Compendium of the most significant studies with reference to properties, intake, effects.

Bárány E, Lindberg M, Lodén M. Unexpected skin barrier influence from nonionic emulsifiers. Int J Pharm. 2000 Feb 15;195(1-2):189-95. doi: 10.1016/s0378-5173(99)00388-9.

Abstract. These results highlight the possibility of absorption of these emulsifiers into the lipid bilayer, which increase TEWL in normal skin and decrease TEWL in damaged skin.

Pasquali, R. C., Taurozzi, M. P., Sacco, N., & Bregni, C. (2008). Birefringent emulsions stabilized with steareth-2 and steareth-21. Lat. Am. J. Pharm, 27(6), 839-44.

Abstract. In this research, birefringent emulsions stabilized with Steareth-2 and Steareth-21 were studied

dos Santos OD, da Rocha-Filho PA. Influence of surfactant on the thermal behavior of marigold oil emulsions with liquid crystal phases. Drug Dev Ind Pharm. 2007 May;33(5):543-9. doi: 10.1080/03639040600975238.

Abstract. In the present work, it was studied that the influence of the size of carbon chain and the number of ethylene oxide moieties of the surfactant on the thermal behavior of eight emulsions prepared with marigold oil stabilized by liquid crystal phases. 

Zanatta CF, de Faria Sato AM, de Camargo FB Jr, Campos PM, Rocha-Filho PA. Rheological behavior, zeta potential, and accelerated stability tests of Buriti oil (Mauritia flexuosa) emulsions containing lyotropic liquid crystals. Drug Dev Ind Pharm. 2010 Jan;36(1):93-101. doi: 10.3109/03639040903099728. 

Abstract. The purpose of this work was to obtain emulsions produced with Buriti oil and non-ionic surfactants.

Panel, C. E., & Cosmetic Ingredient Review Expert Panel. (1988). Final report on the safety assessment of steareth-2,-4,-6,-7,-10,-11,-13,-15, and-20. Journal of the American College of Toxicology, 7, 881-910.

Abstract. On the basis of the available data it is concluded that steareths-2,-4,-6,-7,-10,-11,-13,-15, and-20 are safe as cosmetic ingredients in the present practices of use and concentration.

Steareth-2 is a chemical compound, carbon chains  alkyl polyethylene glycol (PEG (Polyethylene glycol)) ether of ethoxylated fatty stearyl alcohol  (2 mol),   from  palm kernel oils and coconut oils and fats.

Safety. 

The term 'eth' refers to the ethoxylation reaction with ethylene oxide after which residues of ethylene oxide and 1,4-dioxane, chemical compounds considered carcinogenic, may remain. The degree of safety therefore depends on the degree of purity of the compound obtained. At present, no manufacturer is known to provide this information on the label.

It appears as white granular flakes.

What it is used for and where

It is a non-ionic lipophilic surfactant with emulsifying function for water/oil emulsions. Emulsifiers have the property of directly influencing the stability, sensory properties and surface tension of sunscreens by modulating their filmometric performance..

Pharmaceutical

Co-emulsifier for oil/water systems with excellent dispersing power and resistant to extreme pH values and high concentrations of electrolytes and metal ions.

Cosmetics

Surfactant - Emulsifying agent. Emulsions are thermodynamically unstable and are used to soothe or soften the skin and emulsify, so they need a specific, stabilising ingredient. This ingredient forms a film, lowers the surface tension and makes two immiscible liquids miscible. A very important factor affecting the stability of the emulsion is the amount of the emulsifying agent. Emulsifiers have the property of reducing the oil/water or water/oil interfacial tension, improving the stability of the emulsion and also directly influencing the stability, sensory properties and surface tension of sunscreens by modulating the filmometric performance.

Emulsion stabilizer. Emulsions are thermodynamically unstable. Emulsion stabilisers improve the formation and stability of single and double emulsions. It should be noted that in the structure-function relationship, molar mass plays an important role.

Emulsifier for water/oil systems, co-emulsifier for oil/water systems and lubricant in creams, lotions, polar oil emulsions using an oil/water system.

Surfactant - Cleansing agent. Cosmetic products used to cleanse the skin utilise the surface-active action that produces a lowering of the surface tension of the stratum corneum, facilitating the removal of dirt and impurities. 

Steareth-2 studies

Typical commercial product characteristics Polyethylene Glycol Octadecyl Ether

Appearance	White crystals
Boiling Point	~43*C
Melting Point	56-60ºC
Flash Point	154.2ºC
Density	0.867g/cm3
Safety

• Molecular Formula  C₂₂H₄₆O₃
• Molecular Weight     228.243
• CAS  9005-00-9
• UNII    V56DFE46J5
• EC Number   500-017-8
• DSSTox Substance ID  
• IUPAC  2-(2-octadecoxyethoxy)ethanol
• InChI=1S/C22H46O3/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-19-24-21-22-25-20-18-23/h23H,2-22H2,1H3 
• InChl Key      ILCOCZBHMDEIAI-UHFFFAOYSA-N
• SMILES   CCCCCCCCCCCCCCCCCCOCCOCCO
• MDL number  
• PubChem Substance ID    
• ChEBI  
• NACRES NA.24  
• RTECS  

Synonyms:

• Lipocol S-2
• Brij
• Procol SA-2
• Polyethylene Glycol Octadecyl Ether