Iodinated Benzyl Ether PVA for Radiopaque Embolization
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Solution Overview
Problem
Existing radiopaque embolizing compositions for blood vessels and tumors face issues with heterogeneous distribution of contrast agents, leading to potential toxicity and inadequate radiopacity, which can result in inaccurate imaging and clinical complications.
Innovation Solution
Development of radiopaque, non-biodegradable iodinated benzyl ethers of poly(vinyl alcohol) that are covalently grafted with iodine atoms, providing intrinsic radiopacity and stability, allowing for the creation of injectable embolizing compositions that form cohesive masses upon contact with body fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional radiopaque embolizing compositions use suspended contrast agents in polymer solutions, then the compositions can be formulated with biocompatible materials, but the radiopaque contrast agent distribution becomes heterogeneous leading to toxicity and inadequate radiopacity
Solution Approach 1:
The patent combines the polymer matrix and radiopaque contrast agent into a single integrated structure where iodine atoms are covalently grafted onto the poly(vinyl alcohol) chains. This merging eliminates the heterogeneous suspension problem and ensures uniform radiopaque distribution throughout the embolizing composition, resolving the contradiction between radiopacity consistency and toxicity.
Solution Approach 2:
The invention creates a composite material system where iodine-containing benzyl ether groups are covalently bonded to poly(vinyl alcohol) chains. This composite structure integrates the biocompatibility of PVA with the radiopacity of iodine in a molecular level composite, eliminating the need for separate suspended contrast agents and preventing heterogeneous distribution and toxicity.
2Stability of the object's composition
If conventional compositions use water-insoluble contrast agents suspended in polymer solutions, then the compositions can maintain biocompatibility, but the contrast agent sedimentation occurs during catheterization and slow release with time
Solution Approach 1:
The patent merges the contrast agent function directly into the polymer molecular structure through covalent grafting of iodine-containing benzyl ether groups onto PVA chains. This integration eliminates the suspension and sedimentation issues, ensuring the radiopaque contrast agent remains uniformly distributed and stable throughout the composition during catheterization and over time.
Solution Approach 2:
The benzyl ether linkage acts as an intermediary structure that covalently bonds iodine-containing groups to the poly(vinyl alcohol) backbone. This intermediary chemical bond ensures stable integration of the radiopaque contrast agent within the polymer matrix, preventing sedimentation and time-dependent release while maintaining biocompatibility.
3Reliability
If iodinated polymers are used to provide intrinsic radiopacity, then consistent radiopacity is achieved, but the polymer must be non-biodegradable to maintain long-lasting radiopacity
Solution Approach 1:
The patent modifies the chemical structure of poly(vinyl alcohol) by introducing iodine-containing benzyl ether groups through covalent grafting. This parameter change in molecular composition provides intrinsic radiopacity while the ether linkage and overall polymer structure are designed to be non-biodegradable, ensuring long-lasting radiopacity without compromising the stability of the embolizing composition in the vascular environment.
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 iodinated benzyl ethers ensure consistent and long-lasting radiopacity, reducing toxicity risks and improving imaging accuracy, while maintaining stability and reducing the volume of organic solvent required, thus enhancing the efficacy of embolization procedures.
Implementation Method 1
radiopaque, non-biodegradable, water-insoluble iodinated polymers... intrinsic radiopacity... consistent and long-lasting radiopacity
Implementation Method 2
the preformed polymer must be selected to be capable of rapid precipitation to form a well defined cohesive solid or semi-solid mass... forming a cohesive mass upon contact with body fluids
Data Source
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AI summary
The invention concerns a radiopaque, non-biodegradabie, water-insoluble iodinated benzyl ether of polyvinyl alcohol) consisting of a PVA having covalentiy grafted thereon iodinated benzyl groups comprising 1 - 4 iodine atoms per benzyl group, a process for preparing the same comprising reacting a 0 - 100 % hydrolyzed PVA with a iodinated benzyl derivative comprising 1 - 4 iodine atoms per benzyl group in a polar aprotic solvent in the presence of a base in anhydrous conditions. Said iodo-benzylether-PVA is particularly useful as embolic agent in an injectable embolizing composition. The invention also concerns an injectable embolizing composition comprising said iodo-benzylether-PVA and capable of forming a cohesive mass upon contact with a body fluid by precipitation of the iodo- benzylether-PVA. Said injectable embolizing composition is particularly useful for forming in-situ a cohesive mass in a blood vessel or into a tumor. The invention further concerns a coating composition containing said iodo-benzylether-PVA and capable of forming a radiopaque coating on a medical device. The invention further concerns particles formed of said iodo-benzylether-PVA.