Polyethylene glycol

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Iodine/octylphenoxypolyglycolether
)

Polyethylene glycol
Names
IUPAC names
poly(oxyethylene) {structure-based},
poly(ethylene oxide) {source-based}[1]
Other names
Kollisolv, Carbowax, GoLYTELY, GlycoLax, Fortrans, TriLyte, Colyte, Halflytely, macrogol, MiraLAX, MoviPrep
Identifiers
Abbreviations PEG
ChEMBL
ChemSpider
  • none
ECHA InfoCard
100.105.546 Edit this at Wikidata
E number E1521 (additional chemicals)
UNII
Properties
C2nH4n+2On+1
Molar mass 44.05n + 18.02 g/mol
Density 1.125[2]
Pharmacology
A06AD15 (WHO)
Hazards
Flash point 182–287 °C; 360–549 °F; 455–560 K
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Polyethylene glycol (PEG;

molecular weight. The structure of PEG is commonly expressed as H−(O−CH2−CH2)n−OH.[3]

Uses

Medical uses

  • Pharmaceutical-grade PEG is used as an excipient in many pharmaceutical products, in oral, topical, and parenteral dosage forms.[4]
  • PEG is the basis of a number of
    Miralax
    ) is the generic name for polyethylene glycol used as a laxative. The name may be followed by a number which represents the average molecular weight (e.g. macrogol 3350, macrogol 4000 or macrogol 6000).
  • The possibility that PEG could be used to fuse axons is being explored by researchers studying peripheral nerve and spinal cord injury.[5]
  • An example of PEG hydrogels (see Biological uses section) in a therapeutic has been theorized by Ma et al. They propose using the hydrogel to address periodontitis (gum disease) by encapsulating stem cells in the gel that promote healing in the gums.[7] The gel with encapsulated stem cells was to be injected into the site of disease and crosslinked to create the microenvironment required for the stem cells to function.
  • PEGylation of adenoviruses for gene therapy can help prevent adverse reactions due to pre-existing adenovirus immunity.[8]
  • A
    anaphylactic shock.[10][11] The US CDC stated that in their jurisdiction six cases of "severe allergic reaction" had been recorded from more than 250,000 vaccinations, and of those six only one person had a "history of vaccination reactions".[12]

Chemical uses

The remains of the 16th century carrack Mary Rose undergoing conservation treatment with PEG in the 1980s
Terra cotta warrior, showing traces of original color
  • Polyethylene glycol is also commonly used as a polar stationary phase for gas chromatography, as well as a heat transfer fluid in electronic testers.
  • PEG is frequently used to preserve waterlogged wood and other organic artifacts that have been salvaged from underwater archaeological contexts, as was the case with the warship Vasa in Stockholm,[13] and similar cases. It replaces water in wooden objects, making the wood dimensionally stable and preventing warping or shrinking of the wood when it dries.[5] In addition, PEG is used when working with green wood as a stabilizer, and to prevent shrinkage.[14]
  • PEG has been used to preserve the painted colors on Terracotta Warriors unearthed at a UNESCO World Heritage site in China.[15] These painted artifacts were created during the Qin Shi Huang (first emperor of China) era. Within 15 seconds of the terra-cotta pieces being unearthed during excavations, the lacquer beneath the paint begins to curl after being exposed to the dry Xi'an air. The paint would subsequently flake off in about four minutes. The German Bavarian State Conservation Office developed a PEG preservative that when immediately applied to unearthed artifacts has aided in preserving the colors painted on the pieces of clay soldiers.[16]
  • PEG is often used (as an internal calibration compound) in mass spectrometry experiments, with its characteristic fragmentation pattern allowing accurate and reproducible tuning.
  • PEG derivatives, such as
    narrow range ethoxylates, are used as surfactants
    .
  • PEG has been used as the hydrophilic block of
    copolymers used to create some polymersomes.[17]
  • PEG is a component of the propellent used in UGM-133M Trident II Missiles, in service with the United States Navy.[18]

Biological uses

Commercial uses

Industrial uses

Entertainment uses

Health effects

PEG is considered biologically inert and safe by the U.S.

FDA
.

However, a growing body of evidence shows the existence of a detectable level of anti-PEG

PEGylated drugs, based on plasma samples from 1990 to 1999.[38][further explanation needed] Due to its ubiquity in a multitude of products and the large percentage of the population with antibodies to PEG, hypersensitive reactions to PEG are an increasing concern.[39][40] Allergy to PEG is usually discovered after a person has been diagnosed with an allergy to an increasing number of seemingly unrelated products, including processed foods, cosmetics, drugs, and other substances that contain PEG or were manufactured with PEG.[39]

Available forms and nomenclature

PEG, PEO, and POE refer to an oligomer or polymer of ethylene oxide. The three names are chemically synonymous, but historically PEG is preferred in the biomedical field, whereas PEO is more prevalent in the field of polymer chemistry. Because different applications require different polymer chain lengths, PEG has tended to refer to oligomers and polymers with a molecular mass below 20,000 g/mol, PEO to polymers with a molecular mass above 20,000 g/mol, and POE to a polymer of any molecular mass.[41] PEGs are prepared by polymerization of ethylene oxide and are commercially available over a wide range of molecular weights from 300 g/mol to 10,000,000 g/mol.[42]

PEG and PEO are liquids or low-melting solids, depending on their

molecular weights. While PEG and PEO with different molecular weights find use in different applications, and have different physical properties (e.g. viscosity) due to chain length effects, their chemical properties are nearly identical. Different forms of PEG are also available, depending on the initiator used for the polymerization process – the most common initiator is a monofunctional methyl ether PEG, or methoxypoly(ethylene glycol), abbreviated mPEG. Lower-molecular-weight PEGs are also available as purer oligomers, referred to as monodisperse, uniform, or discrete. Very high-purity PEG has recently been shown to be crystalline, allowing determination of a crystal structure by x-ray crystallography.[42]
Since purification and separation of pure oligomers is difficult, the price for this type of quality is often 10–1000 fold that of polydisperse PEG.

PEGs are also available with different geometries.

  • Branched PEGs have three to ten PEG chains emanating from a central core group.
  • Star PEGs have 10 to 100 PEG chains emanating from a central core group.
  • Comb PEGs have multiple PEG chains normally grafted onto a polymer backbone.

The numbers that are often included in the names of PEGs indicate their average molecular weights (e.g. a PEG with n = 9 would have an average molecular weight of approximately 400

polydispersity index (ĐM). Mw and Mn can be measured by mass spectrometry
.

alfa-2b are commonly used injectable treatments for hepatitis C
infection.

PEG is soluble in water, methanol, ethanol, acetonitrile, benzene, and dichloromethane, and is insoluble in diethyl ether and hexane. It is coupled to hydrophobic molecules to produce non-ionic surfactants.[43]

kDa
) nanometric crystallites (4 nm)

PEG and related polymers (PEG phospholipid constructs) are often sonicated when used in biomedical applications. However, as reported by Murali et al., PEG is very sensitive to sonolytic degradation and PEG degradation products can be toxic to mammalian cells. It is, thus, imperative to assess potential PEG degradation to ensure that the final material does not contain undocumented contaminants that can introduce artifacts into experimental results.[44]

PEGs and methoxypolyethylene glycols are manufactured by

octoxynols, and poloxamers
.

Production

Polyethylene glycol 400, pharmaceutical quality
Polyethylene glycol 4000, pharmaceutical quality

The production of polyethylene glycol was first reported in 1859. Both

polydispersity
(narrow molecular weight distribution). Polymer chain length depends on the ratio of reactants.

HOCH2CH2OH + n(CH2CH2O) → HO(CH2CH2O)n+1H

Depending on the catalyst type, the mechanism of

polydispersity
. Polymerization of ethylene oxide is an exothermic process. Overheating or contaminating ethylene oxide with catalysts such as alkalis or metal oxides can lead to runaway polymerization, which can end in an explosion after a few hours.

Polyethylene oxide, or high-molecular-weight polyethylene glycol, is synthesized by

polycondensation process. The reaction is catalyzed by magnesium-, aluminium-, or calcium-organoelement compounds. To prevent coagulation of polymer chains from solution, chelating additives such as dimethylglyoxime
are used.

Alkaline catalysts such as sodium hydroxide (NaOH), potassium hydroxide (KOH), or sodium carbonate (Na2CO3) are used to prepare low-molecular-weight polyethylene glycol.[47]

Safety

PEO's have "very low singledose oral toxicity", on the order of tens of grams per kg body weight (oral).[3] Because of its low toxicity, PEO is used in a variety of edible products.[48] The polymer is used as a lubricating coating for various surfaces in aqueous and non-aqueous environments.[49]

The precursor to PEGs is ethylene oxide, which is hazardous.[50] Ethylene glycol and its ethers are nephrotoxic if applied to damaged skin.[51]

See also

References

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  2. ^ "Poly(ethylene glycol)". ChemSrc. 7 January 2020.
  3. ^ .
  4. ^ "Polyethylene Glycol as Pharmaceutical Excipient". pharmaceutical.basf.com. Retrieved 27 April 2021.
  5. ^ a b c d e f Kean S (2017). "Chemical Hope". Distillations. 2 (4): 5. Retrieved 22 March 2018.
  6. ^ "Polyethyleneglycol (PEG 4000 ) | Laxolite | Medical Dialogues". Medical Dialogues. 19 January 2021. Retrieved 19 January 2021.
  7. PMID 33445388
    .
  8. .
  9. .
  10. ^ Bostock N (9 December 2020). "MHRA warning after allergic reactions in NHS staff given COVID-19 vaccine". GP. Archived from the original on 9 December 2020. Retrieved 9 December 2020.
  11. ^ "Pfizer-BioNTech COVID-19 vaccine: Health Canada recommendations for people with serious allergies". Health Canada. 12 December 2020.
  12. ^ Furtula A, Jordans F (21 December 2020). "EU regulator gives conditional approval to Pfizer-BioNTech COVID-19 vaccine". The Globe and Mail Inc. Reuters.
  13. .
  14. ^ "Anti-Freeze is Not a Green Wood Stabilizer – Buzz Saw". The Rockler Blog. 2 May 2006. Archived from the original on 17 January 2022. Retrieved 30 November 2012.
  15. ^ Reiffert S (18 March 2015). "Conservators preserve the paint layers of the Terracotta Army". tum.de. Technische Universität München. Archived from the original on 22 December 2015. Retrieved 19 December 2015.
  16. National Geographic
    . 221 (6): 74–87.
  17. PMID 18442283
    .
  18. ^ "Facts: Polaris Poseidon Trident". Strategic Systems Programs. U.S. Navy.
  19. S2CID 102369711
    .
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  26. .
  27. .
  28. .
  29. .
  30. ^ Johnson T (21 April 2004). "Army Scientists, Engineers develop Liquid Body Armor".
  31. ^ "Tattoo to monitor diabetes". BBC News. 1 September 2002.
  32. ^ US Government – Food and Drug Agency "Food Additive Status List". Food and Drug Administration. Retrieved 2 May 2017.
  33. ^ "Codex Alimentarius". codexalimentarius.net. Archived from the original on 7 January 2012.{{cite web}}: CS1 maint: unfit URL (link)
  34. ^ "Current EU approved additives and their E Numbers". UK Government – Food Standards Agency. Retrieved 21 October 2010.
  35. .
  36. .
  37. . p. 49.
  38. .
  39. ^ .
  40. .
  41. ^ For example, in the online catalog Archived 29 December 2006 at the Wayback Machine of Scientific Polymer Products, Inc., poly(ethylene glycol) molecular weights run up to about 20,000, while those of poly(ethylene oxide) have six or seven digits.
  42. ^
    PMID 19142918
    .
  43. .
  44. .
  45. . Retrieved 17 July 2017.
  46. ^ Polyethylene glycol, Chemindustry.ru
  47. ^ "PEG 4000, 6000, 8000, 12000 | Polyethylene glycol". www.venus-goa.com. Retrieved 19 January 2023.
  48. ^ Sheftel VO (2000). Indirect Food Additives and Polymers: Migration and Toxicology. CRC. pp. 1114–1116. Archived from the original on 9 August 2007. Retrieved 22 August 2007.
  49. S2CID 109928127
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  50. ^ Center for Food Safety and Applied Nutrition. "Potential Contaminants - 1,4-Dioxane A Manufacturing Byproduct". fda.gov. Retrieved 26 May 2017.
  51. S2CID 86231595
    .

External links