Aqueous Oral Care Composition for Stable Stannous and Potassium Salts

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Solution Overview

Problem

Existing oral care compositions face stability issues with stannous fluoride or stannous chloride due to their reactivity in aqueous solutions, leading to precipitation and loss of therapeutic properties, and formulations with potassium salts often result in poor foaming and potential toxic species formation, making it challenging to create stable, high-water compositions that maintain effective ingredient concentrations.

Innovation Solution

A combination of stannous fluoride or stannous chloride, nitric acid or a soluble nitrate salt, and an alkali metal polyphosphate salt in a high-water oral care composition stabilizes stannous, fluoride, and nitrate, resulting in a single-component, clear, and translucent formulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If stannous fluoride or stannous chloride is used in aqueous oral care compositions, then therapeutic benefits for caries prevention and gingivitis reduction are achieved, but stability is compromised due to hydrolysis and precipitation at pH above 4

Engineering Contradiction:
Improvetherapeutic stabilityVSAvoidchemical stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

A water-soluble polyphosphate salt serves as an intermediary agent that complexes with stannous ions to form stable soluble complexes, preventing direct hydrolysis and precipitation. This mediator allows stannous fluoride or stannous chloride to remain stable in aqueous solutions at physiological pH levels.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite chemical system combining stannous fluoride or stannous chloride with water-soluble polyphosphate salts, forming a multi-component composition where the polyphosphate stabilizes the stannous ion through complexation, enabling simultaneous presence of both ingredients without precipitation.

Inventive Principle:
Principle #40Composite materials

2Reliability

If potassium salts are included for sensitivity relief, then desensitizing benefits are achieved, but foam stability deteriorates due to foam-breaking properties

Engineering Contradiction:
Improvedesensitizing efficacyVSAvoidfoam quality
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention modifies the chemical environment by introducing polyphosphate complexing agents that alter the behavior of potassium ions, reducing their foam-breaking effect while maintaining their desensitizing functionality. This parameter change allows both sensitivity relief and acceptable foam quality.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If both stannous fluoride and potassium salts are combined, then dual therapeutic benefits are achieved, but insoluble stannic salts and toxic species form

Engineering Contradiction:
Improvemulti-ingredient functionalityVSAvoidtoxic species formation
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The water-soluble polyphosphate salt acts as a protective intermediary that complexes with stannous ions before they can react with nitrate to form toxic nitrosamines or reduce to metallic tin. This intermediary prevents harmful reactions while allowing beneficial ingredient combinations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The polyphosphate provides preliminary protection by forming stable complexes with stannous ions in advance, preventing subsequent unwanted reactions with potassium nitrate that would otherwise produce toxic species or insoluble precipitates.

Inventive Principle:
Principle #9Preliminary anti-action

4Stability of the object's composition

If water content is limited to maintain stannous ion stability, then chemical stability improves, but rheological properties and manufacturability worsen

Engineering Contradiction:
Improvestannous ion stabilityVSAvoidrheological control
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The invention changes the chemical parameters by introducing polyphosphate complexing agents, which enable high water content formulations to maintain stannous ion stability. This parameter change eliminates the need for low-water formulations while preserving both stability and rheological properties.

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

The solution achieves stable stannous ion concentrations, clear aesthetics, and effective dental benefits, including caries prevention and sensitivity relief, while avoiding toxic species formation and maintaining desirable foam properties.

Implementation Method 1

stannous salts readily hydrolyze at a pH above 4, resulting in precipitation from solution

Methodology Applied
Scientific EffectComplexation:

Implementation Method 2

Stannous salts readily hydrolyze at a pH above 4, resulting in precipitation from solution

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

attempts to include both stannous fluoride and potassium salts, such as potassium nitrate, in a single-phase, desensitizing dental composition is hampered by the formation of insoluble stannic salts

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentUS12472130B2Oral care compositions and methods
Publication Date: 2025.11.18 COLGATE PALMOLIVE CO

AI summary

This application relates to novel aqueous oral care compositions useful for combining and delivering incompatible stannous fluoride or stannous chloride and potassium salts in a high-water composition, for example, to provide effective caries prevention, protection against dental erosion, and relief from dental hypersensitivity. The compositions comprise stannous fluoride or stannous chloride, nitric acid or a water-soluble nitrate salt, a water-soluble alkali metal polyphosphate and more than 10% water, by weight of the composition.