Prilocaine 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

Prilocaine Hydrochloride contains NLT 98.0% and NMT 102.0% of prilocaine hydrochloride (C₁₃H₂₀N₂O·HCl), calculated on the dried basis.

2 IDENTIFICATION

Change to read:

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

B. Identification Tests—General, Chloride 〈191〉

Analysis: Dissolve 100 mg in 3 mL of water, render the solution alkaline with 6 N ammonium hydroxide, and filter.

Acceptance criteria: The filtrate meets the requirements.

C. 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

Procedure

Buffer: 0.18 g/L of monobasic sodium phosphate and 2.89 g/L of dibasic sodium phosphate dihydrate in water

Mobile phase: Acetonitrile and Buffer (26:74)

System suitability solution: 3 µg/mL each of USP Prilocaine Hydrochloride RS and USP Prilocaine Related Compound B RS in Mobile phase

Standard solution: 0.3 mg/mL of USP Prilocaine Hydrochloride RS in Mobile phase

Sample solution: 0.3 mg/mL of Prilocaine Hydrochloride in Mobile phase

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 240 nm

Column: 4.6-mm × 15-cm; 5-µm packing L1

Flow rate: 1 mL/min

Injection volume: 20 µL

System suitability

Samples: System suitability solution and Standard solution

[Note—See Table 1 for the relative retention times.]

Suitability requirements

Resolution: NLT 3.0 between prilocaine and prilocaine related compound B, System suitability solution

Tailing factor: NMT 1.5, Standard solution

Relative standard deviation: NMT 0.73, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of prilocaine hydrochloride (C₁₃H₂₀N₂O·HCl) in the portion of Prilocaine Hydrochloride taken:

Result = (rᵤ / rₛ) × (Cₛ / Cᵤ) × 100

rᵤ = peak response of prilocaine from the Sample solution

rₛ = peak response of prilocaine from the Standard solution

Cₛ = concentration of USP Prilocaine Hydrochloride RS in the Standard solution (mg/mL)

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

Acceptance criteria: 98.0%–102.0% on the dried basis

4 IMPURITIES

Residue on Ignition 〈281〉: NMT 0.1%

Organic Impurities

Buffer, Mobile phase, System suitability solution, and Chromatographic system: Proceed as directed in the Assay.

Standard solution 1: 3 µg/mL of USP Prilocaine Hydrochloride RS in Mobile phase

Standard solution 2: 0.4 µg/mL of USP Prilocaine Related Compound A RS in Mobile phase

Sample solution: 3 mg/mL of Prilocaine Hydrochloride in Mobile phase

System suitability

Samples: System suitability solution and Standard solution 2

[Note—See Table 1 for the relative retention times.]

Suitability requirements

Resolution: NLT 3.0 between prilocaine and prilocaine related compound B, System suitability solution

Signal-to-noise ratio: NLT 10 for prilocaine related compound A, Standard solution 2

Analysis

Samples: Standard solution 1, Standard solution 2, and Sample solution

Calculate the percentage of prilocaine related compound A in the portion of Prilocaine Hydrochloride taken:

Result = (rᵤ / rₛ) × (Cₛ / Cᵤ) × 100

rᵤ = peak response of prilocaine related compound A from the Sample solution

rₛ = peak response of prilocaine related compound A from Standard solution 2

Cₛ = concentration of USP Prilocaine Related Compound A RS in Standard solution 2 (mg/mL)

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

Calculate the percentage of any individual unspecified impurity in the portion of Prilocaine Hydrochloride taken:

Result = (rᵤ / rₛ) × (Cₛ / Cᵤ) × 100

rᵤ = peak response of any unspecified impurity from the Sample solution

rₛ = peak response of prilocaine from Standard solution 1

Cₛ = concentration of USP Prilocaine Hydrochloride RS in Standard solution 1 (mg/mL)

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

Acceptance criteria: See Table 1.

The reporting level for impurities is 0.05%.

Table 1

5 SPECIFIC TESTS

Loss on Drying 〈731〉

Analysis: Dry a sample at 105° for 4 h.

Acceptance criteria: NMT 0.3%

ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers. Store at room temperature.

USP Reference Standards 〈11〉

USP Prilocaine Hydrochloride RS

USP Prilocaine Related Compound A RS

o-Toluidine hydrochloride.

C₇H₉N·HCl 143.62

USP Prilocaine Related Compound B RS

(RS)-N-(4-Methylphenyl)-2-(propylamino)propanamide.

C₁₃H₂₀N₂O 220.31