Silicone Hydrogel Materials with Low Modulus and High Oxygen Permeability
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Solution Overview
Problem
Conventional hydrogel contact lenses suffer from low oxygen permeability, leading to adverse clinical outcomes like epithelial dehydration, and existing silicone hydrogel materials face issues with incompatibility, high manufacturing costs, and toxicity due to the use of cyclic and linear siloxanes.
Innovation Solution
Development of polymerizable hydrophilic siloxy-based monomers and prepolymers that form high oxygen permeable silicone hydrogels with low modulus elasticity and excellent wetting properties, free from cyclic and linear siloxanes, using a composition comprising (meth)acrylic monomers, vinyl-containing monomers, and hydrophilic side-chain siloxy-based methacrylate monomers, which can be manufactured without non-reactive solubilizing agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hydrogel materials are used, then the material is biocompatible and can be manufactured, but the oxygen permeability is low leading to epithelial dehydration
Solution Approach 1:
The patent combines silicone monomers (for oxygen permeability) with hydrophilic monomers (for biocompatibility and water retention) to create a composite silicone hydrogel material that simultaneously achieves high oxygen permeability and prevents epithelial dehydration
2Reliability
If silicone-based materials are used to improve oxygen permeability, then oxygen transmission increases, but the materials become hydrophobic and incompatible with hydrophilic monomers
Solution Approach 1:
The patent introduces hydrophilic side chains at specific locations on the silicone monomer structure (local modification) to create amphiphilic monomers that maintain the hydrophobic silicone core for oxygen permeability while adding hydrophilic character for compatibility with hydrophilic monomers
Solution Approach 2:
The patent modifies the chemical parameters of silicone monomers by adding hydrophilic functional groups (such as carboxyl, hydroxyl, or amide groups) to change the overall polarity and compatibility characteristics of the material
3Ease of manufacture
If non-reactive solubilizing agents are used to achieve compatibility, then the materials can be manufactured, but the manufacturing cost increases and toxicity concerns arise
Solution Approach 1:
The patent removes the need for non-reactive solubilizing agents by directly incorporating hydrophilic functionality into the reactive silicone monomer structure, eliminating harmful extraneous substances from the formulation
Solution Approach 2:
The silicone monomer structure itself provides the solubilizing function through its hydrophilic side chains, making the material self-compatible with hydrophilic monomers without requiring external solubilizing agents
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 results in contact lenses with improved oxygen permeability, low modulus elasticity, excellent tear strength, and inherent wetting and lubricity, while minimizing manufacturing complexity and toxicity, ensuring better clinical performance and safety.
Implementation Method 1
Hydrogels are hydrophilic polymers that absorb water, and are essentially insoluble in water at physiologic temperature, pH, and ionic strength due to the presence of a three-dimensional polymeric network
Implementation Method 2
These chemistries were the basis for the first successful contact lens materials. Several important classes of monomers are recognized by persons of skill with an interest to prepare hydrogel polymeric materials
Implementation Method 3
The water-swollen equilibrated state of a hydrogel results from a balance between an osmotic force that drives the water to enter the hydrophilic polymer network, and a cohesive force exerted by the polymer chains in resisting expansion
Data Source
AI summary
A composition includes at least one siloxy-based (meth)acrylate monomer or prepolymer, at least one additional methacrylate monomer, UV, and Visible light blocking agents and one or more crosslinking agents. The final product results in a highly wettable material that possesses physical properties such as a low modulus of elasticity and high oxygen permeability without the need for a non-reactive solubilizing agent and that are free of cyclic and linear siloxanes.