Oxybutynin Transdermal Patch Adhesion Stability

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Solution Overview

Problem

Transdermal absorption patches containing cholesterols for skin irritation reduction face issues with increased adhesive fluidity and changes in medication releasability over time, especially under severe storage conditions, affecting adhesion and therapeutic efficacy.

Innovation Solution

A transdermal absorption preparation with a water-repellent support layer treated with a fluorine-containing compound and an adhesive layer containing oxybutynin, cholesterols, and a rubber adhesive base, which maintains adhesion and releasability stability even under severe storage conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If cholesterols are mixed in the adhesive composition to reduce skin irritation, then skin irritation is reduced, but adhesion decreases and fluidity of adhesive composition increases

Engineering Contradiction:
Improveskin irritationVSAvoidadhesion
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent applies parameter changes by modifying the physical and chemical properties of the adhesive composition through controlled incorporation of cholesterols (0.1-10% by mass) and adjusting the molecular weight and composition of the rubber adhesive base. This optimization allows the adhesive to maintain both skin irritation reduction properties and adequate adhesion strength.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining rubber adhesive base with cholesterol molecules in a specific composition ratio. The composite adhesive layer integrates the skin-protective properties of cholesterols with the bonding capabilities of the rubber adhesive base, achieving both irritation reduction and maintained adhesion.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If cholesterols are mixed in the adhesive composition, then skin irritation is reduced, but releasability of medication changes over time under severe storage conditions

Engineering Contradiction:
Improveskin irritationVSAvoidreleasability of medication
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by conducting accelerated stability testing under severe storage conditions (high temperature and humidity) before product launch. This allows the formulation to be optimized in advance to ensure releasability remains within 80-120% of initial values after storage, preventing composition instability issues.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent optimizes the concentration of cholesterols (0.1-10% by mass) and adjusts the molecular weight and composition of the rubber adhesive base to achieve a stable balance between skin protection and medication releasability over time, even under severe storage conditions.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If fluidity of adhesive composition increases due to cholesterols, then skin irritation is reduced, but adhesion and releasability stability over time deteriorate

Engineering Contradiction:
Improveskin irritationVSAvoidadhesion and releasability stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent controls the fluidity increase by precisely adjusting the cholesterol concentration (0.1-10% by mass) and selecting rubber adhesive bases with specific molecular weights and compositions. This parameter optimization ensures that while some fluidity increase occurs for skin protection, adhesion and releasability stability are maintained within acceptable ranges.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite adhesive system where cholesterols and rubber adhesive base work synergistically. The composite structure allows the mixture to maintain appropriate viscosity and stability characteristics, balancing skin irritation reduction with long-term adhesion and releasability stability.

Inventive Principle:
Principle #40Composite materials

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 solution effectively reduces changes in adhesion and medication releasability over time, maintaining therapeutic efficacy and skin irritation reduction while ensuring consistent skin permeability.

Implementation Method 1

a water-repellent surface formed by a water-repellent treatment with a fluorine-containing compound

Methodology Applied
Scientific EffectWater repellency: Hydrophobe

Data Source

PatentEP3498272B1Oxybutynin-containing transdermal absorption preparation
Publication Date: 2024.01.31 HISAMITSU PHARM CO INC
  • EP3498272B1 patent drawingFigure 1~2
  • EP3498272B1 patent drawingFigure 3~4
  • EP3498272B1 patent drawingFigure 5~6

AI summary

An oxybutynin-containing transdermal absorption preparation includes a support layer that is formed of a base fabric and has water repellency in at least a part thereof, and an adhesive layer laminated on one side of the support layer, in which the adhesive layer includes an adhesive composition containing oxybutynin or a pharmaceutically acceptable salt thereof, cholesterols, and a rubber adhesive base. The oxybutynin may be oxybutynin hydrochloride. A portion having the water repellency may be formed by a fluorine-containing compound. The base fabric may be a knitted fabric.