Injectable Chitosan Solution for Biodegradable Fillers

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Solution Overview

Problem

Current fillers for aesthetic and medical applications, such as collagen and hyaluronic acid, face issues with rapid biodegradation and safety concerns, while longer-lasting fillers can cause long-term complications like fibrosis and inflammatory reactions.

Innovation Solution

A homogeneous aqueous solution of chitosan with a degree of acetylation less than 20% and a molecular mass between 100,000 and 1,000,000 g/mol, capable of forming crystalline particles after injection, providing a biocompatible and bioabsorbable filler that promotes long-term biological filling without undesirable side effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If collagen is used as a facial filler, then immediate mechanical filling effect is achieved, but rapid biodegradation occurs leading to short lifespan

Engineering Contradiction:
Improvelifespan of fillerVSAvoidbiodegradation rate
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the filler by using chitosan with specific degree of acetylation (5-20%) and molecular weight (100,000-1,000,000 g/mol), along with controlled pH (4.5-6.5), to achieve both prolonged duration and reliability. The specific parameter optimization allows the filler to resist rapid biodegradation while maintaining stability.

Inventive Principle:
Principle #35Parameter changes

2Duration of action of moving object

If cross-linked hyaluronic acid is used to extend lifespan, then duration is improved, but biocompatibility is reduced

Engineering Contradiction:
Improvelifespan of fillerVSAvoidinflammatory response
Core Design Contradiction:
Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent uses chitosan, a natural biodegradable polymer, as an alternative to cross-linked hyaluronic acid. While chitosan is biodegradable, its controlled degradation profile and natural origin provide both prolonged duration (6-18 months) and maintained biocompatibility, avoiding the inflammatory issues associated with cross-linking.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Duration of action of moving object

If permanent fillers containing synthetic polymers are used, then long-term effect is achieved, but fibrous encapsulation and inflammatory granulomas occur

Engineering Contradiction:
Improvelongevity of fillerVSAvoidfibrous encapsulation
Core Design Contradiction:
Duration of action of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent employs chitosan, a natural biodegradable polymer, as a temporary filler that gradually degrades over 6-18 months. This eliminates the need for permanent synthetic polymers, avoiding fibrous encapsulation and inflammatory granulomas while providing sufficient long-term effect through controlled biodegradation.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Duration of action of moving object

If PLA is used to achieve slower biodegradation, then lifespan is extended to two years, but filling effect is delayed by eight weeks

Engineering Contradiction:
Improvelifespan of fillerVSAvoiddelay in filling effect
Core Design Contradiction:
Duration of action of moving objectVSLoss of time

Solution Approach 1:

The patent provides immediate mechanical filling effect upon injection, satisfying the patient's aesthetic needs right away. The chitosan solution acts as a immediate filler, while simultaneously stimulating collagen production over time. This preliminary action eliminates the 8-week delay associated with PLA, as patients see results immediately rather than waiting for collagen stimulation to manifest.

Inventive Principle:
Principle #10Preliminary action

5Duration of action of moving object

If heterogeneous particle-carrier fillers are used to achieve pro-fibrotic effect, then long-term aesthetic results are improved, but complexity of composition increases

Engineering Contradiction:
Improvelong-term aesthetic effectVSAvoidcomposition complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The patent uses a homogeneous chitosan solution with uniform properties (specific degree of acetylation and molecular weight range) to achieve consistent long-term aesthetic effects. This single-component homogeneous system replaces complex heterogeneous particle-carrier compositions, simplifying the formulation while maintaining or improving performance through controlled biodegradation and collagen stimulation.

Inventive Principle:
Principle #33Homogeneity

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 chitosan solution offers a prolonged bioresorption time, effective immediate biological filling, and bacteriostatic properties, reducing the risk of infection and inflammatory reactions, while promoting collagen synthesis for skin defect filling.

Implementation Method 1

capable of forming crystalline particles of chitosan after injection

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Data Source

PatentEP2849810B1Homogeneous aqueous solution of injectable chitosan
Publication Date: 2019.07.03 BIOXIS PHARMA
  • EP2849810B1 patent drawingFigure 1a~1b
  • EP2849810B1 patent drawingFigure 1c
  • EP2849810B1 patent drawingFigure 2a~2b

AI summary

The present invention relates to a homogeneous aqueous solution of injectable chitosan containing a chitosan having a degree of acetylation lower than 20%, said solution containing between 0.1 and 3.5% by weight of chitosan, said solution presenting a pH lower than 6.2, and said aqueous solution being capable of forming crystalline particles of chitosan after injection. The present invention also relates to compounds containing such a homogeneous aqueous solution of chitosan. The invention also relates to such compounds for their use as dermatological or cosmetic compounds, or for their use as a medical device, advantageously as a bioresorbable implant.