Prefilled Syringe Cap Protrusion for Faster Lyophilizate Dissolution
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Solution Overview
Problem
Lyophilizates and powders in prefilled syringes often solidify in lumps, leading to prolonged dissolution times due to reduced surface area contact with the solution, hindering efficient use.
Innovation Solution
A prefilled syringe design featuring a surface area increasing member, such as a protrusion or protrusions, that increases the contact area between the solidified lyophilizate or powder and the solution by forming recesses or through holes, facilitating easier dissolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lyophilizate or powder is enclosed in a prefilled syringe, then the medicine can be stored in solid form, but the medicine solidifies in a lump with small surface area contact with the solution
Solution Approach 1:
The cap is divided into multiple functional parts: a sealing portion that seals the distal end of the syringe tip, and a protrusion that extends into the syringe body to increase surface area contact. This segmentation allows the cap to simultaneously perform sealing and surface area enhancement functions, resolving the contradiction between storage stability and dissolution efficiency.
Solution Approach 2:
The protrusion extends in the axial direction from the sealing portion, adding a dimensional element into the syringe body. This axial extension creates additional contact surfaces with the lyophilizate or powder, transforming the limited surface area of a simple cap into a multi-faceted contact structure that enhances dissolution while maintaining storage stability.
2Ease of manufacture
If the medicine is solidified in a lump, then storage is simplified, but the dissolution time is prolonged
Solution Approach 1:
The protrusion is pre-formed on the cap before use, positioned to contact the lyophilizate or powder lump. When the cap is attached to the syringe tip, the protrusion automatically engages with the solidified medicine, preliminarily creating surface area contact that will facilitate faster dissolution when solution is introduced, thus reducing dissolution time while maintaining storage simplicity.
Solution Approach 2:
The protrusion acts as an intermediary structure between the cap and the lyophilizate/powder lump. It mediates the interaction by providing additional contact surfaces that transfer solution to the solidified medicine more effectively, accelerating dissolution without requiring changes to the storage format or medicine formulation.
3Device complexity
If a simple cap is used to seal the syringe tip, then the device complexity is reduced, but the surface area contact with the medicine is insufficient
Solution Approach 1:
The cap is designed with multi-functionality: it provides sealing of the syringe tip distal end, structural support, and surface area enhancement through the protrusion. This universal design allows a single component to fulfill multiple roles, increasing surface area contact with the medicine while avoiding the need for additional separate components, thus maintaining relatively simple device complexity.
Solution Approach 2:
The sealing function and surface area enhancement function are merged into a single cap structure. The protrusion is integrated as part of the cap body, combining what could have been separate components (sealing element and surface area increasing element) into one unified component, thereby increasing surface area contact while keeping the device complexity low.
Data Source
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AI summary
A prefilled syringe (10) includes a barrel body (12), a gasket (20) that seals a proximal end side of a medicine chamber (18) of the barrel body, and a cap (14) that is attached to a tip (30) and seals a distal end side of the medicine chamber. The cap includes a surface area increasing member (48) that extends to the proximal end side, is inserted into a flow path of the tip, and protrudes to the medicine chamber to increase a surface area of a medicine (19) solidified in a lump in the medicine chamber.