Phosphate-Buffered PCL Microsphere Pre-Dispersion for Bubble Reduction

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Solution Overview

Problem

Existing methods for preparing polycaprolactone (PCL) microspheres for medical aesthetics face challenges in maintaining smooth surface integrity and uniform dispersion in carboxymethyl cellulose gel, leading to bubble formation and increased degradation rates due to water penetration, which can cause inflammatory responses and reduce the effectiveness of the microspheres.

Innovation Solution

A polycaprolactone microsphere pre-dispersed composition using a phosphate buffer as the dispersion medium, comprising specific phosphate salts and pH regulators, is employed to maintain microsphere integrity and reduce degradation, ensuring smooth dispersion and bubble reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If PCL microspheres are dispersed in CMC gel using conventional methods, then the microspheres can be suspended in the gel, but bubbles form and surface smoothness is lost

Engineering Contradiction:
Improvemicrosphere surface smoothnessVSAvoidbubble formation
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by pre-dispersing PCL microspheres in phosphate buffer solution before mixing with CMC gel. This pre-dispersion step ensures microspheres are properly wetted and positioned, preventing bubble formation during subsequent gel mixing while maintaining surface smoothness.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses phosphate buffer solution as an intermediary medium between PCL microspheres and CMC gel. The buffer facilitates smooth dispersion and mixing by acting as a transition phase, reducing direct interaction between hydrophobic microspheres and hydrophilic gel that causes bubbling.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If water penetrates into PCL microspheres, then the microspheres can be dispersed in the gel, but degradation occurs due to hydrolysis of ester bonds

Engineering Contradiction:
Improvemicrosphere dispersionVSAvoidmicrosphere stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the chemical environment parameter by using phosphate buffer solution with controlled pH instead of pure water or unbuffered solutions. This pH control reduces the rate of hydrolysis of ester bonds in PCL microspheres while still allowing adequate dispersion in the gel matrix.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The phosphate buffer solution creates a chemically inert environment that minimizes water penetration and hydrolytic degradation of PCL microspheres. The buffer system stabilizes the chemical environment, protecting the ester bonds from rapid hydrolysis while permitting necessary dispersion.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Manufacturing precision

If PCL microspheres are mixed evenly in CMC gel, then uniform distribution is achieved, but the mixing process is difficult due to high viscosity

Engineering Contradiction:
Improveuniform dispersionVSAvoidmixing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-dispersing PCL microspheres in phosphate buffer solution before mixing with CMC gel. This pre-dispersion step reduces aggregation and facilitates easier mixing with the viscous gel, achieving uniform distribution with simpler mixing processes.

Inventive Principle:
Principle #10Preliminary action

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 phosphate buffer effectively maintains the smooth spherical form of PCL microspheres, reducing degradation and bubble formation, thereby enhancing product stability and minimizing inflammatory responses post-injection.

Implementation Method 1

hydrolysis of PCL microspheres is related to penetration of microspheres by water. When water penetrates into microspheres, an overall degradation process will take place, with the result that ester bonds throughout the polymer matrix are gradually hydrolysed from the inside

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

some air will be adsorbed on the surface before PCL microspheres are mixed into CMC gel, the problem of liquid and gas starting to contend for the microsphere surface will arise

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP4595989A1Polycaprolactone microsphere pre-dispersion composition and polycaprolactone injectable gel prepared from same
Publication Date: 2025.08.06 SINCLAIR PHARMACEUTICALS LIMITED
  • EP4595989A1 patent drawingFigure 1~3
  • EP4595989A1 patent drawingFigure 4~7
  • EP4595989A1 patent drawingFigure 8~10

AI summary

Disclosed in the present invention are a polycaprolactone microsphere pre-dispersion composition and a polycaprolactone injectable gel prepared from same. In the polycaprolactone microsphere pre-dispersion composition, polycaprolactone microspheres can continue to maintain their integrity as complete spheres with smooth surfaces and good dispersity, and have a reduced degradation rate; and bubbles can be reduced in a mixing process, thereby helping to ensure the stability of product quality, and reducing the occurrence probability of a nodule and a granuloma caused by uneven dispersion after the microspheres are injected into a body. The application value of the polycaprolactone injectable gel prepared from the polycaprolactone microsphere pre-dispersion composition is higher.