poly-

1. More than one; many; much: polyatomic.
2. More than usual; excessive; abnormal: polydipsia.
3. Polymer; polymeric: polyethylene.

[Greek polu-, from polus, much, many.]

Any of a series of water-soluble polymers with the general formula HO—(CH₂—CH₂—O)_n—H. These colorless, odorless compounds range in appearance from viscous liquids to waxy solids. The low-molecular-weight members, diethylene glycol (n = 2) through tetraethylene glycol (n = 4), are produced as pure compounds and find use as humectants, dehydrating solvents for natural gas, textile lubricants, heat-transfer fluids, solvents for aromatic hydrocarbon extractions, and intermediates for polyester resins and plasticizers.

The intermediate members of the series with average molecular weights of 200 to 20,000 are used commercially in ceramic, metal-forming, and rubber-processing operations; as drug suppository bases and in cosmetic creams, lotions, and deodorants; as lubricants; as dispersants for casein, gelatins, and inks; and as antistatic agents. The highest members of the series have molecular weights from 100,000 to 10,000,000. They are of interest because of their ability at very low concentrations to reduce friction of flowing water. See also Ethylene oxide; Polymerization.

Poly(ethylene glycol) has a range of properties making it suitable for medical and biotechnical applications. Since poly(ethylene glycol) is soluble both in water and in most organic solvents, many applications are derived from this amphiphilicity. Other properties include lack of toxicity and immunogenicity, and a tendency to avoid other polymers and particles also present in aqueous solution.

Poly(ethylene glycol) is attached to drugs to enhance water and blood solubility. Similarly, poly(ethylene glycol) is attached to enzymes to impart solubility in organic solvents. These poly(ethylene glycol) enzymes are used as catalysts for industrial reactions in organic solvents. See also Catalysis.

The tendency of poly(ethylene glycol) to avoid interaction with cellular and molecular components of the immune system results in the material being nonimmunogenic. This property leads to a greatly enhanced blood circulation lifetime of poly(ethylene glycol) proteins and to application as pharmaceuticals. Similarly, adsorption of proteins and cells to surfaces is greatly reduced by attaching poly(ethylene glycol) to the surface, and such coated materials find wide application as biomaterials. See also Biomedical chemical engineering.

1. More than one; many; much: polyatomic.
2. More than usual; excessive; abnormal: polydipsia.
3. Polymer; polymeric: polyethylene.