Proparacaine 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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1 DEFINITION

Proparacaine Hydrochloride contains NLT 97.0% and NMT 103.0% of proparacaine hydrochloride (C₁₆H₂₆N₂O₃ · HCl), calculated on the dried basis.

2 IDENTIFICATION

A. Identification—Organic Nitrogenous Bases 〈181〉: Meets the requirements

B. Ultraviolet Absorption

Buffer: Prepare as directed for pH 6.0 phosphate buffer (see Reagents, Indicators, and Solutions—Solutions, Buffer Solutions). Dilute with water to prepare a 10% solution.

Analytical wavelength: 310 nm

Sample stock solution: 0.2 mg/mL of Proparacaine Hydrochloride

Sample solution: 0.02 mg/mL of Proparacaine Hydrochloride prepared as follows. To a volume of the Sample stock solution equivalent to 10% of the flask volume, add 2% of the flask volume of Buffer, and dilute with water to volume.

Acceptance criteria: The UV absorption spectrum of the Sample solution exhibits maxima and minima at the same wavelengths as those of a similarly prepared solution of USP Proparacaine Hydrochloride RS, concomitantly measured, and the respective absorptivities, calculated on the dried basis, do not differ by more than 3.0%.

Change to read:

C. Identification Tests—General 〈191〉, Chemical Identification Tests, Chloride

Sample solution: 20 mg/mL of Proparacaine Hydrochloride

Analysis: Proceed as directed in the chapter using the procedure for ▲amine hydrochlorides.▲ (USP 1-May-2021)

Acceptance criteria: Meets the requirements

3 ASSAY

Procedure

Sample solution: Transfer 250 mg of Proparacaine Hydrochloride to a 250-mL conical flask. Add 80 mL of a 1-in-20 solution of acetic anhydride in glacial acetic acid, and heat on a steam bath for 10 min. Cool to room temperature, and add 10 mL of mercuric acetate TS.

Titrimetric system

Mode: Direct titration

Titrant: 0.1 N perchloric acid VS

Endpoint detection: Visual

Analysis: Titrate with Titrant to a blue-green endpoint using 1 or 2 drops of crystal violet TS as the indicator. Perform a blank determination, and make any necessary correction. Each milliliter of 0.1 N perchloric acid is equivalent to 33.09 mg of proparacaine hydrochloride (C₁₆H₂₆N₂O₃ · HCl).

Acceptance criteria: 97.0%–103.0% on the dried basis

4 IMPURITIES

Residue on Ignition 〈281〉: NMT 0.15%

Ordinary Impurities 〈466〉

Standard solution: Methanol

Sample solution: Methanol

Eluant: Butyl alcohol, glacial acetic acid, and water (5:1:3)

Visualization: 1; 17

Acceptance criteria: Meets the requirements

5 SPECIFIC TESTS

Melting Range or Temperature 〈741〉: 178°–185°, but the range between beginning and end of melting does not exceed 2°

Loss on Drying 〈731〉

Analysis: Dry at 105° for 3 h.

Acceptance criteria: NMT 0.5%

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers.

USP Reference Standards 〈11〉

USP Proparacaine Hydrochloride RS