Rocuronium Bromide

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

Rocuronium Bromide contains NLT 98.0% and NMT 102.0% of rocuronium bromide (C₃₂H₅₃BrN₂O₄), calculated on the anhydrous and 2-propanol-free or acetic-acid-free basis.

2 IDENTIFICATION

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

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

C. Identification Tests—General 〈191〉, Bromide

Sample solution: 10 mg/mL

Acceptance criteria: Meets the requirements of test B

3 ASSAY

Procedure

Diluent: Acetonitrile and water (90:10)

Buffer: 4.53 g/L of tetramethylammonium hydroxide pentahydrate. Adjust with phosphoric acid to pH 7.4.

Mobile phase: Acetonitrile and Buffer (90:10)

Standard solution: 1 mg/mL of USP Rocuronium Bromide RS in Diluent

Sample solution: 1 mg/mL of Rocuronium Bromide in Diluent

Chromatographic system

Mode: LC

Detector: UV 210 nm

Column: 4.6-mm × 25-cm; 5-µm packing L3

Column temperature: 30°

Flow rate: 2 mL/min

Injection volume: 5 µL

System suitability

[Note—The system may need equilibration for 4 h.]

Sample: Standard solution

Tailing factor: NMT 2.0

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Result = (rᵤ / rₛ) × (Cₛ / Cᵤ) × 100

rᵤ = peak response from the Sample solution

rₛ = peak response from the Standard solution

Cₛ = concentration of USP RS (mg/mL)

Cᵤ = concentration of sample (mg/mL)

Acceptance criteria: 98.0%–102.0%

4 IMPURITIES

Residue on Ignition 〈281〉

NMT 0.1%

Organic Impurities

Diluent, Mobile phase, and Chromatographic system: As directed in Assay.

Peak identification solution: 1 mg/mL of USP Rocuronium Peak Identification Mixture RS in Diluent

Standard solution: 0.01 mg/mL USP Rocuronium Bromide RS

Sample solution: 10 mg/mL Rocuronium Bromide in Diluent

Run time: 2.5 × retention time of rocuronium

System suitability

[Note—System may require 4 h equilibration.]

Peak-to-valley ratio: ≥ 1.5

Resolution: ≥ 3.5 between rocuronium and compound C

Analysis

Result = (rᵤ / rₛ) × (Cₛ / Cᵤ) × (1/F) × 100

Acceptance criteria: Table 1

[Note—Disregard peaks before compound A, and peaks < 0.5 the principal standard peak.]

a 3α-Hydroxy-2β-(morpholin-4-yl)-16β-(pyrrolidin-1-yl)-5α-androstan-17β-yl acetate.

▲b 2β-(Morpholin-4-yl)-16β-(pyrrolidin-1-yl)-5α-androstane-3α,17β-diol.▲ (ERR 1-Dec-2022)

c 1-[3α,17β-Bis(acetyloxy)-2β-(pyrrolidin-1-yl)-5α-androstan-16β-yl]-1-(prop-2-enyl)pyrrolidinium.

d 1-[3α,17β-Bis(acetyloxy)-2β-(morpholin-4-yl)-5α-androstan-16β-yl]-1-(prop-2-enyl)pyrrolidinium.

e 1-[3α-(Acetyloxy)-17β-hydroxy-2β-(morpholin-4-yl)-5α-androstan-16β-yl]-1-(prop-2-enyl)pyrrolidinium.

f 1-[17β-(Acetyloxy)-2-(morpholin-4-yl)-3-oxo-5α-androst-1-en-16β-yl]-1-(prop-2-enyl)pyrrolidinium.

g 1-[3α,17β-Dihydroxy-2β-(morpholin-4-yl)-5α-androstan-16β-yl]-1-(prop-2-enyl)pyrrolidinium.

h 1-[17β-(Acetyloxy)-3α-hydroxy-2β-(pyrrolidin-1-yl)-5α-androstan-16β-yl]-1-(prop-2-enyl)pyrrolidinium.

Limit of 2-Propanol

[Note—Perform only if 2-propanol is a known process impurity.]

Standard stock solution

Transfer 35.0 µL ethyl ether, 32.0 µL 2-propanol, 19.0 µL methylene chloride to a 100-mL volumetric flask with 90 mL DMF, dilute to volume.

Standard solution

2.5 mL of stock → 25-mL flask with 20 mL DMF → dilute to volume.

Dilute standard solution

1.0 mL of Standard solution + 4.0 mL water in 20-mL headspace vial. Cap and mix.

Sample solution

50 mg Rocuronium Bromide + 1.0 mL DMF + 4.0 mL water in 20-mL vial. Cap and mix.

Chromatographic system (GC)

Mode: GC

Detector: Flame ionization

Column: 0.32-mm × 60-m fused silica coated with 1.8-µm G43

Temperatures

Carrier gas: Helium 55 cm/s or nitrogen 25 cm/s

Injection type: Split 1:6

Headspace autosampler

Sample equilibration temperature: 90°

Equilibration time: 15 min

Transfer line: 140°

System suitability

[Note—Relative retention times: ethyl ether 0.87, 2-propanol 1.0, methylene chloride 1.08]

Resolution: NLT 1.0 between ether & 2-propanol; and between 2-propanol & methylene chloride

RSD: NMT 10% (2-propanol)

Analysis

Result = [(rᵤ / rₛ) × (V × D / W) × 100] / F

rᵤ = Sample 2-propanol peak

rₛ = Standard 2-propanol peak

V = 2-propanol volume used in stock

D = 0.786 mg/µL

W = sample weight

F = 1000

Acceptance criteria: NMT 1.0%

Limit of Acetic Acid

Mobile phase: 6.1 g sodium perchlorate in 800 mL water, adjust pH 2.0 with 1 N sulfuric acid, dilute to 1 L.

Standard solution: 0.2 mg/mL glacial acetic acid

Sample solution: 6 mg/mL Rocuronium Bromide (sonication may be needed)

Chromatographic system (LC)

Detector: UV 205 nm

Column: 4.6-mm × 15-cm; packing L1

Column temperature: 30°

Flow rate: 1 mL/min

Injection volume: 20 µL

System suitability

[Note—Acetic acid retention ≈ 3.8 min]

Column efficiency: NLT 5000 plates

Tailing factor: NMT 1.8

RSD: NMT 5.0% (three injections)

Analysis

Result = (rᵤ / rₛ) × (Cₛ / Cᵤ) × 100

Acceptance criteria: NMT 5.0%

5 SPECIFIC TESTS

Water Determination 〈921〉 Method Ic: NMT 4.0%

pH 〈791〉

Sample: 10 mg/mL

Acceptance: 7.0–9.5

Specific Rotation 〈781S〉

Sample: 10 mg/mL in 0.05 M HCl

Acceptance: 28.5°–32.0° (anhydrous, solvent-free, at 20°)

Color and Achromicity 〈631〉

Reference: 33 mL Matching Fluid G + 67 mL water

Sample: 10 mg/mL in water

Acceptance: Sample not more intensely colored.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Tight containers, protect from light/moisture. Store in freezer. If containing acetic acid, store at 2°–8°.

USP Reference Standards 〈11〉

USP Rocuronium Bromide RS

USP Rocuronium Peak Identification Mixture RS

Mixture of approximately 0.2% to 0.4% each of rocuronium related compound A, rocuronium related compound B, rocuronium related compound C, rocuronium related compound D, rocuronium related compound E, rocuronium related compound F, rocuronium related compound G, and rocuronium related compound H in a matrix of rocuronium bromide.