Stannous-Zinc Oral Care Composition With Lower Astringency

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Solution Overview

Problem

Conventional oral care compositions using stannous fluoride and zinc sources face challenges such as instability, staining, astringency, unpleasant taste, and manufacturing complexity, necessitating improved formulations with enhanced antibacterial efficacy and palatability.

Innovation Solution

An oral care composition comprising zinc oxide, zinc citrate, stannous pyrophosphate, glycerin, sorbitol, and a thickening system with hydroxyethyl cellulose and carrageenan, which provides improved processing and therapeutic performance while maintaining stability and taste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high concentrations of zinc (2% or more) are used to achieve antibacterial efficacy, then the antibacterial performance is improved, but the composition becomes notably astringent and unpleasant in taste

Engineering Contradiction:
Improveantibacterial efficacyVSAvoidastringent taste
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical form of zinc from conventional salts to zinc oxide nanoparticles, which provides equivalent antibacterial efficacy at lower concentrations (0.03-2% vs 2%+), thereby reducing the astringent taste while maintaining reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite formulation combining zinc oxide nanoparticles with stannous fluoride and pyrophosphates, where the synergistic interaction between components allows for reduced zinc concentration while maintaining or enhancing antibacterial performance

Inventive Principle:
Principle #40Composite materials

2Reliability

If stannous salts are used as anti-microbial agents, then plaque prevention is improved, but the composition suffers from instability, staining, astringency, and unpleasant taste

Engineering Contradiction:
Improveanti-microbial efficacyVSAvoidformulation stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces pyrophosphates as intermediary compounds that complex with stannous ions, stabilizing them in the formulation and preventing unwanted reactions while maintaining anti-microbial efficacy. The pyrophosphates act as mediators between the stannous salts and the aqueous environment

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent develops a composite system where stannous fluoride is combined with pyrophosphates and zinc oxide nanoparticles, creating a multi-component formulation where each ingredient compensates for the weaknesses of others, achieving both stability and efficacy

Inventive Principle:
Principle #40Composite materials

3Reliability

If both stannous fluoride and zinc sources are included in the composition, then antibacterial performance is enhanced, but the formula complexity increases from manufacturing and supply chain perspective

Engineering Contradiction:
Improveantibacterial performanceVSAvoidformula complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes pyrophosphates serve multiple functions simultaneously: they stabilize stannous ions, provide tartar control, enhance antibacterial activity, and improve overall formulation stability. This multi-functionality reduces the need for separate additives, simplifying the manufacturing process while maintaining enhanced antibacterial performance

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If conventional zinc sources are used at effective concentrations, then antibacterial activity is achieved, but the composition requires high concentrations (2% or more) that impart notably astringent taste

Engineering Contradiction:
Improveantibacterial activityVSAvoidpalatability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the physical state and size parameters of zinc by using nanoparticles (1-100 nm scale) instead of conventional bulk zinc salts. This nanoscale transformation increases surface area and reactivity, enabling effective antibacterial activity at much lower concentrations (0.03-2%), thereby improving palatability by reducing astringent taste

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4021385B1Oral care compositions and methods of use
Publication Date: 2026.02.04 COLGATE PALMOLIVE CO

AI summary

The invention relates to oral care compositions comprising a first stannous ion source, a second stannous ion source, wherein the second stannous ion comprises stannous pyrophosphate, and a source of zinc selected from zinc oxide, zinc citrate, zinc lactate, and combinations thereof, and a humectant system comprising glycerin and sorbitol, and a thickening system, as well as to methods of using and making these compositions.