Inhaler Needle and Hole Ratio for Low Flow Dry Powder Delivery
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Solution Overview
Problem
Existing inhalers with low resistance require high flow rates from patients to achieve a minimum pressure decrease of 4 kPa for effective delivery of dry powder medicaments to the lungs, which not all patients can achieve, leading to insufficient absorption of active agents.
Innovation Solution
The inhaler design features a specific ratio of needle diameter to hole diameter (0.1 to 1.0) and turbulence-inducing holes at the capsule chamber outlet to reduce the required flow rate and ensure effective delivery of dry powder medicaments, with diameters of 1 µm to 1000 µm, creating a Reynolds number greater than 4000 for effective turbulence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the inhaler resistance is reduced to facilitate inhalation, then the ease of operation is improved, but the flow rate required by the patient increases, making it difficult for some patients to achieve effective delivery of medicament
Solution Approach 1:
The patent changes the geometric parameters of the needle and hole dimensions to optimize the ratio between needle diameter and hole diameter. This parameter optimization creates a balance between device resistance and required flow rate, allowing effective medicament delivery at lower flow rates that most patients can achieve.
Solution Approach 2:
The patent introduces turbulence-inducing holes that create dynamic flow patterns in the capsule chamber. This dynamic turbulence effect enhances medicament aerosolization and delivery efficiency, allowing effective treatment at lower patient flow rates while maintaining ease of operation.
2Ease of operation
If the needle diameter to hole diameter ratio is optimized to reduce required flow rate, then the ease of operation is improved, but the device complexity increases due to precise dimensional requirements
Solution Approach 1:
The patent defines specific parameter ranges for needle diameter (0.1-1.0 mm) and hole diameter (0.01-0.1 mm) with a recommended ratio of 0.1 to 1.0. These parameter specifications provide manufacturing guidance that balances precision requirements with ease of operation, making the device both effective and manufacturable.
3Productivity
If turbulence is increased to enhance medicament delivery at low flow rates, then the productivity is improved, but the device complexity increases due to additional turbulence-inducing structures
Solution Approach 1:
The patent segments the air flow path by introducing separate turbulence-inducing holes (15a, 15b) distinct from the needle holes. This segmentation allows independent optimization of turbulence generation without complicating the overall device structure, enhancing medicament delivery efficiency while maintaining structural simplicity.
Solution Approach 2:
The turbulence-inducing holes act as intermediary structures that facilitate the transition from laminar to turbulent flow in the capsule chamber. These intermediary elements enhance medicament aerosolization and delivery at low flow rates without requiring complex mechanical components or additional power sources.
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 design allows for effective inhalation by most patients, ensuring sufficient delivery and absorption of active agents with uniform particle size distribution, reducing effort required and preventing agglomeration, thereby enhancing treatment efficacy.
Implementation Method 1
the ratio of the diameter of needles piercing the capsule to the diameter of the holes through which the needles pass and enter the capsule chamber in order to pierce the capsule is in the range of 0.1 to 1.0... creating a Reynolds number greater than 4000 for effective turbulence
Data Source
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AI summary
The present invention relates to an inhaler which is suitable for administration of drugs in dry powder form used in the prophylaxis and the treatment of respiratory tract diseases from capsules and enables inhalation of the medicament easily even at low flow rates in order to ensure an effective inhalation.