Acetic Acid Otic Solution
» Acetic Acid Otic Solution is a solution of Glacial Acetic Acid in a suitable nonaqueous solvent. It contains not less than 85.0 percent and not more than 130.0 percent of the labeled amount of C2H4O2.
Packaging and storage—
Preserve in tight containers, and store at controlled room temperature.
Identification—
A:
Dilute 5 mL with 10 mL of water, and adjust with 1 N sodium hydroxide to a pH of about 7. Add ferric chloride TS: a deep red color is produced, and it is destroyed by the addition of hydrochloric acid.
B:
Warm it with sulfuric acid and alcohol: ethyl acetate, recognizable by its characteristic odor, is evolved.
pH 
791
:
between 2.0 and 4.0, when diluted with an equal volume of water.
791:
between 2.0 and 4.0, when diluted with an equal volume of water.
Assay—
Transfer an accurately known quantity of Otic Solution, containing about 100 mg of glacial acetic acid, to a 250-mL conical flask, and add 5 mL of saturated sodium chloride solution and about 40 mL of water. Add 3 drops of phenolphthalein TS, and 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 C2H4O2.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
| Monograph | Feiwen Mao, M.S.
Scientist 1-301-816-8320 |
(MDOOD05) Monograph Development-Ophthalmics Oncologics and Dermatologicals |
USP32–NF27 Page 1420
Pharmacopeial Forum: Volume No. 27(3) Page 2501