2/13/25, 5:23 PM USP-NF Anethole
Status: Currently Official on 13-Feb-2025
Official Date: Official as of 01-Nov-2022
Document Type: NF Monographs
DocId: GUID-D39F60CC-7DD4-4246-ACB1-9CC4F1441BB1_5_en-US
DOI: https://doi.org/10.31003/USPNF_M4680_05_01
DOI Ref: dkm5y
© 2025 USPC
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Anethole
C10H12O 148.20
Benzene, 1-methoxy-4-(1-propenyl)-, (E)-;
(E)-p-Propenylanisole CAS RN®: 4180-23-8.
Synthetic CAS RN®: 104-46-1.
Change to read:
DEFINITION
Anethole is obtained from Anise Oil and other sources, or it is prepared synthetically. It contains NLT 98.0% and NMT 102.0% of (E)-1-
▲methoxy
▲ (ERR 1-Nov-2022) -4-(1-propenyl) benzene (or trans-anethole) (C10H12O).
IDENTIFICATION
• A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197F
• B. Chromatographic Identity L
IA
Analysis: Proceed as directed in the Assay for trans-Anethole.
Acceptance criteria: The retention time of the major peak, excluding the internal standard peak, of the Sample solution corresponds to the
anethole peak of the Standard solution.
ASSAY
IC
• Assay for trans-Anethole
Internal standard solution: 2 mg/mL of USP Menthol RS (internal standard) in hexanes
Standard solution: 2 mg/mL of USP Anethole RS in Internal standard solution (use a freshly prepared solution)
Sample solution: 2 mg/mL of Anethole in Internal standard solution (use a freshly prepared solution)
FF
Chromatographic system
(See Chromatography 〈621〉, System Suitability.)
Mode: GC
Detector: Flame ionization
Column: 0.53-mm × 30-m capillary; bonded with a 1.0-µm layer of phase G16
O
Temperatures
Injection port: 250°
Detector: 250°
Column: 125° (isothermally)
Carrier gas: Helium
Flow rate: 10 mL/min
Injection volume: 1.0 µL
Injection type: Split injection; split ratio of 10:1
Run time: 30 min
System suitability
Sample: Standard solution
[Note—The relative retention times for menthol and trans-anethole are about 0.5 and 1.0, respectively.]
Suitability requirements
Resolution: NLT 15 between menthol and trans-anethole
Tailing factor: 0.8–2.0 for menthol and trans-anethole peaks
Relative standard deviation: NMT 2.0% for the peak response ratio of trans-anethole to the internal standard
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of trans-anethole (C10H12O) in the portion of Anethole taken:
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2/13/25, 5:23 PM USP-NF Anethole
Result = (RU/RS) × (CS/CU) × 100
RU = peak response ratio of trans-anethole to the internal standard (peak response of trans-anethole/peak response of the internal
standard) from the Sample solution
RS = peak response ratio of trans-anethole to the internal standard (peak response of trans-anethole/peak response of the internal
standard) from the Standard solution
CS = concentration of USP Anethole RS in the Standard solution (mg/mL)
CU = concentration of Anethole in the Sample solution (mg/mL)
Acceptance criteria: 98.0%–102.0%
IMPURITIES
• Limit of cis-Anethole, p-Anisaldehyde, and Other Volatile Impurities
Internal standard solution: 0.01 mg/mL of USP Menthol RS (internal standard) in hexanes
System suitability solution: 4 mg/mL of USP Anethole RS in Internal standard solution after exposure to UV light for 1 h
Standard solution: 0.01 mg/mL of USP Anethole RS and 0.01 mg/mL of USP p-Anisaldehyde RS in Internal standard solution (use a freshly
prepared solution)
Sample solution: 2 mg/mL of Anethole in Internal standard solution (use a freshly prepared solution)
Chromatographic system: Proceed as directed in the Assay, except use a Run time of 60 min.
System suitability
Samples: System suitability solution and Standard solution
[Note—See Table 1 for the relative retention times.]
Table 1
Relative
Name
L Retention
Time
IA
Menthol (internal standard) 0.5
cis-Anethole 0.75
trans-Anethole 1.0
IC
p-Anisaldehyde 2.2
Suitability requirements
FF
Resolution: NLT 5 between cis-anethole and trans-anethole, System suitability solution
Relative standard deviation: NMT 5.0% for the peak response ratio of trans-anethole to the internal standard and NMT 5.0% for the peak
response ratio of p-anisaldehyde to the internal standard, Standard solution
Analysis
Samples: Standard solution and Sample solution
O
Calculate the percentage of p-anisaldehyde in the portion of Anethole taken:
Result = (RU1/RS1) × (CS1/CU) × 100
RU1 = peak response ratio of p-anisaldehyde to the internal standard (peak response of p-anisaldehyde/peak response of the
internal standard) from the Sample solution
RS1 = peak response ratio of p-anisaldehyde to the internal standard (peak response of p-anisaldehyde/peak response of the
internal standard) from the Standard solution
CS1 = concentration of USP p-Anisaldehyde RS in the Standard solution (mg/mL)
CU = concentration of Anethole in the Sample solution (mg/mL)
Calculate the percentage of cis-anethole or any other unspecified volatile impurity in the portion of Anethole taken:
Result = (RU2/RS2) × (CS2/CU) × 100
RU2 = peak response ratio of cis-anethole or any other unspecified impurity to the internal standard (peak response of cis-anethole
or any other unspecified impurity/peak response of the internal standard) from the Sample solution
RS2 = peak response ratio of trans-anethole to the internal standard (peak response of trans-anethole/peak response of the internal
standard) from the Standard solution
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2/13/25, 5:23 PM USP-NF Anethole
CS2 = concentration of USP Anethole RS in the Standard solution (mg/mL)
CU = concentration of Anethole in the Sample solution (mg/mL)
Acceptance criteria: Disregard peaks that are less than 0.05% for any unspecified impurities and any peaks due to solvent.
Total impurities including cis-anethole, p-anisaldehyde, and all other unspecified impurities: NMT 2.0%
• Limit of Phenols
Sample: 1 mL
Analysis: Shake the Sample with 20 mL of water, and allow the liquids to separate. Pass the water layer through a filter paper previously
moistened with water, and to 10 mL of the filtrate add 3 drops of ferric chloride TS.
Acceptance criteria: No purple or purplish color is produced.
SPECIFIC TESTS
• Specific Gravity 〈841〉: 0.983–0.988
• Distilling Range, Method I 〈721〉: 231°–237°, a correction factor of 0.063°/mm being applied as necessary
• Optical Rotation, Angular Rotation 〈781A〉: −0.15° to +0.15°
• Refractive Index 〈831〉: 1.557–1.561
ADDITIONAL REQUIREMENTS
• Packaging and Storage: Preserve in tight, light-resistant containers.
• Labeling: Label to indicate whether it is of natural sources or is prepared synthetically.
• USP Reference Standards 〈11〉
USP Anethole RS
USP p-Anisaldehyde RS
USP Menthol RS
Auxiliary Information - Please check for your question in the FAQs before contacting USP. L
IA
Topic/Question Contact Expert Committee
ANETHOLE Documentary Standards Support SE2020 Simple Excipients
IC
Chromatographic Database Information: Chromatographic Database
Most Recently Appeared In:
Pharmacopeial Forum: Volume No. PF 40(1)
FF
Current DocID: GUID-D39F60CC-7DD4-4246-ACB1-9CC4F1441BB1_5_en-US
DOI: https://doi.org/10.31003/USPNF_M4680_05_01
DOI ref: dkm5y
O
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