Polysorbate 20

• BPPolysorbate 20
• Ph. Eur.Polysorbate 20
• USP–NFPolysorbate 20

Crillet 1; polyoxyethylene 20 sorbitan monolaurate; polysorbatum 20; PEG-20 sorbitan monolaurate; Tween 20; E432

Polyoxyethylene 20 sorbitan monolaurate · [9005-64-5]

C58H114O26 (approximate) · ≈ 1 128

Surfactant, emulsifier

Typical concentrations: — · Dosage forms: Liquid, Semi-solid, Sterile (parenteral/ophthalmic)

A hydrophilic nonionic surfactant used as an emulsifier, solubiliser, wetting agent and dispersant in oral, topical and parenteral products, and widely used at low levels (typically about 0.001–0.1% w/v) to protect therapeutic proteins and monoclonal antibodies from aggregation and surface adsorption. Typical concentrations: emulsifying agent used alone in oil-in-water emulsions 1–15%, or 1–10% when combined with lipophilic emulsifiers; solubilising agent for poorly soluble drugs in aqueous vehicles 1–10%; wetting agent for insoluble solids 0.1–3%.

A mixture of partial lauric acid esters of sorbitol and its anhydrides copolymerised with about 20 moles of ethylene oxide per mole of sorbitol. Lauric acid is the main fatty acid, with smaller amounts of other saturated acids. It is a yellow, oily liquid.

Physical form

yellow to yellowish-green, oily liquid at 25 °C with a characteristic odour and a bitter taste

HLB

about 16.7

Saponification value

about 40–50

Density

about 1.1 g/cm³

Solubility

soluble in water, ethanol and ethyl acetate; practically insoluble in fatty oils and liquid paraffin

Polysorbates are stable to electrolytes and weak acids and bases; strong acids and bases cause gradual saponification. The oleic-acid esters in particular are susceptible to autoxidation, forming peroxides and degrading on exposure to light, heat and metal ions. They are hygroscopic and should be stored in a well-closed, well-filled container, protected from light, in a cool, dry place; nitrogen blanketing helps limit oxidation.

Discoloration or precipitation occurs with various substances, especially phenols, tannins and tars. They reduce the antimicrobial activity of many preservatives, particularly parabens, by micellar binding, and peroxide impurities can oxidise sensitive drugs and proteins.

Prepared by esterifying sorbitol and its anhydrides (mainly sorbitan) with lauric acid and then reacting the product with about 20 moles of ethylene oxide per mole of sorbitol.

Polysorbates are widely used in oral, topical and parenteral products and are generally regarded as non-toxic and non-irritant, although hypersensitivity reactions have occasionally been reported, mainly after injection. JECFA and EFSA have set a group ADI of 25 mg/kg body weight per day for polysorbates 20, 40, 60, 65 and 80.

Observe normal precautions for the quantity handled. Eye protection and gloves are recommended.

Accepted as a food additive in Europe (E432). Included in the FDA Inactive Ingredient Database (injections; nasal, oral, otic and topical preparations) and in parenteral and non-parenteral medicines licensed in Europe.

Polysorbate 40; polysorbate 60; polysorbate 80; sorbitan esters.

Because it is based on a saturated fatty acid, polysorbate 20 is somewhat less prone to autoxidation than polysorbate 80, but both can contain peroxides and are hydrolysed by residual enzymes (lipases) in biological products, releasing free fatty acids that may form visible particles. Low-peroxide grades should be chosen for protein formulations.