Injectable Non-Aqueous Chitosan Alginate Gel for Varicose Vein Occlusion

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Solution Overview

Problem

Current treatments for vascular diseases such as varicose veins are inadequate in providing effective and cosmetically acceptable solutions, as they can cause discomfort and lead to complications like skin changes and ulcer formation.

Innovation Solution

An injectable non-aqueous composition comprising chitosan and alginate, which forms a polyelectrolyte gel in situ upon contact with blood, sealing the vessel and preventing backflow, thereby treating vascular diseases like varicose veins.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional treatments for varicose veins are used, then vascular disease can be treated, but skin changes and ulcer formation occur

Engineering Contradiction:

Improvetreatment effectivenessVSAvoidskin changes and ulcer formation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the physical and chemical parameters of the embolic agent by using a non-aqueous carrier system with specific viscosity ranges (10-10,000 cP) and controlled gelation properties. The composition includes polymers with specific molecular weights and crosslinking densities, allowing the material to gel at controlled rates after injection, thereby preventing skin changes and ulcers while maintaining treatment effectiveness

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses composite materials consisting of multiple polymers (e.g., poly(L-lactide), poly(D,L-lactide), caprolactone) combined in specific ratios within a non-aqueous carrier. This composite approach allows tuning of gelation time, mechanical properties, and biocompatibility, resolving the contradiction between effective occlusion and prevention of skin damage

Inventive Principle:

Principle #40Composite materials

2Reliability

If injectable compositions are used to seal vessels, then blood flow backflow is prevented, but the composition may stain the skin or feel hard under the skin

Engineering Contradiction:

Improvevessel sealing effectivenessVSAvoidskin staining and hard sensation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention controls the gelation kinetics by adjusting polymer concentration (1-20 wt%), molecular weight, and crosslinking density to achieve gelation within specific time frames (minutes to hours). The non-aqueous carrier ensures the composition remains injectable through fine needles while gelling after injection, preventing both skin staining and hard sensation by controlling the transition timing and final gel structure

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The gelated composition forms a porous network structure that allows gradual degradation and absorption by surrounding tissue. The interconnected pores enable nutrient diffusion and cellular infiltration, preventing hard sensation while maintaining vessel occlusion. The porous structure also prevents skin staining by allowing metabolic waste and degradation products to diffuse away

Inventive Principle:

Principle #31Porous materials

3Productivity

If the composition gels quickly upon injection, then vessel occlusion is rapid, but control over gelation time is reduced

Engineering Contradiction:

Improvevessel occlusion speedVSAvoidgelation time control

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The invention creates a dynamic system where the composition transitions from a liquid state (for easy injection and distribution) to a gel state (for stable occlusion). The gelation process can be tuned by selecting different polymer combinations, molecular weights, and crosslinking agents, allowing the practitioner to control gelation time based on the specific clinical situation while ensuring rapid occlusion once gelation begins

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention provides multiple formulations with different gelation kinetics by varying polymer concentration, molecular weight distribution, and crosslinking density. This allows selection of appropriate gelation rates (from rapid to gradual) based on vessel size and clinical requirements, maintaining both productivity and adaptability

Inventive Principle:

Principle #35Parameter changes

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 composition effectively occludes blood vessels, is absorbed by surrounding tissue, and can be tuned for gelation time, ensuring it does not stain the skin or feel hard under the skin, providing a durable and cosmetically acceptable treatment for varicose veins.

Implementation Method 1

chitosan and alginate form a polyelectrolyte gel in situ

Methodology Applied

Scientific EffectPolyelectrolyte gelation: Gel

Implementation Method 2

the chitosan and alginate precipitate and form a gel

Methodology Applied

Scientific EffectPrecipitation: Precipitation

Data Source

PatentUS9801812B1Injectable non-aqueous compositions and methods of treating vascular disease

Publication Date: 2017.10.31 COVIDIEN LP

AI summary

An injectable non-aqueous composition and a method of treating a vascular disease, the non-aqueous composition including: chitosan having a particle size of no greater than 50 μm; alginate having a particle size of no greater than 50 μm; and a non-aqueous carrier; wherein upon combination and injection into the vascular system of a subject, the composition causes a diseased portion of the vascular system to be absorbed into surrounding tissue.