Acetic Acid Otic Solution
Acetic Acid Otic Solution is a solution of Glacial Acetic Acid in a suitable nonaqueous solvent. It contains NLT 85.0% and NMT 130.0% of the labeled amount of C2H4O2.
•  A.
Sample solution:  Dilute 5 mL of Acetic Acid Otic Solution with 10 mL of water.
Analysis:  Adjust the Sample solution with 1 N sodium hydroxide to a pH of 7. Add ferric chloride TS.
Acceptance criteria:  A deep red color is produced, and it is destroyed by the addition of hydrochloric acid.
•  B.
Analysis:  Warm it with sulfuric acid and alcohol.
Acceptance criteria:  Ethyl acetate, recognizable by its characteristic odor, is evolved.
•  Procedure
Sample:  A quantity of Acetic Acid Otic Solution containing 100 mg of glacial acetic acid
Analysis:  Transfer the Sample to a 250-mL conical flask, and add 5 mL of saturated sodium chloride solution, 40 mL of water, and 3 drops of phenolphthalein TS. Titrate with 0.1 N sodium hydroxide VS to a faint pink endpoint. Each mL of 0.1 N sodium hydroxide is equivalent to 6.005 mg of acetic acid (C2H4O2).
Acceptance criteria:  85.0%–130.0%
•  pH 791
Sample solution:  Acetic Acid Otic Solution and water (1:1)
Acceptance criteria:  2.0–4.0
•  Packaging and Storage: Preserve in tight containers, and store at controlled room temperature.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Feiwen Mao, M.S.
Senior Scientific Liaison
(SM32010) Monographs - Small Molecules 3
USP35–NF30 Page 2065
Pharmacopeial Forum: Volume No. 27(3) Page 2501