Sodium Acetate

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

Sodium Acetate contains three molecules of water of hydration, or is anhydrous. It contains NLT 99.0% and NMT 101.0% of sodium acetate (C₂H₃NaO₂), calculated on the dried basis.

2 IDENTIFICATION

A. IDENTIFICATION TESTS—GENERAL 〈191〉 , Chemical Identification Tests, Sodium: Meets the requirements

B. IDENTIFICATION TESTS—GENERAL 〈191〉 , Acetate

Sample solution : 10 mg/mL of Sodium Acetate in water. Adjust with 0.1 N sodium hydroxide VS to a slightly alkaline pH. Acceptance criteria: Meets the requirements in test A

3 ASSAY

PROCEDURE

Sample solution: Equivalent to 200 mg of anhydrous Sodium Acetate in 50 mL of glacial acetic acid. Heat gently on a steam bath for about 5 min to dissolve. Cover the solution and stir while cooling.

Blank: 50 mL of glacial acetic acid

Titrimetric system (See Titrimetry 〈541〉.)

Mode: Direct titration

Titrant: 0.1 N perchloric acid VS Endpoint detection: Potentiometric

Analysis: Titrate the Sample solution with Titrant. Perform a blank determination, and make any necessary correction. Calculate the percentage of sodium acetate (C H NaO ) in the portion of Sodium Acetate taken:

Result = [(V_S − V_B) × N_A × F × 100]/W

V_S = Titrant volume consumed by the Sample solution (mL)

V_B = Titrant volume consumed by the Blank (mL)

N_A = actual normality of the Titrant (mEq/mL)

F = equivalency factor, 82.03 mg/mEq

W = equivalent weight of anhydrous Sodium Acetate in the Sample solution (mg) Acceptance criteria: 99.0%–101.0% on the dried basis

4 IMPURITIES

4.1 CHLORIDE AND SULFATE 〈221〉 , Chloride

Sample: Equivalent to 1.0 g of anhydrous Sodium Acetate

Acceptance criteria: Shows no more chloride than corresponds to 0.50 mL of 0.020 N hydrochloric acid VS (350 ppm).

4.2 CHLORIDE AND SULFATE 〈221〉 , Sulfate

Sample: Equivalent to 10 g of anhydrous Sodium Acetate

Acceptance criteria: Shows no more sulfate than corresponds to 0.50 mL of 0.020 N sulfuric acid VS (50 ppm).

4.3 CALCIUM AND MAGNESIUM 

Sample solution: Equivalent to 10 mg/mL of anhydrous Sodium Acetate

Analysis: To 20 mL of Sample solution, add 2 mL each of 6 N ammonium hydroxide, ammonium oxalate TS, and dibasic sodium phosphate TS.

Acceptance criteria: No turbidity is produced within 5 min.

4.4 POTASSIUM

Sample solution: Dissolve the equivalent of 3 g of anhydrous Sodium Acetate in 5 mL of water.

Analysis: To the Sample solution, add 1 N acetic acid dropwise until the solution is slightly acidic, and then add 5 drops of sodium cobaltinitrite TS.

Acceptance criteria: No precipitate is formed. Change to read:

4.5 ALUMINUM 〈206〉 , Procedure 1 (CN 1-JUN-2023) (where it is labeled as intended for use in hemodialysis)

Test preparation: Prepare as directed in the chapter, using a portion equivalent to 10 g of sodium acetate trihydrate. Acceptance criteria: 0.2 µg/g

5 SPECIFIC TESTS

5.1 PH 〈791〉

Sample solution: Equivalent to 30 mg/mL of anhydrous Sodium Acetate in carbon dioxide-free water Acceptance criteria: 7.5–9.2

5.2 LOSS ON DRYING 〈731〉

Analysis: Dry at 120° to constant weight. Acceptance criteria

Anhydrous: NMT 1.0%

Trihydrate: 38.0%–41.0%

5.3 INSOLUBLE MATTER

Sample: Equivalent to 20 g of anhydrous Sodium Acetate

Analysis: Dissolve the Sample in 150 mL of water, heat to boiling, and digest in a covered beaker on a steam bath for 1 h. Filter through a tared filtering crucible, wash thoroughly, and dry at 105°.

Acceptance criteria: The weight of the residue is NMT 10 mg (0.05%).

6 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight containers.

LABELING: Label it to indicate whether it is the trihydrate or is anhydrous. Where Sodium Acetate is intended for use in hemodialysis, it is so labeled.