended shear and controlled collisions in a less adhesive environment. This removes the primary source of drug hold-up while preserving deagglomeration effectiveness.
Solution Approach 2:
The tortuous passage acts as an intermediary structure between the mesh and the final aerosol output. It provides a controlled environment for particle refinement through shear and collision without the excessive surface contact that causes drug hold-up in helical systems.
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 device achieves improved fine particle fraction and reduced drug hold-up, providing a more efficient delivery of medicament to the lungs while maintaining a comfortable inhalation experience for the user.
Implementation Method 1
creates substantial shear and collision deagglomeration within it
Implementation Method 2
creates significant turbulence and shear within the inhalation airstream, leading to a measure of particle deagglomeration
Implementation Method 3
creates significant turbulence and shear within the inhalation airstream
Implementation Method 4
for a passive dry powder inhaler, that is, the dry powder inhaler which uses only the energy supplied by the patient's breath as they inhale
Data Source
Figure 1A
Figure 1B~1C
Figure 1D
AI summary
Disclosed is a dry powder inhalation device (300) and an insert (100) for use in a mouthpiece (220) of a dry powder inhalation device of the prior art. The dry powder inhalation device comprises: a means to aerosolize powdered medicament and introduce the aerosolized medicament to an airflow (302) directed to a user outlet (318); a primary deagglomeration structure (305) in the form of a baffle (305); and a secondary deagglomeration structure (301) which is a tortuous passage (310). The deagglomeration structures are configured to cause disruption to the airflow in their vicinity whereby the particles of the aerosolized powdered medicament are deagglomerated. The insert defines a tortuous passage which has a trajectory with a centre line, whereby the centre line comprises two or more major bends, involving a first point of inflection between a pair of adjacent bends of the two or more major bends.