Biomaterials Tutorial

Polyethylene Glycol (PEG) or Polyethylene Oxide (PEO)

Felix Simonovsky
University of Washington Engineered Biomaterials

Polyethylene glycol (PEG), or polyethylene oxide (PEO), is a liquid or a wax-like solid at lower molecular weight and is crystalline at higher molecular weight.  It is a soluble polymer synthesized from ethylene oxide. 

PEG is used in many applications in various industries, such as biomedicine, pharmaceuticals, cosmetics, and agriculture due to its broad chemical compatibility, water solubility, non-toxicity, biocompatibility, and multiple physical states.

In the biomedical field, PEG can be used by itself or in combination with other compounds in hydrogel preparations.  It can also be incorporated into polymer backbones or immobilized onto polymeric biomaterial surfaces to make them “nonfouling.”  The nonfouling, or cell and protein resistant, properties of surfaces containing PEG are due to the material’s highly hydrated state. 

PEG is used in drug delivery systems to improve the solubility of drugs and to help stabilize immunogenic or unstable protein drugs.  This can enhance the circulation times and stabilities of drugs in the body.

The process of PEG attachment to other molecules is called pegylation, which can mask certain drugs, such as interferon, from the immune system preventing their rejection by the body.  Pegylation of some drugs can alter their distribution in the body, their metabolism, and their excretion.  Such alteration can lead to improved dosing intervals and may also have beneficial effects on safety and effectiveness.

References:

Bailey FE Jr, Koleske JV. Poly(ethylene oxide). New York: Academic Press; 1976.

Harris JM, Zalipsky S, Editors.  Poly(ethylene glycol): Chemistry and biological applications.  Washington DC: American Chemical Society; 1997.

Ratner BD, Hoffman AS, Schoen FJ, Lemons JE, Editors. Biomaterials science: An introduction to materials in medicine, 2nd ed. London: Elsevier Academic Press; 2004.