Breakable Spacer Dosing Aid for Precise Syringe Volumes
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Solution Overview
Problem
Existing syringes lack precision and user-friendliness for administering exact dosages, particularly in applications like intravitreal injections, where small volumes must be accurately delivered, and prefilled syringes with fixed doses fail to account for individual patient needs.
Innovation Solution
A dosing aid comprising a cylinder with a manually breakable spacer and stop for the piston, allowing adjustable volume settings by breaking off sections at predetermined points, detachably connected to the syringe to set precise doses without requiring scale reading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional syringe with scale is used, then the syringe can indicate the amount of fluid dispensed, but the user must look at the scale during operation which is annoying and prone to reading errors
Solution Approach 1:
The dosing aid acts as an intermediary device between the syringe and the user. It includes a scale that is detachably connected to the syringe barrel, allowing the user to read the dose indication on the dosing aid rather than directly on the syringe scale during operation. This intermediary scale provides the necessary measurement information while improving ease of operation by eliminating the need to look at the syringe scale during injection.
Solution Approach 2:
The dosing aid is segmented into separate components: a scale component and a dosing aid body that can be detachably connected to the syringe. This segmentation allows the scale to be separated from the syringe barrel, enabling the user to read dosing information on the dosing aid body rather than on the syringe itself during operation, thus improving ease of operation while maintaining measurement precision.
2Measurement precision
If a conventional syringe with equidistant scale intervals is used, then the syringe can indicate dose volumes, but it is difficult to position the plunger precisely at a predetermined point when filling the syringe
Solution Approach 1:
The dosing aid incorporates local quality enhancements at specific positions along the scale. The scale is divided into segments with non-uniform interval spacing, where the intervals are smaller near the beginning of the scale and larger toward the end. This local quality variation makes it easier to position the plunger precisely at predetermined points, especially at critical low-volume positions, while maintaining overall dose indication accuracy.
Solution Approach 2:
The dosing aid allows for preliminary positioning of the plunger at predetermined points on the scale before filling the syringe. The scale design with optimized intervals enables the user to easily position the plunger at the desired volume mark during the filling process, ensuring precise dosing preparation before the actual injection occurs.
3Ease of manufacture
If prefilled syringes with fixed doses are used, then the syringe is pre-prepared for injection, but the dose cannot be adapted to individual patient needs
Solution Approach 1:
The dosing aid introduces dynamic adjustability to the otherwise fixed prefilled syringe system. The detachable scale and dosing aid body can be configured at different positions along the syringe barrel, allowing the effective dosing volume to be dynamically adjusted after filling. This enables adaptation to individual patient needs while maintaining the simplicity of prefilled syringe preparation.
Solution Approach 2:
The dosing aid is segmented into a scale component and a body component that can be detachably connected to the syringe. This segmentation allows the dosing aid to be configured at different positions along the syringe barrel, enabling dose adjustment for different patient needs while maintaining the pre-filled syringe format. The segmented design preserves ease of manufacture for prefilled syringes while adding adaptability.
4Measurement precision
If a dosing aid with detachable connection is used, then precise dose settings are achievable, but the dosing aid requires manual breaking off of sections which adds complexity
Solution Approach 1:
The dosing aid is segmented into a scale component and a body component connected by a detachable connection mechanism. This segmentation allows the dosing aid to be attached to and removed from the syringe barrel, providing precise dose settings through the detachable connection while keeping the overall structure relatively simple and manageable.
Solution Approach 2:
The dosing aid with its detachable connection and breakable sections is designed as a single-use component that is discarded after one use. This disposable approach simplifies the overall system complexity by eliminating the need for cleaning, sterilization, and maintenance of the dosing aid mechanism, while still providing precise dose settings during the single use period.
Data Source
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AI summary
For adjusting the volume (17) that can be delivered by a syringe (1), a dosing aid (13) with a spacer (14) is proposed, which can be detachably connected to the syringe (1), wherein the spacer (14) forms a stop (15) for the piston (3) that limits the distal advance of the piston (3) and is connected to a manually breakable section (14') via at least one predetermined breaking point (18).