Polyester Patch Surface Roughness Anchoring
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Solution Overview
Problem
Conventional patches face issues with drug migration into substrates, poor anchoring properties between substrates and adhesive layers, and inadequate skin adaptability, leading to adverse effects and inefficient drug delivery.
Innovation Solution
A patch using a polyester-based film with a surface roughness of 0.05 to 0.8 μm, specifically sandblasted polyethylene terephthalate, combined with a drug-containing adhesive layer containing styrene-isoprene-styrene block copolymer and polyisobutylene, which inhibits drug migration and enhances anchoring properties without the need for a primer layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyester-based films are used as substrates to prevent drug migration, then drug migration is inhibited, but anchoring property between substrate and adhesive layer deteriorates
Solution Approach 1:
The invention applies local quality by creating a rough surface structure specifically at the adhesive contact interface of the polyester substrate, while maintaining the bulk properties of the substrate unchanged. The rough surface is formed only where needed for adhesion, preserving the drug barrier properties of the polyester material.
Solution Approach 2:
The invention changes the surface roughness parameter of the polyester substrate to improve anchoring. By controlling the roughness degree within a specific range (Ra 0.05-0.8 μm), the patent achieves both good adhesion and prevents drug migration, resolving the contradiction between these two properties.
2Strength
If primer layers are applied to improve anchoring property, then adhesion between substrate and adhesive layer is improved, but product value is reduced due to discoloration
Solution Approach 1:
The invention extracts and eliminates the primer layer from the patch structure entirely. Instead of adding a primer layer that causes discoloration, the patent achieves adhesion improvement through surface roughening of the polyester substrate alone, thereby removing the source of the harmful discoloration effect.
Solution Approach 2:
The rough surface structure acts as an intermediary between the polyester substrate and adhesive layer, providing mechanical interlocking without requiring chemical primers. This intermediary structure achieves adhesion improvement while avoiding the discoloration problem associated with primer layers.
3Strength
If anchor-coating agents are used to improve anchoring, then adhesion is enhanced, but percutaneous absorbability is reduced due to drug adsorption
Solution Approach 1:
The invention removes the anchor-coating agent from the system entirely. By relying solely on the rough surface structure of the polyester substrate for mechanical interlocking, the patent eliminates the coating agent that would otherwise adsorb drugs and reduce percutaneous absorbability.
Solution Approach 2:
The polyester substrate serves itself by providing both the drug barrier function and the mechanical interlocking surface for adhesion through its own roughened structure, without requiring external coating agents that would interfere with drug absorption.
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 patch prevents drug migration, ensures strong anchoring without residue, provides comfortable skin application, and maintains effective drug absorption and skin permeability, improving handling and therapeutic efficacy.
Implementation Method 1
the surface roughness (Ra) of the polyester-based film surface on the side in contact with the adhesive layer is from 0.05 to 0.8 μm
Data Source
AI summary
The present invention relates to a patch which is free from any migration of a drug into a substrate and has favorable anchoring properties between the substrate and adhesive layer, in which the drug containing adhesive layer firmly adheres onto the substrate and which gives no adhesion residue when applied to the skin and then peeled off. Namely, a patch comprising a substrate made of a polyester-based film and a drug-containing adhesive layer laminated thereon wherein the surface roughness (also known as “the central line mean roughness” or “Ra”) of the polyester-based film surface in the side in contact with the adhesive layer is from 0.05 to 0.8 μm is provided.