PEG-6 is a chemical compound, hydrophilic wax binder (Polyethylene glycol-6-stearate) that finds various applications in cosmetics, medicine and more.
Breakdown of the name and function of the components
- PEG - Stands for "Polyethylene Glycol", which is a polymer of ethylene oxide.
- 6 - Indicates the approximate average molecular weight or the number of repeating ethylene oxide units in the polymer.
Description and function of the raw materials used in production
- Ethylene oxide - A colorless gas used for producing PEG through polymerization.
- Catalysts - Often used to facilitate and speed up the polymerization reaction.
Summary of its industrial synthesis process step by step
- Polymerization - Ethylene oxide is polymerized in the presence of a catalyst to form a polyethylene glycol chain.
- Molecular Weight Control - The length of the polymer chain and thus the molecular weight is controlled by varying the amount of ethylene oxide and the reaction conditions.
- Purification - The produced PEG is purified to remove any impurities or unreacted substances.
- Drying - The PEG-6 is then dried to remove any residual moisture.
What it is for and where
It is said to be used in more than 500 formulations, most of which are rinsing formulations.
Cosmetics
Solvent. It is the substance for dissolving or dispersing surfactants, oils, dyes, flavourings, bactericidal preservatives in solution.In fact, it dissolves other components present in a cosmetic formulation. Solvents are generally liquid (aqueous and non-aqueous).
Humectant. Hygroscopic compound used to minimise water loss in the skin and to prevent it from drying out by facilitating faster and greater absorption of water into the stratum corneum of the epidermis. The epidermis is the most superficial of the three layers that make up human skin (epidermis, dermis and hypodermis) and is the layer that maintains hydration in all three layers. In turn, the epidermis is composed of five layers: horny, the most superficial, granular, spinous, shiny, and basal. Humectants have the ability to retain the water they attract from the air in the stratum corneum and have the function of moisturising the skin. They are best used before emollients, which are oil-based.
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. No manufacturer appears to provide this information on the label, at least as of the date of this review.
CAS 25322-68-3
There are several types of PEG-6:
- PEG-6 Hexaethylene glycol
Molecular formula: C12H26O7
Molecular weight: 282.33
CAS: 2615-15-8
- PEG-6 Ethylene Glycol Monomethyl Ether
Molecular formula: C3H8O2 or CH3OCH2CH2OH
Molecular weight: 76.095
CAS: 109-86-4
- PEG-6 Dilaurate or Glycol Dilaurate
Molecular formula: C26H50O4
Molecular weight: 426.682
CAS: 624-04-4
- PEG-6 Deceth-6 or Decyl ether
Molecular formula: C22H46O7
Molecular weight: 422.603
CAS: 5168-89-8
- PEG-6 Oleyl ether or 2 - [(Z) -Octadec-9-enoxy] ethanol
Molecular formula: C20H40O2
Molecular weight: 312.538
CAS: 5353-25-3
- PEG-6 Lauryl ether or Laureth-6
Molecular formula: C24H50O7
Molecular weight: 450.657
CAS: 3055-96-7
- PEG-6 TRydecyl ether or 2- (Tridecyloxy) ethanol
Molecular formula: C15H32O2
Molecular weight: 244.419
CAS: 24938-91-8 or 38471-49-7
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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.
PEG-6 
