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

Wang B, Friess W. Lipid-coated mannitol core microparticles for sustained release of protein. Eur J Pharm Biopharm. 2018 Jul;128:91-97. doi: 10.1016/j.ejpb.2018.04.022.

Moldovan M, Lahmar A, Bogdan C, Părăuan S, Tomuţă I, Crişan M. Formulation and evaluation of a water-in-oil cream containing herbal active ingredients and ferulic acid. Clujul Med. 2017;90(2):212-219. doi: 10.15386/cjmed-668.

 Molet-Rodríguez A, Martín-Belloso O, Salvia-Trujillo L. Formation and Stabilization of W1/O/W2 Emulsions with Gelled Lipid Phases. Molecules. 2021 Jan 9;26(2):312. doi: 10.3390/molecules26020312.

de Abreu Martins HH , Turmo-Ibarz A , Hilsdorf Piccoli R , Martín-Belloso O , Salvia-Trujillo L . Influence of lipid nanoparticle physical state on β-carotene stability kinetics under different environmental conditions. Food Funct. 2021 Jan 21;12(2):840-851. doi: 10.1039/d0fo01980a

Guo Q, Bellissimo N, Rousseau D. Effect of Emulsifier Concentration and Physical State on the In Vitro Digestion Behavior of Oil-in-Water Emulsions. J Agric Food Chem. 2018 Jul 18;66(28):7496-7503. doi: 10.1021/acs.jafc.8b02231.

Lupi FR, Shakeel A, Greco V, Oliviero Rossi C, Baldino N, Gabriele D. A rheological and microstructural characterisation of bigels for cosmetic and pharmaceutical uses. Mater Sci Eng C Mater Biol Appl. 2016 Dec 1;69:358-65. doi: 10.1016/j.msec.2016.06.098.

Zhang M, Deng M, Ma J, Wang X. An evaluation of acute hydrogen sulfide poisoning in rats through serum metabolomics based on gas chromatography-mass spectrometry. Chem Pharm Bull (Tokyo). 2014;62(6):505-7. doi: 10.1248/cpb.c13-00988.

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.

Wang L, Schnaare RL, Dezzutti C, Anton PA, Rohan LC. Rectal microbicides: clinically relevant approach to the design of rectal specific placebo formulations. AIDS Res Ther. 2011 Mar 7;8:12. doi: 10.1186/1742-6405-8-12. 

PEG-30 Glyceryl stearate is a chemical compound, glycerol ester of stearic acid. It is produced industrially from vegetable oils such as palm, rapeseed, sunflower and stearic acid.

The name describes the structure of the molecule. 

• "PEG-30" refers to the fact that on average, there are 30 units of ethylene glycol in the molecule. 
• "Glyceryl" refers to the glycerol part of the molecule, which is a simple polyol compound. 
• "Stearate" refers to the stearic acid part of the molecule, which is a long-chain fatty acid.

The synthesis process takes place in several stages:

• Step 1: Preparation of raw materials: polyethylene glycol (PEG), glycerol and stearic acid.
• Step 2: Esterification. Glycerol and stearic acid react together in the presence of a catalyst to form glyceryl stearate. 
• Step 3: Pegylation. Glyceryl stearate is reacted with PEG in a process known as pegylation to form PEG-30 Glyceryl Stearate.
• Step 4: Purification. The resulting PEG-30 Glyceryl Stearate is purified to remove any unreacted glycerol, stearic acid and PEG. This can involve various techniques, including distillation and filtration.
• Step 5: Drying. PEG-30 Glyceryl Stearate Purified is then dried to remove any residual solvent.

It appears in the form of a fine, white powder or in small pellets with a white to slightly yellow colour.

What it is used for and where

Food

Increases consistency in baked goods, gives uniformity to ice cream and whipped cream. Non-stick agent in baking.

Cosmetics

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. 

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.

Moisturiser, stabiliser and emulsifier. Glyceryl stearate together with PEG-75 stearate significantly influenced the consistency and thixotropic behaviour, although to a lesser extent than methyl glucose sesquistearate (1). 

In this study on optimising the formulation of oil/water cosmetic emulsions, Glyceryl stearate was found to be the dominant co-emulsifier influencing the properties of emulsions. Interactions between Glyceryl stearate and other co-emulsifiers also significantly influenced the properties of emulsions (2).

With regard to safety, emulsifiers are considered mild irritants.

Pharmaceuticals

Solidifying agent and release control agent in pharmaceuticals

Other uses

Resins. Lubricant

Plastics. Anti-fogging and anti-static agent

Safety

Since the PEG (Polyethylene glycol) family is very numerous and can be found in cosmetic, industrial, pharmaceutical, medical and other products, we need to make an introductory statement on the subject, which is rather complex from a safety point of view because these products not only come into contact with the skin, but, as in the case of medical products, are ingested.

PEGs (polyethylene glycol) polymerise condensed ethylene oxide and water and are referred to as polyethylene glycols, but are actually complex chemical components, polymers bonded together. For example, plastic is polyethylene and has a hard consistency, while polyethylene combined with glycol forms a liquid. PEGylation is produced not only as etherification, but also as transesterification, which is the transformation of an alcohol by an ester. 

The number appearing after the abbreviation PEG represents the molecular weight and the higher this number is, the less it penetrates the skin.

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.

The most relevant studies and their abstracts have been selected to explore this in more depth:

Glyceryl Stearate studies

Typical commercial product characteristics PEG-30 Glyceryl stearate

• Molecular Formula      C₂₁H₄₂O₄
• Linear Formula    CH₃(CH₂)₁₆COOCH₂CH(OH)CH₂OH
• Molecular Weight   358,6 g/mol
• Exact Mass     358.308319
• CAS    123-94-4
• UNII    258491E1RZ
• EC Number: 204-664-4    250-705-4
• DSSTox Substance ID     DTXSID7027968    DTXSID7029160
• IUPAC  2,3-dihydroxypropyl octadecanoate
• InChl=1S/C21H42O4/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-21(24)25-19-20(23)18-22/h20,22-23H,2-19H2,1H3
• InChl Key      VBICKXHEKHSIBG-UHFFFAOYSA-N
• SMILES     CCCCCCCCCCCCCCCCCC(=O)OCC(CO)O
• FEMA Number 2527
• DSSTox Substance ID: 
• MDL number  MFCD00036186
• PubChem Substance ID 24896595
• RTECS     
• NSC     3875
• JECFA     918
• NCI    C80900
• RXCUI     1311165     1427173
• Beilstein     1728685
• NACRES NA.25

Synonyms: 

• Polyethylene Glycol (30) Glyceryl Monostearate
• GMS
• 2,3-Dihydroxypropyl octadecanoate
• Tagat S
• Momostearin
• 1-Stearoyl-rac-glycerol
• Monoglyceride

Some studies in Medicine that refer to the use of PEG Polyethylene Glycol in various fields.

Bowel

Polyethylene glycol with or without electrolytes is effective for the treatment of functional constipation, both in adults and pediatric patients, with great safety and tolerability. These preparations constitute the most effective osmotic laxatives (more so than lactulose) and are the first-line treatment for functional constipation in the short and long term. They are as effective as enemas in fecalomas, avoid the need for hospitalization, and are well tolerated by patients (especially when administered without electrolytes) (3).

In colonoscopy preparation, Polyethylene glycol tablets have confirmed similar efficacy, acceptability, tolerance, and safety as sodium phosphate (4).

Polyethylene glycol is also used for peripheral nerve repair (5).

Eyes

Dry eye disease is a disorder that affects 5-34% of the world's adult population with reduced quality of life. Artificial tears or lubricants are the most widely used therapy for the treatment of this disease because of their low side effect profile, which attempt to modify the properties of the tear film. Polyethylene glycol has demonstrated clinical efficacy in the treatment of this disease (6).

Brain

Polyethylene glycol facilitates the neuroprotective effects of magnesium in traumatic brain injury (7).

Cancer

By transarterial chemoembolization, Polyethylene glycol is effective and safe for the treatment of liver cancer and, as indicated, gives good tolerability, quality of life, and high tumor response (8).

Cosmetics

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

Safety varies from type to type given the structural complexity (9).

References______________________________________________________________________

(1) Ferreira VTP, Infante VHP, Felippim EC, Campos PMBGM. Application of Factorial Design and Rheology to the Development of Photoprotective Formulations. AAPS PharmSciTech. 2020 Jan 3;21(2):46. doi: 10.1208/s12249-019-1569-7. 

(2) Djuris J, Vasiljevic D, Jokic S, Ibric S. Application of D-optimal experimental design method to optimize the formulation of O/W cosmetic emulsions. Int J Cosmet Sci. 2014 Feb;36(1):79-87. doi: 10.1111/ics.12099. 

 (3) 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.

(4) 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.

(5) 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.

(6) 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.
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.
BMC Ophthalmol. 2016 Sep

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.

(7) 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.

(8) 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.

(9) 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.