Local Anesthetic Patch Composition for Permeability and Cohesion

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Solution Overview

Problem

Existing local anesthetic patches lack sufficient skin permeability, cohesion force, and adhesive properties, making them impractical for pharmaceutical use.

Innovation Solution

A patch comprising a backing layer with an adhesive layer containing a local anesthetic agent, a thermoplastic elastomer, a higher fatty acid ester, and a polyol fatty acid monoester, with specific ratios and components to enhance skin permeability and adhesive properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a local anesthetic patch is designed with simple adhesive layer, then manufacturing is easy, but skin permeability and adhesive properties are insufficient

Engineering Contradiction:
Improveease of manufactureVSAvoidskin permeability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The adhesive layer uses a composite system comprising a thermoplastic elastomer (5-50 mass%), higher fatty acid ester (10-60 mass%), and polyol fatty acid monoester (5-30 mass%). This composite material approach enables simultaneous achievement of adequate skin permeability, adhesive properties, and cohesion force without complicating the manufacturing process

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention optimizes specific parameter ranges: thermoplastic elastomer at 5-50 mass%, higher fatty acid ester at 10-60 mass%, and polyol fatty acid monoester at 5-30 mass%. These parameter adjustments ensure sufficient skin permeability and adhesive performance while maintaining manufacturing simplicity

Inventive Principle:
Principle #35Parameter changes

2Reliability

If local anesthetic patch uses conventional adhesive composition, then adhesive property is basic, but cohesion force is insufficient

Engineering Contradiction:
Improveadhesive propertyVSAvoidcohesion force
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The adhesive layer employs a composite formulation with thermoplastic elastomer (5-50 mass%), higher fatty acid ester (10-60 mass%), and polyol fatty acid monoester (5-30 mass%). This composite structure provides both adequate adhesive property to the skin and sufficient cohesion force within the layer

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention differentiates functional roles within the adhesive layer: the thermoplastic elastomer provides adhesive property, while the higher fatty acid ester and polyol fatty acid monoester contribute to cohesion force and skin permeability. This local quality differentiation ensures both adhesive property and cohesion force are optimized

Inventive Principle:
Principle #3Local quality

3Reliability

If a patch contains multiple functional components in adhesive layer, then skin permeability improves, but device complexity increases

Engineering Contradiction:
Improveskin permeabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The adhesive layer integrates three functional components (thermoplastic elastomer, higher fatty acid ester, polyol fatty acid monoester) into a single homogeneous layer. This composite material approach achieves sufficient skin permeability without increasing device complexity, as all components are incorporated into one adhesive layer rather than requiring separate functional layers

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The adhesive layer serves multiple functions simultaneously: providing adhesion to skin, enabling drug permeation, and ensuring layer cohesion. The thermoplastic elastomer, higher fatty acid ester, and polyol fatty acid monoester work together to achieve these multiple functions within a single layer, avoiding device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3939661B1patch
Publication Date: 2025.09.03 KANEKA CORP

AI summary

The objective of the present invention is to provide a local anesthetic agent-containing patch having a skin permeability, cohesion force and adhesive property practical as a pharmaceutical product. The patch of the present invention is characterized in comprising a backing layer, and an adhesive layer on the backing layer, wherein the adhesive layer comprises at least a local anesthetic agent, a thermoplastic elastomer, a higher fatty acid ester, and a polyol fatty acid monoester, and a ratio of the higher fatty acid ester to 100 mass parts of the thermoplastic elastomer is 25 mass parts or more and 200 mass parts or less.