Absorbable Copolyester Balancing Mechanical Strength and Hydrolysis Rate
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a need for a synthetic absorbable polymer that balances mechanical strength with faster absorption or hydrolysis rates, suitable for medical devices like surgical sutures and microspheres, while maintaining dimensional stability and homogeneous drug encapsulation for controlled release.
Innovation Solution
A semi-crystalline absorbable copolyester is developed, comprising the reaction product of polycondensation polyester and lactone, specifically poly(ethoxyethylene diglycolate) and glycolide, with a crystallinity range of 10-50% and molecular weights optimized for mechanical properties and absorption rates, synthesized through condensation polymerization and ring-opening polymerization techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the crystallinity of the polymer is increased to improve mechanical strength, then the absorption or hydrolysis rate decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the polymer by incorporating specific ratios of hydrophilic monomers (30-70 mol%) and hydrophobic monomers (20-50 mol%) to achieve optimal balance between crystallinity and hydrolysis rate. This compositional parameter adjustment allows the polymer to maintain mechanical strength while enabling controlled absorption rates suitable for different medical applications.
Solution Approach 2:
The patent creates composite polymer structures by combining multiple monomer units with different properties (hydrophilic and hydrophobic components) into a copolymer system. This composite approach at the molecular level allows the material to exhibit both crystalline regions for strength and hydrophilic pathways for water penetration and hydrolysis, resolving the contradiction between mechanical properties and absorption rate.
2Duration of action of moving object
If lactone is used to disrupt crystallinity to enhance absorption rate, then the polymer becomes more hydrophobic and absorption occurs more slowly
Solution Approach 1:
The patent carefully controls the mole percentage of hydrophilic monomers (30-70 mol%) to ensure sufficient hydrophilicity for water penetration while maintaining appropriate crystallinity. This precise parameter control prevents excessive hydrophobicity that would occur with higher lactone content, thereby enabling enhanced absorption rates without sacrificing water affinity.
Solution Approach 2:
The patent creates local hydrophilic regions within the polymer structure by incorporating hydrophilic monomer units at specific concentrations. These localized hydrophilic domains serve as water penetration pathways and hydrolysis sites, enhancing absorption rates without requiring the entire polymer structure to be highly hydrophilic, thus avoiding excessive disruption of crystallinity.
3Duration of action of moving object
If PEG is added to increase hydrophilicity and absorption rate, then mechanical properties deteriorate due to reduced crystallinity
Solution Approach 1:
The patent creates a composite copolymer system that integrates hydrophilic monomer units directly into the polymer backbone rather than adding PEG as a separate component. This molecular-level composite structure maintains crystallinity by incorporating the hydrophilic units in a controlled manner within the semi-crystalline matrix, preserving mechanical properties while achieving enhanced hydrophilicity and absorption rates.
Solution Approach 2:
The patent optimizes the mole percentage of hydrophilic monomers (30-70 mol%) to achieve the desired balance between hydrophilicity and crystallinity. By controlling this compositional parameter, the patent enhances absorption rates through improved water affinity while maintaining sufficient crystalline structure to preserve mechanical strength, avoiding the mechanical property deterioration associated with PEG addition.
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 copolyester achieves a balance of mechanical strength and rapid absorption, ensuring the stability and efficacy of medical devices, including microspheres that can be used for drug delivery with sustained release properties.
Implementation Method 1
the absorption or hydrolysis rate of absorbable polymers
Implementation Method 2
the crystalline or ordered structure of the polymer imparts strength to a medical device
Data Source
AI summary
A semi-crystalline, absorbable copolyester composition comprising the reaction product of a polycondensation polyester and at least one lactone, wherein the polycondensation polyester comprises the reaction product of diglycolic acid and/or a derivative thereof and diethylene glycol; and the copolyester comprises about 30 to 60% by weight of the polycondensation polyester based on the total weight of the copolyester. Also medical devices such as absorbable sutures comprising such copolyesters and absorbable microspheres comprising such copolyesters and methods of making of such absorbable microspheres. Additionally, a method of melt blowing an absorbable copolyester composition and a nonwoven construct are disclosed.