How to Achieve Stable Oil-in-Water Emulsions

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David Shechter
May 20, 2016
min read
How to Achieve Stable Oil-in-Water Emulsions

Oil-in-water (o/w) emulsions are found in a plethora of products, from moisturizers to topical steroid products; the most well-known product, homogenized milk, hails from the food & beverage industry. Thicker than lotion and easier to spread than ointments, o/w-based creams work by penetrating the wall of the skin’s stratum corneum to achieve a local effect. But how to produce this valuable component, particularly one that will be stable enough to last for more than a few days? Below we describe specific ways to achieve a stable o/w emulsion, which can be used to create a product that will out-compete its competitors.


Of course, there’s the given- an o/w emulsion absolutely requires oil droplets suspended in water. Not so obvious are the supportive components it must be prepared with. For example, all emulsions, whether o/w or water-in-oil (w/o), require an emulsifier to provide them with enhanced stability. O/w emulsions optimally incorporate more than one emulsifier because of their generally unstable chemical nature. A variety of emulsifiers exist to suit this function; polysorbate, sorbitan laurate, and cetearyl alcohol are some examples of o/w-compatible emulsifiers. To protect the stability of your emulsion, you can take one of a few steps before and/or during its production process. The emulsifier used, as indicated above, will help to stabilize an emulsion by breaking up droplets, organizing the particles, and adhering to smaller particles. The formulation of each emulsifier, as well as the combination of emulsifiers you select, will play a huge role in the final product’s stability.


Emulsion production requires some form of mixing equipment, as it is the vigorous mixing action that allows oil and water to mix. Specifically, it is important to look for mixers that can apply high pressure along with mechanical forces. For example, high pressure homogenizers are touted for using both intensive pressure and forces like impact, cavitation, and adjustable process intensity to achieve a high quality formulation. Additionally (and importantly), look for a machine that can impart high shear. High shear overcomes the resistance oil and water have to mixing, and provides long-term stability that lower shear mixers cannot achieve. (1)

Pion: The Homogenizer Advantage

Emulsion production involves high pressure mixing, most commonly in the form of homogenization. Homogenization is the preferable method due to its ability to reduce particle sizes more significantly than other blending/emulsification methods. The first step in synthesizing a w/o or o/w emulsion is purchasing equipment that will achieve small and consistent particle size distribution. One such example is the high pressure homogenizer by Pion. Our products are trusted by researchers and lab managers around the world for key benefits, such as production of nano/micro emulsions, dispersions, and suspensions; importantly, this equipment can achieve consistent particle sizes at or below 100 nm, a key benefit for researchers & corporations that synthesize pharmaceutical products.

In addition, Pion's BEE brand has extensive experience assisting its product users as they transition through the drug development process, a booming industry for emulsion production. Our homogenizers are differentiated for R&D, clinical trials, and manufacturing, and our customer support is reliable, experience-driven, and effective.

Learn more about how Pion can enhance your emulsion production process by contacting us today!

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