Needle Shield Assembly Oxygen Barrier Design
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Solution Overview
Problem
Existing rigid needle shields allow oxygen penetration during sterilization, degrading medicaments and reducing the shelf life of syringes, as the inner core is gas permeable and cannot prevent oxygen exposure.
Innovation Solution
A needle shield assembly with a flexible inner shield and a rigid outer shield featuring passages for sterilization agents, accompanied by an oxygen-impermeable cover element to prevent oxygen ingress, and optional gripping elements for easy removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner core is made gas permeable to allow sterilization, then sterilization effectiveness is improved, but oxygen penetration occurs after sterilization degrading the medicament
Solution Approach 1:
The needle shield is divided into two functional layers: an outer gas-permeable layer for sterilization and an inner oxygen-impermeable layer for protection. This segmentation allows each layer to perform its specific function without compromising the other, resolving the contradiction between sterilization effectiveness and oxygen barrier properties
Solution Approach 2:
The needle shield combines materials with different gas permeability characteristics - an outer material permeable to sterilization gases and an inner material impermeable to oxygen. This composite structure enables simultaneous achievement of sterilization access and oxygen exclusion, directly addressing the technical contradiction
2Ease of manufacture
If passages are provided in the outer cover for sterilization, then sterilization access is improved, but oxygen exposure of the medicament occurs
Solution Approach 1:
Different regions of the needle shield have different gas permeability properties - the outer surface allows sterilization gas passage while the inner surface provides oxygen barrier protection. This local differentiation of material properties enables sterilization access without compromising medicament stability
Solution Approach 2:
The inner oxygen-impermeable layer acts as an intermediary barrier between the external environment (including oxygen) and the medicament in the needle. This intermediate layer allows sterilization gases to pass through the outer layer while blocking oxygen from reaching the medicament
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 solution effectively minimizes oxygen exposure, prolonging the shelf life of medicaments by ensuring the interior of the injection needle remains oxygen-free post-sterilization.
Implementation Method 1
The inner core is gas permeable so that the sterilizing gas may reach the injection needle during the sterilization operation
Implementation Method 2
the cover element is made of an oxygen-impermeable material... prevent the interior of the injection needle from being exposed to oxygen via the passages
Data Source
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Figure 3
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AI summary
The present invention relates to a needle shield assembly for a syringe (10), comprising an inner needle shield (16) which is flexible and designed to enclose a major part of a hollow injection needle (18) of said syringe; an outer needle shield (20) which is rigid and designed to enclose a major part of said inner needle shield (16), which outer needle shield (20) is arranged with a number of passages (22) for allowing sterilizing agents to reach said injection needle (18) during a sterilization process. The invention is characterised in that said needle shield assembly further comprises a cover element (24; 36; 46) arranged adjacent said passages (22) such as to prevent the interior of said injection needle (18) from being exposed to oxygen via said passages (22) of said outer needle shield (20) after said sterilization process.