Thermosensitive Star-Shaped Polymer for Solvent-Free Sustained Release
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Solution Overview
Problem
Existing hydrogel formulations, particularly thermosensitive hydrogels, lack effective star-shaped polymers that provide stable, long-acting sustained release of bioactive substances without using organic solvents, and there is a need for minimally invasive delivery methods.
Innovation Solution
A thermosensitive star-shaped polymer with a biodegradable AB-type amphiphilic copolymer structure, comprising a hydrophobic block A and a hydrophilic block B, which undergoes a solution-gel phase transition at body temperature, allowing for the stable release of bioactive substances through diffusion and self-degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If linear block copolymers are used for hydrogel preparation, then the formulation can achieve thermosensitive gelation, but the sustained release effect and stability are insufficient
Solution Approach 1:
The patent employs star-shaped block copolymers with multiple arms (typically 3-12 arms) consisting of hydrophobic and hydrophilic blocks. This composite structure combines the thermosensitive properties of amphiphilic copolymers with the enhanced stability and controlled release characteristics of star-shaped architecture, resolving the contradiction between release stability and structural complexity by providing a well-defined multi-arm structure that outperforms simple linear copolymers.
Solution Approach 2:
The star-shaped polymer is segmented into multiple identical or different arms radiating from a central core, with each arm containing hydrophobic and hydrophilic blocks. This segmentation allows the formulation to achieve both thermosensitive gelation (through hydrophilic-hydrophobic phase separation) and stable sustained release (through controlled degradation of multiple arms), effectively resolving the technical contradiction.
2Ease of manufacture
If organic solvents are used in the embedding process, then the active substance can be embedded, but the active substance may be inactivated
Solution Approach 1:
The star-shaped block copolymer performs self-assembly in aqueous solution to form micelles or gel structures that naturally embed the active substance within their hydrophobic cores or network. This self-service embedding mechanism eliminates the need for organic solvents, thereby maintaining active substance stability while achieving effective embedding, and simplifies the manufacturing process.
Solution Approach 2:
The amphiphilic star-shaped copolymer acts as an intermediary carrier between the hydrophilic active substance and the aqueous environment. Its hydrophobic blocks provide a natural embedding environment for the active substance without requiring organic solvents, thus protecting the active substance from inactivation while facilitating the embedding process.
3Reliability
If traditional solid formulations are implanted, then the active substance can be delivered, but the method is surgical and invasive
Solution Approach 1:
The star-shaped block copolymer formulation exhibits thermosensitive phase transition: it remains as an injectable solution at low temperature and transforms into a gel at body temperature. This phase transition enables minimally invasive injection delivery (improving ease of operation) while ensuring the active substance is retained and released effectively at the target site (maintaining delivery effectiveness), eliminating the need for surgical implantation.
Solution Approach 2:
The formulation dynamically changes its physical state from fluid (for injection) to gel (for sustained release). This dynamic property allows the system to adapt to different operational requirements: injectable state during administration and gel state during sustained release, thereby resolving the contradiction between ease of operation and delivery effectiveness.
4Productivity
If the polymer degrades quickly, then the active substance is released rapidly, but the long-acting sustained release effect is not achieved
Solution Approach 1:
The star-shaped block copolymer degrades in a periodic or staged manner, with different arms or blocks degrading at different rates. This controlled periodic degradation enables sustained release of the active substance over an extended period (days to weeks), resolving the contradiction between release speed and duration by providing both initial release and prolonged sustained release phases.
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 polymer enables stable, long-acting sustained release of bioactive substances with minimal invasiveness, maintaining efficacy and stability without organic solvents, suitable for drug delivery and tissue engineering applications.
Implementation Method 1
thermosensitive hydrogels that are particularly important in fields such as biomedicine. At around human body temperature, they are gels, but when the temperature deviates from human body temperature, they become solutions
Implementation Method 2
The active substance is stably released from inside the gel by the combined action of diffusion and the self-degradation of the gel
Implementation Method 3
The active substance is stably released from inside the gel by the combined action of diffusion and the self-degradation of the gel
Data Source
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AI summary
The present application relates to a polymer and a composition thereof, and specifically provides a thermosensitive polymer represented by formula (I-2) and a preparation method therefor, and a pharmaceutical composition containing same, the polymer having a star-shaped multi-arm structure, and comprising an aromatic core and a biodegradable AB-type amphiphilic copolymer. The polymer can enhance the solubility and stability of a drug or a bioactive agent and control the release of the drug or the bioactive agent. The definition of each group in formula (I-2) is the same as in the description.