Hydrophilic-Hydrophobic Polymer Coating for Ophthalmic Injector Friction
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Solution Overview
Problem
Existing intraocular implant injection devices face issues with lubrication, as migration agents can lead to non-repeatability and residue-related problems, while hydrophilic coatings may peel off or be solubilized during injection, causing inflammation.
Innovation Solution
A polymer with a specific hydrophilic-hydrophobic balance is used to form a slippery coating for the injection device, which is hydrophilic enough to be swollen by viscous products but hydrophobic enough to prevent solubilization, ensuring good adhesion and avoiding peeling or entrainment into the eye.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a migration agent (blooming agent) is integrated into the thermoplastic material to provide lubrication, then the implant can slip through the tip and cartridge, but the migration agent causes white traces on the injected implant and requires numerous rinses to eliminate
Solution Approach 1:
The patent introduces a specific polymer (polyester with hydrophilic groups) as an intermediary lubricating layer between the implant and the tip/cartridge. This polymer forms a slippery coating that reduces friction during injection without migrating to the surface like traditional blooming agents, thus eliminating white traces and residue problems while maintaining ease of implant insertion
Solution Approach 2:
The patent changes the chemical and physical parameters of the lubricating material by using a polyester polymer with specific molecular weight (20,000-1,000,000 g/mol) and specific hydrophilic group content. This parameter optimization allows the polymer to provide sufficient lubrication while remaining bound to the tip/cartridge surface and not transferring to the implant, solving the residue issue
2Ease of operation
If hydrophilic coating is used to reduce friction, then the implant can slide easily, but the coating may peel off or be solubilized during injection causing inflammation
Solution Approach 1:
The patent uses a composite polyester material that combines hydrophobic polyester backbone with hydrophilic groups (such as carboxylic acid, hydroxyl, or amine groups) attached to the polymer chains. This composite structure provides both the hydrophilic lubrication properties needed for easy implant sliding and the structural integrity to prevent peeling and solubilization during injection, thus maintaining coating reliability
Solution Approach 2:
The patent applies local quality by having the polyester polymer with hydrophilic groups concentrate at the interface between the tip/cartridge and the implant only where needed for lubrication. The polymer is grafted or adsorbed onto the tip/cartridge surface, creating a localized slippery layer that maintains its position and does not peel off during the injection process
3Ease of operation
If the polymer has high hydrophilicity to provide lubrication, then the implant can slip easily, but the polymer may be solubilized and carried into the eye
Solution Approach 1:
The patent optimizes the polymer parameters by selecting polyester with specific molecular weight (20,000-1,000,000 g/mol) and controlling the density and type of hydrophilic groups. This parameter optimization creates a balance where the polymer is hydrophilic enough to provide lubrication but has sufficiently high molecular weight and appropriate hydrophilic group density to resist solubilization in aqueous environments, preventing polymer entrainment into the eye
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 coating provides a slippery surface for intraocular implant injection devices, reducing the thrust force required for implant ejection and preventing post-operative complications by maintaining its integrity during and after injection.
Implementation Method 1
ensuring good adhesion and avoiding peeling or entrainment into the eye
Implementation Method 2
hydrophilic enough to be swollen by viscous products
Implementation Method 3
hydrophobic enough to prevent solubilization
Data Source
AI summary
The invention relates to a polymer, the molar masses and the hydrophilic/hydrophobic balance of which are adjusted, able to form a slippery coating on the internal surface of at least part of a device for injecting an intraocular implant. The invention also relates to the use of the polymer for coating the internal surface of one or more parts of a device for injecting an intraocular implant, the method for coating said surface, as well as a device for injecting an intraocular implant comprising at least one portion, the internal surface of which is coated with the polymer.