Medication Injection Device Inverted Filling and Asymmetric Luer Lock
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Solution Overview
Problem
Current pre-filled syringe designs face issues such as air bubbles during medication delivery, mechanical force limitations, luer lock rotation, inability to provide multiple precise injections, compatibility problems with certain medications, and challenges with small gauge needles, leading to inefficiencies and device failures.
Innovation Solution
A medication delivery device with a syringe-like container body featuring a flange at the medication filling end and a ledge at the opposite end, a piston driven by a push rod, and a connector providing a medication outflow pathway, allowing for reduced air bubbles, precise small dose delivery, and incorporation of small gauge needles, while eliminating luer lock rotation and compatibility issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If medication is filled from the piston end in current pre-filled syringe design, then the filling process is simple, but air bubbles are generated during medication delivery
Solution Approach 1:
The patent inverts the traditional filling approach by filling medication from the needle end rather than the piston end. This reversal allows air bubbles to be naturally expelled during the filling process, eliminating the air bubble generation problem while maintaining manufacturing simplicity through the same basic filling equipment
2Ease of manufacture
If syringe inner diameter is smaller at the needle end to match manufacturing limits, then manufacturing is easier, but driving spring has less mechanical force at the needle end
Solution Approach 1:
The patent inverts the traditional syringe geometry by making the needle end have a larger inner diameter than the piston end. This inversion compensates for the reduced mechanical force at the needle end by providing more space for the driving spring to exert force, while the smaller piston end accommodates the piston movement requirements
3Reliability
If luer lock connection is used for glass syringe, then connection is secure, but luer lock rotates during assembling with needle
Solution Approach 1:
The patent introduces asymmetric features to the luer lock connection mechanism, including an asymmetric groove structure and corresponding asymmetric engagement elements. This asymmetry prevents rotation during assembly by ensuring that components can only engage in one specific orientation, eliminating the rotation problem while maintaining secure connection
4Strength
If steel needle is used in pre-filled container, then needle strength is sufficient, but Fe ions cause oxidization of epinephrine
Solution Approach 1:
The patent introduces an intermediary barrier layer between the steel needle and the epinephrine medication. This intermediate layer, typically made of inert material such as silicone or polymer coating, prevents direct contact between the steel needle and medication, thereby blocking the oxidation reaction while the needle maintains its structural strength
5Duration of action of stationary object
If tungsten ion is present in pre-filled glass syringe, then syringe durability is good, but tungsten ion causes aggregation of protein drug
Solution Approach 1:
The patent introduces an intermediary barrier layer between the glass syringe containing tungsten ion and the protein drug. This intermediate layer, typically a polymer or silicone coating, prevents direct interaction between the tungsten ion and protein drug, thereby preventing aggregation while maintaining the syringe's durability
6Measurement precision
If small gauge needle (32G) is required for injection, then injection precision is improved, but staked needle format is not feasible due to design and manufacturing limits
Solution Approach 1:
The patent inverts the traditional needle assembly approach by using a loose-fit needle configuration instead of a staked needle. This inversion allows small gauge needles to be easily assembled and disassembled without complex staking processes, making 32G and smaller needles feasible while maintaining injection precision
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 device effectively reduces air bubbles, enables precise delivery of small doses, prevents luer lock rotation, and ensures compatibility with various medications, allowing for multiple doses and varying injection volumes with the same container body, enhancing usability and reliability.
Implementation Method 1
the driving spring used in autoinjector for pre-filled syringe has less mechanical force when it reaches to the needle end of the syringe
Implementation Method 2
friction force between piston and container body gradually reduces during injection
Data Source
AI summary
An injection device is provided herein comprising a container body for holding medication content having a distal end and a proximal end, the container body providing an outward flange at the distal end and a ledge at the proximal end; a piston placed at the proximal end of the container body for sealing and displacing medication content; a push rod placed inside the container body for moving the piston distally; and a connector providing an orifice for medication content delivery, placed at said distal end of said container body. The orifice in the connector provides medication content injection fluid pathway. With modification of the fundamental structure, a number of innovative device designs are created.