Thymol
If you find any inaccurate information, please let us know by providing your feedback here
Tóm tắt nội dung
This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition
Issued and maintained by the United States Pharmacopeial Convention (USP)
C10H14O 150.22
Phenol, 5-methyl-2-(1-methylethyl)-;
Thymol;
p-Cymen-3-ol CAS RN®: 89-83-8.
1 DEFINITION
Thymol contains NLT 99.0% and NMT 101.0% of thymol (C10H14O).
2 IDENTIFICATION
Change to read:
A. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197K (CN 1-MAY-2020)
B. It meets the requirements in Specific Tests for Melting Range or Temperature(741).
3 ASSAY
PROCEDURE
Sample: 100 mg
Titrimetric system
(See Titrimetry (541).)
Mode: Direct titration
Titrant: 0.1 N bromine VS
Endpoint detection: Visual
Analysis: Transfer the Sample to a 250-mL iodine flask, and dissolve in 25 mL of 1 N sodium hydroxide. Add 20 mL of hot dilute hydrochloric acid (1 in 2), and immediately titrate with Titrant to within 1-2 mL of the calculated endpoint. Warm the solution to between 70° and 80°, add 2 drops of methyl orange TS, and continue the titration slowly, swirling vigorously after each addition. When the color of the methyl orange is bleached, add 2 drops of Titrant, shake for 10 s, add 1 drop of methyl orange TS, and shake vigorously. If the solution is red, continue the titration, dropwise and with shaking, until the color is discharged. Repeat the alternate addition of the Titrant and methyl orange TS until the red color is discharged after the addition of the methyl orange TS. Each mL of Titrant is equivalent to 3.755 mg of thymol (C10H14O).
Acceptance criteria: 99.0%-101.0%
4 IMPURITIES
LIMIT OF NONVOLATILE RESIDUE
Sample: 2 g
Analysis: Volatilize the Sample on a steam bath, and dry at 105° to constant weight.
Acceptance criteria: NMT 0.05%
5 SPECIFIC TESTS
MELTING RANGE OR TEMPERATURE (741): 48°-51°; but when melted, Thymol remains liquid at a considerably lower temperature.
6 ADDITIONAL REQUIREMENTS
6.1 PACKAGING AND STORAGE
Preserve in tight, light-resistant containers.
6.2 USP REFERENCE STANDARDS (11)
USP Thymol RS
