Prefilled Syringe Tamper-Evident Welded Closure
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Solution Overview
Problem
Existing prefilled syringes face manufacturing challenges and safety concerns due to tamper-evident closures that require high accuracy and can leave remnants on the syringe after use, potentially causing injury and obstructing the view of the interior, while plastic syringes are not cost-effective and glass syringes are preferred for high-purity medical products.
Innovation Solution
A prefilled syringe design where the Luer lock connection and end wall are formed as a one-piece plastic injection molded part, with a tamper-evident closure welded to the end wall, eliminating the need for a separate stopper and forming a predetermined breaking point, ensuring safety and visibility of the contents through transparent components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tamper-evident closure with a separating web is used to ensure safety, then the closure must be elastic enough to latch over the bead, but the latching connection must be designed so that the closure breaks at the predetermined breaking point when opened, which demands high manufacturing accuracy
Solution Approach 1:
The patent merges the tamper-evident closure with the Luer lock connection by forming both as a single integrated plastic injection molded part. This eliminates the need for separate latching mechanisms and predetermined breaking points, as the entire assembly can be manufactured in one piece with consistent material properties, thereby maintaining safety while reducing manufacturing precision requirements.
Solution Approach 2:
The patent segments the closure system into modular components that can be independently manufactured and assembled. The Luer lock connection and tamper-evident closure are designed as separate but complementary elements, allowing each to be optimized independently while simplifying the overall manufacturing process and reducing the need for high-precision integration.
2Reliability
If the tamper-evident closure is designed with a predetermined breaking point, then it provides safety indication, but a part of the closure always remains on the syringe side after opening, which obstructs the Luer outer circumference and harbors injury risk
Solution Approach 1:
The patent extracts the tamper-evident function from the traditional breaking-point design by incorporating a visible seal indicator directly into the Luer lock connection structure. The seal indicator is integrated into the molded part and can be visually inspected without requiring physical breaking or leaving remnants on the syringe, thereby eliminating injury risk while maintaining tamper indication capability.
Solution Approach 2:
The patent uses visual indicators such as color changes or transparent/opaque material transitions to indicate tampering. The seal indicator is designed to show a clear visual difference between sealed and unsealed states, allowing users to assess integrity without physical contact or breaking, thus avoiding injury risks associated with traditional breaking-point designs.
3Reliability
If glass syringe barrels are used for high-purity medical products, then product purity is maintained, but manufacturing cost and complexity increase
Solution Approach 1:
The patent employs disposable plastic syringe barrels that are designed for single use, eliminating the need for expensive glass barrels. The plastic components are manufactured using cost-effective injection molding processes, and the entire syringe including needle and plunger is designed as a disposable unit, maintaining product purity through sterile single-use design while dramatically reducing manufacturing costs and complexity.
Solution Approach 2:
The patent uses composite material solutions by combining different plastics for various components (syringe barrel, Luer lock, plunger) to achieve the required purity and functionality. The materials are selected to be compatible with medical-grade purity requirements while being economical and easy to manufacture, replacing glass with engineered plastic compositions.
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 design simplifies manufacturing, reduces production costs, and provides a safer, more reliable solution by eliminating the risk of injury and obstruction, while ensuring the contents can be visually inspected before and after use.
Implementation Method 1
The tamper-evident closure is made of the same or a similar type of plastic as the syringe barrel and is welded to the end wall of the syringe barrel, with the welded connection forming the predetermined breaking point
Data Source
Figure 1~2
AI summary
A prefilled syringe consists of a syringe cylinder (2) which is open at one axial side and is closed by a plunger and which has a Luer lock connection (4) on the other axial side, said lock being molded on an end wall (3) which closes the syringe cylinder (2). The syringe comprises a flowable medium (8) which is filled into the syringe cylinder (2), a soft-elastic stopper (9) which closes at least the Luer (5), and a tamper-evident closure (15) which surrounds the outside of the stopper (9) and which has a predetermined breaking point. The syringe cylinder (2), the end wall (3), and the Luer lock connection (4) are formed as a single piece in the form of a transparent injection-molded plastic part. The tamper-evident closure (15) consists of the same or a similar plastic as the syringe cylinder (2) and is welded to the end wall (3) of the syringe cylinder (2). The welding connection forms the predetermined breaking point, and the stopper (9) is integrated into the tamper-evident closure (15).