Dibucaine 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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C₂₀H₂₉N₃O₂·HCl 379.92

4-Quinolinecarboxamide, 2-butoxy-N-[2-(diethylamino)ethyl]-, monohydrochloride;

2-Butoxy-N-[2-(diethylamino)ethyl]cinchoninamide monohydrochloride  CAS RN®: 61-12-1.

1 DEFINITION

Dibucaine Hydrochloride contains NLT 97.0% and NMT 100.5% of dibucaine hydrochloride (C₂₀H₂₉N₃O₂·HCl), calculated on the dried basis.

2 IDENTIFICATION

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197M

B. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

Change to read:

C. Identification Tests-General 〈191〉, Chemical Identification Tests, Chloride: Meets the requirements when tested as specified for amine hydrochlorides

3 ASSAY

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3.1 Procedure

Mobile phase: Dissolve 1.20 g of sodium dodecyl sulfate, 0.20 g of sodium acetate, and 2.0 mL of triethylamine in 300 mL of water. Adjust with glacial acetic acid to a pH of 5.6. Add 700 mL of methanol, mix, and pass through a filter of 0.5-µm or finer pore size.

Diluent: Methanol and water (70:30)

Standard solution: 1 mg/mL of USP Dibucaine Hydrochloride RS in Diluent. Pass through a filter of 0.5-µm or finer pore size.

Sample solution: 1 mg/mL of Dibucaine Hydrochloride in Diluent. Pass through a filter of 0.5-µm or finer pore size.

Chromatographic system

• (See Chromatography 〈621〉, System Suitability.)
• Mode: LC
• Detector: UV 254 nm
• Column: 3.9-mm × 30-cm; 10-µm packing L1
• Flow rate: 1.5 mL/min
• Injection volume: 10 µL
• Run time: NLT 2.5 times the retention time of dibucaine

System suitability

• Sample: Standard solution
• Suitability requirements
• Column efficiency: NLT 1500 theoretical plates
• Tailing factor: NMT 3.0
• Relative standard deviation: NMT 2%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of dibucaine hydrochloride (C₂₀H₂₉N₃O₂·HCl) in the portion of Dibucaine Hydrochloride taken:

Result = (rᵤ/rₛ) × (Cₛ/Cᵤ) × 100

rᵤ = peak response of dibucaine from the Sample solution

rₛ = peak response of dibucaine from the Standard solution

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

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

Acceptance criteria: 97.0%–100.5% on the dried basis

4 IMPURITIES

4.1 Residue on Ignition 〈281〉: NMT 0.1%

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4.2 Organic Impurities

Standard solution: 40 mg/mL of USP Dibucaine Hydrochloride RS in chloroform

Sample solution: 40 mg/mL of Dibucaine Hydrochloride in chloroform

Comparison solution A: 40 µg/mL of USP Dibucaine Hydrochloride RS from the Standard solution in chloroform (0.1%)

Comparison solution B: 120 µg/mL of USP Dibucaine Hydrochloride RS from the Standard solution in chloroform (0.3%)

Comparison solution C: 200 µg/mL of USP Dibucaine Hydrochloride RS from the Standard solution in chloroform (0.5%)

Chromatographic system

• (See Chromatography 〈621〉, General Procedures, Thin-Layer Chromatography.)
• Mode: TLC
• Adsorbent: 0.25-mm layer of chromatographic silica gel mixture
• Application volume: 5 µL
• Developing solvent system: Toluene, acetone, methanol, and ammonium hydroxide (50:30:5:1)
• Spray reagent: 5 mg/mL of potassium dichromate in 7 N sulfuric acid TS

Analysis

Samples: Standard solution, Sample solution, and each Comparison solution

Proceed as directed in the general chapter. Develop the chromatogram in the Developing solvent system until the solvent front has moved three-fourths of the length of the plate. Remove the plate from the chamber, mark the solvent front, and air-dry. Spray the plate heavily with Spray reagent. Place the plate in an oven at 140° for 10 min, and view under short-wavelength UV light.

Acceptance criteria: The principal spot from the Sample solution corresponds in Rf value, color, and intensity to that from the Standard solution; the sum of the intensities of any secondary spots, if present in the Sample solution, is NMT 1.0%, and the intensity of any secondary spot does not exceed 0.5% of that of the principal spot from the Standard solution on the basis of comparison with the spots from each Comparison solution.

5 SPECIFIC TESTS

5.1 Loss on Drying 〈731〉

Analysis: Dry at 80° for 5 h.

Acceptance criteria: NMT 2.0%

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight, light-resistant containers.

USP Reference Standards 〈11〉

USP Dibucaine Hydrochloride RS