1,2-Hexanediol Stabilizes O/W Emulsions Against Phase Inversion
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Solution Overview
Problem
Oil-in-water emulsions with hydrophilic emulsifiers tend to experience phase inversion during production and storage, leading to instability, especially when using moderately polar to polar lipids with interfacial tension below 30 mN/m.
Innovation Solution
Incorporating 1,2-hexanediol in concentrations of 0.3% to 3% by weight and using oil-in-water emulsifiers like glyceryl stearate citrate, polyglyceryl methyl glucose distearate, and polyethylene glycol monostearate, along with additives such as tocopheryl acetate and phenoxyethanol, while maintaining a temperature between 30°C to 85°C during the emulsion production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hydrophilic emulsifiers with HLB value ≥10 are used to produce O/W emulsions, then the emulsion can be formulated with water-soluble characteristics, but phase inversion occurs during production and storage leading to instability
Solution Approach 1:
The patent changes the chemical composition parameters of the oil phase by incorporating specific lipid types (neutral fats, fatty acid esters, triglycerides) with controlled interfacial tension properties. This parameter modification prevents phase inversion while maintaining the desired O/W emulsion structure and stability throughout storage.
Solution Approach 2:
The patent creates a composite emulsion system combining hydrophilic emulsifiers with specifically selected lipid components. This composite approach synergistically prevents phase inversion by balancing the hydrophilic-lipophilic interactions, achieving both formulation flexibility and storage stability simultaneously.
2Ease of manufacture
If moderately polar to polar lipids with interfacial tension <30 mN/m are used in the oil phase, then the emulsion can be formulated with hydrophilic emulsifiers, but phase inversion tendency increases during storage
Solution Approach 1:
The patent modifies the interfacial tension parameter of the oil phase by selecting lipids with specific surface activity characteristics. This parameter adjustment allows the use of hydrophilic emulsifiers while preventing phase inversion during storage, achieving both ease of manufacture and storage reliability.
Solution Approach 2:
The patent introduces specific lipid components as intermediary substances that mediate between the hydrophilic emulsifier and the oil phase. These intermediary lipids with controlled interfacial tension properties prevent direct unfavorable interactions that would lead to phase inversion, maintaining stability throughout the product lifecycle.
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 method significantly reduces phase inversion tendencies, resulting in a more stable cosmetic oil-in-water emulsion suitable for use as ointments, creams, or lotions, maintaining stability throughout storage.
Implementation Method 1
the problem often occurs that with the use of primarily moderately polar to polar lipids in the oil phase (i.e., lipids with a interfacial tension toward water of less than about 30 mN/m) an undesirable inversion of phases can occur. Furthermore, O/W emulsions of this type have a tendency towards phase inversion during storage
Implementation Method 2
Emulsifiers as a rule are molecules with a polar, hydrophilic structural element and a nonpolar, lipophilic structural element
Implementation Method 3
lipids with a interfacial tension toward water of less than about 30 mN/m
Implementation Method 4
one of the two liquids is dispersed in the form of very fine droplets in the other liquid. Outwardly and viewed with the naked eye, emulsions appear homogeneous
Data Source
AI summary
A cosmetic oil-in-water emulsion which comprises 1,2-hexanediol and a method of preparing same.