Stannous Ion Stabilization in Dentifrice via Sodium Bicarbonate

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Solution Overview

Problem

Maximizing and stabilizing stannous ion (tin II) in dentifrice formulations remains a challenge due to its rapid oxidation to stannous ion (tin IV), affecting the efficacy of stannous fluoride in oral care products.

Innovation Solution

Incorporating a high amount of sodium bicarbonate (>50% by weight) and zinc oxide in dentifrice compositions to stabilize stannous ion, forming insoluble stannous bicarbonate and/or stannous hydroxide, which are more resistant to oxidation, and using zinc oxide to adsorb stannous ions, maintaining their bioavailability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If water is reduced to stabilize stannous ion, then stannous ion stability is improved, but rheology and thickening properties deteriorate

Engineering Contradiction:
Improvestannous ion stabilityVSAvoidrheology and thickening properties
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters by introducing sodium bicarbonate as a stabilizing agent替代 traditional water reduction methods. This parameter change maintains stannous ion stability while preserving acceptable rheology and thickening properties through the unique chemical interactions of sodium bicarbonate with stannous ions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Sodium bicarbonate acts as an intermediary substance that mediates between the conflicting requirements of stannous ion stability and rheological properties. It provides a chemical environment that stabilizes stannous ions without the negative rheological effects of water reduction, effectively bridging the gap between these two opposing requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If chelating agents are added to stabilize stannous ion, then stannous ion stability is improved, but formulation complexity increases

Engineering Contradiction:
Improvestannous ion stabilityVSAvoidformulation complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent employs sodium bicarbonate, a simple, inexpensive, and readily available substance,替代 complex chelating agents. This approach achieves stannous ion stability using a basic, short-lived stabilizing mechanism that does not require complex molecular structures, thereby reducing formulation complexity while maintaining effectiveness.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention changes the stabilization mechanism from complex chelation to a simpler pH-based stabilization using sodium bicarbonate. This parameter change in the stabilization approach reduces formulation complexity by eliminating the need for complex chelating agent molecules while achieving the same stability goal.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If stannous fluoride is used for oral care benefits, then oral health benefits are improved, but oxidation to stannic ion increases

Engineering Contradiction:
Improveoral health benefitsVSAvoidstannous ion form stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary anti-action by adding sodium bicarbonate to create a protective chemical environment that prevents oxidation before it can occur. The sodium bicarbonate establishes a stable pH environment that actively counteracts the oxidation tendency of stannous ions, preserving them in the bioactive tin(II) form throughout the product shelf life.

Inventive Principle:
Principle #9Preliminary anti-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 high proportion of stannous ion in the tin II form is maintained, enhancing the stability and biofilm inhibiting efficacy of the dentifrice, even after aging, with improved oral health benefits such as reduced plaque and caries formation.

Implementation Method 1

Incorporating a high amount of sodium bicarbonate (>50% by weight) and zinc oxide in dentifrice compositions to stabilize stannous ion, forming insoluble stannous bicarbonate and/or stannous hydroxide, which are more resistant to oxidation

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Implementation Method 2

using zinc oxide to adsorb stannous ions, maintaining their bioavailability

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP3880160B1Dentifrice containing sodium bicarbonate and stannous ions.
Publication Date: 2023.03.01 COLGATE PALMOLIVE CO

AI summary

This invention relates to dentifrice compositions comprising a high level of sodium bicarbonate and a stannous ion source, as well as to methods of using these compositions. Optionally, the dentifrice compositions further comprise zinc oxide.