Tin Ion Stabilization in Alkaline Oral Care via Polyol Complexation
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Solution Overview
Problem
The incorporation of tin ions, such as stannous fluoride, into aqueous dentifrice compositions at a pH greater than 7 is challenging due to reactivity with other components and the formation of insoluble tin compounds like Sn(OH)2, which reduces tin ion availability for oral health benefits.
Innovation Solution
The formulation of oral care compositions that include a tin ion source, a stabilizing polyol with five or six carbon atoms, and a gum strengthening polyol with seven or more hydroxyl functional groups, all at a pH greater than 7, which helps to prevent the formation of insoluble tin compounds and maintain tin ion stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stannous fluoride is added to aqueous dentifrice compositions at pH greater than 7, then antimicrobial and antisensitivity benefits are provided, but insoluble tin compounds like Sn(OH)2 form and tin ion availability decreases
Solution Approach 1:
The patent introduces polyols (glycerin, sorbitol, xylitol) as intermediary substances that mediate between tin ions and the aqueous environment. These polyols form soluble complexes with tin ions, preventing direct reaction with water to form insoluble Sn(OH)2 while still allowing tin ions to be delivered to oral surfaces for therapeutic effects.
Solution Approach 2:
The patent changes the chemical environment parameters by adjusting pH to greater than 7 and incorporating specific polyol concentrations (5-50% w/w). This parameter change transforms the unstable tin ion-water interaction into a stable tin ion-polyol complex system that maintains solubility and availability at elevated pH levels.
2Stability of the object's composition
If chelants such as gluconate or citrate are used to stabilize tin ions, then chemical instability is mitigated, but tin ion availability for oral surface binding is reduced
Solution Approach 1:
The patent replaces traditional chelants with polyols that provide temporary stabilization during storage but do not form strong, persistent complexes. The polyol-tin complexes are stable enough to prevent precipitation during shelf storage but labile enough to allow tin ion release and binding to oral surfaces during use, effectively providing 'short-living' stabilization.
Solution Approach 2:
The patent changes the stabilizing mechanism from strong chelant-tin binding to weaker polyol-tin interactions enabled by specific pH and polyol concentration parameters. This creates a balance where stabilization is sufficient to prevent precipitation but insufficient to prevent therapeutic binding to oral surfaces.
3Stability of the object's composition
If anhydrous conditions are used with polyols as carrier material, then stable compositions with stannous fluoride are formulated, but cost increases relative to water-based compositions
Solution Approach 1:
The patent changes the water content parameter from near-zero (anhydrous) to significant levels (up to 45% w/w), transforming the system from anhydrous to aqueous. This parameter change enables the use of water as a carrier material while maintaining stability through the combined presence of polyols and elevated pH, thereby reducing cost.
Solution Approach 2:
The patent creates a composite stabilization system combining polyols and elevated pH conditions, replacing the need for expensive anhydrous conditions. This composite approach uses inexpensive water-based materials while achieving stability through the synergistic interaction of multiple components.
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
This approach results in stable, shelf-stable dentifrice compositions with minimal formation of Sn(OH)2, ensuring that tin ions remain available for their antimicrobial and antisensitivity benefits, even at elevated pH conditions.
Implementation Method 1
the formation of insoluble tin compounds at particular pH conditions... tin ion sources can be difficult to incorporate into dentifrice compositions due to (i) the reactivity between tin ions and other dentifrice components
Implementation Method 2
The chemical instability in solution of tin ions can be mitigated by lowering the pH of the solution, providing anionic chelants, such as anions of organic acids, or providing polymeric chelants, such as polyphosphates or polycarboxylates
Data Source
AI summary
An oral care composition with a tin, polyol with five or six carbon atoms, polyol with seven or more hydroxyl functional groups, and a pH of greater than 7. An oral care composition with a tin ion source, a fluoride ion source, a polyol with five or six carbon atoms, a non reducing sugar or sugar alcohol with seven or more hydroxyl functional groups, and a pH of greater than 7. Oral care compositions with a high tin ion availability.