Block Copolymer Stent Coatings for Drug Release and Mechanical Compatibility
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Solution Overview
Problem
Current drug-eluting stents face challenges in optimizing polymeric coatings for controlled drug release, biocompatibility, and mechanical compatibility with balloon surfaces and vessel walls, leading to issues like in-stent restenosis.
Innovation Solution
The development of implantable and insertable medical devices featuring block-copolymer-containing polymeric regions, specifically combining polyaromatic and polyalkene blocks with sulfonated high Tg polymers or fluorinated polymer blocks, which enhance biocompatibility, surface tack, elasticity, and therapeutic agent diffusivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymeric coating is applied to the stent for controlled drug release, then drug delivery performance is improved, but mechanical compatibility with balloon surface and vessel wall may deteriorate
Solution Approach 1:
The patent employs block copolymer compositions comprising polyaromatic blocks and polyalkene blocks to create a composite polymeric material that simultaneously provides controlled drug release properties and mechanical compatibility with both balloon surface and vessel wall, resolving the contradiction between drug delivery performance and mechanical adaptability
Solution Approach 2:
The patent utilizes sulfonated high Tg polymers to modify the physical and chemical characteristics of the polymeric coating, changing parameters such as glass transition temperature, surface properties, and elasticity to achieve both controlled drug release and optimal mechanical compatibility with different interfaces
2Object-affected harmful factors
If the polymeric coating is optimized for biocompatibility, then interaction with vessel wall is improved, but drug release control may deteriorate
Solution Approach 1:
The block copolymer structure with distinct polyaromatic and polyalkene blocks creates microphase-separated domains where one block interacts with the vessel wall to provide biocompatibility while the other block controls drug release, allowing both functions to operate simultaneously without compromising either
3Adaptability or versatility
If the polymeric coating is made more elastic, then mechanical compatibility with balloon is improved, but structural stability may deteriorate
Solution Approach 1:
The patent utilizes the glass transition temperature (Tg) characteristics of sulfonated polymers to create a coating that exhibits elastic behavior during balloon expansion (below Tg) while maintaining structural stability after deployment (above Tg), effectively resolving the contradiction between elasticity and structural stability through temperature-dependent property 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
These polymeric regions offer tailored physical and chemical characteristics, improving biocompatibility and therapeutic agent delivery while reducing surface defects and in-stent restenosis, ensuring optimal performance with both balloon and vessel wall interfaces.
Implementation Method 1
the hard phase domains become physically crosslinked to one another via the elastomeric blocks. Moreover, because the crosslinks are not covalent in nature, they can be reversed, for example, by dissolving or melting the block copolymer.
Implementation Method 2
SIBS tends to phase separate, with the elastomeric blocks aggregating to form elastomeric phase domains and the hard blocks aggregating to form hard phase domains.
Implementation Method 3
therapeutic agent diffusivity (where a therapeutic agent is present), and hydrophobic/hydrophilic balance (influencing, for example, wettability, as well as water diffusivity and therapeutic agent diffusivity, where a therapeutic agent is present)
Data Source
AI summary
In accordance with various aspects of the invention, implantable and insertable medical devices are provided, which contain one or more polymeric regions. In one aspect, the polymeric regions comprise (a) a block copolymer that comprises a polyaromatic block and a polyalkene block admixed with (b) a sulfonated high Tg polymer. In another aspect, the polymeric regions comprise a block copolymer that comprises (a) a sulfonated polymer block and (b) fluorinated polymer block.