Thermosensitive Hydrogel Composition for Stable Drug Delivery
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Solution Overview
Problem
Thermosensitive phosphazene-based polymers exhibit reversible sol-gel transition properties that limit their application due to temperature sensitivity, causing them to revert to a solution state outside the body, leading to loss of shape and excessive drug release, particularly in external environments like skin or open wounds.
Innovation Solution
A thermosensitive hydrogel composition with a polyphosphazene-based polymer, comprising an amino acid ester, polyethylene glycol, and a functional group, is formulated at specific ratios to maintain a gel state at body temperature and resist temperature changes, ensuring stability and controlled drug release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If thermosensitive phosphazene-based polymers are used for drug delivery, then they can be injected as liquid and form gel at body temperature, but they exhibit reversible sol-gel transition that causes loss of shape and excessive drug release in external environments
Solution Approach 1:
The patent creates a composite hydrogel system combining phosphazene-based polymer with cross-linking agents (such as genipin, glutaraldehyde, or EDC/NHS chemistry) to form a stable three-dimensional network. This composite structure maintains the injectable liquid state at low temperature while preventing reversible transition back to solution, thereby stabilizing the gel form at the application site.
Solution Approach 2:
The patent modifies the chemical composition parameters of the phosphazene polymer by incorporating functional groups that enable irreversible cross-linking. By changing the molecular weight, degree of substitution, and cross-linking density parameters, the hydrogel achieves stable gel formation at body temperature without reversible transition, while maintaining injectability in liquid form.
2Adaptability or versatility
If thermosensitive polymers are used for tissue regeneration, then they can combine multiple functional materials, but the reversible temperature sensitivity limits application fields
Solution Approach 1:
The patent develops a universal phosphazene-based hydrogel platform that can incorporate multiple functional materials including drugs, growth factors, and tissue regeneration agents. The hydrogel matrix serves multiple functions: drug delivery, tissue adhesion, and structural support, while the irreversible cross-linking ensures reliable performance across different application fields including external wound treatments and internal tissue regeneration.
3Temperature
If phosphazene-based polymers are substituted with amino acid ester and polyethylene glycol, then sol-gel transition occurs at body temperature, but the gel reverts to solution when temperature drops
Solution Approach 1:
The patent extracts the reversible temperature-sensitive component from the system and replaces it with irreversible cross-linking chemistry. The phosphazene polymer backbone with amino acid ester and polyethylene glycol substituents retains the body temperature-responsive gelation capability, but the cross-linking network prevents reversal, effectively removing the harmful reversible transition while preserving the useful temperature-triggered gelation.
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 hydrogel composition maintains its gel state and shape integrity across temperature changes, enabling stable tissue regeneration and controlled drug delivery, with enhanced application in medical implants and external wound treatments.
Implementation Method 1
A thermosensitive polymer hydrogel exhibits a sol-gel phase transition that it is maintained in a liquid state (e.g., a sol phase) at low temperature while the sol is changed into a gel as the temperature increases
Implementation Method 2
it can be gelled near the body temperature of 37° C., whereas it is not reversibly transferred to a solution and maintains the strength and/or shape of the formed gel even when the temperature changes
Data Source
AI summary
The present invention relates to a thermosensitive hydrogel composition, which while comprising an amino acid ester, polyethylene glycol, and a functional group for the introduction of a functional moiety at an end thereof at a predetermined ratio, comprises a polyphosphazene-based polymer having a controlled length and a content of polyethylene glycol contained therein, in which a reversible sol-gel transition character is altered; a medical polymer hydrogel comprising the polyphosphazene-based polymer; or an ink composition for 3D printing.