Biodegradable Segmented Copolymers for Controlled Drug Delivery
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Solution Overview
Problem
Existing biodegradable thermoplastic phase-separated segmented multiblock copolymers face issues such as high processing temperatures, degradation, and foreign body reactions due to high melting points and long-lasting biomaterial fragments, limiting their applications in biomedical and pharmaceutical fields.
Innovation Solution
A biodegradable phase-separated copolymer with a soft segment having a glass transition temperature (Tg) not more than 37°C and a hard segment with a phase transition temperature between 40-100°C, linked by a multifunctional chain-extender, which maintains phase separation at body temperature, providing improved mechanical and degradation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If poly-glycolide rich polyesters are used for fast resorbable biomedical articles, then resorption speed is improved, but processing temperature becomes too high causing degradation and trans-esterification
Solution Approach 1:
The patent segments the polymer structure into distinct soft segments (amorphous, low Tg) and hard segments (crystalline, higher Tm), allowing each segment to contribute different properties. The soft segments provide fast resorption while the hard segments maintain structural integrity at processing temperatures, eliminating the need for excessively high processing temperatures.
Solution Approach 2:
The patent changes the thermal parameters by introducing segments with specific glass transition temperatures (Tg ≤ 37°C for soft segments) and melting points (40-100°C for hard segments). This parameter optimization allows the material to be processed at moderate temperatures while maintaining fast resorption characteristics.
2Duration of action of moving object
If poly-L-lactide rich copolyesters are used for slow resorption applications, then resorption time is improved, but mechanical properties become insufficient and foreign body reactions occur
Solution Approach 1:
The patent creates segmented multiblock copolymers with distinct soft and hard segments. The hard segments (with Tm of 40-100°C) provide crystalline structure and mechanical strength, while the soft segments (with Tg ≤ 37°C) provide flexibility and controlled degradation. This segmentation resolves the contradiction between slow resorption and adequate mechanical properties.
Solution Approach 2:
The patent uses composite material design by combining different polymer segments with complementary properties. The amorphous soft segments and crystalline hard segments work together as a composite structure, providing both slow resorption capability and sufficient mechanical strength, thereby reducing foreign body reactions.
3Strength
If high melting point segments are used to improve mechanical properties, then strength is improved, but processing becomes difficult and degradation increases
Solution Approach 1:
The patent segments the material into soft segments (amorphous, low Tg) and hard segments (crystalline, higher Tm). The hard segments provide mechanical strength while the soft segments lower the overall processing temperature requirement. This segmentation allows the material to be processed easily despite containing strengthening crystalline phases.
Solution Approach 2:
The patent optimizes thermal parameters by controlling the glass transition temperature of soft segments (Tg ≤ 37°C) and melting point of hard segments (Tm of 40-100°C). These parameter changes enable the material to maintain mechanical strength while being processable at moderate temperatures, improving ease of manufacture.
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 copolymer exhibits enhanced mechanical properties, allowing for controlled drug delivery and reduced foreign body reactions, enabling new medical applications with tunable degradation and drug release properties.
Implementation Method 1
the prepolymers do not form a homogeneous mixture when combined, neither when combined as a physical mixture of the prepolymers, nor when the prepolymers are combined in a single chemical species as 'chemical mixture', viz. as copolymer
Implementation Method 2
a low glass transition temperature (Tg), flexible 'soft', amorphous segment
Implementation Method 3
a high Tm (semi)crystalline 'hard' segment
Data Source
AI summary
The invention is directed to biodegradable, thermoplastic, phase separated segmented multi-block copolymers. The copolymers of the present invention find use in various biomedical applications as well as in pharmaceutical applications. According to the invention, a biodegradable, phase separated copolymer is provided, comprising segments of a soft prepolymer (A) having a glass transition temperature, Tg, lower than 37° C.; and segments of a hard prepolymer (B) having a phase transition temperature, Tm, of 40-100° C.