Core Stabilized Microcapsules with Inorganic Oxide Shell

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Solution Overview

Problem

Existing microcapsule technologies face challenges in stabilizing active agents within a core encapsulated by an inorganic oxide shell, particularly with phase changing materials, which often result in 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, adjusting the pH to 3-5, and subjecting it to microcapsule forming conditions, incorporating inorganic oxide nanoparticles to create a stable inorganic oxide shell around the core containing active agents and phase changing materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing microcapsule technologies are used to encapsulate active agents with inorganic oxide shells, 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 microcapsule structure is segmented into distinct functional layers: an inner core containing active agents and phase changing materials, and an outer inorganic oxide shell formed through sol-gel process. This segmentation allows each layer to perform its specific function optimally, with the phase changing material providing thermal stabilization and the inorganic oxide shell providing structural integrity and leakage prevention.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite materials combining organic phase changing materials with inorganic oxide components. The phase changing material (such as paraffin or fatty acids) is combined with sol-gel precursors (such as tetraethyl orthosilicate) to create a hybrid system where the organic component provides thermal response and the inorganic component provides structural stability, resolving the contradiction between flexibility and durability.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If phase changing materials are incorporated into the core, then thermal stability is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvethermal stability of coreVSAvoidcomplexity of microcapsule structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The invention exploits phase transitions of the phase changing material (PCM) within the core to achieve thermal stability. The PCM undergoes reversible phase transitions (solid-liquid) at specific temperatures, absorbing or releasing heat to stabilize the core temperature and protect active agents from thermal degradation, thereby improving compositional stability through natural physical phenomena.

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The phase changing material acts as an intermediary between the active agents and the external environment, absorbing thermal shocks and stabilizing the core conditions. This intermediary layer protects the active agents from direct exposure to temperature fluctuations, reducing the need for complex temperature control mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If sol-gel precursor is used in both phases, then shell formation is improved, but manufacturing time increases

Engineering Contradiction:
Improveuniformity of inorganic oxide shellVSAvoidspeed of microcapsule production
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The sol-gel precursors are pre-incorporated into both the oily and aqueous phases during emulsion formation, before the actual shell formation process. This preliminary distribution ensures uniform shell formation throughout the microcapsules, as the precursors are already in position to form the inorganic oxide network, eliminating the need for subsequent complex coating steps.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention merges the core formation and shell formation processes into a single integrated microencapsulation step. By incorporating sol-gel precursors into both phases beforehand and performing one-step emulsification, the process combines what would traditionally be separate operations, reducing manufacturing time while maintaining shell uniformity.

Inventive Principle:
Principle #5Merging (Combining)

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

This method provides microcapsules with enhanced stability, maintaining active agents within the core for extended periods with minimal leakage, achieving stability for up to 2 years at room temperature, and ensuring the integrity of the encapsulated pharmaceutical, cosmetic, or dermatological agents.

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

subjecting said emulsion to microcapsule forming conditions; thereby obtaining said microcapsules

Methodology Applied
Scientific EffectPhase separation: Phase Change

Data Source

PatentUS10653899B2Core stabilized microcapsules, method of their preparation and uses thereof
Publication Date: 2020.05.19 MAYNE PHARMA LLC

AI summary

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