Sodium Dehydroacetate

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 Dehydroacetate contains NLT 98.0% and NMT 100.5% of sodium dehydroacetate (C₈H₇NaO₄), calculated on the anhydrous basis.

2 IDENTIFICATION

A. Melting Range or Temperature 〈741〉

Sample solution: 150 mg/mL

Analysis: To 10 mL of the Sample solution add 5 mL of 3 N hydrochloric acid, collect the crystals by filtration with suction, wash with 10 mL of water, and dry at 80° for 4 h. Determine the melting point as directed in the chapter.

Acceptance criteria: 109°–111°

B. Identification Tests—General, Sodium〈191〉

Sample solution: 1 in 20

Acceptance criteria: Meets the requirements

3 ASSAY

Procedure

Sample: 500 mg

Blank: 25 mL of glacial acetic acid containing p-naphtholbenzein TS, which has been previously neutralized to a blue color

Titrimetric system

(See Titrimetry 〈541〉.)

Mode: Direct titration

Titrant: 0.1 N perchloric acid VS

Endpoint detection: Visual

Analysis: Transfer the Sample to a 125-mL conical flask, and dissolve it in 25 mL of glacial acetic acid containing p-naphtholbenzein TS, which has been previously neutralized to a blue color. Titrate with 0.1 N perchloric acid VS to the original blue color. Perform a blank determination.

Calculate the percentage of dehydroacetate (C₈H₇NaO₄) in the Sample taken:

Result = {[(V_S − V_B) × N × F]/W} × 100

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

V_B = volume of the Titrant consumed by the Blank (mL)

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

F = equivalency factor, 190.1 mg/mEq

W = weight of the Sample (mg)

Acceptance criteria: 98.0%–100.5% on the anhydrous basis

4 SPECIFIC TESTS

Water Determination, Method I〈921〉: 8.5%–10.0%

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers.