Acetazolamide 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

Acetazolamide Tablets contain NLT 95.0% and NMT 105.0% of the labeled amount of acetazolamide (C₄H₆N₄O₃S₂).

2 IDENTIFICATION

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

Sample: Extract a quantity of nely powdered Tablets, equivalent to about 500 mg of acetazolamide, with 50 mL of acetone. Filter, and add sucient solvent hexane to the ltrate to cause formation of a heavy, white precipitate. Collect the precipitate on a medium-porosity, sintered-glass funnel, and dry with suction.

Acceptance criteria: Meet the requirements

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

3.1 Procedure

Mobile phase: Dissolve 4.1 g of anhydrous sodium acetate in 950 mL of water, add 20 mL of methanol and 30 mL of acetonitrile, and mix. Adjust with glacial acetic acid to a pH of 4.0.

Standard solution: 0.1 mg/mL of USP Acetazolamide RS prepared as follows. Transfer USP Acetazolamide RS into a suitable volumetric flask, add 0.5 N sodium hydroxide equivalent to 10% of the nal volume, and dilute with water to volume.

Sample stock solution: Nominally equivalent to 1.0 mg/mL of acetazolamide prepared as follows. Transfer a portion of the powder, from NLT 20 Tablets, equivalent to 100 mg acetazolamide into a 100-mL volumetric flask. Add 10 mL of 0.5 N sodium hydroxide, sonicate for 5 min, cool to room temperature, and dilute with water to volume. Filter a portion of this solution, discarding the rst 20 mL of the ltrate.

Sample solution: Nominally equivalent to 0.1 mg/mL of acetazolamide prepared as follows. Transfer 10.0 mL of Sample stock solution and 10mL of 0.5 N sodium hydroxide to a 100-mL volumetric flask, and dilute with water to volume.

3.2 Chromatographic system

Mode: LC

Detector: UV 254 nm

Column: 4.6-mm × 25-cm; packing L1

Flow rate: 2 mL/min

Injection volume: 20 μL

3.3 System suitability

Sample: Standard solution

3.4 Suitability requirements

Tailing factor: NMT 1.5

Relative standard deviation: NMT 1.0%

3.5 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of acetazolamide (C₄H₆N₄O₃S₂) in the portion of Tablets taken:

Result = (r_u/r_s) × (C_s/C_u) × 100

r_u = acetazolamide peak response from the Sample solution

r_s = acetazolamide peak response from the Standard solution

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

C_u = nominal concentration of acetazolamide in the Sample solution (mg/mL)

Acceptance criteria: 95.0%–105.0%

4 PERFORMANCE TESTS

Change to read:

4.1 Dissolution

Test 1 (RB 1-Feb-2024)

Medium: 0.01 N hydrochloric acid; 900 mL

Apparatus 1: 100 rpm

Time: 60 min

Standard solution: USP Acetazolamide RS in Medium

Sample solution: Dilute with Medium if necessary.

4.2 Instrumental conditions

Mode: UV

Analytical wavelength: 265 nm

4.3 Analysis

Samples: Standard solution and Sample solution

Determine the percentage of the labeled amount of acetazolamide (C₄H₆N₄O₃S₂) dissolved:

(A_u /A_s ) × C_s × D × (V/L) × 100

A_u = absorbance of the Sample solution

A_s = absorbance of the Standard solution

C_s = concentration of the Standard solution (mg/mL)

D = dilution factor of the Sample solution, if needed

V = volume of Medium, 900 mL

L = label claim (mg/Tablet)

Tolerances: NLT 75% (Q) of the labeled amount of acetazolamide (C₄H₆N₄O₃S₂) is dissolved.

Test 2: If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 2.

Medium: 0.01 N hydrochloric acid, deaerated, if necessary; 900 mL

Apparatus 1: 100 mesh; 100 rpm

Time: 20 min

4.4 Standard solution

For Tablets labeled to contain 125 mg: (L/900) mg/mL of USP Acetazolamide RS prepared as follows. Transfer an appropriate quantity of USP Acetazolamide RS to a suitable volumetric flask, add 10% of the flask volume of acetonitrile, and sonicate to dissolve, if necessary. Dilute with Medium to volume.

For Tablets labeled to contain 250 mg: (L/900) mg/mL of USP Acetazolamide RS prepared as follows. Transfer an appropriate quantity of USP Acetazolamide RS to a suitable volumetric flask, add 20% of the flask volume of acetonitrile, and sonicate to dissolve, if necessary. Dilute with Medium to volume.

Sample solution: Pass through a suitable lter of 0.45-μm pore size, discarding an appropriate volume of ltrate so that a consistent result can be obtained.

4.5 Instrumental conditions

Mode: UV

Analytical wavelength: 265 nm

Cell: 1 mm

Blank: Medium

4.6 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of acetazolamide (C H N O S ) dissolved:

Result = (A_u/A_s) × C_s × V × (1/L) × 100

A_u = absorbance from the Sample solution

A_s = absorbance from the Standard solution

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

V = volume of the Medium, 900 mL

L = label claim (mg/Tablet)

Tolerances: NLT 80% (Q) of the labeled amount of acetazolamide (C H N O S ) is dissolved.▲ (RB 1-Feb-2024)

Uniformity of Dosage Units 〈905〉: Meet the requirements

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers, and store at controlled room temperature.