Core-Shell Microcapsules for Topical Formulation Stability

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Solution Overview

Problem

Microencapsulated benzoyl peroxide (BPO) and retinoid compositions face stability and microbial issues during long-term storage, especially at elevated temperatures, with antimicrobials and stabilizers often causing retinoid degradation.

Innovation Solution

The development of compositions featuring separate core-shell microcapsules for benzoyl peroxide and retinoid, each with an inorganic polymer shell, in combination with a stabilizing agent that includes non-ionic surfactants and antimicrobials, maintains the stability and microbial integrity of the active ingredients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If antimicrobials are added to address microbial content problems, then microbial stability is improved, but retinoid degradation increases

Engineering Contradiction:

Improvemicrobial stabilityVSAvoidretinoid degradation

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent divides the formulation into separate functional components: microencapsulated BPO for antimicrobial activity, microencapsulated retinoid for skin treatment, and specific stabilizers for physical stability. This segmentation allows each component to perform its function without harmful interactions, resolving the contradiction between microbial stability and retinoid stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces specific stabilizing agents (polyoxylstearate and glycerylstearate) as intermediaries that mediate between the microencapsulated BPO and retinoid, preventing direct harmful interactions while maintaining both antimicrobial activity and retinoid stability throughout the formulation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If surface active stabilizers are added to address physical stability problems, then physical stability is improved, but retinoid degradation increases

Engineering Contradiction:

Improvephysical stabilityVSAvoidretinoid degradation

Core Design Contradiction:

Stability of the object's compositionVSLoss of substance

Solution Approach 1:

The patent carefully controls the parameters of the stabilizing agents, specifically using polyoxylstearate and glycerylstearate in defined ratios (0.1:10 to 10:0.1), to achieve physical stability without retinoid degradation. This parameter optimization resolves the contradiction by finding the precise conditions where stabilizers work without causing harmful effects.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If microencapsulated BPO and retinoid are combined in a single formulation, then product versatility is improved, but stability problems increase

Engineering Contradiction:

Improveproduct versatilityVSAvoidformulation stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent maintains separate microencapsulated forms of BPO and retinoid within the same formulation, allowing both active ingredients to be present without direct interaction. This segmentation approach enables product versatility while preserving formulation stability over time.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses specific stabilizing agents as intermediaries that facilitate the coexistence of microencapsulated BPO and retinoid, preventing instability issues while maintaining the benefits of combining multiple active ingredients in one product.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution ensures that benzoyl peroxide and retinoid levels remain above 90% and microbial counts meet USP criteria after storage at various conditions, with viscosity maintained within acceptable ranges, addressing physical and microbial stability concerns.

Implementation Method 1

Microcapsules having a core surrounded within a metal oxide shell have been proposed as controlled forms of topically administered compositions

Methodology Applied

Scientific EffectEncapsulation: Physical Containment

Implementation Method 2

the composition is an oil in water emulsion comprising a polyoxylstearate and a glycerylstearate

Methodology Applied

Scientific EffectSurfactant action: Surfactant

Implementation Method 3

it was believed that compositions containing BPO would be unlikely to have microbial content problems because BPO is a strong oxidizing agent and effective antimicrobial

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS12053546B2Stabilized topical formulations containing core-shell microcapsules

Publication Date: 2024.08.06 MAYNE PHARMA LLC

AI summary

The present disclosure relates to compositions for topical application, where the compositions comprise microcapsules having a core that comprises benzoyl peroxide and a shell that comprises an inorganic polymer, microcapsules having a core that comprises a retinoid and a shell that comprises an inorganic polymer, and a stabilizing agent. The composition can be in a variety of forms, such as emulsion and gel.