Deformable Stopper Reducing Breakout Force in Medical Syringes
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Solution Overview
Problem
Medical syringe technology faces challenges with high initial breakout force required to slide the plunger due to static friction, which can lead to uneven application and difficulty in actuating the syringe, especially when storing or delivering medical agents like biologics, where traditional lubricants may cause protein aggregation or harm.
Innovation Solution
A stopper arrangement within a hollow body, actuated by a post that transitions from a static to an advancing state, reducing static friction by radially contracting and axially stretching the primary wall, thereby reducing the breakout force, and providing an aseptic barrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional rigid stoppers are used in syringes, then the sealing barrier is strong, but the breakout force required to slide the plunger is high due to static friction
Solution Approach 1:
The stopper is designed with dynamic deformation capabilities, transitioning from a rigid static state to a flexible advancing state. The stopper wall includes a deformation zone that allows controlled radial contraction and axial stretching during plunger movement, enabling the stopper to adapt its mechanical properties during operation to reduce breakout force while maintaining sealing.
Solution Approach 2:
The stopper's physical parameters change during operation: the wall thickness varies along the axial direction with a minimum thickness at the deformation zone, and the material properties are optimized to allow controlled deformation. This parameter variation enables the stopper to balance sealing strength with reduced friction during plunger sliding.
2Ease of operation
If silicone lubricants are used to reduce static friction, then piston glide improves, but protein aggregation occurs reducing efficacy or causing harm
Solution Approach 1:
The harmful silicone lubricant layer is completely removed from the system. Instead of using external lubrication, the invention achieves smooth piston glide through the intrinsic deformation capability of the stopper structure itself, eliminating the source of protein aggregation and harm while maintaining ease of operation.
Solution Approach 2:
The stopper serves its own lubrication function through controlled deformation of its wall structure. The deformation zone allows the stopper to self-adjust during plunger movement, reducing friction without requiring external lubricants that could contaminate the pharmaceutical agent.
3Reliability
If high compressive load is applied to the stopper sidewall to improve barrier quality, then sealing is enhanced, but static friction increases making actuation difficult
Solution Approach 1:
The stopper wall is segmented into different zones with distinct functions: a sealing zone with higher compressive load for barrier quality, and a deformation zone with reduced wall thickness for flexibility. This segmentation allows the stopper to provide both strong sealing and easy actuation by distributing the compressive load non-uniformly along the axial direction.
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 solution reduces the initial force needed to initiate the withdrawal or discharge of medical agents, ensuring smooth operation and preventing contamination, while being compatible with emerging medical therapies.
Implementation Method 1
the primary wall of the stopper may be radially contracted and axially stretched. Such actuation may reduce the compression of the primary wall against the sidewall, thereby reducing the static friction force/breakout force
Implementation Method 2
the stopper may provide an aseptic barrier preventing the entry of contaminating particles such as pathogens, pyrogens, viruses, bacteria, etc.
Data Source
AI summary
Disclosed is an administration device able to transition between a static state and an advancing state. The administration device includes a stopper and an actuator with a post, both disposed within a hollow body that has a sidewall disposed radially within along its longitudinal length. The actuator and post can move axially within the hollow body. The stopper has a primary wall configured to exert a pressure to seal against the sidewall when the post is in a first position. This seal can provide an aseptic barrier and prevent communication of contaminating particles such as pathogens, pyrogens, viruses, bacteria, and across the seal.