Polyurethane-Polyurea Hydrogel for Wound Dressing

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Solution Overview

Problem

Current wound dressings with water-containing hydrogels, particularly those using propylene glycol, can lead to skin irritation and suboptimal patient adherence to therapy, and do not adequately address the complex needs of wound healing across different phases, often resulting in prolonged healing times and potential tissue damage.

Innovation Solution

A water-containing hydrogel composition formed by reacting amine-terminated and isocyanate-terminated prepolymers with polyalkylene oxide units in the presence of a polyhydric alcohol, such as glycerol, and water, which provides improved absorption, moisture retention, and cell compatibility, reducing skin irritation and enhancing wound healing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If propylene glycol is used in water-containing hydrogels for wound dressings, then absorption capacity and moisture release capacity are maintained, but skin irritation occurs and patient adherence to therapy deteriorates

Engineering Contradiction:
Improveabsorption capacity and moisture release capacityVSAvoidskin irritation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameter by replacing propylene glycol with a mixture of ethylene glycol (10-30 wt%) and sorbitol (70-90 wt%). This parameter substitution maintains the hydrogel's absorption and moisture release capacities while eliminating the skin irritation caused by propylene glycol, thereby improving patient comfort and therapy adherence.

Inventive Principle:
Principle #35Parameter changes

2Duration of action of moving object

If wound dressings are worn for extended periods to reduce changing frequency, then patient comfort improves, but adhesion to wound tissue causes traumatic removal and tissue damage

Engineering Contradiction:
Improvewear durationVSAvoidtissue damage during removal
Core Design Contradiction:
Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the adhesive properties by adjusting the hydrogel's chemical composition, specifically using ethylene glycol and sorbitol in optimized ratios. This creates a balanced adhesion force that is sufficient for secure wear over extended periods (up to 7 days) but gentle enough to allow non-traumatic removal without damaging wound tissue or surrounding skin.

Inventive Principle:
Principle #35Parameter changes

3Strength

If initial adhesion is increased for better fixation, then dressing stability improves, but adhesion to sensitive skin causes trauma during removal

Engineering Contradiction:
Improveadhesion strengthVSAvoidskin trauma
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies the principle of local quality by creating different adhesion characteristics in different regions of the hydrogel. The hydrogel exhibits stronger adhesion to wound tissue (promoting healing and stability) while maintaining gentler adhesion to surrounding sensitive skin (preventing trauma during removal). This spatial differentiation of adhesion properties resolves the contradiction between fixation strength and skin protection.

Inventive Principle:
Principle #3Local quality

4Reliability

If wound dressings are changed frequently to maintain optimal wound environment, then wound healing is promoted, but patient adherence to therapy deteriorates due to discomfort and inconvenience

Engineering Contradiction:
Improvewound healing environmentVSAvoidpatient adherence
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the chemical parameters of the hydrogel by using ethylene glycol and sorbitol in specific proportions (10-30 wt% and 70-90 wt% respectively). This composition optimization enables the dressing to maintain optimal wound healing conditions (moisture balance, absorption capacity) while extending wear duration to up to 7 days, thereby reducing changing frequency and improving patient adherence without compromising wound healing.

Inventive Principle:
Principle #35Parameter changes

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 hydrogel composition promotes rapid and effective wound healing by maintaining a conducive environment, reducing tissue damage, and minimizing skin irritation, while allowing for gentle dressing changes and prolonged wear without compromising patient comfort.

Implementation Method 1

They are able to absorb wound exudate emerging from the wound into the gel matrix and release moisture from the gel matrix

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

water-containing hydrogels for the treatment of wounds obtainable by reacting a) an amine-terminated prepolymer containing polyalkylene oxide units with a b) isocyanate-terminated prepolymer containing polyalkylene oxide units

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Data Source

PatentEP3558400B1Water-containing hydrogels for dressing wounds
Publication Date: 2021.11.10 PAUL HARTMANN AG
  • EP3558400B1 patent drawingFigure 1~2
  • EP3558400B1 patent drawingFigure 3~3a
  • EP3558400B1 patent drawingFigure 4

AI summary

The invention relates to water-containing hydrogels for dressing wounds, comprising a polyurethane-polyurea copolymer having a polyvalent alcohol, except propylene glycol.