Electroosmotic Pump Pulse Control for Drug Injection Blockage
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Solution Overview
Problem
Miniaturized and automated insulin injectors face challenges in maintaining stability due to back pressure caused by reactions between the drug and biological fluid at the cannula or needle tip, leading to blockage issues, especially during slow or small-volume injections.
Innovation Solution
A drug injection device utilizing an electroosmotic pump operates in a basal infusion mode with a speed-based injection sequence, which includes pulse blocks defining voltage or current pulses and pause blocks maintaining zero voltage or current for a predetermined time. This sequence alternately generates negative and positive pressure to suck and discharge drugs, preventing blockages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the insulin injector is miniaturized and automated, then the convenience for users is improved, but the stability of operation deteriorates due to back pressure and blockage
Solution Approach 1:
The patent applies periodic action by implementing a pulse-based control system that alternates between injection phases and pause phases. The controller delivers drug in controlled pulses followed by pause periods, creating a rhythmic injection pattern that prevents continuous back pressure buildup and reduces blockage risk while maintaining automated operation
Solution Approach 2:
The patent ensures continuity of useful action by maintaining the pump in a ready state between pulses and ensuring complete drug delivery within each pulse cycle. The system continuously monitors and adjusts to ensure uninterrupted drug supply to the cannula, preventing operational instability while keeping the device miniaturized and automated
2Manufacturing precision
If the amount of injected drug is small or injection speed is slow, then the precision of drug delivery is improved, but the blockage phenomenon becomes more serious
Solution Approach 1:
The patent uses periodic action by implementing pulse-width modulation where the duty cycle and pulse duration are adjusted based on the required injection speed. During slow or low-volume injection phases, the controller extends pause periods between pulses, allowing pressure equalization and preventing blockage while maintaining precise drug delivery control
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the pulse width, duty cycle, and inter-pause timing based on the injection rate and detected back pressure. The controller modifies these electrical parameters to the electroosmotic pump to optimize flow characteristics, preventing blockage during slow or low-volume injection while preserving delivery precision
3Productivity
If back pressure is caused by reactions between drug and biological fluid, then the drug delivery function is maintained, but the injection path becomes blocked
Solution Approach 1:
The patent maintains continuity of useful action by ensuring the pump continues to operate through multiple pulse cycles, delivering drug continuously despite the presence of back pressure. The system monitors pressure changes and adjusts pulse parameters to maintain flow through the cannula, preventing blockage while preserving drug delivery function
Solution Approach 2:
The patent implements feedback by monitoring back pressure and using this information to adjust the pulse parameters in real-time. The controller detects pressure changes at the cannula tip and modifies the electroosmotic pump parameters accordingly, creating a closed-loop system that prevents blockage while maintaining drug delivery
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 ensures stable and accurate drug delivery by preventing blockages, maintaining the integrity of the injection path, and allowing for precise control of drug injection speed and volume.
Implementation Method 1
a drug injector configured to suck a drug from a drug storage by electrochemically operating an electroosmotic pump and discharge an sucked drug to an injection target
Implementation Method 2
electrochemically operating an electroosmotic pump
Implementation Method 3
one of a voltage pulse and a current pulse applied to the electroosmotic pump
Data Source
AI summary
A drug injection device includes a drug injector configured to suck a drug from storage by operating an electroosmotic pump and discharge it to an injection target; and a controller configured to output to the injector a control signal for a speed-based injection sequence, causing the electroosmotic pump to operate in basal infusion mode. The speed-based injection sequence includes at least one pulse block defining a voltage or current pulse applied to the pump and at least one pause block maintaining 0 volt or 0 ampere for a predetermined time after the pulse block. The pulse block defines a pair of signals, a forward and reverse pulse, applied to the electroosmotic pump to alternately generate negative and positive pressure, enabling drug suction and discharge.