Alginate Nucleus Pulposus Filler With In Situ Partial Curing

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Solution Overview

Problem

Existing treatments for intervertebral disc degeneration, such as intervertebral nucleotomy, often lead to recurrence of herniation and scarring, with limited self-repairing capacity of the nucleus pulposus and high mechanical strength concerns for hydrogel materials used for filling.

Innovation Solution

A composition comprising a low endotoxin monovalent metal salt of alginic acid is applied to the nucleus pulposus site, partially cured by a crosslinking agent, providing fluidity and mechanical strength for effective filling and regeneration, reducing the risk of spinal nerve compression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydrogel materials are used for filling the nucleus pulposus, then the self-repairing capacity is improved, but the mechanical strength is insufficient

Engineering Contradiction:

Improveself-repairing capacityVSAvoidmechanical strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent uses a composite material system consisting of sodium alginate (providing gel structure and biocompatibility) crosslinked with calcium ions (providing mechanical strength). This composite approach combines the advantages of both materials: the hydrogel provides self-repairing capacity and biocompatibility, while the calcium crosslinking provides the necessary mechanical strength to withstand disc loads.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent controls the molecular weight of sodium alginate (80,000 or more) and adjusts the concentration and crosslinking degree to optimize both mechanical strength and self-repairing capacity. By changing these parameters, the composition achieves adequate mechanical properties while maintaining the ability to promote nucleus pulposus regeneration.

Inventive Principle:

Principle #35Parameter changes

2Strength

If the composition is fully cured, then the mechanical strength is improved, but the fluidity is lost making application difficult

Engineering Contradiction:

Improvemechanical strengthVSAvoidfluidity for application

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The patent applies partial curing by introducing calcium ions only at the injection site rather than pre-crosslinking the entire composition. This allows the composition to maintain fluidity during injection while achieving sufficient mechanical strength after partial crosslinking at the target location, resolving the contradiction between applicability and structural integrity.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent replaces mechanical mixing or pre-crosslinking with a chemical crosslinking mechanism that occurs in situ. Calcium ions are introduced after injection and spontaneously crosslink the sodium alginate chains at the injection site, providing strength without compromising the fluidity needed for injection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Object-generated harmful factors

If traditional nucleotomy is performed, then the herniation is removed, but the recurrence rate is high due to lack of regeneration

Engineering Contradiction:

Improveherniation removalVSAvoidrecurrence prevention

Core Design Contradiction:

Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent employs sodium alginate, a biocompatible material that actively promotes nucleus pulposus cell proliferation and extracellular matrix production. The composition serves itself by creating a favorable microenvironment that stimulates endogenous regeneration, allowing the disc to repair itself rather than relying solely on mechanical removal of herniated tissue.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The sodium alginate composition acts as an intermediary between the surgical intervention and the natural regeneration process. It provides a scaffold and biochemical signals that mediate the transition from tissue removal to active regeneration, bridging the gap between nucleotomy and complete disc repair.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 promotes nucleus pulposus regeneration, suppresses degeneration, and reduces recurrence of herniation, while maintaining safety and ease of application, even in minimally invasive procedures.

Implementation Method 1

a composition for filling a nucleus pulposus of an intervertebral disc comprising a low endotoxin monovalent metal salt of alginic acid, which is used so as to be applied to a nucleus pulposus site of a subject and partially cured after the application

Methodology Applied

Scientific EffectGelation: Gel

Implementation Method 2

partially cured by a crosslinking agent, providing fluidity and mechanical strength for effective filling and regeneration

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding

Data Source

PatentUS12478636B2Composition for treating intervertebral disc

Publication Date: 2025.11.25 MOCHIDA PHARM CO LTD

AI summary

The present invention provides a composition for filling the nucleus pulposus of an intervertebral disc, the composition containing a low endotoxin monovalent metal salt of alginic acid. The composition is applied to a nucleus pulposus site of a subject, is used so as to be cured partially after application, and has fluidity when applied to the nucleus pulposus site. Accordingly, a composition for filling nucleus pulposus is provided, the composition being capable of promoting the regeneration of the nucleus pulposus of an intervertebral disc.