Injection Pressure Sensing for Accurate Dose Completion
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Solution Overview
Problem
Existing injection devices lack effective methods for monitoring injection duration and compliance, particularly in autoinjectors, which are crucial for ensuring proper medication delivery and device functionality.
Innovation Solution
A medicament delivery device equipped with a pressure sensor that measures pressure changes within a cavity to determine injection duration, using a flexible lip or valve to maintain threshold pressure and detect injection start and end times, and optionally includes a plunger with slits for atmospheric connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is integrated into an injection device, then dosing accuracy and patient safety are improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The pressure sensor is integrated directly into the injection device housing, merging the sensing function with the existing device structure. The sensor is positioned to detect pressure changes in the fluid pathway, combining measurement capability with the delivery mechanism without requiring separate external monitoring systems.
Solution Approach 2:
The pressure sensor serves multiple functions: it monitors pressure during injection to ensure accurate dosing, detects blockages in the fluid pathway, and provides safety feedback to the control system. This multi-functionality reduces the need for additional specialized components.
2Measurement precision
If a pressure sensor is integrated into an injection device, then dosing accuracy is improved, but manufacturing precision requirements increase
Solution Approach 1:
The pressure sensor is pre-assembled with its signal processing circuitry in a modular unit before integration into the injection device. This preliminary assembly allows for quality control and calibration of the sensing system independently, reducing the precision requirements for the final integration step.
Solution Approach 2:
A flexible conduit or fluid pathway is used as an intermediary between the pressure sensor and the injection site. This flexible connection accommodates manufacturing tolerances while maintaining effective pressure transmission, reducing the need for perfectly precise rigid alignments.
3Reliability
If pressure monitoring is implemented, then patient safety is improved, but the device complexity increases
Solution Approach 1:
The pressure sensor continuously monitors fluid pathway pressure and provides real-time feedback to the control system. When abnormal pressure levels are detected (indicating potential blockage or dosing error), the system automatically adjusts or alerts the user, creating a closed-loop safety mechanism.
Solution Approach 2:
The pressure monitoring system is integrated into the device's own control architecture, using the device's existing processor and power supply. The sensor leverages the device's own operational parameters (pump speed, fluid flow) to self-diagnose and self-regulate, rather than requiring external monitoring equipment.
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
Accurately monitors injection duration and compliance, preventing stalling and ensuring complete medication delivery, while being applicable to various injection devices including autoinjectors, syringes, and patch-type infusion devices.
Implementation Method 1
The pressure sensor (e.g., 130) may include a piezoelectric element (e.g., 132) that generates an electrical signal in response to applied pressure.
Data Source
Figure 1a
Figure 1b~2
Figure 3
AI summary
The present application relates to pressure sensors for injection devices. According to a first aspect, the specification discloses an injection device comprising: a medicament container comprising medicament container walls and a sealing element; a stopper translatably disposed inside the medicament container; a pressure sensor; and a plunger passing through an axial bore of the sealing element, the plunger being operable to displace the stopper, wherein the sealing element, stopper and medicament container walls define a cavity inside the medicament container; and wherein the pressure sensor is configured to measure the pressure inside the cavity during an injection.