Polyethylene glycol (PEG), also known as polyethylene oxide (PEO) or polyoxyethylene (POE), refers to a polymer of ethylene oxide. These three names are generally synonymous today, but historically polyethylene glycol often refers to oligomers and polymers with a molecular mass of less than 20,000 g/mol, PEO refers to polymers with a molecular weight of more than 20,000, and POE can refer to any Molecular mass of polymer.
PEO and POE may be liquid or low melting solids depending on the molecular weight. Due to the influence of chain length, polyethylene glycols of different molecular weights often have different physical properties (such as viscosity) and different applications, but most of the polyethylene glycols are chemically similar. Low molecular weight polyethylene glycol usually refers to purer oligomers, which is more monodisperse; high purity polyethylene glycol has crystallinity, so X-ray can be used to determine its crystal structure. Since it is more difficult to purify and isolate the oligomeric polyethylene glycol, the price is usually 10-1000 times that of polydisperse polyethylene glycol. Those with a relative molecular mass between 700 and 900 are semi-solid. Those having a relative molecular mass of 1000 or more are a pale white waxy solid or a flake-like paraffin or a fluid powder. It is miscible in water and soluble in many organic solvents such as alcohols, ketones, chloroforms, glycerides and aromatic hydrocarbons. It is insoluble in ether and n-hexane. Its product after binding to a hydrophobic molecule can be used as a nonionic surfactant. As the molecular weight increases, the water solubility, vapor pressure, water absorption and solubility of organic solvents decrease correspondingly, while the freezing point, relative density, flash point and viscosity increase accordingly. It is stable to heat and does not work with many chemicals and does not hydrolyze.
Polycondensed from ethylene glycol or polyadded from ethylene oxide and water
Polyethylene glycol can be used to modify drug proteins to protect drug molecules from extending their half-life.
Polyethylene glycol can be used as a cell fusion agent. It causes adhesion of adjacent cell membranes, which in turn fuses the cells into one cell.
In addition, polyethylene glycol is also a kind of food additive, which is often used for coating candy and chocolate products. The dosage is referred to GB 2760-2011. It can be used as a filming agent in foods. It can also be used as a dispersant, carrier solvent, binder, plasticizer, coating agent, lubricant, and fragrance additive. PEG400 is best suited for soft capsules. Since PEG400 is a liquid, it has broad compatibility with various solutions, is a good solvent and thickener, and is widely used in liquid preparations such as oral liquids and the like. PEG is the material of choice when vegetable oils are not suitable as active ingredient carriers. This is mainly due to the stability of PEG and its difficulty in deterioration. In addition, it can be mixed with high molecular weight (PEG) and its mixture has good solubility and good compatibility. PEG4000, PEG6000, PEG8000 are used for tablets, capsules, film coats, pills, suppositories, and the like. High molecular weight PEG (PEG4000, PEG6000, PEG 8000) is very useful as an adhesive for the manufacture of tablets due to the plasticity of PEG during the tableting process and its ability to increase the release of the drug from tablets. PEG can make the surface of the tablet shiny and smooth, while being less susceptible to damage. In addition, a small amount of high molecular weight PEG (PEG4000, PEG6000, PEG8000) can prevent the bonding between the sugar-coated tablets and the bottle.