Bioerodible Polymers via Amide-to-Ester Linkage Switch
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Solution Overview
Problem
Current biocompatible polymers for medical devices lack desirable bioresorbability, biodegradability, mechanical strength, and processibility under thermal conditions, with amide linkages leading to high melt viscosity and unpredictable mechanical property changes.
Innovation Solution
Development of bioerodible polymers using hydroxyacid-phenolic monomers, such as tyrosyl lactates and glycolates, which provide rigidity, flexibility, and controlled degradability through condensation polymerizations with diphenolic monomers, resulting in polycarbonates and polyarylates with iodine incorporation for radio-opacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If amide linkages are used to connect tyrosine molecules or tyrosine analogs, then the polymers exhibit bioresorbability and biodegradability, but the melt viscosity becomes very high making thermal processing difficult
Solution Approach 1:
The patent changes the chemical linkage type from amide to ester or carbonate linkages, fundamentally altering the chemical parameters of the polymer backbone. This parameter change reduces intermolecular hydrogen bonding and dramatically lowers melt viscosity while preserving bioresorbability, enabling both improved manufacturability and maintained reliability
Solution Approach 2:
The patent substitutes the amide linkage mechanism with ester or carbonate linkage mechanisms. This chemical mechanism substitution eliminates the strong hydrogen bonding network characteristic of amides, thereby reducing melt viscosity and improving thermal processing capabilities while maintaining the desired bioresorbable properties
2Reliability
If amide linkages are used to connect tyrosine molecules or tyrosine analogs, then the polymers exhibit bioresorbability and biodegradability, but the monomers have low solubility in water and dissolve very slowly
Solution Approach 1:
The patent changes the chemical parameter of the linkage from amide to ester or carbonate, which fundamentally alters the polymer's interaction with water. This parameter change enhances water solubility and dissolution rate while preserving the bioresorbable character of the material, thereby improving productivity without sacrificing reliability
3Strength
If diphenolic monomers are prepared by linking two tyrosine molecules via amide linkage, then the polymers exhibit mechanical strength, but the melt viscosity is very high
Solution Approach 1:
The patent changes the chemical parameter of the linkage from amide to ester or carbonate, which reduces intermolecular forces and melt viscosity. This allows the polymer to maintain mechanical strength through controlled degradation and structural design while enabling proper thermal processing that was previously difficult with high-viscosity amide-based polymers
4Reliability
If polymers are designed for extended period performance under demanding mechanical conditions, then the mechanical integrity is maintained, but the processing complexity increases
Solution Approach 1:
The patent changes the chemical composition parameter from amide-based to ester/carbonate-based linkages, which simplifies the processing parameters. This parameter change reduces melt viscosity and improves processability while allowing the polymer to maintain mechanical integrity under demanding conditions through controlled degradation and structural design, thereby reducing processing complexity
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 polymers offer enhanced mechanical strength, controlled bioerosion rates, and improved processibility, making them suitable for medical devices that maintain integrity and performance over extended periods while being biocompatible and radiopaque.
Implementation Method 1
These can be prepared, for example, by using tyrosol as the initiator for the ring opening reactions of cyclic reaction partners such as lactides, lactones and cyclic carbonates. Using such monomers as co-monomers together with other diphenolic monomers in condensation polymerizations provides rigidity and mechanical strength
Implementation Method 2
Further, due to hydrogen bonding of amide hydrogen the melt viscosity of the polymers derived from these monomers is very high, which makes thermal processing more difficult
Implementation Method 3
halogenated polymers useful as radiopaque polymers for use in medical devices... wherein y1 is 1, 2, 3, or 4... representing the number of halogen atoms, particularly iodine atoms
Data Source
AI summary
The present invention provides new classes of phenolic compounds derived from hydroxyacids and tyrosol or tyrosol analogues, useful as monomers for preparation of biocompatible polymers, and the biocompatible polymers prepared from these monomelic hydroxyarid-phenolic compounds, including novel biodegradable and/or bioresorbable polymers. These biocompatible polymers or polymer compositions with enhanced bioresorbability and processibility are useful in a variety of medical applications., such as in medical devices and controlled-release therapeutic formulations. The invention also provides methods for preparing these monomeric hydroxy acid-phenolic compounds and biocompatible polymers.