Chlorhexidine Free Base Antimicrobial Composition

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Solution Overview

Problem

Chlorhexidine compositions used for skin disinfection face issues of irritation, reduced adhesion of medical tapes and dressings under wet conditions, and ineffective antimicrobial activity due to interaction with salts and surfactants, necessitating a formulation that is low in irritation, maintains adhesion, and provides persistent antimicrobial efficacy.

Innovation Solution

A hydroalcoholic composition comprising a C2-C5 lower alcohol, a fatty component with free hydroxyl groups, and a cationic antimicrobial agent, with the absence of surfactants and hydrophilic polymers, which enhances antimicrobial efficacy and adhesion of medical articles to the skin, even in moist conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chlorhexidine compositions are used for skin disinfection, then antimicrobial efficacy is achieved, but skin irritation occurs and adhesion of medical articles is reduced under wet conditions

Engineering Contradiction:

Improveantimicrobial efficacyVSAvoidskin irritation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameters of the composition by using chlorhexidine free base instead of chlorhexidine salts, and formulating with specific fatty acids and esters at controlled concentrations. This parameter change maintains antimicrobial efficacy while reducing skin irritation and improving adhesion properties under wet conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite formulation combining chlorhexidine free base with specific fatty acids (lauric, myristic, palmitic, stearic, oleic, linoleic) and their esters. This composite approach allows the different components to work synergistically, providing both antimicrobial activity and improved skin compatibility with reduced irritation.

Inventive Principle:

Principle #40Composite materials

2Duration of action of stationary object

If chlorhexidine salts are used, then persistent antimicrobial activity is achieved, but adhesion of surgical drapes and dressings is lost under wet conditions

Engineering Contradiction:

Improvepersistent antimicrobial activityVSAvoidadhesion loss

Core Design Contradiction:

Duration of action of stationary objectVSObject-generated harmful factors

Solution Approach 1:

Instead of using chlorhexidine salts (the conventional approach), the invention inverts the chemical form to use chlorhexidine free base. This inversion fundamentally changes the properties of the composition, eliminating the hydrophilic salt character that causes adhesion loss while maintaining persistent antimicrobial activity through the free base form.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the physical-chemical parameters by formulation with specific fatty acids and esters that modify the surface properties of the composition. These parameter changes allow the chlorhexidine free base to provide persistent antimicrobial activity without the adhesion-loss problem associated with chlorhexidine salts under wet conditions.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If higher concentration of chlorhexidine is used, then antimicrobial efficacy is improved, but skin irritation increases significantly

Engineering Contradiction:

Improveantimicrobial efficacyVSAvoidskin irritation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical form parameter from chlorhexidine salts to chlorhexidine free base, and optimizes the concentration parameters of fatty acids and esters. This allows achieving effective antimicrobial efficacy at lower chlorhexidine concentrations, thereby reducing skin irritation while maintaining therapeutic effectiveness.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The composite formulation with fatty acids and esters modifies the overall properties of the composition, allowing for reduced chlorhexidine concentration while maintaining antimicrobial efficacy. The fatty components provide skin compatibility and reduce irritation even when higher concentrations of active agent are needed.

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 composition achieves rapid and persistent antimicrobial activity, improved cosmetic feel, and enhanced adhesion of medical articles, reducing skin irritation and wash-off effects while maintaining antimicrobial efficacy, even in the presence of moisture.

Implementation Method 1

rapid and persistent antimicrobial activity

Methodology Applied

Scientific EffectProtein denaturation:

Implementation Method 2

a fatty component containing one or more free hydroxyl groups... enhanced adhesion of medical articles to the skin

Methodology Applied

Scientific EffectHydroxyl group interaction:

Implementation Method 3

a cationic antimicrobial agent... persistent antimicrobial activity

Methodology Applied

Scientific EffectElectrostatic interaction:

Implementation Method 4

hydroalcoholic composition... rapid and persistent antimicrobial activity

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS8338491B2Antimicrobial compositions

Publication Date: 2012.12.25 SOLVENTUM INTELLECTUAL PROPERTIES CO

AI summary

Antimicrobial compositions are provided that include a hydroalcoholic solvent system comprising a lower C2-C5 alcohol and water; a cationic antimicrobial agent such as chlorhexidine gluconate; a fatty component containing at least one free hydroxyl group, such as a C12-C21 fatty alcohol, a C12-C21 fatty ester, a C12-C21 fatty ether, a C12-C21 fatty amide, and combinations thereof; and optionally an emollient ester such as diesters of bibasic acids and triesters of citric acid. The compositions described herein display improved antimicrobial efficacy and improved cosmetic elegance.