Contact Lens Packaging Buffering for pH Stability

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Contact lens packaging solutions with small volumes struggle to maintain stable pH levels during storage, leading to potential eye irritation and vision correction issues due to fluctuations in pH caused by elution of polymer base materials or carbon dioxide absorption.

Innovation Solution

A contact lens packaging method using a packaging solution with a buffering capacity of 3 mmol/L or greater, sealed in a compact container with a volume of 0.1 to 1.0 mL, to maintain pH stability and prevent eye irritation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a small volume packaging solution (0.1 to 1.0 mL) is used in compact contact lens packages, then space efficiency and carrying convenience are improved, but pH stability deteriorates due to easy fluctuations from elution and carbon dioxide absorption

Engineering Contradiction:
Improvepackaging solution volumeVSAvoidpH stability
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical composition parameters of the packaging solution by incorporating buffering agents (phosphate buffer, borate buffer, or carbonate buffer) at specific concentrations. This parameter modification enables the solution to resist pH fluctuations despite the small volume (0.1 to 1.0 mL), thereby maintaining pH stability while achieving compact packaging.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If a buffering capacity of 3 mmol/L or greater is provided in the packaging solution, then pH stability is improved, but the complexity of solution formulation increases

Engineering Contradiction:
ImprovepH stabilityVSAvoidsolution formulation complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent specifies precise parameter ranges for buffering agents (phosphate buffer: 1-10 mmol/L, borate buffer: 1-10 mmol/L, or carbonate buffer: 1-10 mmol/L) to achieve the required buffering capacity of 3 mmol/L or greater. By defining clear parameter boundaries, the patent simplifies the formulation process while ensuring adequate pH stability.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If compact packaging with small volume packaging solution is used, then storage and distribution costs are reduced, but the risk of eye irritation and vision correction issues increases due to pH fluctuations

Engineering Contradiction:
Improvepackaging solution volumeVSAvoideye irritation and vision correction issues
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical parameters of the packaging solution by adding buffering agents at controlled concentrations (1-10 mmol/L for phosphate, borate, or carbonate buffers). This parameter change ensures that even in small volumes (0.1 to 1.0 mL), the solution maintains pH stability, thereby preventing eye irritation and vision correction problems while enabling compact packaging that reduces storage and distribution costs.

Inventive Principle:
Principle #35Parameter changes

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 maintains pH stability during storage and use, preventing adverse effects on vision correction and eye irritation, while allowing for a compact and space-efficient packaging that reduces storage and distribution costs.

Implementation Method 1

a buffering capability of the packaging solution is 3 mmol/L or more

Methodology Applied
Scientific EffectBuffering capacity:

Implementation Method 2

carbon dioxide dissolution from outside the contact lens packaging into the packaging solution

Methodology Applied
Scientific EffectCarbon dioxide dissolution: Absorption (physical)

Data Source

PatentEP2407817B1Storage method for contact lens and contact lens package
Publication Date: 2013.12.18 MENICON CO LTD
  • EP2407817B1 patent drawingFigure 1
  • EP2407817B1 patent drawingFigure 2
  • EP2407817B1 patent drawingFigure 3

AI summary

A contact lens distribution/storage method with which contact lenses (12) can be reliably stored in a small space. To achieve this with a method for storing contact lenses (12) for distribution using a contact lens package (10, 30) containing a packaging solution (14) and the contact lens (12), a soft contact lens is used as the contact lens (12). A fluid volume of the packaging solution (14) is 0.1 to 1.0 mL, and the buffering capability of the packaging solution (14) is 3 mmol/L or greater measured in buffering capacity.