Citrate-Stabilized Oral Care Compositions for Soluble Calcium Fluoride

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Solution Overview

Problem

Conventional oral care compositions face challenges in stabilizing calcium and fluoride ions due to the formation of insoluble calcium fluoride, requiring physiological pH for calcium or phosphate release, and limited bioavailability of ions like zinc or strontium, which hinders effective remineralization and antimicrobial activity.

Innovation Solution

A method involving the formation of a metastable supersaturated aqueous solution of calcium citrate followed by the timely addition of fluoride salt, creating a stable complex with calcium, fluoride, and citrate, maintaining solubility and bioavailability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If calcium ions and fluoride ions are combined in aqueous solutions, then remineralization benefit is achieved, but calcium fluoride precipitates forming highly insoluble compounds with limited bioavailability

Engineering Contradiction:
Improveconcentration of calcium and fluoride ionsVSAvoidsolubility of calcium fluoride
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent uses citrate ions as an intermediary substance that complexes with calcium ions to form soluble calcium citrate complexes. This mediator prevents direct precipitation of calcium fluoride by keeping calcium ions in solution through chelation, thereby maintaining high concentrations of both calcium and fluoride ions without forming insoluble precipitates.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical parameters of the solution by introducing citrate ions, which alter the speciation of calcium from free Ca2+ ions to calcium citrate complexes. This parameter change increases the solubility product effectively, allowing much higher concentrations of calcium and fluoride to coexist in solution without precipitation.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If calcium phosphate or hydroxyapatite compounds are added to release calcium or phosphate, then remineralization is aided, but physiological pH is required to dissolve tooth structure hydroxyapatite which is counterproductive

Engineering Contradiction:
Improverelease of calcium or phosphateVSAvoidphysiological pH requirement
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The patent changes the pH parameter requirement by using citrate-based calcium complexes instead of calcium phosphate or hydroxyapatite. The calcium citrate complexes remain soluble across a broader pH range and do not require acidic physiological conditions to release calcium, thus avoiding the counterproductive effect of dissolving tooth structure hydroxyapatite.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If other desirable ions like zinc or strontium are added, then additional benefits such as antimicrobial activity and matrix reinforcement are provided, but insoluble fluorides form with minimal ionic bioavailability

Engineering Contradiction:
Improveadditional benefits (antimicrobial activity, matrix reinforcement)VSAvoidsolubility of zinc fluoride and strontium fluoride
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent extends the use of citrate as an intermediary to complex with multiple cations including zinc and strontium ions. The citrate forms soluble complexes with these ions, preventing precipitation of their fluorides and maintaining their bioavailability while preserving their beneficial functions such as antimicrobial activity and matrix reinforcement.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution maintains high concentrations of free fluoride and calcium, preventing precipitation, ensuring stability and bioavailability for effective remineralization and antimicrobial effects, with extended shelf life and compatibility with additional active agents.

Implementation Method 1

employing a citrate to stabilize calcium ions in aqueous solution in a metastable concentration of calcium exceeding the solubility product of calcium fluoride in the presence of fluoride

Methodology Applied
Scientific EffectMetastability: Metastability

Implementation Method 2

formation of a metastable supersaturated aqueous solution of calcium citrate

Methodology Applied
Scientific EffectSupersaturation: Supersaturation

Implementation Method 3

employing a chelating agent, such as citrate, to stabilize calcium ions in aqueous solution

Methodology Applied
Scientific EffectChelation:

Data Source

PatentUS20250213439A1Oral Care Compositions, Methods, and Kits
Publication Date: 2025.07.03 SOLVENTUM INTELLECTUAL PROPERTIES CO

AI summary

An aqueous oral care composition includes calcium, fluoride, citrate, and water. The composition includes at least 2 moles of citrate for every 3 moles of calcium, and at least 1 mole of fluoride for every 1 mole of calcium. Water is present in the composition in an amount of at least 50 wt %, based on the total weight of the composition. The composition is a solution.