Diluted Acetic Acid

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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DEFINITION

Diluted Acetic Acid is a solution containing, in each 100 mL, NLT 5.7 g and NMT 6.3 g of acetic acid (C₂H₄O₂).

Prepare Diluted Acetic Acid as follows (see Pharmaceutical Compounding—Nonsterile Preparations 〈795〉).

Mix the ingredients.

1 IDENTIFICATION

A. Identification Tests—General, Acetate 〈191〉: Meets the requirements

2 ASSAY

Procedure

Sample: 25 Ml

Analysis: To the Sample add 15 mL of carbon dioxide-free water. Add phenolphthalein TS, and titrate with 1 N sodium hydroxide VS. Each mL of 1 N sodium hydroxide is equivalent to 60.05 mg of acetic acid (C₂H₄O₂).

Acceptance criteria: 5.7–6.3 g of acetic acid per 100 mL of Diluted Acetic Acid

3 IMPURITIES

3.1 Limit of Chloride

Sample solution: A solution of Diluted Acetic Acid in water (6 in 10)

Analysis: Add 5 drops of silver nitrate TS to 10 mL of the Sample solution.

Acceptance criteria: No opalescence is found.

3.2 Limit of Sulfate

Sample solution: A solution of Diluted Acetic Acid in water (6 in 10)

Analysis: Add 5 drops of barium chloride TS to 10 mL of the Sample solution.

Acceptance criteria: No turbidity is produced.

3.3 Limit of Nonvolatile Residue

Sample: 20 mL

Analysis: Evaporate the Sample in a tared porcelain dish on a steam bath, and dry it at 105° for 1 h.

Acceptance criteria: The weight of the residue does not exceed 1.0 mg (NMT 0.005%).

4 SPECIFIC TESTS

Readily Oxidizable Substances

Sample: 20 mL in a glass-stoppered ask

Analysis: Add 0.30 mL of 0.10 N potassium permanganate to the Sample.

Acceptance criteria: The pink color is not changed to brown immediately, and the liquid does not become entirely brown or free from a pink tint in less than 30 s.

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers.