Stearoyl Polyoxylglycerides

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

DOWNLOAD PDF HERE

1 DEFINITION

Stearoyl Polyoxylglycerides is a mixture of monoesters, diesters, and triesters of Glycerol and monoesters and diesters of polyethylene glycols. The polyethylene glycols used have a mean molecular weight between 300 and 4000. It is produced by partial alcoholysis of saturated oils, mainly containing triglycerides of stearic acid, with polyethylene glycol, by esterification of glycerol and polyethylene glycol with fatty acids, or as a mixture of glycerol esters and ethylene oxide condensate with the fatty acids of the hydrogenated oils. The hydroxyl value is NLT 85% and NMT 115% of the labeled nominal value, and the saponification value is NLT 90% and NMT 110% of the labeled nominal value. Stearoyl

Polyoxylglycerides may contain free polyethylene glycols.

2 IDENTIFICATION

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K

B. Thin-Layer Chromatographic Identification Test 〈201〉

Standard solution: 50 mg/mL of USP Stearoyl Polyoxylglycerides RS in methylene chloride

Sample solution: 50 mg/mL of Stearoyl Polyoxylglycerides in methylene chloride

Chromatographic system

Application volume: 10 μL

Developing solvent system: Ether and hexanes (70:30)

Spray reagent: 0.1 mg/mL of rhodamine B in alcohol

Analysis

Samples: Standard solution and Sample solution

Proceed as directed in the chapter. Then spray the plate with Spray reagent, and locate the spots on the plate by examination under UV light at a wavelength of 365 nm.

Acceptance criteria: The R values of the principal spots of the Sample solution correspond to those of the Standard solution.

C. It meets the requirements in Specific Tests (see Table 1) for Fats and Fixed Oils 〈401〉, Procedures, Fatty Acid Composition.

3 IMPURITIES

Articles of Botanical Origin 〈561〉, Methods of Analysis, Total Ash: NMT 0.2%

Alkaline Impurities

Sample: 5.0 g

Analysis: Heat the Sample slightly until the test substance melts, add 10 mL of alcohol and 0.05 mL of bromophenol blue TS, and mix well.

While the solution is still warm, titrate with 0.01 N hydrochloric acid VS to change the color to yellow.

Acceptance criteria: NMT 1.0 mL of 0.01 N hydrochloric acid VS is required.

Limit of Free Ethylene Oxide and Dioxane

Analysis: Proceed as directed in Ethylene Oxide and Dioxane 〈228〉, Method I.

Acceptance criteria

Ethylene oxide: NMT 1 μg/g

Dioxane: NMT 10 μg/g

Limit of Free Glycerol

Sample: 1.20 g

Periodic acetic acid solution: Dissolve 0.446 g of sodium periodate in 2.5 mL of a 25% (v/v) solution of sulfuric acid, diluting with glacial acetic acid to 100.0 mL.

Potassium iodide solution: 75 mg/mL of potassium iodide

Analysis: Dissolve the Sample in 25 mL of methylene chloride, heating if necessary. Cool, and add 100 mL of water and 25.0 mL of the

Periodic acetic acid solution. Shake, and allow to stand for 30 min. Add 40 mL of the Potassium iodide solution, and allow to stand for 1 min.

Add 1 mL of starch TS, and titrate the liberated iodine with 0.1 M sodium thiosulfate VS. Perform a blank determination, and make any necessary correction (see Titrimetry 〈541〉). Calculate the percentage of glycerol in the sample taken:

Result = {[(V_B − V_S) × N × F]/W} × 100

V_B = Titrant volume consumed by the Blank (mL)

V_S = Titrant volume consumed by the Sample (mL)

N = actual normality of the Titrant (mEq/mL)

F = equivalency factor, 23.0 mg/mEq

W = Sample weight (mg)

Acceptance criteria: NMT 5.0%

4 SPECIFIC TESTS

Fats and Fixed Oils 〈401〉, Procedures, Acid Value

Sample: 2.0 g

Acceptance criteria: NMT 2.0

Change to read:

Fats and Fixed Oils 〈401〉, Procedures, Fatty Acid Composition: Stearoyl Polyoxylglycerides exhibits the following composition profile of fatty acids, as determined in the chapter (see Table 1).

Table 1

Fats and Fixed Oils 〈401〉, Procedures, Hydroxyl Value

Sample: 1.0 g

Acceptance criteria: 25–56, 85%–115% of the labeled nominal value

Fats and Fixed Oils 〈401〉, Procedures, Iodine Value: NMT 2.0

Fats and Fixed Oils 〈401〉, Procedures, Peroxide Value

Sample: 2.0 g

Acceptance criteria: NMT 6.0

Fats and Fixed Oils 〈401〉, Procedures, Saponification Value

Sample: 2.0 g

Acceptance criteria: 67–112, 90%–110% of the labeled nominal value

Water Determination 〈921〉, Method I

Sample: 1.0 g

Solvent: Anhydrous pyridine or a mixture of methylene chloride and anhydrous methanol (70:30)

Acceptance criteria: NMT 1.0%

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers, protected from light and moisture. Store at controlled room temperature.

Labeling: Label it to indicate the type and the average nominal molecular weight of polyethylene glycols used as part of the oficial title. The label also indicates the hydroxyl value and the saponification value.

USP Reference Standards 〈11〉

USP Stearoyl Polyoxylglycerides RS