Oxidized Cellulose Embolization Solution Dissolution

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Solution Overview

Problem

Current cellulose dissolution processes are cumbersome, expensive, and lead to degradation, especially for oxidized cellulose, due to high thermal treatment and physical manipulation, limiting their application in medical devices like embolization solutions for blood vessels.

Innovation Solution

A polar aprotic solvent and salt are used in a step-wise manner to dissolve oxidized cellulose, minimizing degradation by controlling temperature and shearing forces, resulting in a solution with 5% to 25% w/v soluble oxidized cellulose for embolization purposes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional cellulose dissolution processes (cuprammonium, xanthate) are used, then cellulose can be dissolved, but the process becomes cumbersome, expensive, and causes degradation of oxidized cellulose due to high thermal treatment and physical manipulation

Engineering Contradiction:
Improveease of dissolution processVSAvoiddegradation of oxidized cellulose
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the dissolution parameters by using lithium chloride in N,N-dimethylacetamide at controlled temperatures (0-25°C) instead of traditional high-temperature processes. This parameter change enables dissolution of oxidized cellulose while minimizing thermal degradation and eliminating the need for cumbersome traditional solvents like cuprammonium or xanthate.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces excessive physical manipulation (stirring, mechanical treatment) with a chemical dissolution mechanism using lithium chloride-N,N-dimethylacetamide complex. This substitution eliminates the need for intensive mechanical processing that causes degradation of oxidized cellulose chains.

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

2Productivity

If high thermal treatment and excessive physical manipulation are applied to dissolve cellulose, then dissolution efficiency improves, but degradation of oxidized cellulose and removal of oxidized groups occurs

Engineering Contradiction:
Improvedissolution efficiencyVSAvoidloss of oxidized groups
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The patent maintains dissolution efficiency by using the lithium chloride-N,N-dimethylacetamide system at low temperatures (0-25°C) with adequate dissolution time (1-24 hours). This parameter combination achieves complete dissolution without thermal degradation, preserving the oxidized groups on cellulose chains.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional embolization materials are used, then embolism formation is achieved, but recanalization time cannot be adjusted and may cause complications

Engineering Contradiction:
Improveembolism formationVSAvoidadjustability of recanalization time
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic control of recanalization time by adjusting the degree of oxidation (5-50%) and molecular weight distribution of the oxidized cellulose. This allows the embolization material to be tailored for different clinical scenarios, enabling adjustment of recanalization time from days to weeks while maintaining reliable embolism formation.

Inventive Principle:
Principle #15Dynamics

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 process effectively dissolves oxidized cellulose with minimal degradation, enabling the formation of embolization solutions that can be guided through blood vessels to impede tumor blood supply, with adjustable recanalization time by modifying the degree of oxidation and molecular weight distribution.

Implementation Method 1

lithium chloride and N,N-dimethylacetamide, in a step-wise manner, to dissolve the oxidized cellulose

Methodology Applied
Scientific EffectSolvation: Solvation

Data Source

PatentEP3085396B1Resorbable oxidized cellulose embolization solution
Publication Date: 2022.07.20 COVIDIEN LP
  • EP3085396B1 patent drawingFigure 1~5
  • EP3085396B1 patent drawingFigure 6~10
  • EP3085396B1 patent drawingFigure 11~15

AI summary

A method for forming an embolism within a blood vessel is disclosed. The method includes including: implanting an oxidized cellulose embolization solution into a lumen of a blood vessel to form an embolism within the lumen. The oxidized cellulose is present in an amount from about 10% by weight to 20% by weight of the oxidized cellulose embolization solution. The method also includes adjusting recanalization time of the embolism, which may be adjusted by tailoring a degradation rate of the oxidized cellulose.