Colloidal Silver Emulsions with Oxide Coating for Stability
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Solution Overview
Problem
Existing silver-containing compositions in cosmetic and dermatologic formulations face challenges such as discoloration, rheology instability, and oxidation of components due to high silver concentrations, which affect their efficacy and stability.
Innovation Solution
The use of silver particles in the +2 oxidation state, coated with a multivalent silver oxide layer, is incorporated into emulsion formulations, providing potent antimicrobial properties while maintaining stability and bioavailability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high concentrations of silver particles are used in formulations, then antimicrobial efficacy is improved, but discoloration and oxidation of components occur
Solution Approach 1:
The patent changes the oxidation state parameter of silver from conventional +1 or 0 to +2, and controls particle size parameters (1-100 nm), enabling effective antimicrobial activity at lower concentrations (1-100 ppm) while avoiding discoloration and oxidation problems associated with higher concentrations
Solution Approach 2:
The patent creates a composite structure with silver core and silver oxide shell (Ag4O4 coating), combining the antimicrobial properties of metallic silver with the stability and anti-oxidation properties of silver oxide, thereby achieving efficacy without the harmful side effects of high silver concentrations
2Reliability
If high concentrations of silver particles are used, then antimicrobial benefits are enhanced, but rheology instability occurs
Solution Approach 1:
By changing the oxidation state to +2 and controlling particle size distribution (with at least 75% of particles having diameters between 0.005-0.015 micrometers), the patent achieves stable rheology at low concentrations (1-100 ppm) while maintaining antimicrobial benefits
Solution Approach 2:
The silver oxide coating acts as an intermediary layer between the silver core and the formulation matrix, preventing direct interactions that cause rheology instability while allowing antimicrobial activity to proceed effectively
3Reliability
If higher silver concentrations are used, then antimicrobial activity increases, but formulation stability decreases
Solution Approach 1:
The patent optimizes multiple parameters including oxidation state (+2), particle size (1-100 nm), and concentration (1-100 ppm) to achieve a synergistic effect where high antimicrobial activity is obtained at low concentrations without compromising formulation stability
Solution Approach 2:
The core-shell structure with silver core and silver oxide shell provides both antimicrobial activity and formulation stability, as the silver oxide coating prevents aggregation and oxidation while maintaining the antimicrobial properties of the silver core
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 approach allows for lower concentrations of silver particles, reducing undesirable side-reactions and maintaining the formulation's stability, color, and consistency over time, while providing effective antimicrobial benefits.
Implementation Method 1
silver particles, and more particularly, silver particles having an interior of metallic silver and an exterior surface of silver oxide
Implementation Method 2
The present disclosure provides emulsions and formulations thereof, and in particular emulsions that contain silver particles... providing potent antimicrobial properties
Data Source
AI summary
Colloidal silver particles are incorporated into emulsions and other compositions that find use, for example, as pharmaceutical and dermatological serums, creams, lotions and ointments.