PEG-120 Methyl Glucose Dioleate: properties, uses, pros, cons, safety, alternatives

PEG-120 Methyl Glucose Dioleate is a chemical compound, a natural derivative of corn glucose obtained by ethoxylation process.

It is a non-ionic surfactant and thickening agent primarily used in the cosmetics and personal care industry. It is derived from the reaction of methyl glucose with oleic acid and polyethylene glycol (PEG). It is commonly used in shampoos, body washes, facial cleansers, and other skincare and hair care products for its foaming, thickening, and conditioning properties.

Chemical Composition and Structure

PEG-120 Methyl Glucose Dioleate is an ester formed by combining methyl glucose, a sugar derivative, with oleic acid, an unsaturated fatty acid found in many vegetable oils, and a polyethylene glycol chain. This structure allows the compound to act as an emulsifier and surfactant, helping to create a rich lather and improving the texture of cosmetic products.

The name describes the structure of the molecule:

• PEG-120 stands for polyethylene glycol with an average molecular weight of about 120. Polyethylene glycol (PEG) is a polymer obtained from ethylene oxide and water that can have different molecular weights depending on how it is synthesised.
• Methyl Glucose is a glucose molecule that has been methylated, i.e. to which a methyl group (CH3) has been added.
• Dioleate indicates the presence of two oleate groups. Oleate is the salt or ester of oleic acid, a monounsaturated fatty acid commonly found in various animal and vegetable fats.

Description of the raw materials used in its production:

• Polyethylene Glycol (PEG) - Polyethylene glycols are polymers of ethylene glycol. They are obtained through the polymerization of ethylene oxide. The number following the PEG prefix (as in the case of PEG-120) indicates the average molecular weight of the polymer.
• Methyl Glucose Dioleate is a diester of Methyl Glucose and oleic acid. It is derived from Methyl Glucose, which is obtained from the reaction of glucose with methanol, and oleic acid, which is a natural fatty acid found in various vegetable oils.

The synthesis of PEG-120 Methyl Glucose generally involves the following steps:

• Preparation of Components: The main ingredients for producing PEG-120 Methyl Glucose Dioleate include methyl glucose and oleic fatty acids. These components are weighed and prepared for the reaction.

• Esterification: Methyl glucose is treated with oleic fatty acids in an esterification process. This is done by heating methyl glucose with the fatty acids in the presence of a catalyst, usually an acid, to promote the formation of the ester.

• Ethoxylation Reaction: During the process, an ethoxylation reaction occurs, where PEG (polyethylene glycol) is incorporated into the product. This reaction involves heating methyl glucose and the fatty acids in the presence of ethylene oxide, modifying the properties of the ester and improving its solubility and stability.

• Purification: The produced PEG-120 Methyl Glucose Dioleate is purified to remove any impurities and chemical residues. This may include filtration and washing processes to ensure a high-quality product.

• Quality Control and Packaging: Finally, PEG-120 Methyl Glucose Dioleate undergoes quality control checks to verify its purity and functional properties. After analysis, it is packaged for distribution and use in cosmetic and personal care products.

What it is used for and where

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.

It is an high efficiency non-ionic thickener of anionic and amphoteric surfactants, emulsifier used by cosmetic industry.

Applications

Surfactant - PEG-120 Methyl Glucose Dioleate reduces surface tension between two substances, like oil and water, facilitating their mixing.

Emulsifier - It helps in forming stable emulsions, preventing the separation of oil-based and water-based components in products like creams and lotions.

Viscosity Enhancer - Used in cosmetic and personal care products to improve consistency and thickness, making the product thicker.

Skin Conditioning - Can impart a smooth and soft feel to the skin.

Compatibility - It's known for its good skin tolerance and can be used in formulations intended even for sensitive skin.

It is particularly suitable for amino acid surfactants that are rather difficult to thicken. It does not irritate the eyes and can reduce irritation associated with surfactants.

Safety

It is an ethoxylated product, but since 120 ethylene oxide units are not easily absorbed through the stratum corneum, it seems unlikely that skin penetration would cause damage.

Alternatives

Molecular Formula: C₄₃H₇₈O₈

Molecular Weight: 723.07462

CAS  86893-19-8

EC number  617-932-4

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And a premise on PEG.

Since the PEG (1) family is numerous and is found in many cosmetic, cleaning and medicinal products and others, we need a cognitive premise on the subject that is rather complex from the point of view of safety because these products not only come into contact with the skin but, as in the case of medicine, they are also ingested.

PEG or polyethylene glycols polymerise the condensed ethylene oxide and water and are called polyethylene glycols, but in reality, they are complex chemical components, polymers bound together. For example,  plastic is polyethylene and has a hard consistency, while  polyethylene aggregated to the glycol forms a liquid.

The number that appears after the initials PEG represents the molecular weight and the higher this number is, the less it penetrates  the skin. 

Here below are some studies in Medicine that refer to the use of PEG Polyethylene glycol in various fields.

Intestine

Polyethylene glycol with or without electrolytes is effective for the treatment of functional constipation, both in adults and in paediatric patients, with great safety and tolerability. These preparations are the most effective osmotic laxatives (more than lactulose) and are the first-line treatment for functional constipation in the short- and long-term. They are as effective as enemas in faecalomas, avoid the need for hospitalisation and are well tolerated by patients (especially when given without electrolytes) (2).

In the preparation  for colonoscopy,  polyethylene glycol tablets confirmed efficacy, acceptability, tolerance and safety similar to those of sodium phosphate (3).

For peripheral nerve repair (4).

Eyes

Dry eye syndrome is a disorder that affects 5-34% of the world's adult population with reduced quality of life. Artificial or lubricating tears are the most used therapy for treating this condition due to their low side effects profile, which attempt to modify the properties of the tear film. Polyethylene glycol has demonstrated clinical efficacy in the treatment of this condition (5).

Brain

Polyethylene glycol facilitates the neuroprotective effects of magnesium in head injuries (6).

Tumors

For transarterial chemoembolization, Polyethylene glycol is effective and safe for the treatment of liver cancer, as indicated by good tolerability, quality of life and high tumour response (7). 

Cosmetics

Many types of PEG are hydrophilic and are used as creams, topical dermatological preparations and in cosmetic products such as surfactants, emulsifiers, detergents, humectants and skin conditioners.

Safety varies from type to type given the structural complexity (8).

References___________________________________________________________________

(1) Fruijtier-Pölloth C. Safety assessment on polyethylene glycols (PEGs) and their derivatives as used in cosmetic products. Toxicology. 2005 Oct 15;214(1-2):1-38. doi: 10.1016/j.tox.2005.06.001.

(2) Mínguez M, López Higueras A, Júdez J. Use of polyethylene glycol in functional constipation and fecal impaction. Rev Esp Enferm Dig. 2016 Dec;108(12):790-806. doi: 10.17235/reed.2016.4571/2016.

Santos-Jasso KA, Arredondo-García JL, Maza-Vallejos J, Lezama-Del Valle P. Effectiveness of senna vs polyethylene glycol as laxative therapy in children with constipation related to anorectal malformation. J Pediatr Surg. 2017 Jan;52(1):84-88. doi: 10.1016/j.jpedsurg.2016.10.021.

(3) Chaussade S, Schmöcker C, Toulemonde P, Muñoz-Navas M, O'Mahony V, Henri F. Phosphate tablets or polyethylene glycol for preparation to colonoscopy? A multicentre non-inferiority randomized controlled trial. Surg Endosc. 2017 May;31(5):2166-2173. doi: 10.1007/s00464-016-5214-1.
Tsunoda T, Sogo T, Iwasawa K, Umetsu S, Oikawa-Kawamoto M, Inui A, Fujisawa T. Feasibility and safety of bowel cleansing using low-volume polyethylene glycol with ascorbic acid before pediatric colonoscopy: A pilot study. Dig Endosc. 2017 Mar;29(2):160-167. doi: 10.1111/den.12756.

(4) Hoffman AN, Bamba R, Pollins AC, Thayer WP. Analysis of polyethylene glycol (PEG) fusion in cultured neuroblastoma cells via flow cytometry: Techniques & optimization. J Clin Neurosci. 2017 Feb;36:125-128. doi: 10.1016/j.jocn.2016.10.032.

(5) Pérez-Balbuena AL, Ochoa-Tabares JC, Belalcazar-Rey S, Urzúa-Salinas C, Saucedo-Rodríguez LR, Velasco-Ramos R, Suárez-Sánchez RG, Rodríguez-Carrizalez AD, Oregón-Miranda AA. Efficacy of a fixed combination of 0.09 % xanthan gum/0.1 % chondroitin sulfate preservative free vs polyethylene glycol/propylene glycol in subjects with dry eye disease: a multicenter randomized controlled trial. BMC Ophthalmol. 2016 Sep 20;16(1):164. doi: 10.1186/s12886-016-0343-9.

Labetoulle M, Messmer EM, Pisella PJ, Ogundele A, Baudouin C. Safety and efficacy of a hydroxypropyl guar/polyethylene glycol/propylene glycol-based lubricant eye-drop in patients with dry eye. Br J Ophthalmol. 2017 Apr;101(4):487-492. doi: 10.1136/bjophthalmol-2016-308608.

(6) Busingye DS, Turner RJ, Vink R. Combined Magnesium/Polyethylene Glycol Facilitates the Neuroprotective Effects of Magnesium in Traumatic Brain Injury at a Reduced Magnesium Dose. CNS Neurosci Ther. 2016 Oct;22(10):854-9. doi: 10.1111/cns.12591.

(7) Aliberti C, Carandina R, Sarti D, Mulazzani L, Catalano V, Felicioli A, Coschiera P, Fiorentini G. Hepatic Arterial Infusion of Polyethylene Glycol Drug-eluting Beads for Primary and Metastatic Liver Cancer Therapy. Anticancer Res. 2016 Jul;36(7):3515-21.

(8) Jang HJ, Shin CY, Kim KB. Safety Evaluation of Polyethylene Glycol (PEG) Compounds for Cosmetic Use. Toxicol Res. 2015 Jun;31(2):105-36. doi: 10.5487/TR.2015.31.2.105.