Zinc Toothpaste Rheological Stabilization With PEG 600 and PG
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Solution Overview
Problem
Formulating oral care compositions with a zinc amino acid halide complex (ZLC) that maintain good long-term stability and yield stress has been challenging.
Innovation Solution
Incorporating a humectant system comprising PEG 600 and PG in specific amounts, along with an organic or inorganic acid, to improve the rheological stability of toothpaste compositions containing a zinc lysine chloride complex.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a zinc amino acid halide complex is incorporated into toothpaste composition, then antibacterial and anti-plaque properties are improved, but long-term stability and yield stress deteriorate
Solution Approach 1:
The patent introduces PEG and PG as intermediary substances that mediate between the zinc amino acid halide complex and water. These humectants form complexes with zinc species, preventing direct interaction between zinc and water that would cause precipitation. This intermediary mechanism maintains the stability and yield stress of the toothpaste composition while preserving the antibacterial and anti-plaque properties of the zinc complex.
Solution Approach 2:
The patent changes the rheological parameters of the toothpaste composition by incorporating PEG and PG at specific concentrations (PEG: 2-4%, PG: 3-5%). This parameter change modifies the viscosity and yield stress of the composition, transforming it from an unstable system to a stable one. The humectants alter the physical state of the zinc complex, preventing precipitation and maintaining long-term stability.
2Stability of the object's composition
If PEG and PG are used as humectants in toothpaste, then rheological stability is improved, but interaction with zinc species and water increases complexity
Solution Approach 1:
PEG and PG serve as intermediary substances that simplify the overall system behavior. By forming stable complexes with zinc species, they mediate the interaction between zinc and water, transforming a complex multi-component interaction into a more manageable system. This intermediary approach actually reduces the apparent complexity by providing a clear mechanism for stability.
Solution Approach 2:
The patent creates a composite humectant system combining PEG and PG in specific proportions. This composite approach leverages the complementary properties of both substances to achieve optimal rheological stability. The combination provides a synergistic effect that maintains composition stability while managing the interactions with zinc species and water.
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 combination of PEG 600, PG, and an acid enhances the stability and yield stress of toothpaste compositions, providing improved rheological properties.
Implementation Method 1
These humectants have previously never been demonstrated to have any interaction or impact the toothpaste compositions rheologically. Nevertheless, the present disclosure has demonstrated their significant impact on rheology of the toothpaste compositions. Experiments indicate that PEG and PG do not remain innocuous in the formulation but rather interact strongly with the zinc species and water present to impact rheology of the toothpaste compositions such as viscosity.
Implementation Method 2
the composition comprises an organic or inorganic acid to reduce the pH, selected from one or more of phosphoric acid, hydrochloric acid, sulfuric acid, citric acid, tartaric acid, malic acid, maleic acid, fumaric acid, lactic acid, gluconic acid and benzoic acid, in an amount of from 0.05 to 5% by weight of the toothpaste composition
Data Source
AI summary
Disclosed herein are oral care compositions comprising a zinc amino acid halide complex, and a humectant system comprising polyethylene glycol and propylene glycol as structuring humectants, which compositions have improved rheological stability. Methods of making and using the compositions are also provided.