When an ingredient performs more than one function in a formula it serves as a very useful tool for the cosmetic chemist. Multifunctional materials help chemical inventory, likely lower the cost, and certainly simplify the formula. An offering called Hest-18-0 from Global Seven, Franklin, NJ makes this claim. Its INCI name is glycereth-18 ethylhexanonate (and) glycereth-18. It is produced by esterification of ethylhexanoic acid with glycereth-18, and is both alcohol and water soluble.
According to Global Seven, Hest-18-0:
• Exhibits long lasting anti-microbial activity against a wide range of organisms and thus can reduce or eliminate other preservatives such as parabens or formaldehyde donors.
• Produces a warming effect on the skin.
• Reduces tack or drag of other ingredients while leaving a smooth light emollient after feel similar to silicone.
• Acts as a solvent for water insoluble materials such as salicylic acid. In fact, 20% salicylic acid is soluble in this material and a stable solution is achieved at room temperature.
• Since it is water soluble, it can be added to the water phase before it is emulsified or it can be added later to the already formed oil-in-water emulsion.
A Wide Range of Uses
Hest G-18-0 was checked for skin irritation as is (undiluted) under occlusive conditions, and was used as a 20% solution in water to test for ocular irritation. In both tests, it was found to be non-irritating.
As an anti-microbial, its Minimum Inhibitory Concentration was determined against various microbes such as gram positive bacteria (S. aureus and B. subtilis), gram negative bacteria (E. coli and P. aeruginosa), and yeast and mold (A. niger, P. notatum and C. albicans). It was found to be effective at 1-2% or less. The exact amount will vary with the application.
Hest G-18-0 is exothermic when it is dissolved in water. This temperature rise is about 2-3 times more than the same amount of glycerine or propylene glycol provides. The maximum rise is 12°C when about 60% by weight of the material is used. The other two chemicals only rise 5%.
The formula provided below illustrates the use of this material as a heat producer.
Warming Body MassageIngredient % Wt.
Hest G-18-0 99
Propylene glycol 0.5
Procedure: Mix well together at room temperature.
Its use as an anti-microbial is shown below which is called “preservative free.”
Sunscreen with Avobenzone
Ingredient % Wt.
Hest G-18-0 4.0
VP/Eicosene copolymer 2.0
DEA-Cetyl phosphate 3.0
Glyceryl stearate 4.0
Cetyl alcohol 2.0
Dibehenyl fumarate 2.0
Octyldodecyl neopentanoate 10.0
Procedure: Add Hest G-18-0 to water and heat to 90°C. Add other ingredients in separate container with mixing to 90°C. Add oil phase to water phase, and mix while cooling to 45°C.
In the final formula below, Hest G-18-0 is used as a moisturizer.
Clear Hand Sanitizer
Ingredient % Wt.
Acrylates/C10-30 alkyl acrylate 0.40
SD Alcohol 40-B 63.0
Aminomethyl propanol 0.36
Hest G-18-0 5.50
Procedure: Add ingredients in indicated order. Mix slowly at room temperature until product is uniform.