Dynamic Hydrogel Filtration With Rotating Discs for Faster Purification

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Solution Overview

Problem

Conventional methods for dialysis of cross-linked hyaluronic acid gels are time-consuming, labor-intensive, and increase the risk of microbial contamination, while using potentially toxic cross-linking agents like BDDE, necessitating a method to efficiently remove unwanted molecules and reduce production time and costs.

Innovation Solution

A dynamic filtration method using a semipermeable filter disc-equipped device with controlled rotational speed and overpressure to conduct diafiltration, reducing unwanted molecules such as unreactive cross-linker molecules and their degradation products from cross-linked biopolymer-based hydrogels, including hyaluronic acid gels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional dialysis methods are used for cross-linked hyaluronic acid gels, then unwanted molecules can be removed, but the process requires high manual time and effort, decreases quality and reproducibility, and increases production time and costs

Engineering Contradiction:
Improvequality and reproducibilityVSAvoidproduction time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces manual dialysis operations with an automated dynamic filtration system using a rotating filter device. The mechanical rotation of the filter device automates the filtration process, eliminating manual intervention and associated variability, thereby improving quality and reproducibility while reducing production time through continuous operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs dynamic filtration parameters including rotational speed (50-500 rpm) and pressure gradients to optimize the removal of unwanted molecules. By controlling these parameters, the system achieves efficient purification faster than conventional dialysis, resolving the contradiction between production time and quality/reproducibility.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional dialysis methods are used for cross-linked hyaluronic acid gels, then unwanted molecules can be removed, but the risk of microbial contamination increases with process time

Engineering Contradiction:
Improvemicrobial contamination riskVSAvoidprocess time
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The automated dynamic filtration system replaces time-consuming manual dialysis with a faster mechanical filtration process. The rotating filter device enables continuous operation that completes purification in shorter time, thereby reducing the window for microbial contamination while maintaining effective removal of unwanted molecules.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The dynamic filtration process operates continuously without the interruptions inherent in manual dialysis. The continuous rotation and filtration action maintains constant separation efficiency, achieving purification faster and reducing the time during which microbial contamination could occur.

Inventive Principle:
Principle #20Continuity of useful action

3Stability of the object's composition

If cross-linking agents like BDDE are used to maintain gel stability, then degradation is decreased and desired effects are maintained, but the cross-linking agents may be toxic and increase unwanted molecules

Engineering Contradiction:
Improvegel stabilityVSAvoidtoxicity of cross-linking agents
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The dynamic filtration system specifically extracts and removes unreacted cross-linking agents (BDDE) and their degradation products from the hydrogel matrix. The rotating filter device separates these harmful small molecules from the larger gel structure, maintaining gel stability while eliminating toxicity concerns.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The filtration process uses optimized pressure gradients and rotational speeds to selectively remove cross-linking agents while preserving the cross-linked gel structure. This parameter control allows differentiation between desired stable gel network and harmful unreacted agents, resolving the contradiction between stability and toxicity.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If dynamic filtration with rotating filter discs is used, then flux rates increase and process time decreases, but the device complexity increases

Engineering Contradiction:
Improveflux rateVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent employs a dynamic filtration device with rotating filter discs that spin at controlled speeds (50-500 rpm). This dynamic motion creates centrifugal forces and continuous renewal of the filtration surface, dramatically increasing flux rates compared to static filters. The mechanical complexity is justified by the substantial productivity gain.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses pressure-driven flow (0.5-6 bar) combined with mechanical rotation to achieve high flux rates. The hydraulic pressure forces the gel suspension through the rotating filter discs, while the rotation prevents clogging and maintains high flow rates, achieving productivity improvement that outweighs the device complexity.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 method significantly reduces process time, increases flux rates, and maintains structural stability of the hydrogel, achieving a higher concentration of the retentate while minimizing the presence of unwanted molecules below the limit of quantification.

Implementation Method 1

conducting a diafiltration to reduce unwanted molecules, selected from unreactive or unbound polymer cross-linker molecules and their degradation products, by applying a rotational speed within the range of 20 1/min to 500 1/min and a overpressure within the range of 0.5 to 6 bar

Methodology Applied
Scientific EffectDiafiltration: Semipermeable Membrane

Implementation Method 2

concentrating the gel by applying a rotational speed within the range of 20 1/min to 500 1/min and a overpressure within the range of 0.5 to 6 bar to a predetermined concentration

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3833695B1Method for dynamic filtration of a cross-linked hydrogel
Publication Date: 2026.01.07 MERZ PHARMA GMBH & CO KGAA
  • EP3833695B1 patent drawingFigure 1
  • EP3833695B1 patent drawingFigure 2
  • EP3833695B1 patent drawingFigure 3

AI summary

The present invention relates to a method for dynamic filtration of a cross-linked biopolymer-based hydrogel to remove unwanted molecules from the gel. In particular, the invention relates to dynamic filtration of a hyaluronic acid hydrogel using a dynamic filtration construction with rotating and semipermeable filter discs.