Naftifine Hydrochloride

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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C₂₁H₂₁N · HCl  323.86

1-Naphthalenemethanamine, N-methyl-N-(3-phenyl-2-propenyl)-, hydrochloride, (E)-;

(E)-N-Cinnamyl-N-methyl-1-naphthalenemethylamine hydrochloride  CAS RN®: 65473-14-5; UNII: 25UR9N9041.

1 DEFINITION

Naftifine Hydrochloride contains NLT 99.0% and NMT 101.0% of naftifine hydrochloride (C₂₁H₂₁N · HCl), 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: n-Hexane, absolute alcohol, dimethylformamide, and formic acid (200:60:40:2). Cover tightly with a moisture-proof film, and allow to stand for 12 h at room temperature.

Standard solution: 0.2 mg/mL of USP Naftifine Hydrochloride RS in Mobile phase

Sample solution: 0.2 mg/mL of Naftifine Hydrochloride in Mobile phase

Chromatographic system

• (See Chromatography 〈621〉, System Suitability.)
• Mode: LC
• Detector: UV 270 nm
• Column: 4.6-mm × 25-cm; 5-µm packing L3
• Flow rate: 2 mL/min
• Injection volume: 15 µL

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of naftifine hydrochloride (C₂₁H₂₁N · HCl) in the portion of Naftifine Hydrochloride 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 Naftifine Hydrochloride RS in the Standard solution (mg/mL)

Cᵤ = concentration of the Sample solution (mg/mL)

Acceptance criteria: 99.0%–101.0% on the dried basis

4 IMPURITIES

4.1 Residue on Ignition 〈281〉: NMT 0.1%

4.2 Organic Impurities

Mobile phase, Standard solution, Sample solution, and Chromatographic system: Proceed as directed in the Assay.

Analysis

Sample: Sample solution

Calculate the percentage of each impurity in the portion of Naftifine Hydrochloride taken:

Result = (r_U/r_T) × 100

r_U = peak response for each impurity

r_T = sum of all the peak responses

Acceptance criteria

• Individual impurity: NMT 0.1%
• Total impurities: NMT 1.0%

5 SPECIFIC TESTS

5.1 Loss on Drying 〈731〉

Analysis: Dry over phosphorus pentoxide at 105° for 4 h.

Acceptance criteria: NMT 0.5%

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers.

USP Reference Standards 〈11〉

USP Naftifine Hydrochloride RS