Dynamic Flow Governor for Medicinal Inhalers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional pressurized metered dose inhalers (pMDIs) face challenges in delivering aerosolized medicaments effectively due to poor coordination between inhalation and dose release, leading to sub-optimal flow rates and variability in drug deposition, which can result in reduced therapeutic benefits for patients with respiratory diseases like asthma and COPD.
Innovation Solution
The development of a flow governor assembly that dynamically adjusts air flow resistance based on pressure drop, incorporating a tubular element with flexible walls that flex inwardly and an internal support structure to maintain a predetermined cross-sectional area, allowing for consistent inhalation flow rates and reducing inter-patient and intra-patient variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional pMDI devices are used with press-and-breathe coordination, then device simplicity is maintained, but inhalation flow rate consistency and drug deposition reliability deteriorate
Solution Approach 1:
The flow governor incorporates a flexible tubular element that dynamically changes its cross-sectional area in response to varying inhalation flow rates. As flow rate increases, the flexible wall flexes inwardly, increasing flow resistance to maintain consistent governing flow rate. This dynamic adaptation resolves the contradiction by automatically adjusting to patient inhalation variability without requiring complex electronic controls.
Solution Approach 2:
The flow governor changes the physical parameter of flow resistance dynamically based on flow rate conditions. The flexible tubular element's cross-sectional area changes in response to flow rate, thereby changing the resistance parameter to maintain consistent governing flow rate. This parameter change approach allows the system to maintain reliability of drug deposition while preserving ease of operation.
2Speed
If high inspiratory flow rates are used, then inhalation speed increases, but drug deposition on the back of the throat increases and lung penetration decreases
Solution Approach 1:
The flow governor provides dynamic flow resistance that increases with flow rate. When patients inhale at high speed, the flexible tubular element flexes inwardly to increase resistance, automatically reducing the governing flow rate to the optimal range. This prevents excessive drug deposition on the back of the throat while allowing patients to inhale at their natural speed without restriction.
3Object-generated harmful factors
If low inspiratory flow rates are used, then throat deposition is reduced, but aerosol entrainment quality deteriorates
Solution Approach 1:
The flow governor automatically adjusts flow resistance to maintain the governing flow rate within the optimal range of 30-60 L/min. When flow rate is too low, the flexible element maintains its shape to provide lower resistance, allowing improved aerosol entrainment. When flow rate exceeds the optimal range, the flexible element flexes to increase resistance. This dynamic balance resolves the contradiction between reducing throat deposition and maintaining aerosol entrainment quality.
4Ease of operation
If flow governor with flexible tubular element is added, then inhalation flow rate control improves, but device complexity increases
Solution Approach 1:
The flow governor is designed to be self-regulating without requiring external power sources, electronic controls, or complex mechanisms. The flexible tubular element automatically adjusts its cross-sectional area in response to flow rate changes, providing flow control through passive elastic deformation. This self-service approach improves inhalation flow rate control while minimizing the increase in device complexity.
Solution Approach 2:
The flow governor utilizes a flexible tubular element with elastic walls that deform in response to flow rate changes. This flexible shell structure provides the necessary flow control function through simple elastic deformation rather than complex mechanical or electronic mechanisms, thereby improving flow rate control while limiting the increase in device complexity.
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 flow governor assembly enhances the consistency of inhalation flow rates, improving drug deposition in the lungs and reducing variability, thereby increasing the therapeutic effectiveness of pMDIs by ensuring a more reproducible delivery of medicaments.
Implementation Method 1
a flow governor positioned in the air flow path between the air inlet and the air outlet to govern air flow to a target volumetric flow rate. The flow governor can be configured to provide a dynamic resistance to air flow in the air flow path as a function of air pressure drop between an inlet and an outlet of the flow governor
Implementation Method 2
a tubular element that defines at least a portion of an air flow path, the tubular element comprising at least one flexible wall configured to flex inwardly in response to an air flow in the air flow path
Implementation Method 3
an internal support structure, located within the tubular element and configured to preserve at least a predetermined cross-sectional area of the air flow path within the tubular element when the at least one flexible wall of the tubular element flexes inwardly
Data Source
AI summary
A flow governor assembly for use with a medicinal inhaler. The assembly can include a housing that defines an air flow path; a flow governor positioned in the air flow path to govern air flow in the air flow path to a target governing volumetric flow rate; and a constriction in the air flow path. The flow governor can be configured to provide a variable, or dynamic, resistance to air flow in the air flow path as a function of air pressure drop between an inlet and an outlet of the flow governor. The constriction can be configured to provide a fixed, or static, resistance to air flow in the air flow path.