Glyceryl Monooleate
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Oleic acid, 2,3-dihydroxypropyl ester, (±).
(RS)-1-Glyceryl oleateNF27 356.54 [25496-72-4].
» Glyceryl Monooleate is a mixture of monoglycerides, mainly glyceryl monooleate, together with variable quantities of diglycerides and triglycerides. It is obtained by partial glycerolysis of vegetable oil that consists mainly of triglycerides of oleic acid, or by esterification of glycerol with oleic acid of vegetable or animal origin. It is defined by the nominal content of monoglycerides, and the assay requirements differ as set forth in the accompanying table. A suitable antioxidant may be added.
Nominal Content of Monoglycerides (%)
40 60 90
Monoglycerides 32.0–52.0 55.0–65.0 90.0–101.0
Diglycerides 30.0–50.0 15.0–35.0 <10.0
Triglycerides 5.0–20.0 2.0–10.0 <2.0
Packaging and storage— Preserve in tight containers. No storage requirements specified.
Labeling— The labeling indicates the nominal content of monoglycerides and the name and the concentration of any added antioxidant.
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USP Reference standards 11
USP Glyceryl Monooleate 40% RS.

USP Glyceryl Monooleate 90% RS.
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A: Thin-Layer Chromatographic Identification Test 201
Standard solution: a solution of USP Glyceryl Monooleate 40% RS or USP Glyceryl Monooleate 90% RS in methylene chloride, containing 50 mg per mL.NF27
Test solution: a solution in methylene chloride containing about 50 mg per mL.
Developing solvent: a mixture of ether and hexane (70:30).
Spray reagent: a solution containing 20 mg of rhodamine B in 200 mL of alcohol.
Procedure— Proceed as directed in the chapter. Spray with the Spray reagent, and locate the spots on the plate by examination under UV light at a wavelength of 365 nm: the principal spot obtained from the Test solution corresponds in color, size, and RF value to that of the spot obtained from the Reference Standard used to prepare the Standard solution.NF27
B: It meets the requirements of the test for Iodine value.
Acid value 401: not more than 6.0, determined on 1.0 g.
Iodine value 401: between 65.0 and 95.0.
Peroxide value 401: not more than 12.0, determined on 2.0 g.
Change to read:
Saponification value 401: between 150 and 175,NF27 determined on 2.0 g.
Fatty acid composition 401 Glyceryl Monooleate exhibits the following composition profile of fatty acids, determined as directed in the chapter.
No. of
Double Bonds
16 0 not more than 12.0
18 0 not more than 6.0
18 1 not less than 60.0
18 2 not more than 35.0
18 3 not more than 2.0
20 0 not more than 2.0
20 1 not more than 2.0
Water, Method I 921: not more than 1.0%, using a mixture of methanol and methylene chloride (1:1, v/v) in place of methanol in the titration vessel.
Total ash 561: not more than 0.1%.
Limit of free glycerin—
Mobile phase and Chromatographic system— Proceed as directed in the Assay.
Standard solutions— Prepare four solutions by dissolving accurately weighed quantities of glycerin in tetrahydrofuran, and diluting each with tetrahydrofuran, as necessary, to obtain solutions having known concentrations of about 0.4, 1.0, 2.0, and 4.0 mg per mL.
Test solution— Use the Assay preparation, prepared as directed in the Assay.
Procedure— Separately inject equal volumes (about 40 µL) of the Standard solutions and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the glycerin peaks. Plot the glycerin peak responses obtained versus the concentration, in mg per mL, of glycerin in the Standard solutions. From the standard curve so obtained, determine the glycerin concentration, C, in mg per mL, in the Test solution. Calculate the percentage of free glycerin in the portion of Glyceryl Monooleate taken by the formula:
in which C is as obtained above; and W is the amount, in mg, of Glyceryl Monooleate taken to prepare the Test solution: not more than 6.0% of free glycerin is found.
Mobile phase: tetrahydrofuran.
Assay preparation— Transfer about 200 mg of Glyceryl Monooleate, accurately weighed, to a 5-mL volumetric flask, dissolve in and dilute with tetrahydrofuran to volume, and mix.
Chromatographic system (see Chromatography 621) Prepare as directed in the Assay under Glyceryl Distearate. Chromatograph the Assay preparation, and record the peak responses as directed for Procedure: the relative retention times are about 1.0 for glycerin, 0.85 for monoglycerides, 0.79 for diglycerides, and 0.76 for triglycerides; the resolution, R, between the diglycerides and monoglycerides is not less than 1.0; and the relative standard deviation for replicate injections determined from the monoglycerides peak is not more than 2.0%.
Procedure— Inject a volume (about 40 µL) of the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the percentage of monoglycerides, diglycerides, and triglycerides in the portion of Glyceryl Monooleate taken by the formula:
100(ri / rs)
in which ri is the individual peak response for the monoglycerides, diglycerides, and triglycerides, as appropriate; and rs is the sum of the responses for all of the glyceride peaks.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Robert H. Lafaver, B.A.
(EM105) Excipient Monographs 1
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 1246
Pharmacopeial Forum: Volume No. 33(6) Page 1249