Injection Stopper with Switchable Seal for Viscous Drug Delivery
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Solution Overview
Problem
Existing medical injection devices face challenges in easily injecting high-viscosity compositions, causing user strain and repetitive injuries, and suffer from mixing of contents due to inadequate sealing and dead volume issues, leading to inaccuracies and waste.
Innovation Solution
A stopper design featuring a gasket and insert that transitions between closed and open configurations, ensuring optimal sealing and minimizing dead volume, allowing easy injection of viscous compositions while preventing mixing until the first composition is fully expelled.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a small diameter opening is provided in the mobile diaphragm to prevent mixing of two solutions, then sealing between chambers is improved, but the force required to inject the second solution increases significantly
Solution Approach 1:
The stopper is designed to transition between two dynamic states: a first configuration where the stopper maintains a sealed position with the opening closed to prevent mixing, and a second configuration where the stopper shifts to open the fluidic pathway for injection. This dynamic reconfiguration allows the system to optimize for both sealing and ease of injection at different operational stages.
Solution Approach 2:
The stopper is pre-configured with an asymmetric structure including an eccentric protrusion that, when subjected to injection force, automatically triggers a pivoting motion. This preliminary design ensures that once injection begins, the stopper self-activates to the open configuration, reducing the sustained force needed by the user.
2Reliability
If a plug with flanges and eccentric protrusion is used to separate chambers, then chamber separation is achieved, but user effort during injection increases and sealing reliability decreases
Solution Approach 1:
The invention replaces the rigid plug with flanges with a flexible membrane stopper. The membrane material provides adequate sealing between chambers while allowing the stopper to deform and pivot more easily during injection, significantly reducing the force required from the user compared to rigid flanged plugs.
3Reliability
If a small opening diameter is used in the diaphragm, then mixing prevention is improved, but injection difficulty increases due to high force requirements
Solution Approach 1:
The stopper transitions from a sealed configuration with the opening closed to an open configuration during injection. This dynamic behavior allows the system to maintain small opening dimensions for effective mixing prevention while enabling easy injection through the configuration change that opens the pathway.
4Reliability
If the stopper remains in a fixed sealed position, then mixing prevention is maintained, but dead volume increases and injection accuracy decreases
Solution Approach 1:
The stopper dynamically reconfigures during operation, transitioning from a sealed position that prevents mixing to an open position that enables complete expulsion of the first composition. This ensures both mixing prevention and accurate dosage delivery by eliminating dead volume.
Solution Approach 2:
The asymmetric stopper design with eccentric protrusion is pre-configured to automatically trigger the configuration change at the appropriate moment, ensuring that the transition to the open state occurs precisely when needed to minimize dead volume and maximize injection accuracy.
Data Source
AI summary
The present disclosure relates to a stopper configured to be positioned inside a barrel of an injection device for injecting at least one composition, said stopper including: a gasket including a proximal end, a distal end, a lateral wall, and a through hole extending from the proximal end to the distal end, an insert inserted in the through hole, wherein the stopper is adapted to deform between: a closed configuration wherein the gasket cooperates with the insert to hermetically close the through hole, for preventing flow of the composition between the proximal end and the distal end of the gasket, and an open configuration wherein the gasket cooperates with the insert to open a fluidic pathway in the through hole between the proximal end and the distal end of the gasket for allowing flow of the composition.