Optical Piston Rod Sensing for Accurate Medicament Dosing

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Solution Overview

Problem

Existing medicament delivery devices lack accurate and reliable mechanisms for monitoring the position of the piston rod within the housing, which affects the precision of medicament dosing.

Innovation Solution

A medicament delivery device with a position-sensing mechanism that includes a light source, sensor, and a blocking member, where the varying light pattern is detected by the sensor to determine the position of the piston rod, using a projecting member that blocks light based on its position relative to the light source and sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a catheter-based delivery system is used to deliver medicament to the heart, then the medicament can be delivered directly to the target tissue, but the system becomes complex and requires specialized procedures

Engineering Contradiction:
Improvemedicament delivery efficiencyVSAvoiddelivery system complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The device separates the oral delivery system into distinct functional modules: a capsule containing the medicament, a delivery device with reservoir and membrane, and a control mechanism. This segmentation allows each component to be optimized independently while maintaining overall system simplicity, avoiding the need for complex catheter-based systems.

Inventive Principle:
Principle #1Segmentation

2Reliability

If controlled release mechanisms are implemented to maintain steady medicament levels, then therapeutic effectiveness improves, but the device structure becomes more complex

Engineering Contradiction:
Improvesteady medicament level maintenanceVSAvoidrelease mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The device employs a self-regulating controlled-release mechanism where the medicament is released in response to physiological conditions (pH changes, enzymatic activity, or mechanical stimulation) without requiring external control systems. The membrane or matrix automatically adjusts release based on the local environment, maintaining steady levels through intrinsic properties rather than complex active control.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If non-invasive oral delivery is used instead of catheter-based delivery, then patient comfort and ease of administration improve, but achieving targeted delivery to the heart becomes more difficult

Engineering Contradiction:
Improveadministration easeVSAvoidtargeted delivery precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The device uses an intermediary mechanism (such as a pH-sensitive membrane, enzymatic trigger, or mechanical activation system) that remains inert during oral transit and only activates under specific cardiac conditions. This intermediary allows the medicament to pass through the digestive system unchanged until it reaches the target site, where physiological cues trigger precise localized release.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 precise monitoring of the piston rod position, ensuring accurate dosing of medicaments, and allows for both reusable and disposable configurations.

Implementation Method 1

The medicament for delivery to the heart is contained in a reservoir behind a pH-sensitive membrane in an oral delivery device

Methodology Applied
Scientific EffectpH-sensitive release: Phase Change

Data Source

PatentEP3697477B1Medicament delivery device with optical sensor
Publication Date: 2026.05.06 SANOFI SA(FR)
  • EP3697477B1 patent drawingFigure 1A~1B
  • EP3697477B1 patent drawingFigure 2~3
  • EP3697477B1 patent drawingFigure 4~5

AI summary

The present disclosure relates to a medicament delivery device (20, 40, 60, 70). The medicament delivery device (20, 40, 60, 70) comprises a housing (22) configured to receive a container of medicament and a piston rod (23) moveable within the housing (22) and configured to engage a container of medicament when received within the housing (22). The medicament delivery device (20, 40, 60, 70) further comprises a position-sensing mechanism (25) configured to detect the position of the piston rod (23) within the housing (22). The position-sensing mechanism (25) comprises a first light source (28) configured to emit light, a first sensor (29) disposed proximate the first light source (28) and configured to receive light emitted by the first light source (28),anda blocking member (24, 26, 41, 51, 66) moveable between the first light source (28) and the first sensor (29). The position-sensing mechanism (25) is configured such that a varying light pattern reaches the first sensor (29) dependent on the position of the blocking member (26) relative to the first light source (28) and the first sensor (28),andthe first sensor (29) is configured to detect the light pattern received to determine the position of the piston rod (23) within the housing (22).