Nanoemulsion Preparation via HLB Phase Inversion

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Solution Overview

Problem

Current methods for preparing nanoemulsions are costly and lack stability, primarily due to the need for high-energy systems and the absence of standardized scientific criteria for formulation, particularly for water-in-oil nanoemulsions, which are difficult to produce using low-energy methods.

Innovation Solution

A low-energy process that varies the hydrophilic and lipophilic balance (HLB) of surface-active agents to achieve stable water-in-oil and oil-in-water nanoemulsions by diluting a homogeneous blend with a low interface tension, allowing for instantaneous phase inversion and formation of nanoemulsions with droplets less than 500 nm in diameter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If high-energy systems such as high pressure homogenisers are used to prepare nanoemulsions, then the nanoemulsions can be obtained with small droplet dimensions, but the preparation cost increases and stability is limited

Engineering Contradiction:
Improvedroplet dimensionVSAvoidstability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent changes the HLB parameter of surface-active agents to control phase inversion and achieve stable nanoemulsions. By varying the HLB value during the process, the system transitions from macroemulsion to microemulsion to nanoemulsion phases, resolving the contradiction between small droplet size and stability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs dynamic phase inversion where the system transitions through different emulsion phases (macroemulsion → microemulsion → nanoemulsion) by changing conditions. This dynamic approach allows the system to self-adjust and achieve stable nanoemulsions without high-energy input

Inventive Principle:
Principle #15Dynamics

2Reliability

If high-energy systems are used for nanoemulsion preparation, then stable nanoemulsions can be obtained, but the preparation cost increases

Engineering Contradiction:
ImprovestabilityVSAvoidpreparation cost
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent enables the system to self-assemble nanoemulsions through spontaneous phase inversion driven by HLB changes. The surfactant system automatically reorganizes into stable nanoemulsion structures without requiring external high-energy input, reducing preparation costs while maintaining stability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent utilizes phase transitions during spontaneous emulsification, where the system naturally transitions through macroemulsion, microemulsion, and nanoemulsion phases. This phase transition approach achieves stable nanoemulsions through thermodynamic driving forces rather than high-energy mechanical input

Inventive Principle:
Principle #36Phase transitions

3Use of energy by moving object

If low-energy methods are used to prepare water-in-oil nanoemulsions, then preparation cost is reduced, but the process is difficult to implement and lacks standardization

Engineering Contradiction:
Improvepreparation costVSAvoidease of implementation
Core Design Contradiction:
Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent performs preliminary formulation of a homogeneous blend with specifically selected surface-active agents having appropriate HLB values. This pre-prepared blend contains all necessary components in correct proportions, making the subsequent nanoemulsion formation simple and standardized without requiring complex low-energy equipment

Inventive Principle:
Principle #10Preliminary action

4Volume of moving object

If the droplet dimensions are reduced to less than 500 nm, then the nanoemulsion technology becomes more effective, but higher energy is necessary

Engineering Contradiction:
Improvedroplet dimensionVSAvoidenergy requirement
Core Design Contradiction:
Volume of moving objectVSUse of energy by moving object

Solution Approach 1:

The patent replaces mechanical homogenization systems with a chemical/thermodynamic approach based on phase inversion and HLB control. The nanoemulsion formation is driven by molecular self-organization and interfacial tension reduction rather than mechanical force, achieving small droplet sizes without high energy consumption

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 process results in stable nanoemulsions that can be maintained for over six months, is simpler to implement, and has a wider applicability range compared to existing methods, enabling the preparation of mono-dispersed nanoemulsions with high formation kinetics.

Implementation Method 1

The highest critical point for the formation of nanoemulsions with respect to the corresponding macroemulsions, lies in the higher energy necessary for obtaining them

Methodology Applied
Scientific EffectSurface tension reduction: Surface Tension

Implementation Method 2

nanoemulsions can be obtained through a spontaneous emulsioning by means of phase inversion, such as the classical PIT (Phase Inversion Temperature) method

Methodology Applied
Scientific EffectPhase inversion: Phase Change

Implementation Method 3

the formation of said water-in-oil or oil-in-water nanoemulsion by dilution of the blend (1) in a dispersing phase consisting of oil or water with the addition of a surface-active agent

Methodology Applied
Scientific EffectPhase inversion: Phase Change

Implementation Method 4

obtaining them by varying the hydrophilic and lipophilic balance (HLB) of the surface-active agents present in the system

Methodology Applied
Scientific EffectSpontaneous emulsification: Emulsion

Data Source

PatentEP2001981B1Process for the preparation of water-in-oil and oil-in-water nanoemulsions
Publication Date: 2020.01.15 VERSALIS SPA

AI summary

Process for the preparation of a water-in-oil or oil-in- water nanoemulsion wherein the dispersed phase is distributed in the dispersing phase in the form of droplets having a diameter ranging from 1 to 500 nm, comprising: 1) the preparation of a homogeneous water/oil blend (I) characterized by an interface tension lower than 1 mN/m, comprising water in an amount of 30 to 70% by weight, at least two surface-active agents having a different HLB, selected from non-ionic, anionic, polymeric surface-active agents, said surface-active agents being present in such a quantity as to make the blend homogeneous; 2) the dilution of the blend (I) in a dispersing phase consisting of oil or water with the addition of a surface- active agent, selected from non-ionic, anionic, polymeric surface-active agents, the quantity of the dispersing phase and surface-active agent being such as to obtain a nanoemulsion having a HLB different from that of the blend (I) .