Low-Solubility Chlorhexidine Surface Coatings for Pathogen Persistence

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Solution Overview

Problem

Existing antiviral, antibacterial, and antifungal agents face challenges in maintaining persistence on surfaces due to high solubility issues, particularly with chlorhexidine gluconate, which leads to reduced effectiveness against resistant pathogens like noroviruses and drug-resistant bacteria and fungi, as they elute with moisture, compromising safety and efficacy.

Innovation Solution

Employing low-solubility chlorhexidine salts, such as anion-free chlorhexidine or chlorhexidine hydrochloride, in combination with solvents like methyl acetate, acetone, or water, and additives like ZnO nanoparticles, to create antiviral, antibacterial, and antifungal agents that adhere effectively to surfaces, ensuring sustained activity against enveloped and non-enveloped viruses, bacteria, and fungi.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If chlorhexidine gluconate is used to increase solubility, then ease of manufacture and application is improved, but persistence on surfaces and effectiveness against resistant pathogens deteriorates due to elution with moisture

Engineering Contradiction:

ImprovesolubilityVSAvoidpersistence

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the chemical parameter of chlorhexidine from its common gluconate salt form (high solubility) to low-solubility forms such as free base or hydrochloride salt. This parameter change reduces solubility in aqueous environments, preventing elution with moisture and thereby improving persistence on surfaces while maintaining antimicrobial effectiveness against resistant pathogens

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates composite formulations by combining low-solubility chlorhexidine with specific solvents (e.g., isopropyl alcohol, ethylene glycol monomethyl ether) and optionally with other antimicrobial agents. This composite approach allows the formulation to achieve both adequate solubility for application and low solubility for persistence, resolving the contradiction between ease of manufacture and reliability

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If high-solubility chlorhexidine salts are used, then application and distribution is improved, but effectiveness against drug-resistant bacteria and fungi deteriorates due to rapid elution

Engineering Contradiction:

ImproveapplicationVSAvoideffectiveness

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent modifies the solubility parameter of chlorhexidine by selecting low-solubility salt forms or free base forms. This parameter change ensures that while the agent can be applied effectively (especially in alcoholic formulations), it does not rapidly elute with moisture, thereby maintaining sustained effectiveness against drug-resistant bacteria and fungi

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

By using low-solubility chlorhexidine formulations, the patent ensures continuous antimicrobial action over extended periods. The reduced solubility prevents rapid elution, allowing the agent to maintain persistent presence and continuous effectiveness against resistant pathogens on surfaces, rather than acting only temporarily during initial application

Inventive Principle:

Principle #20Continuity of useful action

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 low-solubility chlorhexidine agents demonstrate enhanced persistence and effectiveness, maintaining antiviral, antibacterial, and antifungal properties by preventing elution into moisture, thus ensuring prolonged protection against a wide range of pathogens, including resistant strains, while ensuring safety with controlled concentrations.

Implementation Method 1

low-solubility chlorhexidine salts, such as anion-free chlorhexidine or chlorhexidine hydrochloride

Methodology Applied

Scientific EffectSolubility:

Data Source

PatentUS20240215584A1Article having antiviral properties, article having antimicrobial properties, and article having antifungal properties

Publication Date: 2024.07.04 NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE & TECHNOLOGY

AI summary

An antiviral agent has a solvent and a low-solubility chlorhexidine. An article has an antiviral property in which a low-solubility chlorhexidine having solubility of 150 mg/100 mL or less in water at 20° C. is applied on a base material. An antimicrobial agent has a solvent and a low-solubility chlorhexidine. An article has an antimicrobial property in which a low-solubility chlorhexidine having solubility of 150 mg/100 mL or less in water at 20° C. is applied on a base material. An antifungal agent has a solvent and a low-solubility chlorhexidine. An article has an antifungal property in which a low-solubility chlorhexidine having solubility of 150 mg/100 mL or less in water at 20° C. is applied on a base material.