The difference between Tween 20 and Tween 80 Tween is also called Tween-type emulsifier. It is a condensate of Span (sorbitol fatty acid ester) and ethylene oxide. It is a kind of non-ionic detergent. Chemical name: polyoxyethylene sorbitan fatty acid ester, abbreviated polysorbate. Since the Span is an ester formed from sorbitol and different higher fatty acids, Twain is actually a series of products of the same type. There are 20, 40, 60, 80 kinds of products in general fine chemical stores or chemical reagent companies, depending on the Need to choose. Tween-60 is stearate; Tween-80 is oleate; Tween-20 is laurate, is polyoxyethylene sorbitan monolaurate and part of polyoxyethylene sorbitan monohydrate. A mixture of laurate. 1. Tween 20 Alias: polyoxyethylene sorbitan fatty acid ester; Tween-20; Properties: This product is a yellow or amber clear oily liquid, with a special odor and weak bitter taste. Relative density 1.01, boiling point 321 °C, flash point 321 °C, refractive index 1.472, viscosity (25 °C) 0.25 ~ 0.40Pa / s. The molecule contains more hydrophilic groups and is miscible with water, ethanol, methanol and ethyl acetate. It is insoluble in liquid paraffin, fixed oil and light petroleum. It is soluble in 130 parts of cottonseed oil and 200 parts. In toluene, 5% aqueous solution pH5~7.HLB value was 16.7. Function and purpose: Polysorbate is a large class of non-ionic surfactants, with emulsification, diffusion, solubilization, stability and other effects. In the pharmaceutical, daily chemical, food, textile and other industries, widely used as emulsifiers, dispersants, solubilizers, stabilizers and so on. As an emulsifier with high concentration of electrolyte and pH value has little effect on its emulsifying ability, it is a large class of excellent oil/water emulsifiers. When the oil/water emulsifier is prepared, it is often used in combination with sorbitan esters, and the stability of the emulsion is better. By changing the type and amount of emulsifier used in combination with it, water/oil type or oil/water can be prepared 2. Tween 80 is a hydrophilic surfactant with a strong cell membrane disruption that causes irritating, hemolytic and histamine release (sensitization). The purity of Tween 80 as a polymer itself fluctuates greatly. High-purity Tween 80 is colorless and transparent, while most Tween products are yellow to brown, containing large amounts of impurities or degradation products. Tween 80 lipophilic components include unsaturated fatty acids, these unsaturated fatty acids are easily oxidative degradation and produce more toxic components, and the resulting toxic side effects will exceed the benefits of the product itself. The medical community has confirmed that Tween 80 is used in injections and can cause allergic reactions including shock, dyspnea, hypotension, angioedema, rubella and other allergic-like symptoms. These adverse reactions can be very serious in human clinical trials. There are deaths reported. Therefore, there are severe restrictions on the use of Tween 80. It is a potentially insecure excipient. Improper use can have a major impact on human health.