Ophthalmic Packaging Solution for Contact Lens Wetting
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Solution Overview
Problem
Contact lenses often cause discomfort due to dryness and eye irritation, especially towards the end of the day, as they may not be adequately wetted during storage, and existing packaging solutions face challenges with surfactant addition, which can affect lens comfort and shelf-life.
Innovation Solution
A packaging system using a sealed container with an aqueous solution containing a polymerization product from a monomer mixture of a zwitterionic monomer bearing a center of permanent positive charge and a non-ionic ethylenically unsaturated monomer, maintaining an osmolality of at least 200 mOsm/kg and a pH of 4 to 9, which is heat sterilized, to provide a comfortable and extended wear solution for contact lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If saline or deionized water is used to store contact lenses in blister-packs, then the packaging is simple and cost-effective, but the lenses become inadequately wetted causing dryness and discomfort during wear
Solution Approach 1:
The patent modifies the chemical composition parameters of the packaging solution by incorporating specific polymers (polyvinyl pyrrolidone, polyacrylamide, carboxymethyl cellulose) and surfactants (poloxamer 407, hydroxypropyl betaine) at controlled concentrations. These parameter changes transform the solution from simple saline to a complex formulation that provides adequate lens wetting while maintaining storage stability and comfort during extended wear.
2Object-affected harmful factors
If surfactants are added to packaging solutions to improve lens wetting and comfort, then lens comfort is enhanced, but shelf-life is reduced and adverse reactions occur during heat sterilization
Solution Approach 1:
The patent introduces polymers such as polyvinyl pyrrolidone and polyacrylamide as intermediary substances that mediate between the surfactants and the lens material. These polymers enhance lens wetting and comfort while protecting the surfactants from degradation during heat sterilization, thereby maintaining both comfort and shelf-life stability.
Solution Approach 2:
The packaging solution employs a composite formulation combining multiple components: polymers (polyvinyl pyrrolidone, polyacrylamide, carboxymethyl cellulose), surfactants (poloxamer 407, hydroxypropyl betaine), and electrolytes. This composite material approach allows the solution to provide lens wetting and comfort enhancement while maintaining stability during storage and heat sterilization, resolving the contradiction between comfort improvement and reliability maintenance.
3Duration of action of moving object
If contact lenses are worn for extended periods, then convenience is improved, but dryness and eye irritation increase particularly towards the end of the day
Solution Approach 1:
The patent applies preliminary action by incorporating lens-wetting polymers and surfactants into the packaging solution before the lens is worn. These substances pre-condition the lens surface with a protective wetting layer that persists during extended wear, preventing dryness and irritation from developing during the wear period rather than treating them after they occur.
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 ensures that contact lenses are comfortable to wear, reducing dryness and irritation by maintaining adequate wetting and extending wear time without adverse effects on the cornea, while also being safe for direct placement on the eye without rinsing.
Implementation Method 1
a monomer bearing at least a center of permanent positive charge
Implementation Method 2
the solution has an osmolality of at least about 200 mOsm/kg
Implementation Method 3
which is heat sterilized
Data Source
AI summary
Disclosed are ophthalmic solutions such as packaging solutions for storing ophthalmic devices and lens care solutions for cleaning, disinfecting, rinsing and/or storing ophthalmic devices. The ophthalmic solutions contain at least a polymerization product obtained from a monomeric mixture comprising (a) a monomer bearing a center of permanent positive charge and (b) a non-ionic ethylenically unsaturated monomer, wherein the solution has an osmolality of at least about 200 mθsm/kg, and a pH of about 4 to about 9.