Electrolyzed Brine Sterilization for Contact Lens Packaging

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Solution Overview

Problem

The existing autoclave-based terminal sterilization process for contact lenses is time-consuming, costly, and inefficient, causing mechanical distortion in packaging, cosmetic deterioration of materials, and potential adverse reactions due to high temperatures, while also requiring complex equipment and monitoring, which complicates the use of certain saline additives and UV blockers.

Innovation Solution

The use of electrolyzed brine as a sterilizing agent in the packaging solution, which decomposes into innocuous saline within hours or days, providing a 6 log reduction in viable microorganisms without the need for autoclaving, and can be combined with other sterilization techniques to achieve the required sterility assurance level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If autoclave sterilization is used to achieve required sterility level, then sterilization effectiveness is improved, but production time and manufacturing cost increase

Engineering Contradiction:
Improvesterilization effectivenessVSAvoidproduction time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent extracts the sterilization function from the thermal autoclave process and implements it through chemical sterilants (e.g., hydrogen peroxide, peracetic acid) applied directly to the contact lenses during manufacturing. This eliminates the need for batch autoclave processing while maintaining sterilization effectiveness, thereby improving production time and manufacturing efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/thermal autoclave system with a chemical sterilization system using liquid or gaseous sterilants. This substitution eliminates the need for high-temperature steam autoclaving, allowing for continuous processing and reducing both production time and equipment complexity while achieving the required 10^-6 sterility assurance level.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If autoclave sterilization is used to ensure sterility, then microbial elimination is improved, but packaging material integrity deteriorates

Engineering Contradiction:
Improvesterilization effectivenessVSAvoidpackaging material integrity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the sterilization parameters from high-temperature thermal processing (autoclave at 121°C or higher) to chemical sterilization using agents like hydrogen peroxide or peracetic acid at lower temperatures. This parameter change preserves the integrity of packaging materials such as polypropylene blisters and laminated foils while achieving the required sterilization effectiveness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs strong oxidizing sterilants such as hydrogen peroxide and peracetic acid to achieve sterilization through oxidation of microorganisms. These chemical oxidants effectively eliminate microbes without requiring the high temperatures that cause packaging material distortion, foil wrinkling, and cosmetic deterioration, thereby maintaining packaging integrity.

Inventive Principle:
Principle #38Strong oxidants (Accelerated oxidation)

3Reliability

If autoclave sterilization is used to achieve sterility, then microbial inactivation is improved, but manufacturing process complexity increases

Engineering Contradiction:
Improvesterilization effectivenessVSAvoidequipment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the sterilization function from the complex autoclave system and implements it through simpler chemical sterilization processes that can be integrated into existing manufacturing lines. This eliminates the need for specialized autoclave equipment, temperature sensors, and pressure monitoring systems, thereby reducing equipment complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the complex mechanical autoclave system with a chemical sterilization system that uses liquid or gaseous sterilants applied through straightforward dispensing or exposure processes. This substitution eliminates the need for complex thermal processing equipment, temperature control systems, and pressure regulation mechanisms, significantly reducing equipment complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If autoclave sterilization is used to ensure sterility, then microbial elimination is improved, but manufacturing cost increases

Engineering Contradiction:
Improvesterilization effectivenessVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the sterilization function from the costly autoclave process and implements it through more economical chemical sterilants that can be applied directly during manufacturing. This eliminates the need for expensive autoclave equipment, energy-intensive thermal processing, and complex monitoring systems, thereby reducing manufacturing costs while maintaining sterilization effectiveness.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the expensive autoclave system with a chemical sterilization process that uses cost-effective sterilants and simpler application equipment. This substitution eliminates the need for costly thermal processing equipment, temperature control systems, and pressure regulation mechanisms, significantly reducing capital equipment costs and operational expenses.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This approach allows for a continuous flow-line manufacturing process, reducing production time and costs, avoiding adverse reactions, and maintaining the integrity of packaging materials, while ensuring the necessary level of sterilization is achieved without the drawbacks of traditional methods.

Implementation Method 1

The use of electrolyzed brine as a sterilizing agent in the packaging solution, which decomposes into innocuous saline within hours or days

Methodology Applied
Scientific EffectDecomposition: Decomposition (biological)

Data Source

PatentEP1976570B1Methods and systems for contact lens sterilization
Publication Date: 2019.06.19 MENICON SINGAPORE PTE LTD
  • EP1976570B1 patent drawingFigure 1
  • EP1976570B1 patent drawingFigure 2
  • EP1976570B1 patent drawingFigure 3

AI summary

A method of sterilizing a contact lens (105) includes at least partially sterilizing the contact lens (105) with an application of electrolyzed brine (190). A system for at least partially sterilizing a contact lens (105) in initial packaging (110, 162) includes a generator (152) for producing electrolyzed brine (190) with biocidal activity, and a dispenser (163) for dispensing a quantity of electrolyzed brine (190) from the generator (152) into the initial packaging (110, 162) with the contact lens (105).