Polysorbate 20

(pol'' ee sor' bate).

Sorbitan, monododecanoate, poly(oxy-1,2-ethanediyl) derivs.;
Polyoxyethylene 20 sorbitan monolaurate

[9005-64-5].

DEFINITION

Polysorbate 20 is a laurate ester of sorbitol and its anhydrides copolymerized with approximately 20 moles of ethylene oxide for each mole of sorbitol and sorbitol anhydrides.

IDENTIFICATION

• A.

Sample solution: 1 in 20, in water

Analysis: To 5 mL of the Sample solution add 5 mL of sodium hydroxide TS. Boil for a few min, cool, and acidify with 3 N hydrochloric acid.

Acceptance criteria: The solution is strongly opalescent.

• B.

Sample solution: 1 in 20, in water

Analysis: To 2 mL of the Sample solution add 0.5 mL of bromine TS, dropwise.

Acceptance criteria: The bromine is not decolorized (distinction from polysorbate 80).

IMPURITIES

• Residue on Ignition

281

: NMT 0.25%

• Heavy Metals, Method II

231

: NMT 10 ppm

SPECIFIC TESTS

• Acid Value

Sample: 10.0 of Polysorbate 20

Analysis: Transfer the Sample to a wide-mouth, 250-mL conical flask, and add 50 mL of neutralized alcohol. Heat on a steam bath nearly to boiling, shaking thoroughly occasionally while heating. Invert a beaker over the mouth of the flask, cool under running water, and add 5 drops of phenolphthalein TS. Titrate with 0.1 N sodium hydroxide VS.

Acceptance criteria: NMT 4 mL of 0.1 N sodium hydroxide, corresponding to an acid value of 2.2

• Fats and Fixed Oils, Hydroxyl Value

401

: 96–108

• Fats and Fixed Oils, Saponification Value

401

: 40–50

• Water Determination, Method I

921

: NMT 3.0%

ADDITIONAL REQUIREMENTS

• Packaging and Storage: Preserve in tight containers.

Auxiliary Information— Please check for your question in the FAQs before contacting USP.

Topic/Question	Contact	Expert Committee
Monograph	Robert H. Lafaver, M.S. Scientific Liaison 1-301-816-8335	(EXC2010) Monographs - Excipients

USP35–NF30 Page 1919

Pharmacopeial Forum: Volume No. 37(4)