Clonazepam Tablets

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

Clonazepam Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of clonazepam (C₁₅H₁₀ClN₃O₃).

2 IDENTIFICATION

A. The UV spectrum of the major peak of the Identification sample solution corresponds to that of the Identification standard solution, as obtained in the Assay.

B. 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

Change to read:

3.1 Procedure

Buffer: 6.6 g/L of dibasic ammonium phosphate prepared as follows. Transfer a suitable amount of dibasic ammonium phosphate to an appropriate volumetric flask. Add 95% of the flask volume of water and adjust with 1 N phosphoric acid or 1 N sodium hydroxide to a pH of 8.0. Dilute with water to volume.

Mobile phase: Methanol, tetrahydrofuran, and Buffer (52:13:60)

Diluent: Methanol, tetrahydrofuran, and water (52:13:60)

System suitability solution: 40 µg/mL each of USP Clonazepam Related Compound A RS, USP Clonazepam Related Compound B RS, and USP Clonazepam RS in Diluent

Standard solution: 100 µg/mL of USP Clonazepam RS in Diluent

Identification standard solution: 40 µg/mL of USP Clonazepam RS from the Standard solution in Diluent. [Note—This solution is used for Identification A.]

Sample solution: Nominally 100 µg/mL of clonazepam from Tablets prepared as follows. Finely powder NLT 10 Tablets. Transfer a portion of powder equivalent to 10 mg of clonazepam to a 100-mL volumetric flask, and dissolve, with sonication, in 75 mL of Diluent. Cool to room temperature, dilute with Diluent to volume, mix, and filter, discarding the first few milliliters of the filtrate.

Identification sample solution: Nominally 40 µg/mL of clonazepam from the Sample solution in Diluent. [Note-This solution is used for Identification A.]

Chromatographic system

• (See Chromatography (621), System Suitability.)
• Mode: LC
• Detector: UV 254 nm. For Identification A, use a diode array detector in the range of 220–400 nm.
• Column: 4.6-mm × 15-cm; 5-µm packing L7
• Flow rate: 1 mL/min
• Injection volume: 50 µL
• Run time: NLT 3 times the retention time of clonazepam

System suitability

• Samples: System suitability solution and Standard solution
• [Note-See Table 1 for the relative retention times.]
• Suitability requirements
• Resolution: NLT 2.0 between clonazepam related compound A and clonazepam related compound B, System suitability solution
• Tailing factor: NMT 1.5, Standard solution
• Relative standard deviation: NMT 1.0%, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of clonazepam (C₁₅H₁₀ClN₃O₃) in the portion of Tablets taken:

Result = (r_u/r_s) × (C_s/C_u) × 100

r_u = peak response for clonazepam from the Sample solution

r_s = peak response for clonazepam from the Standard solution

C_s = concentration of USP Clonazepam RS in the Standard solution (µg/mL)

C_u = nominal concentration of clonazepam in the Sample solution (µg/mL)

Acceptance criteria: 90.0%-110.0%

4 PERFORMANCE TESTS

Change to read:

4.1 Dissolution 〈711〉

Medium: Water; 900 mL, degassed

Apparatus 2: 75 rpm

Time: 45 min

Mobile phase: Methanol, acetonitrile, and water (30:30:40)

Standard stock solution: 0.05 mg/mL of USP Clonazepam RS in methanol

Standard solution: (L/900) mg/mL of USP Clonazepam RS from Standard stock solution in Medium where L is the label claim in mg/Tablet

Sample solution: Use a portion of the solution under test.

Chromatographic system

• (See Chromatography (621), System Suitability.)
• Mode: LC
• Detector: UV 254 nm
• Column: 4-mm × 30-cm; 10-µm packing L1
• Flow rate: 1 mL/min
• Injection volume: 100 µL

System suitability

• Sample: Standard solution
• Suitability requirements
• Tailing factor: NMT 2.0
• Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of clonazepam (C₁₅H₁₀ClN₃O₃) dissolved in the portion of Tablets taken:

Result = (r_u/r_s) × C_s × V × (1/L) × 100

r_u = peak response of clonazepam from the Sample solution

r_s = peak response of clonazepam from the Standard solution

C_s = concentration of USP Clonazepam RS in the Standard solution (mg/mL)

V = volume of Medium, 900 mL

L = label claim (mg/Tablet)

Tolerances: NLT 75% (Q) of the labeled amount of clonazepam (C₁₅H₁₀ClN₃O₃) is dissolved

4.2 Uniformity of Dosage Units 〈905〉: Meet the requirements

5 IMPURITIES

Change to read:

5.1 Organic Impurities

5.1.1 Procedure

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

Sensitivity solution: 0.1 µg/mL of USP Clonazepam RS in Diluent

System suitability

• Samples: System suitability solution, Standard solution, and Sensitivity solution
• [Note-See Table 1 for the relative retention times.]
• Suitability requirements
• Resolution: NLT 2.0 between clonazepam related compound A and clonazepam related compound B, System suitability solution
• Tailing factor: NMT 1.5, Standard solution
• Relative standard deviation: NMT 2.0%, Standard solution
• Signal-to-noise ratio: NLT 10, Sensitivity solution

Analysis

Samples: Sample solution and Standard solution

Calculate the percentage of each impurity in the portion of Tablets taken:

Result = (r_u/r_s) × (C_s/C_u) × (1/F) × 100

r_u = peak response from the Sample solution

r_s = peak response from the Standard solution

C_s = concentration of USP Clonazepam RS in the Standard solution (µg/mL)

C_u = nominal concentration of clonazepam in the Sample solution (µg/mL)

F = relative response factor (see Table 1)

Acceptance criteria: See Table 1. The reporting threshold is 0.1%.

a. May not be present in all formulations.

b. Clonazepam related compound A, clonazepam related compound B, and the unknown impurity with a relative retention time of 0.7 are not included in the total impurities

6 ADDITIONAL REQUIREMENTS

Change to read:

6.1 Packaging and Storage

Preserve in tight, light-resistant containers. Store at controlled room temperature.

6.2 USP Reference Standards 〈11〉

USP Clonazepam RS

USP Clonazepam Related Compound A RS

3-Amino-4-(2-chlorophenyl)-6-nitrocarbostyril.

C₁₅H₁₀ClN₃O₃ 315.72

USP Clonazepam Related Compound B RS

2-Amino-2′-chloro-5-nitrobenzophenone.

C₁₃H₉ClN₂O₃ 276.68