Polysorbate 40
(pol'' ee sor' bate).

Sorbitan, monohexadecanoate, poly(oxy-1,2-ethanediyl) derivs.
Polyoxyethylene 20 sorbitan monopalmitate. Compound usually contains also associated fatty acids [9005-66-7].
» Polysorbate 40 is a palmitate ester of sorbitol and its anhydrides copolymerized with approximately 20 moles of ethylene oxide for each mole of sorbitol and sorbitol anhydrides.
Packaging and storage— Preserve in tight containers.
A: To 5 mL of a solution (1 in 20) add 5 mL of sodium hydroxide TS. Boil for a few minutes, cool, and acidify with 3 N hydrochloric acid: the solution is strongly opalescent.
B: To 2 mL of a solution (1 in 20) add 0.5 mL of bromine TS, dropwise: the bromine is not decolorized (distinction from Polysorbate 80).
C: A mixture of 60 volumes of it and 40 volumes of water yields a gelatinous mass at normal and lower than normal room temperatures.
Hydroxyl value 401: between 89 and 105.
Saponification value 401: between 41 and 52.
Acid value— Weigh 10.0 g into 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, add 5 drops of phenolphthalein TS, and titrate with 0.1 N sodium hydroxide VS: not more than 4 mL of 0.100 N sodium hydroxide is required, corresponding to an acid value of 2.2.
Water, Method I 921: not more than 3.0%.
Residue on ignition 281: not more than 0.25%.
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
(EXC2010) Monographs - Excipients
USP35–NF30 Page 1919
Pharmacopeial Forum: Volume No. 37(4)