Optical Volume Measurement for Micro-Needle Drug Solutions

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Solution Overview

Problem

Current methods for measuring the volume of aqueous drug solutions in needle-like recesses of micro-needle arrays are prone to instability due to environmental factors and material properties, leading to inaccurate and time-consuming measurements, especially when high precision is required, and are not suitable for high-speed or non-destructive, mass production processes.

Innovation Solution

A measurement method using the intensity of light transmitted through the drug solution in each needle-like recess, employing two different wavelength ranges to calculate the volume accurately, allowing for high-speed and non-destructive measurement, and enabling feedback for real-time adjustment of filling amounts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high-precision electronic balance is used to measure the volume of aqueous drug solution, then measurement precision is improved, but measurement speed deteriorates and reliability worsens due to environmental factors

Engineering Contradiction:
Improvevolume measurement precisionVSAvoidmeasurement speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical weighing system (electronic balance) with an optical measurement system. The imaging unit captures images of the needle-like recesses, and the control unit calculates volumes based on image analysis, eliminating the need for mechanical weighing and its associated environmental sensitivities.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces light as an intermediary to measure the volume of drug solutions. By using light transmission through the mold and analyzing the intensity distribution in captured images, the system indirectly determines volume without direct physical contact or weighing, thereby improving both speed and reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If high-precision electronic balance is used to measure the volume of aqueous drug solution, then measurement precision is improved, but measurement reliability deteriorates due to environmental factors and mold material properties

Engineering Contradiction:
Improvevolume measurement precisionVSAvoidmeasurement stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the mechanical weighing system with an optical measurement system that is not sensitive to environmental factors such as temperature, humidity, and convection. The imaging-based method measures light transmission directly, eliminating the instability issues associated with electronic balances.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If destructive measurement method is used to quantify drug amount, then measurement precision is improved, but the micro-needle array is destroyed

Engineering Contradiction:
Improvedrug amount quantification precisionVSAvoidproduct integrity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent performs volume measurement before the drug solution is dried and the micro-needles are formed. By measuring the filled mold while the drug solution is still in liquid form, the system obtains precise volume data without destroying the final MNA product, enabling non-destructive quality control.

Inventive Principle:
Principle #10Preliminary action

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

This approach provides high-accuracy, high-speed measurement of drug volumes in each recess, suitable for mass production, independent of drug type, and allows for precise adjustment of filling quantities, enhancing the efficiency of micro-needle array manufacturing.

Implementation Method 1

a measurement method using the intensity of light transmitted through the drug solution in each needle-like recess

Methodology Applied
Scientific EffectLight transmission: Light

Implementation Method 2

employing two different wavelength ranges to calculate the volume accurately

Methodology Applied
Scientific EffectOptical absorption: Absorption (EM radiation)

Data Source

PatentEP3270120B1Measurement method, measurement device, and program
Publication Date: 2021.12.08 FUJIFILM CORP
  • EP3270120B1 patent drawingFigure 1
  • EP3270120B1 patent drawingFigure 2
  • EP3270120B1 patent drawingFigure 3

AI summary

The present invention provides a measurement method, a measurement device, and a program capable of non-destructively measuring a volume of an aqueous solution of a drug in each needle-like recess of a mold with high accuracy. A measurement method according to a preferred embodiment of the present invention includes a measurement wave intensity acquisition step of acquiring, for each needle-like recess, an intensity of a measurement wave transmitted through a drug in a needle-like recess, absorbed by the drug by an amount according to a distance by which the measurement wave is transmitted through the drug, and emitted from the drug; and a volume acquisition step of acquiring a volume for each needle-like recess on the basis of the intensity of the measurement wave for each needle-like recess acquired in the measurement wave intensity acquisition step.