Syringe Sensor for Fluid Flow Measurement via Pressure Differential
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Solution Overview
Problem
There is a lack of devices capable of accurately monitoring patient adherence to injectable therapeutic agent regimens, particularly for standard pre-fillable syringes, which are essential for ensuring the accuracy and consistency of drug delivery in self-administered treatments.
Innovation Solution
A device comprising a syringe barrel, plunger, and sensor that measures fluid flow by detecting pressure differential caused by ambient air entering the syringe, allowing for the calculation of the volume of liquid expelled, thereby providing an objective means to monitor drug adherence and delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure differential measurement is used to measure fluid flow, then measurement precision is improved, but device complexity increases due to additional sensor ports and fluid communication pathways
Solution Approach 1:
The patent uses ambient air as an intermediary fluid to create a pressure differential that reflects the actual drug flow. The air enters through the proximal port when the plunger moves, creating a measurable pressure change without requiring direct contact with the drug solution. This mediator approach enables indirect but accurate measurement of fluid flow while maintaining device simplicity.
2Device complexity
If plunger displacement measurement is used to calculate drug volume, then device complexity is reduced, but measurement precision deteriorates due to seal leakage and incomplete plunger contact
Solution Approach 1:
The patent replaces the mechanical plunger displacement measurement system with a pressure-based measurement system. Instead of mechanically tracking plunger position and calculating volume from displacement, the system uses pressure differential sensing to directly measure fluid flow. This substitution eliminates errors from seal leakage and incomplete plunger contact while providing more accurate real-time flow measurement.
3Ease of operation
If standard pre-fillable syringes are used for patient self-injection, then ease of operation is improved, but reliability deteriorates due to lack of adherence monitoring capability
Solution Approach 1:
The patent incorporates a feedback mechanism by measuring and recording the actual drug delivery through pressure differential sensing. The system provides real-time data on whether the full prescribed dose was administered, enabling verification of patient adherence. This feedback loop transforms a passive syringe into an active monitoring device that confirms proper usage without interfering with the simplicity of self-injection.
4Reliability
If complex wearable injection devices are used to monitor adherence, then reliability is improved, but ease of operation deteriorates and adaptability decreases due to incompatibility with standard syringes
Solution Approach 1:
The patent creates a universal monitoring system that can be applied to standard pre-fillable syringes through the addition of a sensor assembly with ports configured to interface with the syringe barrel. The design accommodates various syringe types and sizes while maintaining the same measurement principle. This universal approach enables adherence monitoring across different therapeutic agents and syringe formulations without requiring device-specific customization.
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
Enables accurate monitoring of drug adherence and delivery, suitable for low-volume syringes, and can be retrofitted into existing injection systems without major modifications, ensuring precise tracking of drug administration without relying on plunger displacement measurements.
Implementation Method 1
a sensor configured to measure pressure-differential cause by a flow of fluid on the non-drug contact side of the syringe plunger
Data Source
AI summary
A device and method for measuring a volume of liquid expelled from a syringe is provided. The device generally includes a syringe barrel, a plunger actuated with a plunger rod, and a sensor. The sensor may include two ports with one port being in fluid communication with a source of fluid external to the syringe barrel, while the second port is in fluid communication either with a proximal end portion of the syringe barrel or a hollow plunger rod having a first end closed by the plunger. The method may include expelling liquid from the syringe; detecting and recording differential pressure with the sensor over time; and calculating the volume of liquid expelled from the syringe from the recorded differential pressure over time.