Silica Microcapsule Encapsulation of Lipophilic Actives at Mild pH
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Solution Overview
Problem
Existing microencapsulation methods for lipophilic active ingredients are not eco-friendly and do not optimize encapsulation, leading to potential toxicity and inefficient delivery.
Innovation Solution
A process for synthesizing silica microcapsules using a mild chemical method involving hydrolysis of silica precursors in an acidic medium, followed by condensation with a matrix phase formed from branched or linear basic polycationic polymers and anions, allowing for controlled encapsulation of lipophilic active ingredients under alkaline conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sol-gel condensation using strong bases like concentrated ammonia is used, then silica microcapsules can be formed, but the process is not eco-friendly and may cause toxicity issues
Solution Approach 1:
The patent changes the pH parameter from strongly basic (concentrated ammonia) to mildly basic (pH 8-10 using sodium carbonate or potassium carbonate), thereby maintaining microcapsule formation capability while eliminating toxicity issues associated with strong bases
Solution Approach 2:
The patent replaces expensive and hazardous strong bases with inexpensive, environmentally friendly weak bases like sodium carbonate or potassium carbonate, which are safer and more eco-friendly while achieving the same technical result
2Stability of the object's composition
If high silica precursor to oily phase ratio is used, then silica matrix forms properly, but lipophilic active ingredient delivery efficiency decreases
Solution Approach 1:
The patent optimizes the silica precursor to oily phase weight ratio to a specific range (1:1 to 7:1), which balances matrix stability with active ingredient loading capacity, thereby improving delivery efficiency while maintaining structural integrity
Solution Approach 2:
The patent uses a controlled amount of silica precursor that is sufficient to form a stable matrix but not excessive, allowing optimal active ingredient encapsulation and delivery while avoiding over-stabilization that would reduce delivery rate
3Quantity of substance
If conventional microencapsulation methods are used, then active ingredient can be encapsulated, but encapsulation efficiency is not optimized leading to potential toxicity
Solution Approach 1:
The patent introduces a surfactant as an intermediary substance that facilitates the encapsulation of lipophilic active ingredients into silica microcapsules, thereby improving encapsulation efficiency and preventing toxicity through complete encapsulation
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 enhances lipophilic active ingredient delivery, improves encapsulation efficiency, reduces toxicity exposure, and ensures biocompatibility, making it suitable for various applications including cosmetics and pharmaceuticals.
Implementation Method 1
preparation of silica nuclei by hydrolysis of at least one silica precursor in water in an acidic catalytic medium
Implementation Method 2
mixing at least one condensation agent selected from at least one branched or linear basic polycationic polymer... and at least one monovalent anion, divalent or trivalent
Implementation Method 3
condensation in a basic medium of the silica nuclei obtained in step a) and of the oily phase by mixing under stirring with the matrix phase obtained in step b)
Data Source
Figure 1~2
Figure 3~4A
Figure 4B~5A
AI summary
The invention relates to a process for the synthesis of silica microcapsules comprising an oily phase comprising at least one lipophilic active ingredient comprising the following steps: a) preparation of silica nuclei by hydrolysis of at least one silica precursor in water in an acidic catalytic medium, a') addition at the end of step a) or during step a) of an oily phase in an oily phase / silica precursor ratio greater than or equal to 1/1 b) formation of a matrix phase by mixing at least one condensation agent selected from at least one branched or linear basic polycationic polymer, and at least one monovalent, divalent or trivalent anion, c) condensation in a basic medium of the silica nuclei obtained in step a) and of the oily phase by mixing under stirring with the matrix phase obtained in step b) at an alkaline pH less than or equal to 10.