Core Stabilized Microcapsules with Metal Oxide Shell

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Solution Overview

Problem

Existing microcapsule technologies face challenges in stabilizing active agents within a core encapsulated by a metal oxide shell, particularly with phase changing materials, leading to instability and leakage over time.

Innovation Solution

A process involving the preparation of an oil-in-water emulsion with a sol-gel precursor in both phases, followed by microcapsule forming conditions, incorporating metal oxide nanoparticles and phase changing materials to create a stable core encapsulated by a metal oxide shell with a viscosity range of 300 cP to 1,000,000 cP, enhancing the stability of the encapsulated active agents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing microcapsule technologies are used to encapsulate active agents with metal oxide shell, then encapsulation is achieved, but instability and leakage occur over time

Engineering Contradiction:
Improvestability of encapsulated active agentsVSAvoidduration of encapsulation integrity
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The invention uses composite materials by combining sol-gel precursors (metal alkoxides) with phase changing materials in the core and metal oxide nanoparticles in the shell. This composite structure creates a more stable encapsulation system where the sol-gel derived metal oxide shell provides structural integrity while the phase changing material stabilizes the core, preventing leakage over time through synergistic interaction between different materials.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention applies parameter changes by controlling the hydrolysis and condensation rates of sol-gel precursors through pH adjustment and catalyst addition. By optimizing these chemical parameters, the metal oxide shell forms with controlled porosity and density, achieving optimal balance between structural stability and active agent retention. The phase changing material also undergoes parameter changes (phase transitions) that help stabilize the core structure.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If sol-gel precursor is used in both oily and aqueous phases, then microcapsule stability is improved, but process complexity increases

Engineering Contradiction:
Improvestability of microcapsulesVSAvoidcomplexity of emulsion preparation process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sol-gel precursor serves multiple functions simultaneously: it forms the metal oxide shell structure, provides porosity control, and contributes to the core material composition when present in both phases. This multi-functionality reduces the need for separate stabilizing agents and simplifies the overall formulation, despite the enhanced process requirements for controlling sol-gel reactions in dual-phase emulsion.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Strength

If metal oxide nanoparticles are added to aqueous phase, then shell stability is enhanced, but manufacturing complexity increases

Engineering Contradiction:
Improvestrength of metal oxide shellVSAvoidease of microcapsule preparation
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

Metal oxide nanoparticles are pre-added to the aqueous phase before emulsion formation, allowing them to be uniformly distributed and positioned at the oil-water interface during encapsulation. This preliminary action ensures even shell formation and enhanced structural strength without requiring complex post-processing steps, as the nanoparticles self-organize during the emulsion drying and sol-gel processing stages.

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 process results in microcapsules with improved stability, maintaining active agents within the core with minimal leakage over extended periods, suitable for applications in dermatological and pharmaceutical uses.

Implementation Method 1

wherein said shell is obtained from a hydrolyzed and polymerized sol gel precursor

Methodology Applied
Scientific EffectSol-gel process: Sol

Implementation Method 2

wherein said shell is obtained from a hydrolyzed and polymerized sol gel precursor

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

comprising at least one active agent and at least one phase changing material

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 4

preparing an oil-in-water emulsion by emulsification of an oily phase

Methodology Applied
Scientific EffectEmulsion: Emulsion

Data Source

PatentUS10512796B2Core stabilized microcapsules, method of their preparation and uses thereof
Publication Date: 2019.12.24 MAYNE PHARMA LLC

AI summary

The present invention provides core-stabilized microcapsules, wherein said core comprises at least one active agent encapsulated within a metal oxide shell, processes for their preparations, comparisons comprising them and uses thereof.