Zinc Salt Solubility Gradient for Oral Care Antimicrobial Efficacy

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Solution Overview

Problem

Existing oral care compositions fail to provide effective antimicrobial activity, high flavor intensity, and a pleasant taste while leaving a fresh feeling in the mouth.

Innovation Solution

A non-aqueous oral care composition comprising a combination of zinc salts with varying solubilities, including zinc sulphate, zinc citrate, and zinc oxide, along with calcium carbonate for mechanical cleaning, and surfactants for foaming, formulated into a compressed tablet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single zinc salt is used in oral care composition, then the formulation is simple, but the antimicrobial activity and flavor intensity are insufficient

Engineering Contradiction:
Improveantimicrobial activityVSAvoidformulation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a composite zinc salt system comprising three distinct zinc salts (zinc sulfate, zinc citrate, and zinc oxide) with varying solubilities. This composite approach synergistically combines the antimicrobial efficacy of different zinc compounds while achieving high flavor intensity and fresh feeling, resolving the contradiction between simple formulation and effective performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by selecting zinc salts with specific solubility characteristics for specific functions. Zinc sulfate (high solubility >500g/litre) provides immediate antimicrobial action and flavor, zinc citrate (moderate solubility 0.05-500g/litre) provides sustained release, and zinc oxide (low solubility <0.05g/litre) provides long-lasting antimicrobial protection. This differentiated assignment of properties to different components resolves the contradiction between formulation simplicity and performance effectiveness.

Inventive Principle:
Principle #3Local quality

2Reliability

If highly soluble zinc salts are used, then antimicrobial activity is high, but flavor intensity and pleasant taste are reduced

Engineering Contradiction:
Improveantimicrobial activityVSAvoidunpleasant taste
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent assigns different zinc salts with specific solubility profiles to different functional roles. Zinc sulfate (highly soluble, >500g/litre) delivers immediate antimicrobial activity and flavor intensity, while zinc oxide (low soluble, <0.05g/litre) provides sustained, gentle antimicrobial protection without overwhelming the taste buds. This localized functional assignment resolves the contradiction between high antimicrobial activity and pleasant taste.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the solubility parameter of zinc compounds by selecting three distinct zinc salts with progressively lower solubilities. This parameter variation creates a staged release profile where highly soluble zinc sulfate provides immediate effect, and progressively less soluble zinc citrate and zinc oxide provide sustained release, maintaining pleasant taste while ensuring continuous antimicrobial activity.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If water-soluble zinc salts are used, then antimicrobial efficacy is achieved, but flavor intensity and fresh feeling are compromised

Engineering Contradiction:
Improveantimicrobial efficacyVSAvoidreduced flavor intensity
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the solubility parameter across the zinc salt components, with zinc sulfate having very high solubility (>500g/litre) to provide immediate antimicrobial efficacy and high flavor intensity, while zinc citrate (0.05-500g/litre) and zinc oxide (<0.05g/litre) provide progressive sustained release. This parameter gradient resolves the contradiction between antimicrobial efficacy and flavor intensity by ensuring both immediate and sustained effects.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite zinc salt system where zinc sulfate, zinc citrate, and zinc oxide work synergistically. The highly soluble zinc sulfate provides immediate antimicrobial action and flavor impact, while the progressively less soluble zinc citrate and zinc oxide ensure sustained release and prolonged fresh feeling, collectively resolving the contradiction between efficacy and sensory properties.

Inventive Principle:
Principle #40Composite materials

4Reliability

If multiple zinc salts with different solubilities are combined, then antimicrobial activity and flavor intensity are improved, but the formulation complexity increases

Engineering Contradiction:
Improveantimicrobial activityVSAvoidformulation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by assigning each zinc salt a specific solubility range and functional role: zinc sulfate (>500g/litre) for immediate antimicrobial action, zinc citrate (0.05-500g/litre) for intermediate release, and zinc oxide (<0.05g/litre) for sustained protection. This differentiated functional assignment justifies the increased formulation complexity by achieving superior antimicrobial activity and flavor intensity that cannot be obtained with single zinc salts.

Inventive Principle:
Principle #3Local quality

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 achieves antimicrobial efficacy, high flavor intensity, and a fresh feeling, maintaining a pleasant taste and effective cleaning performance.

Implementation Method 1

a combination of zinc salts having differing solubilities... the first zinc salt having a solubility at 20°C in water of greater than 500g/litre... the second zinc salt having a solubility at 20°C of from 0.01g/litre to 300g/litre... the third zinc salt/oxide having a solubility at 20°C of less than 0.005g/litre

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 2

The tablets are made from a combination of a mild tooth abrasive with a binding agent and flavouring

Methodology Applied
Scientific EffectAbrasion: Abrasion

Implementation Method 3

the sodium lauryl sulphate causes foaming upon brushing the teeth

Methodology Applied
Scientific EffectFoaming: Foam

Data Source

PatentEP3277384B1Solid oral care compositions
Publication Date: 2021.10.13 UNILEVER IP HLDG BV

AI summary

An oral care composition comprising at least three zinc salts/oxides: i) the first that at 20°C having a solubility great than 500g/litre in water; ii) the second having at 20°C a solubility from 0.05g/litre to 500g/litre in water iii) the third having at 20°C having a solubility less than 0.05g/litre in water.