Glyceryl Stearate SE is a chemical compound, polyethylene glycol ether of glyceryl stearate, of vegetable origin, monoglyceric monoester obtained by the esterification of glycerine and carboxylic acids (an equivalent of a carboxylic acid and an equivalent of glycerine), in this ingredient the stearic acid and a blend of  the  sodium and/or potassium oleate.

Raw Materials and Their Functions

• Glycerin. Glycerin is a fundamental raw material for Glyceryl Stearate SE. Glycerin is an organic compound that can be of natural or synthetic origin. It is used as a base for the synthesis of the compound.
• Stearic acid. Stearic acid is a long-chain fatty acid used in the synthesis of Glyceryl Stearate SE. It can be of vegetable or animal origin.

Industrial Chemical Synthesis

• Preparation of reagents. The necessary reagents for the synthesis of Glyceryl Stearate SE, such as glycerin and stearic acid, are collected and prepared.
• Melting of stearic acid. Stearic acid is melted at an appropriate temperature.
• Addition of glycerin. Glycerin is added to the melted stearic acid and mixed to promote the reaction.
• Esterification reaction. The mixture of glycerin and stearic acid undergoes an esterification reaction, forming the desired Glyceryl Stearate SE.
• Cooling and solidification. The reactive mixture is cooled, allowing the Glyceryl Stearate SE to solidify.
• Crushing and milling of the solidified product. The solidified product is crushed and milled to obtain the desired form and consistency.
• Purification of the product. Glyceryl Stearate SE is purified to remove any impurities or unwanted residues.
• Characterization of the product. The product is characterized using chemical and physical analyses to confirm its identity and assess its quality.
• Packaging of Glyceryl Stearate SE into appropriate containers for distribution and use.

Safety. The purity level of commercial monoglyceric monoester is about 90 per cent, and impurities include fatty acids, monoglyceric diesters, mono-, di- and tri-glycerides.

It is produced industrially from vegetable oils such as rapeseed, palm and stearic acids. SE (Self-Emulsifying) means a self-emulsifying product.

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

• Skin conditioning agent - Emollient. Emollients have the characteristic of enhancing the skin barrier through a source of exogenous lipids that adhere to the skin, improving barrier properties by filling gaps in intercorneocyte clusters to improve hydration while protecting against inflammation. In practice, they have the ability to create a barrier that prevents transepidermal water loss.  Emollients are described as degreasing or refreshing additives that improve the lipid content of the upper layers of the skin by preventing degreasing and drying of the skin. The problem with emollients is that many have a strong lipophilic character and are identified as occlusive ingredients; they are oily and fatty materials that remain on the skin surface and reduce transepidermal water loss. In cosmetics, emollients and moisturisers are often considered synonymous with humectants and occlusives.

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

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    11099-07-3     85666-92-8
• UNII    258491E1RZ
• EC Number    234-325-6
• 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

Premise on PEGs

Since the PEG family is very numerous and is found in many cosmetic, cleaning, medical and other products, it is necessary to make a preliminary knowledge on the subject that is quite 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, are ingested.

PEGs polymerize condensed ethylene oxide and water and are referred to as polyethylene glycols, but they are actually complex chemical components, polymers bonded together. For example, plastic is polyethylene and has a hard consistency, while polyethylene aggregated with glycol forms a liquid.

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

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.