Adhesion-Based Needle Retraction in Drug Delivery Devices
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Solution Overview
Problem
Existing drug delivery devices with retractable needles face challenges in securely connecting the plunger and needle assembly to retract the needle safely into the body unit, often requiring complex mechanisms that can be difficult to engage and may pose a risk of needle injury.
Innovation Solution
A drug delivery device design featuring a proximal end of the needle assembly and a distal end of the plunger configured for an adhesion connection, utilizing plane connecting surfaces that form a thin liquid film to create a strong adhesion force, allowing the needle assembly to be drawn back into the body unit with reduced resistance and without the need for high engagement forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a key-lock-mechanism is used to connect the plunger and needle assembly, then the connection strength is improved, but the device complexity increases and the ease of operation deteriorates
Solution Approach 1:
The patent replaces the mechanical key-lock connection system with an adhesion-based connection system. The plunger and needle assembly are connected through adhesion forces generated by a thin liquid film between their connecting surfaces, eliminating the need for complex mechanical interlocking mechanisms while maintaining connection strength.
Solution Approach 2:
The patent changes the physical state and properties of the connecting surfaces by introducing a liquid film. The adhesion connection relies on the physical and chemical properties of the liquid film (viscosity, surface tension, adhesion characteristics) rather than mechanical geometry, allowing for simpler device design while achieving reliable connection.
2Strength
If a key-lock-mechanism is used to connect the plunger and needle assembly, then the connection strength is improved, but the ease of operation worsens
Solution Approach 1:
The patent replaces the mechanical key-lock connection system with an adhesion-based connection system. The plunger and needle assembly are connected through adhesion forces generated by a thin liquid film between their connecting surfaces, eliminating the need for complex mechanical interlocking mechanisms while maintaining connection strength.
3Strength
If high engagement forces are used to connect the plunger and needle assembly, then the connection strength is improved, but the risk of needle injury increases
Solution Approach 1:
The patent replaces the mechanical key-lock connection system with an adhesion-based connection system. The plunger and needle assembly are connected through adhesion forces generated by a thin liquid film between their connecting surfaces, eliminating the need for complex mechanical interlocking mechanisms while maintaining connection strength.
Solution Approach 2:
The patent changes the physical state and properties of the connecting surfaces by introducing a liquid film. The adhesion connection relies on the physical and chemical properties of the liquid film (viscosity, surface tension, adhesion characteristics) rather than mechanical geometry, allowing for simpler device design while achieving reliable connection.
4Strength
If complex mechanical connection mechanisms are used, then the connection strength is improved, but the device complexity increases
Solution Approach 1:
The patent replaces the mechanical key-lock connection system with an adhesion-based connection system. The plunger and needle assembly are connected through adhesion forces generated by a thin liquid film between their connecting surfaces, eliminating the need for complex mechanical interlocking mechanisms while maintaining connection strength.
Solution Approach 2:
The patent changes the physical state and properties of the connecting surfaces by introducing a liquid film. The adhesion connection relies on the physical and chemical properties of the liquid film (viscosity, surface tension, adhesion characteristics) rather than mechanical geometry, allowing for simpler device design while achieving reliable connection.
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 adhesion connection mechanism enables safe and efficient retraction of the needle assembly into the body unit, reducing the risk of injury and simplifying the engagement process compared to traditional key-lock mechanisms, while maintaining the needle's position relative to the body unit to prevent further advancement.
Implementation Method 1
The proximal end of the needle assembly and the distal end of the plunger are configured such that they can get into an adhesion connection
Data Source
AI summary
Drug delivery device, comprising a body unit having a first opening and a second opening, a plunger arranged such that its distal end is positioned inside the body unit, wherein the plunger is moveable in the distal direction with respect to the body unit, a needle assembly, with a proximal end and a distal end comprising a needle, wherein the proximal end of the needle assembly and the distal end of the plunger are configured such that they can get into an adhesion connection.