Sesame Oil

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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1 DEFINITION

Sesame Oil is the refined fixed oil obtained from the seed of one or more cultivated varieties of Sesamum indicum L. (Fam. Pedaliaceae). It may contain suitable antioxidants.

2 IDENTIFICATION

A. Identity by Triglyceride Profile

Analysis:

Proceed as directed in the test for Triglyceride Composition.

Acceptance criteria:

The peak responses of the eight major triglycerides—LLL, OLL, PLL, OOL, POL, OOO, SOL, and POO—elute between 0 and about 40 min, in the order specified, and at relative retention times of about 0.55, 0.65, 0.69, 0.77, 0.82, 0.93, 0.97, and 1.0, respectively, as obtained in the Sample solution in the test for Triglyceride Composition.

3 ASSAY

Triglyceride Composition

[Note—The fatty acid radicals are designated as linoleic (L), oleic (O), palmitic (P), and stearic (S), and the common abbreviations for triglycerides used are as follows: trilinolein (LLL), 1,2-dilinoleoyl-3-oleoyl-rac-glycerol (OLL), 1,2-dilinoleoyl-3-palmitoyl-rac-glycerol (PLL), 1,2-dioleoyl-3-linoleoyl-rac-glycerol (OOL), 1-palmitoyl-2-oleoyl-3-linoleoyl-rac-glycerol (POL), triolein (OOO), 1-linoleoyl-2-oleoyl-3-stearoyl-rac-glycerol (SOL), and 1,2-dioleoyl-3-palmitoyl-rac-glycerol (POO).]

Mobile phase:

Acetonitrile and methylene chloride (60:40)

System suitability solution:

3.0 mg/mL each of USP Sesame Oil Related Compound A RS and USP Sesame Oil Related Compound B RS in Mobile phase.

[Note—USP Sesame Oil Related Compound A RS is OLL, and USP Sesame Oil Related Compound B RS is PLL.]

Sample solution:

20 mg/mL of Sesame Oil in Mobile phase

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: Refractive index

Columns: Two 4.6-mm × 25-cm in series; packings L1

Column temperature: 30°

Flow rate: 1.0 mL/min

Injection volume: 20 µL

System suitability

Sample: System suitability solution

[Note—The relative retention times for OLL and PLL are about 0.93 and 1.0, respectively.]

Suitability requirements:

Resolution: NLT 1.8 between OLL and PLL

Relative standard deviation: NMT 1.5% determined from peak areas; NMT 2.2% determined from the peak area ratio of OLL to PLL

Analysis

[Note—The relative retention times for the eight major triglyceride peaks are listed in Table 1.]

Sample: Sample solution

Calculate the percentage of each of these triglycerides in the portion of the Sample taken:

Result = (A/B) × 100

A = peak area of each individual triglyceride

B = sum of the areas of all the peaks, excluding the solvent peak.

4 IMPURITIES

Alkaline Impurities

Sample: 10 mL of Sesame Oil

Analysis:

Mix 10 mL of freshly opened acetone and 0.3 mL of water, and add 0.05 mL of bromophenol blue TS. Add the Sample, shake, and allow to stand. Titrate with 0.01 N hydrochloric acid VS to change the color of the upper layer to yellow.

Acceptance criteria:

NMT 0.1 mL of 0.01 N hydrochloric acid is required.

5 SPECIFIC TESTS

Specific Gravity 〈841〉: 0.912–0.921

Fats and Fixed Oils 〈401〉, Acid Value (Free Fatty Acids)

Sample: 10 g

Acceptance criteria: NMT 2.0 mL of 0.020 N sodium hydroxide is required for neutralization.

Fats and Fixed Oils 〈401〉, Iodine Value: 103–116

Fats and Fixed Oils 〈401〉, Saponification Value: 188–195

Fats and Fixed Oils 〈401〉, Solidification Temperature of Fatty Acids: 20°–25°

Fats and Fixed Oils, Peroxide Value 〈401〉: NMT 10.0

Fats and Fixed Oils 〈401〉, Unsaponifiable Matter: NMT 1.5%

Cottonseed Oil

Sample: 5 mL

Analysis:

Mix the Sample in a test tube with 5 mL of a mixture of equal volumes of amyl alcohol and a 10-mg/mL solution of sulfur in carbon disulfide. Warm the mixture carefully until the carbon disulfide is expelled, and immerse the tube to one-third of its depth in a boiling saturated solution of sodium chloride.

Acceptance criteria:

No reddish color develops within 15 min.

Water Determination, Method Ic 〈921〉: NMT 0.1%

6 ADDITIONAL REQUIREMENTS

Packaging and Storage:

Preserve in tight, light-resistant containers, and prevent exposure to excessive heat.

Labeling:

Label it to indicate the name and quantity of any added antioxidant. Where Sesame Oil is intended for use in the manufacture of injectable dosage forms, it is so labeled.

Other Requirements:

For Sesame Oil intended for use in injectable dosage forms, which is specified in the labeling, the requirements must be met for Unsaponifiable Matter, Acid Value, Peroxide Value, and Water, Method Ic, under Specific Tests in Injections and Implanted Drug Products 〈1〉, Vehicles and added substances, Nonaqueous vehicles.

USP Reference Standards 〈11〉

USP Sesame Oil Related Compound A RS

USP Sesame Oil Related Compound B RS