Dioxybenzone
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This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition
Issued and maintained by the United States Pharmacopeial Convention (USP)
C₁₄H₁₂O₄ 244.24
Methanone, (2-hydroxy-4-methoxyphenyl)(2-hydroxyphenyl)-;
2,2'-Dihydroxy-4-methoxybenzophenone CAS RN®: 131-53-3; UNII: B762XZ551X.
1 DEFINITION
Dioxybenzone contains NLT 97.0% and NMT 103.0% of dioxybenzone (C₁₄H₁₂O₄), calculated on the dried basis.
2 IDENTIFICATION
Change to read:
A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K
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 (60:40)
Standard solution: 0.1 mg/mL of USP Dioxybenzone RS in Mobile phase. Sonicate if necessary to dissolve.
Sample solution: 0.1 mg/mL of Dioxybenzone in Mobile phase. Sonicate if necessary to dissolve.
Chromatographic system
- (See Chromatography 〈621〉, System Suitability.)
- Mode: LC
- Detector: UV 286 nm
- Column: 4.6-mm × 7.5-cm; 3.5-µm packing L1
- Flow rate: 1 mL/min
- Injection volume: 20 µL
System suitability
- Sample: Standard solution
- Suitability requirements
- Tailing factor: NMT 1.5
- Relative standard deviation: NMT 0.73%
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of dioxybenzone (C₁₄H₁₂O₄) in the portion of Dioxybenzone taken:
Result = (rᵤ/rₛ) × (Cₛ/Cᵤ) × 100
rᵤ = peak response from the Sample solution
rₛ = peak response from the Standard solution
Cₛ = concentration of USP Dioxybenzone RS in the Standard solution (mg/mL)
Cᵤ = concentration of Dioxybenzone in the Sample solution (mg/mL)
Acceptance criteria: 97.0%–103.0% on the dried basis
4 SPECIFIC TESTS
Congealing Temperature 〈651〉: NLT 68.0°
Loss on Drying 〈731〉
- Analysis: Dry a sample under vacuum at 40° for 2 h.
- Acceptance criteria: NMT 2.0%
5 ADDITIONAL REQUIREMENTS
Packaging and Storage: Preserve in tight, light-resistant containers.
USP Reference Standards 〈11〉
USP Dioxybenzone RS
