Polysorbate 65 (Polyoxyethylene sorbitan tristearate) is a chemical compound produced by the reaction of lauric acid, ethylene oxide and sorbitol through ethoxylation of sorbitan monolaurate. Polysorbate is a sugar alcohol, sorbitol, which is transformed into sorbitan by a dehydration process and then passes through ethoxylation before lauric acid is added. The number 65 indicates the molecule with 65 repeated polyethylene glycol units.
It appears as a white powder or as a stable yellowish viscous liquid. Incompatible with strong oxidising agents. Soluble in water, ethanol, methanol, carbinol, isopropanol, isopropyl alcohol and other solvents, insoluble in mineral oil.
What it is used for and where
Chemical auxiliary agent, chemical intermediate, hydrophilic and non-ionic surfactant. Generally regarded as a fatty acid ethoxylated sorbitan ester.
Food
Ingredient included in the list of European food additives as E436 with an emulsifying function.
Cosmetics
Surfactant - Emulsifying agent. Emulsions are thermodynamically unstable and are used to soothe or soften the skin and emulsify, so they need a specific, stabilising ingredient. This ingredient forms a film, lowers the surface tension and makes two immiscible liquids miscible. A very important factor affecting the stability of the emulsion is the amount of the emulsifying agent. Emulsifiers have the property of reducing the oil/water or water/oil interfacial tension, improving the stability of the emulsion and also directly influencing the stability, sensory properties and surface tension of sunscreens by modulating the filmometric performance.
Surfactant - Cleansing agent. Cosmetic products used to cleanse the skin utilise the surface-active action that produces a lowering of the surface tension of the stratum corneum, facilitating the removal of dirt and impurities.
Safety
The Joint Food and Agriculture Organization of the United Nations (FAO)/World Health Organization (WHO)Expert Committee on Food Additives (JECFA)derived an Acceptable Daily Intake (ADI) of 25mg/kg body weight (bw)/day (group ADI for polysorbates 20, 40, 60, 65 and 80) and the Scientific Committee on Food (SCF) derived a group ADI of 10mg/kg bw/day. Small amounts of polyoxyethylene sorbitansare absorbed. Similar toxicokinetics would be expected for all polysorbates based on their similarities in structure and metabolic fate. The acute toxicity is very low. There is no concern regarding genotoxicity, carcinogenicity or developmental toxicity. From a limited number of studies,there is no indication of reproductive toxicity. The Panel recommended that the maximum limits for the impurities of toxic elements (arsenic, lead, cadmium and mercury) in the EC specification for polysorbates (E432–E436) should be revised in order to ascertain that polysorbates (E432–E436) as food additives will not be a significant source of exposure to those toxic elements in food (1).
- Molecular Formula C65H124O20
- Molecular Weight
- CAS 9005-71-4
- UNII
- EC Number
- MFCD00165348
- RTECS WG2934600
References____________________________________________________________________
(1) EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS), 2015. Scientific Opinion on the re‐evaluation of polyoxyethylene sorbitan monolaurate (E 432), polyoxyethylene sorbitan monooleate (E 433), polyoxyethylene sorbitan monopalmitate (E 434), polyoxyethylene sorbitan monostearate (E 435) and polyoxyethylene sorbitan tristearate (E 436) as food additives. Efsa Journal, 13(7), p.4152.
Polysorbate 65 
