Expandable Tube End-of-Dose Detection for Needle Retraction
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Solution Overview
Problem
Existing drug delivery systems face challenges in maintaining contact between the device and the patient's skin during prolonged injections, especially for volumes above 1 mL, and in automatically withdrawing the needle after the dose is complete.
Innovation Solution
A drug delivery system with a needle actuator assembly and an expandable tube that expands during medicament delivery, deflating at the end of the dose to allow needle retraction, and an end-of-dose detection assembly that prevents needle movement during delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the injection time is increased to deliver larger volumes of fluid, then the injection capacity is improved, but the patient's ability to maintain contact between the device and target area deteriorates
Solution Approach 1:
The device automatically maintains contact with the patient's skin through the needle actuator assembly that self-adjusts during injection. The expandable portion of the tube provides automatic feedback to the needle actuator to maintain proper positioning without requiring patient intervention throughout the extended injection period.
Solution Approach 2:
The expandable portion of the tube acts as a feedback mechanism that communicates injection progress and pressure changes to the needle actuator assembly, enabling automatic adjustment of needle position to maintain contact stability during prolonged injection procedures.
2Quantity of substance
If the injection time is extended for larger volumes, then the injection capacity is improved, but the device stability during injection deteriorates
Solution Approach 1:
The needle actuator assembly incorporates movable portions that can dynamically adjust during injection to maintain optimal contact. The expandable tube portion provides real-time dynamic feedback about injection status to enable continuous stabilization adjustments throughout the extended injection period.
3Extent of automation
If automatic needle withdrawal is implemented at end of dose, then the automation level is improved, but the complexity of the detection mechanism increases
Solution Approach 1:
The expandable portion of the tube serves as an intermediary element that translates injection pressure changes into mechanical feedback for the needle actuator. This intermediary mechanism enables automatic end-of-dose detection and needle withdrawal without requiring complex electronic sensors or control systems.
4Reliability
If the needle actuator is prevented from moving during delivery, then the injection reliability is improved, but the flexibility of needle positioning deteriorates
Solution Approach 1:
The needle actuator assembly is segmented into movable and fixed portions that work in coordination. The expandable tube portion creates distinct functional zones that allow the needle to be securely held during injection while maintaining the capability for controlled positioning adjustments when needed.
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
Ensures stable needle withdrawal after the dose is completed, maintaining device-patient contact and facilitating smooth injection processes for larger volumes without user intervention.
Implementation Method 1
The expandable portion is configured to be in the expanded state upon actuation of the drive assembly and a non-expanded state when the needle is in the post-use position
Implementation Method 2
the tube comprising an expandable portion having an expanded state and a non-expanded state
Implementation Method 3
a needle actuator assembly comprising a movable portion biased by a biasing member and configured to move the needle between a pre-use position, a use position for delivery of the medicament to the patient, and a post-use position after delivery of the medicament is completed
Data Source
AI summary
A drug delivery system having an end-of-dose detection arrangement for injecting a medicament. The system including a container configured to receive a medicament, a drive assembly which, upon actuation, is configured to expel the medicament from the container, a needle for injecting the medicament to a patient, a needle actuator assembly comprising a movable portion biased by a biasing member and configured to move the needle between a pre-use position, a use position for delivery of the medicament to the patient, and a post-use position after delivery of the medicament is completed, and a tube in fluid communication with the container and the needle, the tube comprising an expandable portion having an expanded state and a non-expanded state, wherein the expandable portion is configured to be in the expanded state upon actuation of the drive assembly and a non-expanded state when the needle is in the post-use position.