Single-Phase Non-Aqueous Dentifrice for Fluoride-Zinc Stability
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Solution Overview
Problem
Combining stannous fluoride and zinc salts in a single-phase non-aqueous dentifrice composition is challenging due to their different chemical and physical properties, leading to instability and formulation issues, such as syneresis and rheological problems, which affect stability and consumer acceptability.
Innovation Solution
A stable single-phase non-aqueous dentifrice composition is achieved by using a solvent combination of glycerol and polyethylene glycol with carrageenan, along with polyacrylic acid polymer, sodium lauryl sulphate, and cocamidopropyl betaine surfactants, to stabilize stannous fluoride and zinc chloride, maintaining effective levels for oral health benefits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stannous fluoride and zinc salts are combined in a single-phase non-aqueous dentifrice composition, then the formulation can provide stable storage and effective delivery of both actives, but the different chemical and physical properties of the actives cause instability, syneresis and rheological problems
Solution Approach 1:
The patent introduces specific intermediaries including polyacrylic acid (PAA) polymer, carrageenan, and a solvent system comprising glycerol and polyethylene glycol (PEG). These intermediaries act as stabilizing agents that mediate between stannous fluoride and zinc salts, preventing direct harmful interactions while maintaining their individual efficacy. The PAA and carrageenan form a polymeric network that stabilizes the non-aqueous formulation, preventing syneresis and rheological degradation.
Solution Approach 2:
The patent changes the physical-chemical parameters of the formulation by using non-aqueous solvents (glycerol and PEG) instead of water, adjusting pH levels, and optimizing the concentration ranges of actives (zinc salt: 0.05-1%, stannous fluoride: 0.05-0.5%). These parameter changes create a stable environment that prevents degradation of the actives while maintaining their oral health benefits.
2Reliability
If separate formulations are used for stannous fluoride and zinc salts, then each active can be optimised, but the manufacture becomes more complex requiring separate tubes and containment arrangements
Solution Approach 1:
The patent merges two separate dentifrice formulations into a single-phase non-aqueous composition that simultaneously contains stannous fluoride and zinc salts. This consolidation eliminates the need for separate tubes, containment arrangements, and application mechanisms, while maintaining the efficacy of both actives through careful formulation chemistry and stabilizing agents.
3Adaptability or versatility
If striped toothpaste is used to combine actives, then a single dentifrice can contain combined actives, but the actives are combined only briefly on the brush prior to use reducing stability
Solution Approach 1:
The patent performs preliminary stabilization of the actives within the dentifrice formulation itself, creating a stable non-aqueous environment that preserves both stannous fluoride and zinc salts before application. The polymeric network and solvent system maintain the actives in a stable, bioavailable state within the tube, eliminating the need for brief combination on the brush and ensuring consistent delivery throughout the product lifecycle.
Data Source
AI summary
A stable single phase non-aqueous dentifrice composition comprising stannous fluoride and at least one zinc salt. Preferably wherein the dentifrice composition comprises a toothpaste formulation.