Polyoxyl Lauryl Ether
(pol'' ee ox' il lawr' il ee' ther).

CH3(CH2)11(OCH2CH2)nOH, n = 3–23
Polyethylene glycol monolauryl ether     [9002-92-0].
Polyoxyl Lauryl Ether is a mixture of the monolauryl ethers of mixed polyethylene glycols, the average polymer length being equivalent to NLT 3 and NMT 23 oxyethylene units (nominal value). It contains various amounts of free lauryl alcohol, and it may contain some free polyethylene glycols.
•  A. Infrared Absorption 197F
Sample:  Use a thin film of melted Polyoxyl Lauryl Ether if the material is a solid.
Acceptance criteria:  Meets the requirements
•  B. Procedure
Sample:  0.1 g
Analysis:  Dissolve or disperse the Sample in 5 mL of alcohol, and add 10 mL of diluted hydrochloric acid, 5 mL of barium chloride TS, and 10 mL of phosphomolybdic acid solution (1 in 10).
Acceptance criteria:  A precipitate is formed.
•  C. It meets the requirements of the test for Fats and Fixed Oil, Hydroxyl Values 401.
Organic Impurities 
•  Procedure: Limit of Free Ethylene Oxide and Dioxane
Analysis:  Proceed as directed in Ethylene Oxide and Dioxane, Method I 228.
Acceptance criteria 
Ethylene oxide:  NMT 1 µg/g (ppm)
Dioxane:  NMT 10 µg/g (ppm)
•  Alkalinity
Sample:  2.0 g of Polyoxyl Lauryl Ether
Analysis:  Dissolve the Sample in a hot mixture of 10 mL of alcohol and 10 mL of water. Add 0.05 mL of bromothymol blue TS, and titrate with 0.1 N hydrochloric acid to a yellow endpoint.
Acceptance criteria:  NMT 0.5 mL of 0.1 N hydrochloric acid is required.
•  Appearance of Solution: 5.0 g of Polyoxyl Lauryl Ether in 50.0 mL of alcohol. The solution is not more intensely colored than a solution prepared immediately before use by mixing 12.0 mL of ferric chloride CS, 5.0 mL of cobaltous chloride CS, and 2.0 mL of cupric sulfate CS with dilute hydrochloric acid (10 g/L) to make 50.0 mL, and diluting 12.5 mL of this solution with dilute hydrochloric acid (10 g/L) to make 100.0 mL. Make the comparison by viewing the substance and the solution downward in matched color-comparison tubes against a white surface (see Color and Achromicity 631).
•  Articles of Botanical Origin, Total Ash 561: NMT 0.2%, determined on 2.0 g
•  Fats and Fixed Oils, Acid Value 401: NMT 1.0, determined on 5.0 g
•  Fats and Fixed Oils, Hydroxyl Value 401: Within the ranges specified in the accompanying table
(Nominal Value)
Hydroxyl Value
3 165–185
4 145–165
5 130–140
9 90–100
10 85–95
12 73–83
15 64–74
20–23 40–60
•  Fats and Fixed Oils, Saponification Value 401: NMT 3.0, determined on 10.0 g
•  Packaging and Storage: Preserve in tight containers, and store in a cool, dry place.
•  Labeling: Label it to indicate the average nominal number of oxyethylene units.
•  USP Reference Standards 11
USP Polyoxyl 4 Lauryl Ether RS
USP Polyoxyl 9 Lauryl Ether RS
USP Polyoxyl 23 Lauryl Ether RS
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
Reference Standards RS Technical Services
USP35–NF30 Page 1917
Pharmacopeial Forum: Volume No. 36(4) Page 949