Oral Care Composition Using Low pKa Buffer for Fluoride Uptake
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Solution Overview
Problem
Conventional oral care products formulated at neutral pH fail to effectively form CaF2 layers on tooth enamel due to the high buffer capacity of saliva, resulting in poor fluoride uptake.
Innovation Solution
An oral care composition comprising an amine fluoride and a buffer with a pKa of less than 7.0, specifically an aqueous solution of certain acids and their salts, is used to maintain a pH between 3.5 and 5.0, enhancing fluoride uptake by counteracting the buffering effect of saliva.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oral care products are formulated at neutral pH, then they are stable and easy to manufacture, but they fail to effectively form CaF2 layers on tooth enamel due to poor fluoride uptake
Solution Approach 1:
The patent changes the pH parameter from neutral to slightly acidic (pH 3.5-5.0) to enable effective CaF2 layer formation on tooth enamel. This parameter change resolves the contradiction by creating conditions where fluoride can be effectively taken up by teeth while maintaining product stability through the use of buffers and acid-number control.
Solution Approach 2:
The patent applies preliminary action by pre-formulating the oral care composition with specific buffers and acids at controlled concentrations before application. The composition is pre-adjusted to have an acid number greater than 6.0 and contains buffering agents that will maintain the slightly acidic pH environment needed for CaF2 formation during the product's residence time in the mouth.
2Quantity of substance
If oral care products are formulated at slightly acidic pH to promote CaF2 formation, then fluoride uptake improves, but the high buffer capacity of saliva causes pH to rise and prevents maintenance of the desired acidic level
Solution Approach 1:
The patent introduces buffers as intermediary substances that mediate between the slightly acidic formulation and the high buffer capacity of saliva. These buffers act as pH stabilizers that resist changes in acidity, allowing the composition to maintain its slightly acidic pH (3.5-5.0) environment throughout the application period despite the challenging oral environment.
Solution Approach 2:
The patent applies beforehand cushioning by incorporating buffering agents into the oral care composition in advance. These buffers provide a cushioning effect against pH changes, absorbing or releasing protons as needed to maintain the slightly acidic pH level. This pre-built buffer capacity cushions the formulation against the alkaline challenge from saliva buffering.
3Quantity of substance
If buffers are added to maintain slightly acidic pH, then CaF2 layer formation is enhanced, but the composition requires careful formulation to achieve and maintain the target pH range
Solution Approach 1:
The patent systematically adjusts multiple formulation parameters including buffer concentration, acid type, and acid number to achieve the target pH range. By controlling the acid number (greater than 6.0) and selecting appropriate buffer systems, the formulation achieves the desired slightly acidic pH that promotes CaF2 formation while providing a stable final product.
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 composition effectively maintains a slightly acidic pH, leading to increased fluoride uptake and improved formation of CaF2 layers, thereby enhancing oral care benefits such as reduced dental cavity formation and teeth remineralization.
Implementation Method 1
a buffer having a pKa of less than 7.0 wherein the buffer comprises an aqueous solution of an acid and a salt of the acid... the buffer is able to buffer the oral care composition at the desired pH
Implementation Method 2
fluoride anti caries efficacy is related to the prior formation of a CaF2 depot (ideally in form of a layer) on the enamel surface... For efficient formation of CaF2, conditions need to be slightly acidic
Data Source
AI summary
Described herein is an oral care composition comprising an orally acceptable vehicle, a fluoride ion and a buffer having a pKa of less than 7.0 wherein the pH of the oral composition is greater than 3.5 and less than 5.0, and wherein the oral composition has an acid number greater than 4.5.