Injection Stopper With Deformable Insert for Viscous Drug Delivery
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Solution Overview
Problem
Existing medical injection devices face challenges in easily injecting high-viscosity compositions, leading to user effort and repetitive strain injuries, and suffer from mixing of compositions due to inadequate sealing and dead volume issues.
Innovation Solution
A stopper design comprising a gasket and pin, with a one-way membrane and fluidic pathways, ensures easy injection of high-viscosity compositions by minimizing user effort and preventing composition mixing until the first composition is fully injected, while reducing dead volume through collapsible design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stopper is designed to remain compressed in a distal position to prevent accidental injection, then patient safety is improved, but the device complexity increases due to additional components needed to maintain the compressed state
Solution Approach 1:
The stopper is segmented into a proximal portion and a distal portion with a through-hole, allowing the distal portion to be compressed into the proximal portion. This segmentation enables the stopper to achieve a compact stored state while maintaining structural integrity, reducing the need for additional locking components.
Solution Approach 2:
The distal portion of the stopper is compressed and nested within the proximal portion, creating a compact configuration when not in use. This nesting mechanism allows the stopper to maintain a low-profile stored state without requiring external retaining structures, thereby reducing device complexity while ensuring accidental injection prevention.
2Ease of operation
If a stopper is designed to be easily replaceable, then ease of operation is improved, but the risk of improper installation increases which may compromise sealing
Solution Approach 1:
The stopper incorporates a flange with radial lips at the proximal end, creating localized sealing features that engage with corresponding features in the barrel. This local quality enhancement ensures that even with simple replacement operations, proper seating and sealing are achieved through the specialized flange structure.
Solution Approach 2:
The stopper includes a visual indicator feature that changes appearance based on installation status. When the stopper is properly installed, the indicator displays a specific visual state, providing immediate feedback to the operator. This visual feedback mechanism ensures that ease of replacement does not compromise sealing integrity, as improper installation is immediately detectable.
3Reliability
If the stopper is retained in a proximal position by friction or mechanical means, then accidental injection is prevented, but the force required to replace the stopper increases
Solution Approach 1:
The stopper utilizes elastic deformation of the distal portion to achieve retention in the proximal position. The material's elastic properties provide continuous frictional engagement with the barrel without requiring rigid mechanical locking. This dynamic elastic retention prevents accidental injection while allowing controlled replacement with minimal force when needed.
Solution Approach 2:
The invention replaces complex mechanical retention systems (such as springs or latches) with an elastic friction-based retention mechanism. The distal portion of the stopper is designed to elastically deform and maintain frictional engagement with the barrel, providing reliable retention without the need for additional mechanical components that would increase replacement force requirements.
4Reliability
If the stopper material is highly elastic to maintain sealing, then sealing performance is improved, but the stopper may deform permanently under repeated compression cycles
Solution Approach 1:
The stopper is constructed from elastomeric materials specifically selected for their high elastic recovery properties and resistance to permanent deformation. The elastomeric composition allows the stopper to maintain sealing performance through repeated compression and expansion cycles while resisting material fatigue and permanent set, thus preserving both sealing performance and material stability.
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
Facilitates easy injection of high-viscosity compositions with reduced user effort, prevents composition mixing, and minimizes dead volume, enhancing precision and reducing waste.
Implementation Method 1
the stopper is adapted to deform between: a closed configuration wherein an outer surface (55) of the insert (50) sealingly engages an inner surface of the through hole (71)... and an open configuration wherein the protruding portion (60) of the insert abuts a distal end (104) of the barrel
Data Source
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AI summary
The present invention relates to a stopper (1) configured to be positioned inside a barrel (101) of an injection device (100), said stopper (1) comprising: - a gasket (10) comprising a holder (70) inserted in the gasket and a through hole (71), - an insert (50), wherein the stopper is adapted to deform between: - a closed configuration wherein an outer surface (55) of the insert (50) sealingly engages an inner surface of the through hole (71) for preventing flow of the composition between the proximal end (11) and the distal end (12) of the gasket, and a protruding portion (60) of the insert protrudes distally from the gasket (10), and - an open configuration wherein the protruding portion (60) of the insert abuts a distal end (104) of the barrel, and the outer surface (55) of the insert disengages from the through hole to open the fluidic pathway between the insert (50) and the barrel (101).