Nonionic Surfactant Contact Lens Packaging Solution

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Solution Overview

Problem

Existing contact lens packaging solutions fail to inhibit the sticking of flexible silicone hydrogel lenses to hydrophobic packaging containers, leading to deformation and breakage, and methyl cellulose-based solutions have issues with solubility and contamination.

Innovation Solution

A packaging solution containing a nonionic surfactant with a linear alkyl moiety of 12 or more carbon atoms and an oxyethylene moiety with an average addition mole number of 30 or more is used to prevent adhesion between silicone hydrogel contact lenses and polypropylene packaging containers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a packaging solution containing polysorbate or poloxamer is used, then the sticking of a lens to a packaging material is prevented, but the adhesion of flexible silicone hydrogel lenses to hydrophobic packaging containers cannot be inhibited

Engineering Contradiction:

Improveprevention of lens stickingVSAvoideffectiveness for flexible silicone hydrogel lenses

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the chemical parameters of the surfactant by specifying a nonionic surfactant with a linear alkyl moiety of 12-20 carbon atoms and an oxyethylene moiety with an average addition mole number of 30-100. This specific parameter configuration provides optimal balance between hydrophobicity and hydrophilicity, enabling effective prevention of adhesion for flexible silicone hydrogel lenses while maintaining compatibility with hydrophobic packaging containers.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If methyl cellulose is used as a surfactant, then the sticking of a soft lens to a hydrophobic packaging material is inhibited, but heating is required for dissolution and contamination with impurities occurs

Engineering Contradiction:

Improveinhibition of lens stickingVSAvoiddissolution process and purity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a nonionic surfactant with specific parameters (linear alkyl moiety of 12-20 carbon atoms and oxyethylene moiety of 30-100 average addition moles) that provides effective adhesion inhibition without requiring heating for dissolution. This surfactant system achieves the desired functionality with improved ease of manufacture and reduced contamination risks compared to methyl cellulose-based solutions.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Ease of operation

If flexible silicone hydrogel contact lenses with low elastic modulus are used, then wearing comfort is improved, but the area of contact with packaging container increases leading to sticking

Engineering Contradiction:

Improvewearing comfortVSAvoidadhesion to packaging container

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a nonionic surfactant as an intermediary substance between the flexible silicone hydrogel lens and the hydrophobic packaging container. The surfactant with specific parameters (linear alkyl moiety of 12-20 carbon atoms and oxyethylene moiety of 30-100 average addition moles) mediates the interaction by providing balanced hydrophobicity and hydrophilicity, preventing direct adhesion while allowing the lens to maintain its flexible properties for comfortable wear.

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 effectively inhibits the sticking of silicone hydrogel contact lenses to polypropylene containers, maintaining lens integrity and comfort by balancing hydrophobicity and hydrophilicity, thus preventing deformation and breakage.

Implementation Method 1

a packaging solution containing a nonionic surfactant, the nonionic surfactant including a linear alkyl moiety having 12 or more carbon atoms and an oxyethylene moiety, the average addition mole number of oxyethylene being 30 or more per mole of the nonionic surfactant

Methodology Applied

Scientific EffectSurfactant action: Surfactant

Implementation Method 2

a hydrophilic unit of the surfactant attracted to surfaces of the lens seems to be directed toward the surfaces (in the solution) to impart hydrophilicity to the surfaces of the lens

Methodology Applied

Scientific EffectHydrophilicity: Hydrophile

Implementation Method 3

the nonionic surfactant has a good affinity for a hydrophobic portion of the silicone hydrogel. In general, silicone hydrogels have high hydrophobicity. Thus, the silicone hydrogel seems to interact strongly with a hydrophobic portion of the nonionic surfactant in water

Methodology Applied

Scientific EffectHydrophobic interaction: Hydrophobe

Data Source

PatentUS11181753B2Contact lens package and method for producing the same

Publication Date: 2021.11.23 MENICON CO LTD

AI summary

A contact lens package includes a silicone hydrogel contact lens, a packaging container composed of a polypropylene, and a packaging solution containing a nonionic surfactant, the nonionic surfactant including a linear alkyl moiety having 12 or more carbon atoms and an oxyethylene moiety, the average addition mole number of oxyethylene being 30 or more per mole of the nonionic surfactant.