Inhaler Spacer for Low-Speed Aerosol Delivery
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Solution Overview
Problem
Inhalers, particularly soft mist inhalers (SMIs), face challenges in coordinating the actuation of medicament atomization with breathing, leading to suboptimal inhalation, especially for children, due to the difficulty in synchronizing the slow aerosol delivery and inhalation process.
Innovation Solution
An add-on device with a chamber for intermediate storage of atomized medicament is integrated downstream of the inhaler's delivery nozzle, allowing for extended aerosol delivery time and low speed, facilitating easier inhalation by preventing backflow and ensuring the aerosol is inhaled without synchronization requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the aerosol is delivered at high speed (as in MDI), then the delivery time is short, but the particles are deposited on the throat walls instead of reaching the lungs
Solution Approach 1:
The patent introduces an intermediary chamber (spacer) between the inhaler nozzle and the user's mouth. This chamber acts as a mediator that decelerates the aerosol particles from high speed (>2 m/s) to low speed, allowing them to be gently inhaled into the lungs without depositing on the throat walls. The chamber volume (0.5-2.0 L) is specifically designed to provide sufficient residence time for speed reduction.
Solution Approach 2:
The aerosol is delivered into the chamber in advance before the user inhales. This preliminary action allows the aerosol cloud to form and stabilize in the chamber, and the particles to decelerate naturally, so that when the user breathes in, the particles are already at appropriate speed for lung deposition rather than throat deposition.
2Ease of operation
If the user coordinates breathing with inhaler actuation, then the aerosol can be inhaled directly, but this is difficult for children and unskilled users
Solution Approach 1:
The inhaler actuates and delivers the aerosol into the chamber in advance, creating a reservoir of medicament before the user begins to inhale. This eliminates the need for coordination because the aerosol is already prepared and waiting in the chamber when the user breathes in naturally, making it easy for children and unskilled users to use effectively.
Solution Approach 2:
The chamber serves as an intermediary that decouples the actuation event from the inhalation act. The chamber buffers the timing difference between when the aerosol is generated and when it is inhaled, allowing users to inhale at their own pace without needing to synchronize with the actuation mechanism.
3Ease of operation
If a chamber is added for intermediate storage, then aerosol delivery time is extended and coordination is simplified, but the device complexity increases
Solution Approach 1:
The chamber is designed to perform multiple functions: it serves as an intermediate storage reservoir for the aerosol, acts as a flow expander to reduce particle speed, provides a larger target area for proper inhalation, and functions as a visual indicator that the aerosol is ready for inhalation. This multi-functionality justifies the added complexity by delivering multiple benefits from a single component.
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 configuration enhances the delivery of the active substance to the lungs, improving therapy efficacy and making the inhaler universally usable, particularly for children, by ensuring a higher and more consistent deposition of the active substance in the lungs while minimizing throat deposition.
Implementation Method 1
a pressure producing means having a drive spring for conveying and nebulising the medicament preparation. Atomisation is carried out without the use of a propellant gas, namely by the force of the drive spring.
Implementation Method 2
an add-on device having a chamber for the intermediate storage of an atomised medicament preparation
Implementation Method 3
the particles (droplets) of the aerosol are largely deposited on the walls of the user's throat as a result of the high speed during direct inhalation
Data Source
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AI summary
An inhaler (1) is proposed for the propellant-free nebulisation of a medicament preparation. The inhaler produces an aerosol at low speed. The inhaler is combined with an add-on device (23) for intermediate storage of the aerosol produced, so as to allow easier inhalation, particularly for children.