Oxybenzone

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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C₁₄H₁₂O₃ 228.24

Methanone, (2-hydroxy-4-methoxyphenyl)phenyl-;

2-Hydroxy-4-methoxybenzophenone CAS RN^®: 131-57-7; UNII: 95OOS7VE0Y.

1 DEFINITION

Oxybenzone contains NLT 97.0% and NMT 103.0% of oxybenzone (C₁₄H₁₂O₃), calculated on the dried basis.

2 IDENTIFICATION

Change to read:

A. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197K (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

Mobile phase: Methanol and water (70:30)

Standard solution: 0.1 mg/mL of USP Oxybenzone RS in Mobile phase. Sonicate if necessary to dissolve.

Sample solution: 0.1 mg/mL of Oxybenzone in Mobile phase. Sonicate if necessary to dissolve.

3.2 Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 289 nm

Column: 4.6-mm x 7.5-cm; 3.5-µm packing L1

Flow rate: 1 mL/min

Injection volume: 20 µL

3.3 System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 1.5

Relative standard deviation: NMT 0.73%

3.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of oxybenzone (C₁₄H₁₂O₃) in the portion of Oxybenzone taken:

Result = (r_U/r_S) x (C_S/C_U) x 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

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

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

Acceptance criteria: 97.0%-103.0% on the dried basis

4 SPECIFIC TESTS

4.1 CONGEALING TEMPERATURE (651)

NLT 62.0°

4.2 LOSS ON DRYING (731)

Analysis: Dry a sample in a vacuum at 40° for 2 h.

Acceptance criteria: NMT 2.0%

5 ADDITIONAL REQUIREMENTS

5.1 PACKAGING AND STORAGE

Preserve in tight, light-resistant containers.

5.2 USP REFERENCE STANDARDS (11)

USP Oxybenzone RS