Terpin Hydrate

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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1 DEFINITION

Terpin Hydrate contains NLT 98.0% and NMT 100.5% of terpin (C₁₀H₂₀O₂), calculated on the anhydrous basis.

2 IDENTIFICATION

Change to read:

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

Sample: Dried over a suitable desiccant for 4 h

Acceptance criteria: Meets the requirements

B.

Analysis: Add a few drops of sulfuric acid to a hot solution.

Acceptance criteria: The liquid becomes turbid and develops a strong aromatic odor.

3 ASSAY

Procedure

Internal standard solution: 20 mg/mL of biphenyl in chloroform

Standard solution: Transfer 170 mg of USP Terpin Hydrate RS to a 100-mL volumetric flask, dissolve in 5 mL of alcohol, add 5.00 mL of Internal standard solution, and dilute with chloroform to volume.

Sample solution: Transfer 170 mg of Terpin Hydrate to a 100-mL volumetric flask, dissolve in 5 mL of alcohol, add 5.00 mL of Internal standard solution, and dilute with chloroform to volume.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: GC

Detector: Flame ionization

Column: 3.5-mm × 1.2-m glass; packed with 6% G1 on support S1A

Temperatures

Injection port: 260°

Detector: 260°

Column: 120°

Carrier gas: Nitrogen

Flow rate: Necessary to yield approximate retention times of 7 min for terpin and 11 min for biphenyl

Injection volume: 1 μL

System suitability

Sample: Standard solution

Suitability requirements

Resolution: NLT 2.0 between the terpin and biphenyl peaks

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of terpin (C₁₀H₂₀O₂) in the portion of Terpin Hydrate taken:

Result = (R_U/R_S) × (C_S/C) × 100

R_U = peak response ratio of terpin to biphenyl from the Sample solution

R_S = peak response ratio of terpin to biphenyl from the Standard solution

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

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

Acceptance criteria: 98.0%–100.5% on the anhydrous basis

4 IMPURITIES

Residue on Ignition 〈281〉: NMT 0.1%

5 SPECIFIC TESTS

Water Determination, Method I〈921〉: 9.0%–10.0%

Residual Turpentine: No odor of turpentine oil

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers.

USP Reference Standards 〈11〉

USP Terpin Hydrate RS