Benoxinate 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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C₁₇H₂₈N₂O₃ . HCI  344.88

Benzoic acid, 4-amino-3-butoxy-, 2-(diethylamino) ethyl ester, monohydrochloride;

2-(Diethylamino)ethyl 4-amino-3-butoxybenzoate monohydrochloride CAS RN®: 5987-82-6; UNII: OVE4U49K15.

1 DEFINITION

Benoxinate Hydrochloride contains NLT 98.5% and NMT 101.5% of benoxinate hydrochloride (C₁₇H₂₈N₂O₃ . HCI), calculated on the dried basis.

2 IDENTIFICATION

Change to read:

2.1 A. ASPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197K (CN 1-MAY-2020)

Sample: Previously dried

Acceptance criteria: Meets the requirements

Change to read:

2.2 B. ASPECTROSCOPIC IDENTIFICATION TESTS (197), Ultraviolet-Visible Spectroscopy: 1970 (CN 1-MAY-2020)

Sample solution: 15 µg/mL in water

Acceptance criteria: Meets the requirements

2.3 C. IDENTIFICATION TESTS-GENERAL, Chloride (191)

Sample solution: 10 mg/mL

Acceptance criteria: Meets the requirements

3 ASSAY

3.1 PROCEDURE

Sample solution: Dissolve 250 mg of Benoxinate Hydrochloride in a mixture of 20 mL of glacial acetic acid and 20 mL of acetic anhydride.

Titrimetric system

Mode: Direct titration

Titrant: 0.1 N perchloric acid VS

Endpoint detection: Potentiometric

Analysis: Titrate, perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 34.49 mg of benoxinate hydrochloride (C₁₇H₂₈N₂O₃ . HCI).

Acceptance criteria: 98.5%-101.5% on the dried basis

4 IMPURITIES

4.1 RESIDUE ON IGNITION (281)

NMT 0.2%

4.2 ORDINARY IMPURITIES (466)

Standard solution:

Methanol

Sample solution: Methanol

Eluant: A mixture of chloroform, cyclohexane, and diethylamine (5:4:1)

Visualization: 12

5 SPECIFIC TESTS

5.1 PH (791)

Sample solution: 10 mg/mL

Acceptance criteria: 5.0-6.0

5.2 LOSS ON DRYING (731)

Analysis: Dry a sample at 105° for 3 h.

Acceptance criteria: NMT 1.0%

6 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in well-closed containers.

USP REFERENCE STANDARDS (11).

USP Benoxinate Hydrochloride RS