Topic: Optimization of Emulsion Formulations Using Particle Size Analysis

 

Many products are sold as emulsions or emulsifiable concentrates and optimizing the emulsion formulation may have a direct impact on efficacy, stability in long term storage, interactions with containers or how the product is perceived by consumers.

 

Changing ingredients in any formulation may have unpredicted consequences. One of the best tools for optimizing emulsion quality is droplet size analysis. This lends information as to the stability of the product in long term storage and of the quality of the emulsion.

 

Microemulsions are thermodynamically stable systems that tend to form spontaneously and have potentially infinite physical stability. Microemulsions consist of a swollen surfactant micelle containing the internal (usually oil) phase suspended in the continuous (usually aqueous) phase. Because of their very small droplet size, typically 0.01 - 0.5 microns, they are usually transparent or translucent.

 

Conventional emulsions are opaque, usually white and have a droplet size in the 1 - 50 micron range. They are stabilized kinetically or sterically either by density matching of the 2 phases or by the addition viscosity modifying agents. In some applications a fine droplet product is required to optimize efficacy, in others a quick-breaking emulsion with a larger droplet size is desired.

 

EcoSafe Natural Products Inc. uses the Malvern Laser Mastersizer 2000S to achieve detection of droplets between 0.02 and 3,000 microns. When formulating emulsions of varying active ingredients, surfactants or solvents, the laser particle size analyzer quickly reveals the details of micelle formation.

 

Examples of emulsions and microemulsions and their corresponding droplet sizes are shown below.

 

A translucent Microemulsion and its typical particle size distribution

 

 

A white opaque regular emulsion and its typical particle size distribution

 

 

A large droplet emulsion with a tendency to cream and its typical particle size distribution

 

If you are formulating emulsions or improving products, EcoSafe Natural Products Inc. will be glad to assess the quality of your products, make recommendations for improvement and assist with bringing the product to market.