Sucrose Stearate

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

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

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C₃₀H₅₆O₁₂ 608.76

C₄₈H₉₀O₁₃ 875.22 

C₆₆H₁₂₄O₁₄ 1141.68  

Sucrose monostearate; 

Sucrose octadecanoate CAS RN®: 25168-73-4.

1 DEFINITION 

Sucrose Stearate is a mixture of sucrose esters, mainly sucrose stearate, obtained by transesterication of stearic acid methyl esters derived from vegetable origin with sucrose. The manufacture of the fatty acid methyl esters includes a distillation step. The mono- and diesters requirements differ for the two types of sucrose stearate as set forth in the following table. 

2 IDENTIFICATION 

A. It meets the requirements of the Fatty Acid Composition test. 

B. It meets the requirements of Content of Monoesters, Diesters, Triesters, and Polyesters. 

3 ASSAY 

Content of Monoesters, Diesters, Triesters, and Polyesters 

Mobile phase: Tetrahydrofuran 

Sample solution: 15 mg/mL of Sucrose Stearate in tetrahydrofuran 

Chromatographic system 

(See Chromatography 〈621〉, System Suitability.) 

Mode: LC, size-exclusion 

Detector: Differential refractometer 

Column: 7-mm × 60-cm; packing L21, 100 Å. [Note—Two 7-mm × 30-cm L21 columns may be used in place of one 60-cm column, provided system suitability requirements are met.] 

Flow rate: 1.2 mL/min 

Injection size: 20 µL 

Analysis 

Sample: Sample solution 

[Note—The relative retention time with reference to the monoester peak (retention time is approximately 10 min) is about 0.92 for diesters, and about 0.90 for triesters and polyesters.] 

[Note—Disregard solvent peaks and peaks having a signal-to-noise ratio less than 10.] 

Calculate the percentage of monoesters in the portion of Sucrose Stearate taken: 

Result = A × (100 − D − S − E)/100 

A = percentage of monoesters determined by peak normalization 

D = percentage of free fatty acids, obtained by AV × 284.5/561.1, where AV is the acid value 

S = percentage of free sucrose (see Free Sucrose in Organic Impurities) 

E = percentage of water (see Water Determination, Ia in Specific Tests) 

AV = acid value 

Calculate the percentage of diesters in the portion of Sucrose Stearate taken: 

Result = B × (100 − D − S − E)/100 

B = percentage of diesters determined by peak normalization 

D = percentage of free fatty acids (above) 

S = percentage of free sucrose (see Free Sucrose in Organic Impurities) 

E = percentage of water (see Water Determination, Ia in Specific Tests) 

Calculate the percentage of triesters and polyesters in the portion of Sucrose Stearate taken: 

Result = C × (100 − D − S − E)/100 

C = percentage of triesters and polyesters determined by peak normalization 

D = percentage of free fatty acids (above) 

S = percentage of free sucrose (see Free Sucrose in Organic Impurities) 

E = percentage of water (see Water Determination, Ia in Specific Tests) 

Fatty Acid Composition: Sucrose Stearate exhibits the following composition proles of fatty acids, as determined in Fats and Fixed Oils 〈401〉, Fatty Acid Composition. 

IMPURITIES 

Inorganic Impurities 

Fats and Fixed Oils, Acid Value 〈401〉: NMT 6, determined on a 3-g sample. Use a freshly neutralized mixture of 2-propanol and water (2:1), and gently heat. 

Organic Impurities 

Procedure: Free Sucrose 

Solution A: 10 µg/mL of ammonium acetate in acetonitrile 

Solution B: 10 µg/mL of ammonium acetate in tetrahydrofuran and water (90:10) 

Diluent: Tetrahydrofuran and water (87.5:12.5) 

System suitability solution: 500 µg/mL of USP Sucrose RS in Diluent 

Standard solutions: 0.50, 1.0, 2.0, and 2.5 mg/mL of USP Sucrose RS in Diluent 

Sample solution: 50 mg/mL of Sucrose Stearate in Diluent 

Chromatographic system 

(See Chromatography 〈621〉, System Suitability.) 

Mode: LC 

Detector: Evaporative light-scattering. [Note—If the detector has different setting parameters, adjust the detector settings so as to comply with the System Suitability requirements.] 

Carrier gas: Nitrogen 

Detector temperature: 45° 

Nebulizer temperature: 40° 

Column: 4.6-mm × 0.25-m; packing L8 

Injection size: 20 µL 

Mobile phase and flow rate: See the gradient table below. 

System suitability 

Sample: System suitability solution 

[Note—The retention time for sucrose stearate is about 26 min.] 

Suitability requirements 

Signal-to-noise ratio: 10:1 

Analysis 

Samples: Standard solutions and Sample solution 

Prepare a standard curve by plotting the peak response versus concentration of sucrose in the Standard solution. Calculate the quantity of free sucrose in the Sucrose Stearate taken. 

Acceptance criteria: NMT 4.0% 

5 SPECIFIC TESTS 

Water Determination, Method Ia 〈921〉: NMT 4.0%, on a 0.20-g sample 

Total Ash 

Analysis: Heat a silica or platinum crucible to redness for 30 min, allow to cool in a desiccator, and weigh. Transfer a 1.0-g sample into a crucible. Dry at 100°–105° for 1 h and ignite to constant weight in a muffle furnace at 600 ± 25°, allowing the crucible to cool in a desiccator after each ignition. Flames should not be produced at any time during the procedure. If after prolonged ignition the ash still contains black particles, add hot water, pass through an ashless filter paper, and ignite the residue and the filter paper. Combine the filtrate with the ash, carefully evaporate to dryness, and ignite to constant weight. 

Acceptance criteria: NMT 1.5% 

6 ADDITIONAL REQUIREMENTS 

Labeling: Label to indicate whether it is Type I or Type II. 

Packaging and Storage: Preserve in a well-closed container. Protect from humidity and avoid high temperatures. 

USP Reference Standards 〈11〉 

USP Sucrose RS