Injectable Alginic Acid Hydrogel for Contrast and Drug Retention
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Solution Overview
Problem
Existing image contrast agents like indocyanine green suffer from concentration-dependent aggregation, chemical instability, and rapid diffusion, leading to reduced image discrimination and drug persistence issues, while hydrophobic and hydrophilic drugs face challenges in maintaining therapeutic effects at target sites due to rapid absorption and spread.
Innovation Solution
An alginic acid-based injectable hydrogel system using polyvalent ions as an ionic cross-linking agent, combined with a crosslinking rate controller, to form a gel at the target site, allowing image contrast agents and drugs to remain and release slowly without spreading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If indocyanine green is used as a fluorescent contrast agent, then the lesion can be detected by fluorescence imaging, but the agent spreads rapidly to surrounding tissues reducing image discrimination accuracy
Solution Approach 1:
The patent introduces alginic acid hydrogel as an intermediary carrier that binds to the fluorescent contrast agent. This mediator prevents direct diffusion of the free contrast agent into surrounding tissues while maintaining its fluorescence properties, thereby resolving the contradiction between detection capability and diffusion control.
Solution Approach 2:
The patent creates a composite material system consisting of alginic acid hydrogel combined with fluorescent contrast agent (indocyanine green or ZW800-1). This composite structure allows the contrast agent to be delivered and retained at the target site without rapid diffusion, improving both image discrimination and localization precision.
2Illumination intensity
If indocyanine green is used at high concentration to enhance fluorescence signal, then detection sensitivity improves, but concentration-dependent aggregation reduces fluorescence brightness
Solution Approach 1:
The patent changes the physical state and local environment of the contrast agent by incorporating it into the alginic acid hydrogel matrix. This parameter change prevents the concentration-dependent aggregation that occurs in free solution, allowing high concentrations to be used without fluorescence quenching, thereby maintaining both brightness and chemical stability.
3Reliability
If drugs are injected locally to maximize therapeutic effect at target site, then treatment efficacy improves, but hydrophobic drugs are not easily soluble and hydrophilic drugs spread quickly reducing duration of action
Solution Approach 1:
The patent applies local quality by creating a hydrogel formulation with specific physical properties (viscosity, gelation time) that are optimized for local injection. The alginic acid hydrogel provides a local environment that retains both hydrophobic and hydrophilic drugs at the injection site, preventing systemic diffusion while maintaining solubility and therapeutic efficacy.
Solution Approach 2:
The patent uses composite material formulation by combining alginic acid hydrogel with drugs of different solubility characteristics. This composite system provides a unified delivery platform that solves the solubility and retention problems for both hydrophobic and hydrophilic drugs simultaneously, extending duration of action while maintaining target site efficacy.
4Measurement precision
If Indian ink is injected to label lesion for surgical resection, then the region can be visually identified, but the ink spreads around the injected area widening the resection range
Solution Approach 1:
The patent uses alginic acid hydrogel as an intermediary carrier for the contrast agent, replacing direct injection of free-flowing Indian ink. This mediator prevents the ink from spreading beyond the injection site while maintaining sufficient concentration for visual identification, thereby preserving lesion location accuracy and minimizing resection area.
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 system enables accurate image labeling and prolonged drug efficacy at the target site by preventing diffusion, enhancing image discrimination and reducing side effects on surrounding tissues.
Implementation Method 1
An alginic acid-based injectable hydrogel system using polyvalent ions as an ionic cross-linking agent
Implementation Method 2
to form a gel at the target site
Implementation Method 3
releasing the drug contained in alginic acid at the target site
Data Source
Figure 1~2A
Figure 2B~2C
Figure 3A~3B
AI summary
The present invention provides an alginic acid-based injectable hydrogel system for labeling an accurate position of a disease lesion and effectively delivering a drug to a target region. The formulation of the present invention can make it easy to locally inject a contrast agent and a drug into a target region while controlling the release rate of the contrast agent or the drug, with the formation of the hydrogel in the injected region. Through the advantages, the labeled position can be accurately determined from images, thereby enhancing the precision of surgical operation, with a minimal incision formed therefor. In addition, when used, the alginic acid-based injectable hydrogel system allows the effective local delivery of a drug to a target region while increasing the long-acting effect of the drug.