Squalane

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

Squalane is a saturated hydrocarbon that contains NLT 97.0% and NMT 102.0% of 2,6,10,15,19,23-hexamethyltetracosane (C H ). It is obtained either by hydrogenation of squalene, an aliphatic triterpene derived from certain fish oils, particularly shark liver oil, or from β- farnesene, a fermentation product of plant sugars.

2 IDENTIFICATION

Change to read:

A. SPECTROSCOPIC IDENTIFICATION TESTS 〈197〉 , Infrared Spectroscopy: 197F (CN 1-M  -2020)

Sample: Undried specimen

Acceptance criteria: Meets the requirements

B. CHROMATOGRAPHIC IDENTITY

Analysis: Proceed as directed in the Assay.

Acceptance criteria: The retention time of the major peak of the Sample solution, excluding the solvent peak, corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

PROCEDURE

Diluent: n-Heptane

System suitability solution: 4 mg/mL of USP Squalane RS and 4 µL/mL of methyl erucate in Diluent Standard solution: 4 mg/mL of USP Squalane RS in Diluent

Sample solution: 4 mg/mL of Squalane in Diluent

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: GC

Detector: Flame ionization

Column: 0.32-mm × 30-m fused silica capillary; coated with a 1-µm film of phase G2

Temperatures

Injection port: 275°

Detector: 300° Column: See Table 1.

Table 1

Carrier gas: Helium Flow rate: 1.7 mL/min

Injection volume: 1 µL

Injection type: Split; split ratio, 12:1

Liner: General purpose split/splitless liner with deactivated wool

System suitability

Samples: System suitability solution and Standard solution

[NOTE—The relative retention times for methyl erucate and squalane are 0.9 and 1.0, respectively.]

Suitability requirements

Resolution: NLT 5 between the peaks due to methyl erucate and squalane, System suitability solution

Relative standard deviation: NMT 2%, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of squalane (C H ) in the portion of Squalane taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak area from the Sample solution

r_S = peak area from the Standard solution

C_S = concentration of USP Squalane RS in the Standard solution (mg/mL)

C_U = concentration of Squalane in the Sample solution (mg/mL)

Acceptance criteria: 97.0%–102.0%

4 IMPURITIES

RESIDUE ON IGNITION 〈281〉: NMT 0.5%

5 SPECIFIC TESTS

SPECIFIC GRAVITY 〈841〉: 0.807–0.810 at 20°

FATS AND FIXED OILS 〈401〉 , Procedures, Acid Value: NMT 0.2

FATS AND FIXED OILS, Iodine Value 〈401〉: NMT 4

FATS AND FIXED OILS, Saponification Value 〈401〉: NMT 2

REFRACTIVE INDEX 〈831〉: 1.4510–1.4525 at 20°

6 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight containers.

LABELING: Label to indicate whether it is derived from animal or plant sources.

USP REFERENCE STANDARDS 〈11〉

USP Squalane RS