Octisalate

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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C₁₅H₂₂O₃ 250.33

Benzoic acid, 2-hydroxy-, 2-ethylhexyl ester;

2-Ethylhexyl salicylate

CAS RN^®: 118-60-5; UNII: 4X49Y0596W

1 DEFINITION

Octisalate contains NLT 95.0% and NMT 105.0% of octisalate (C₁₅H₂₂O₃), calculated on the as-is basis.

2 IDENTIFICATION

Change to read:

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197A or 197F (CN 1-May-2020)

B. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

3.1 Procedure

Standard solution: 20 mg/mL of USP Octisalate RS in tert-butyl methyl ether

Sample solution: 20 mg/mL of Octisalate in tert-butyl methyl ether

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: GC

Detector: Flame ionization

Column: 0.32-mm × 25-m; coated with a 0.1-µm film of phase G1

Temperatures

Injector: 240°

Detector: 260°

Column: See Table 1.

Table 1

Carrier gas: Helium

Flow rate: 6 mL/min

Injection volume: 1 µL

Injection type: Split; split ratio 50:1.

[Note—Split ratio can be modified to optimize the performance.]

System suitability

Sample: Standard solution

Suitability requirements

Resolution: NLT 1.0 between octisalate and any other peak

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of octisalate (C₁₅H₂₂O₃) in the portion of Octisalate taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

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

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

Acceptance criteria: 95.0%–105.0% on the as-is basis

4 IMPURITIES

4.1 Organic Impurities

Standard solution, Sample solution, Chromatographic system, and System suitability: Proceed as directed in the Assay.

Analysis

Sample: Sample solution

Calculate the percentage of each impurity in the portion of Octisalate taken:

Result = (r_U/r_T) × 100

r_U = peak response of each impurity from the Sample solution

r_T = sum of all the peak responses from the Sample solution

Acceptance criteria

Individual impurities: NMT 0.5%

Total impurities: NMT 2.0%

5 SPECIFIC TESTS

Specific Gravity 〈841〉: 1.011–1.016

Refractive Index 〈831〉: 1.500–1.503 at 20°

Acidity

Sample solution: 5.0 mL of measured Octisalate

Titrimetric system

Mode: Direct titration

Titrant: 0.1 N sodium hydroxide

Endpoint detection: Visual

Analysis: Transfer 50 mL of alcohol to a suitable container, add 1 mL of phenol red TS, and add sufficient Titrant to obtain a persistent pink color. Transfer 50 mL of this solution to a suitable container, add the Sample solution, mix, and titrate with Titrant.

Acceptance criteria: NMT 0.2 mL of 0.1 N sodium hydroxide per milliliter of Octisalate is required for neutralization.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers.

USP Reference Standards 〈11〉

USP Octisalate RS