Acetazolamide for Injection

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 for Injection is prepared from Acetazolamide with the aid of sodium hydroxide. It is suitable for parenteral use. The contents of each container, when constituted as directed in the labeling, yield a solution containing NLT 95.0% and NMT 110.0% of the labeled amount of acetazolamide (C₄H₆N₄O₃S₂).

2 IDENTIFICATION

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

Sample: Dissolve 500 mg in 5 mL of water, add 2 drops of hydrochloric acid, and allow the mixture to stand for about 15 min. Filter through a ne sintered-glass funnel, wash with several small portions of water, and dry under vacuum over silica gel for 3 h.

Acceptance criteria: Meets 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.

C. Identification Tests-General 〈191〉, Chemical Identification Tests, Sodium: Meets the requirements

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 to a suitable volumetric flask, add 0.5 N sodium hydroxide equivalent to 10% of the nal volume, and dilute with water to volume.

Sample solution: Nominally 0.1 mg/mL of acetazolamide from Acetazolamide for Injection prepared as follows. Dissolve the contents of one container of Acetazolamide for Injection in a volume of water corresponding to the volume of solvent specied in the labeling. Dilute with water as needed.

3.2 Chromatographic system

Mode: LC

Detector: UV 254 nm

Column: 4.6-mm × 25-cm; 10-μm 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 Acetazolamide for Injection taken:

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

r_u = peak response of acetazolamide from the Sample solution

r_s = peak response of acetazolamide 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%–110.0%

4 PERFORMANCE TESTS

Uniformity of Dosage Units 〈905〉: Meets the requirements

5 IMPURITIES

5.1 Organic Impurities

Buffer: 6.8 g/L of monobasic potassium phosphate in water

Mobile phase: Acetonitrile and Buffer (10:90)

System suitability solution: 0.16 μg/mL each of USP Acetazolamide Related Compound D RS and USP Acetazolamide Related Compound E RS in Mobile phase

Standard stock solution: 0.1 mg/mL of USP Acetazolamide RS prepared as follows. Transfer a weighed amount of USP Acetazolamide RS to a suitable volumetric flask and add acetonitrile equivalent to 10% of the nal volume and Buffer equivalent to 20% of the nal volume. Sonicate to dissolve and dilute with Buffer to volume.

Standard solution: 0.8 μg/mL of USP Acetazolamide RS from Standard stock solution in Mobile phase

Sample solution: Nominally 0.4 mg/mL of acetazolamide from Acetazolamide for Injection prepared as follows. Dissolve the contents of one container of Acetazolamide for Injection in water corresponding to the volume of solvent specied in the labeling. Dilute with Mobile phase as needed.

5.2 Chromatographic system

Mode: LC

Detector: 265 nm

Column: 4.6-mm × 15-cm; 3.5-μm packing L11

Flow rate: 1.0 mL/min

Injection volume: 25 μL

Run time: NLT 3.5 times the retention time of acetazolamide

5.3 System suitability

Samples: System suitability solution and Standard solution

5.4 Suitability requirements

Resolution: NLT 1.5 between acetazolamide related compound E and acetazolamide related compound D, System suitability solution

Relative standard deviation: NMT 5.0%, Standard solution

5.5 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of each impurity in the portion of Acetazolamide for Injection taken:

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

r_u = peak area of each impurity from the Sample solution

r_s = peak area of acetazolamide 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)

F = relative response factor (see Table 1)

Acceptance criteria: See Table 1. Disregard any impurity peak less than 0.05%.

Table 1

^a This process impurity is controlled in the drug substance. It is included in the table for identi cation only and is not to be reported in the total degradation products.

^b 5-Amino-1,3,4-thiadiazole-2-thiol.

^c N-(1,3,4-Thiadiazol-2-yl)acetamide.

^d N-(5-Mercapto-1,3,4-thiadiazol-2-yl)acetamide.

^e N-(5-Chloro-1,3,4-thiadiazol-2-yl)acetamide.

^f N,N′-{5,5′-[(Hydrosulfonylamino)sulfonyl]bis(1,3,4-thiadiazole-5,2-diyl)}diacetamide.

6 SPECIFIC TESTS

pH

Sample solution: Freshly prepared solution (1 in 10)

Acceptance criteria: 9.0–10.0

Bacterial Endotoxins Test 〈85〉: It contains NMT 0.5 USP Endotoxin Units/mg of acetazolamide.

Injections and Implanted Drug Products 〈1〉, Product Quality Tests Common to Parenteral Dosage Forms, Specific Tests, Completeness and Clarity of Solutions: Meets the requirements at the time of use

Sterility Tests: Meets the requirements

7 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve as described in Packaging and Storage Requirements 〈659〉, Injection Packaging, Packaging for constitution, preferably in containers of Type III glass, and store at room temperature.

Labeling 〈7〉, Labels and Labeling for Injectable Products: Meets the requirements

USP Reference Standards 〈11〉

USP Acetazolamide RS

USP Acetazolamide Related Compound D RS

5-Amino-1,3,4-thiadiazole-2-sulfonamide.

C₂H₄N₄O₂S₂ 180.21

USP Acetazolamide Related Compound E RS

5-Acetamido-1,3,4-thiadiazole-2-sulfonic acid potassium salt.

C₄H₄KN₃O₄S₂ 261.32