Chlorhexidine Gluconate Adhesive Incorporation via Freeze Drying

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Solution Overview

Problem

Chlorhexidine gluconate has not been effectively incorporated into solvent-based acrylic adhesives due to its hydrophilic properties and sensitivity to high temperatures, leading to challenges in dispersion and retention of efficacy in adhesive formulations, particularly in medical and surgical applications.

Innovation Solution

A method involving active drying techniques such as freeze drying or spray drying to convert chlorhexidine gluconate into a solid powder, which is then dissolved in a compatible solvent like methanol and combined with the adhesive, ensuring effective incorporation into solvent-based adhesives like acrylic adhesives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If chlorhexidine gluconate is directly incorporated into solvent-based acrylic adhesives, then the adhesive formulation can be simplified, but the compound fails to disperse effectively and loses antimicrobial efficacy due to hydrophilic properties and temperature sensitivity

Engineering Contradiction:
Improveease of incorporationVSAvoidantimicrobial efficacy
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by converting chlorhexidine gluconate into a solid powder form through active drying (freeze drying or spray drying) before incorporation into the adhesive. This pre-processing step ensures the compound is in a suitable physical state for effective dispersion in solvent-based adhesives, preventing loss of antimicrobial efficacy while simplifying the incorporation process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the physical state parameter of chlorhexidine gluconate from aqueous solution to solid powder through active drying processes. This parameter change enables effective incorporation into solvent-based acrylic adhesives by matching the physical form requirements of the adhesive system, thereby maintaining both ease of manufacture and antimicrobial efficacy.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If active drying techniques are used to convert chlorhexidine gluconate into solid powder, then dispersion and efficacy are improved, but the manufacturing process becomes more complex

Engineering Contradiction:
Improveantimicrobial efficacyVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary solid powder form of chlorhexidine gluconate that serves as a bridge between the aqueous solution and the solvent-based adhesive system. This intermediary form, created through active drying, enables effective incorporation while the use of standard drying equipment (freeze dryers or spray dryers) keeps the added complexity manageable.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If chlorhexidine gluconate is incorporated into the adhesive, then antimicrobial protection is enhanced, but the adhesive formulation complexity increases

Engineering Contradiction:
Improvemicrobial growth preventionVSAvoidformulation complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent changes the physical state of chlorhexidine gluconate to solid powder before incorporation, which simplifies the formulation process compared to incorporating aqueous solutions. This parameter change allows for easier mixing and distribution within the adhesive while maintaining the antimicrobial protection function, thereby enhancing microbial growth prevention without proportionally increasing formulation complexity.

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

This method allows for the successful dispersion and retention of chlorhexidine gluconate's antimicrobial efficacy within the adhesive, enhancing the antimicrobial properties of medical products without compromising the adhesive's performance.

Implementation Method 1

actively drying the aqueous solution to thereby obtain the chlorhexidine digluconate in solid form

Methodology Applied
Scientific EffectFreeze drying: Freeze Drying

Implementation Method 2

actively drying includes at least one of freeze drying and spray drying

Methodology Applied
Scientific EffectSpray drying: Spray

Implementation Method 3

solubilising the solid form chlorhexidine digluconate in the solvent to form a chlorhexidine digluconate solution

Methodology Applied
Scientific EffectSolubilization: Solvation

Data Source

PatentEP2665363B1Chlorhexidine gluconate containing adhesive
Publication Date: 2019.12.25 AVERY DENNISON CORP
  • EP2665363B1 patent drawingFigure 1~2
  • EP2665363B1 patent drawing

AI summary

Methods for incorporating chlorhexidine salts into solvent based adhesives are described. The methods involve freeze drying an aqueous solution of the chlorhexidine salt and obtaining the chlorhexidine salt in a particulate form. The dry powder can then be dissolved into an appropriate solvent used with the adhesive of interest. Also described are particles including chlorhexidine salts that are incorporated in adhesives. Also described are various medical products utilizing the adhesive and chlorhexidine compound, and related methods of use.