Overview

Polyethylene glycol is a high-molecular polymer with a chemical formula of HO(CH2CH2O)nH, non-irritating, slightly bitter taste, good water solubility, and good compatibility with many organic components. It has excellent lubricity, moisture retention, dispersibility, and adhesiveness. It can be used as antistatic agent and softener. It is used in cosmetics, pharmaceuticals, chemical fibers, rubber, plastics, papermaking, paint, electroplating, pesticides, metal processing and food It is widely used in processing and other industries.

Chemical properties

The properties are different according to the relative molecular mass, from colorless, odorless viscous liquid to waxy solid. Those with a molecular weight of 200-600 are liquid at room temperature, and those with a molecular weight above 600 gradually become semi-solid. The properties vary with the average molecular weight. From colorless and odorless viscous liquid to waxy solid. As the molecular weight increases, its moisture absorption capacity decreases accordingly. This product is soluble in water, ethanol and many other organic solvents. Low vapor pressure, stable to heat, acid and alkali. Does not work with many chemicals. It has good hygroscopicity, lubricity and cohesiveness. Non-toxic and non-irritating. The average molecular weight is 300, n=5~5.75, the melting point is -15~8℃, and the relative density is 1.124~1.130. The average molecular weight is 600, n=12~13, the melting point is 20~25°C, the flash point is 246°C, and the relative density is 1.13 (20°C). The average molecular weight is 4000, n=70-85, and the melting point is 53-56°C. Under normal conditions, polyethylene glycol is very stable, but it can react with oxygen in the air at a temperature of 120°C or higher. In an inert atmosphere (such as nitrogen and carbon dioxide), it will not change even if it is heated to 200-240 ° C, and thermal cracking will occur when the temperature rises to 300 ° C. Adding antioxidants, such as phenothiazine with a mass fraction of 0.25% to 0.5%, can improve its chemical stability. Any of its decomposition products are volatile and do not form crusty or slimy precipitates. Polyethylene glycol is a polymer of ethylene oxide hydrolysis product, non-toxic, non-irritating, widely used in various pharmaceutical preparations. Low-molecular-weight polyethylene glycols are relatively more toxic. On the whole, the toxicity of glycols is quite low. Topical application of polyethylene glycol, especially mucosal administration, can cause irritating pain. In external lotion, this product can increase the flexibility of the skin and has a moisturizing effect similar to glycerin. Oral large doses can cause diarrhea. In injections, the maximum concentration of polyethylene glycol 300 is about 30% (V/V), and hemolysis may occur when the concentration is greater than 40% (V/V).

Fusogen

An excellent chemical fusogenic agent for protoplast fusion. It is a polymer of ethylene glycol, and its molecular formula is HOCH2(CH2O·CH2)nCH2OH. It is white yellowish waxy solid, soluble in water, with slight odor. There are a series of polymers with different relative molecular weights, those with a relative molecular weight between 200 and 6000 can be used as fusogenic agents, but those with a relative molecular weight of 1000 are better (in liquid state at this time). PEG has strong water solubility. In the liquid medium, the ether bond on the molecular surface has a weak negative charge. With the participation of Ca2+ ions, the positively charged surface protein or negatively charged glycoprotein can pass through the Ca2+ bridge. Connected, so that cells aggregate and fuse. In 50% PEG, free water disappears, which can lead to dehydration of cells, resulting in changes in plasma membrane structure and cell fusion. The advantages of PEG in cell fusion are: ① Strong versatility, it can be used in various cells of animals, plants and microorganisms. ②It is easier to prepare and control than Sendai virus. ③The activity is stable and easy to use. The disadvantages are: ①The effective concentration range is narrow (50%-55%), but it is more toxic to cells at this time. ② The process of cell fusion cannot be observed under a microscope. ③The frequency of induced hybrid cells is low (about 1×10-5). In addition to being used as a fusogenic agent, it can also be used to promote the uptake of exogenous transformed DNA by yeast, and can be used as a precipitant in clinical chemistry and an osmotic concentrate for aqueous solutions or suspensions such as serum.

Safety

In the Food Additive Supplement Regulations of the US Federal Food, Drug and Cosmetic Regulations, it has been approved to directly or indirectly use food chemical pharmacopoeia grade polyethylene glycol as a food additive. In 1985, FAO/WHO stipulated that the ADI value was 0-10 mg/kg body weight. GRAS (FDA, §172.820, 1985). Acute oral toxicity (mouse) LD5033 ~ 35g/kg, intraperitoneal toxicity LD5010 ~ 13g/kg. Does not irritate eyes, does not cause skin irritation and allergies.