Sensor-Based End-of-Dose Switch for Insulin Pen
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Solution Overview
Problem
Self-administration of insulin using pen-type drug delivery devices often results in inaccurate dose recording due to incorrect use, where users may release pressure before the full dose is dispensed, leading to underdosing and potential errors in dose logging.
Innovation Solution
A drug delivery device with a sensor-based end-of-dose switch mechanism that records the duration of pressure application and generates an error code if the dose delivery is incomplete, featuring a first sensor element on the drug delivery mechanism and a second sensor element within the housing, which triggers a switch position to ensure accurate dose logging and alert the user to incomplete dosing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanical stop position is used to indicate end of dose, then the device structure is simple, but users may release pressure before the full dose is dispensed leading to inaccurate dose recording
Solution Approach 1:
The patent replaces the purely mechanical stop position system with a sensor-based detection system. A sensor (optical, magnetic, or capacitive) detects when the drug delivery mechanism reaches the end of its travel, providing electronic feedback to the controller. This substitution allows for more precise dose recording by detecting the actual moment the mechanism stops, rather than relying on a mechanical stop that may be reached before complete dose delivery.
Solution Approach 2:
The patent implements a feedback mechanism where the sensor continuously monitors the position of the drug delivery mechanism and provides real-time feedback to the controller. The controller compares the detected position with the expected end position and can detect when the user releases pressure prematurely. This feedback loop enables accurate dose recording by detecting the actual end of dose delivery, regardless of mechanical stop position.
2Reliability
If the end of dose switch is triggered immediately when pressure is released, then the response time is fast, but it may trigger before the complete dose is dispensed causing false errors
Solution Approach 1:
The patent performs preliminary detection of the end of dose delivery using the sensor before triggering the error code. The sensor detects when the drug delivery mechanism reaches its end position, and the controller waits for a predetermined time period to ensure complete dose delivery. This preliminary action allows the system to prepare for error detection while accounting for the time needed to complete the dosing sequence.
Solution Approach 2:
The patent introduces a dynamic time period that can be adjusted based on the specific dosing scenario. The controller monitors the duration between sensor trigger and user pressure release, and only generates an error code if this duration exceeds the predetermined threshold. This dynamic approach allows the system to adapt to different user speeds and ensure accurate error detection without false positives.
3Ease of operation
If no error detection mechanism is provided, then the device is simple to operate, but users cannot be alerted to incomplete dosing leading to underdosing
Solution Approach 1:
The patent provides feedback to the user through visual, auditory, or haptic signals when the sensor detects premature pressure release. The controller compares the actual dose delivered with the expected dose and provides immediate feedback to the user. This feedback mechanism maintains ease of operation by providing clear, intuitive signals without complex interfaces, while ensuring complete dosing through real-time monitoring and user alerting.
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 device effectively prevents underdosing by recording the complete dose dispensed and alerting the user to potential errors, ensuring accurate logging and user awareness of correct dosing, with a delay period set to account for human reaction time to minimize errors.
Implementation Method 1
an end of dose switch configured to be triggered when relative movement of the first sensor element and the second sensor element causes the first and second sensor elements to move into a switch position
Implementation Method 2
a drug delivery mechanism provided at least partially within the housing and displaceable between a pre-delivery position and a mechanical stop position to dispense medicament from the drug delivery device when a user presses down on a proximal end of the drug delivery mechanism
Data Source
AI summary
A drug delivery device includes a housing, a drug delivery mechanism within the housing and displaceable between pre-delivery and mechanical stop positions, and an end of dose switch. The end of dose switch includes a first sensor disposed on the drug delivery mechanism and a second sensor element disposed within the housing. The switch is configured to be triggered when relative movement of the first and second sensors causes the first and second sensor elements to move into a switch position. The delivery mechanism is biased in a proximal direction away from the mechanical stop position. The device includes a controller configured to: record when the end of dose switch is triggered;measure a duration of time between triggering the switch and the first and second sensors moving out of the switch position; and generate an error code indicative of a deviation between manipulations applied and a predetermined handling scheme.