Nanoemulsion pH Segmentation for Skin Agent Delivery

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Solution Overview

Problem

Existing nanoemulsions face challenges in delivering high concentrations of water-insoluble skin benefit agents in a neutral pH environment, which is essential for skin tolerance and effective topical application, as the pH requirements often hinder the solubility of these agents in the water phase.

Innovation Solution

An oil continuous nanoemulsion is created by combining macroemulsions with pH ranges of 10 to 14 and 2 to 5, and then subjecting the mixture to a low-energy shearing process, resulting in a nanoemulsion with a particle size of 150 to 900 nm and 0.15 to 5% by weight of the skin benefit agent in the water phase, suitable for neutral pH applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the pH is adjusted to neutral (5.5-7.5) for skin tolerance, then skin irritation is reduced, but the solubility of water-insoluble skin benefit agents in the water phase decreases

Engineering Contradiction:
Improveskin irritationVSAvoidconcentration of skin benefit agent in water phase
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The patent divides the emulsion into distinct oil and water phases, with the skin benefit agent primarily located in the oil phase. This segmentation allows the water phase to maintain a skin-friendly neutral pH while the oil phase provides a suitable environment for the water-insoluble benefit agent, thus resolving the contradiction between skin tolerance and agent solubility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary approach by using an oil-continuous or water-continuous emulsion system where emulsifiers mediate between the oil phase (containing the benefit agent) and the water phase (maintaining neutral pH). This intermediary structure allows both requirements to coexist: the water phase remains skin-tolerant while the benefit agent is effectively delivered through the emulsion system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If high concentration of water-insoluble skin benefit agent is delivered in the water phase, then penetration and topical benefits are enhanced, but the pH must be adjusted away from neutral which increases skin irritation

Engineering Contradiction:
Improveconcentration of skin benefit agent in water phaseVSAvoidskin irritation
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent segments the benefit agent into the oil phase rather than forcing dissolution in the water phase. This allows high concentration of the water-insoluble agent to be achieved in the overall emulsion while the water phase maintains neutral pH, eliminating the need to compromise skin tolerance for enhanced penetration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the physical state and distribution parameters of the skin benefit agent by forming an emulsion system. Instead of requiring high concentration in the water phase at non-neutral pH, the agent is dispersed in the oil phase of the emulsion, which can then be applied to skin at neutral pH, achieving both effective delivery and skin tolerance.

Inventive Principle:
Principle #35Parameter changes

3Length of moving object

If macroemulsion is processed through high-energy shearing to reduce particle size, then nanoemulsion is formed with enhanced penetration, but energy consumption and process complexity increase

Engineering Contradiction:
Improveparticle sizeVSAvoidenergy consumption in shearing process
Core Design Contradiction:
Length of moving objectVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by using low-energy shearing processes that are sufficient to achieve the desired nanoemulsion particle size range (150-900 nm) without excessive energy input. The process is optimized to provide just enough mechanical energy to break down the macroemulsion into nanoemulsion droplets, avoiding the diminishing returns and high energy consumption associated with more intensive shearing methods.

Inventive Principle:
Principle #16Partial or excessive 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

This method allows for the delivery of a high concentration of water-insoluble skin benefit agents in the water phase of the nanoemulsion at a neutral pH, enhancing skin penetration and topical benefits while maintaining skin tolerance.

Implementation Method 1

shearing the mixture of macroemulsions to produce a nanoemulsion having a particle size from 150 to 900 nm

Methodology Applied
Scientific EffectShear stress: Shear Stress

Implementation Method 2

Nanoemulsions can carry actives in their water and oil phases and are desirable since they enhance penetration of active through the skin

Methodology Applied
Scientific EffectPenetration enhancement:

Data Source

PatentUS11540984B2Nanoemulsions and a method for making the same
Publication Date: 2023.01.03 CONOPCO INC

AI summary

Nanoemulsions and a method for making the same are described. The nanoemulsions comprise a skin benefit agent in the water phase and they are made from two macroemulsions that have non-identical pH values.