Packaging and storage—
Preserve in tight containers, and store at room temperature.
Identification—
B:
Dissolve about 100 mg in 5 mL of 1 N sodium hydroxide. Add 5 mL of a solution made by dissolving 100 mg of hydroxylamine hydrochloride and 80 mg of cupric sulfate in 10 mL of water. Mix, and heat the resulting pale yellow solution on a steam bath for 5 minutes: a clear, bright yellow solution is produced. No heavy precipitate or dark brown color results after the mixing or heating.
Chloride 
221
—
Digest 1.5 g with 75 mL of water at about 70
for 5 minutes. Cool to room temperature, and filter: a 25-mL portion of the filtrate shows no more chloride than corresponds to 0.10 mL of 0.020 N hydrochloric acid (0.014%).
Sulfate 221—
A 25-mL portion of the filtrate prepared in the test for
Chloride shows no more sulfate than corresponds to 0.20 mL of 0.020 N sulfuric acid (0.04%).
Heavy metals, Method II 231:
0.002%.
Silver-reducing substances—
Thoroughly wet 5.0 g with alcohol. Add 125 mL of water, 10 mL of nitric acid, and 5.0 mL of 0.1 N silver nitrate VS. Stir with a mechanical stirrer for 30 minutes. Filter, add 5 mL of
ferric ammonium sulfate TS to the filtrate, and titrate with 0.1 N ammonium thiocyanate VS to a reddish-brown endpoint: not less than 4.8 mL of 0.1 N ammonium thiocyanate is required.
Ordinary impurities 466—
Test solution:
a mixture of acetone and methanol (1:1).
Standard solution:
a mixture of acetone and methanol (1:1).
Eluant:
a mixture of n-propyl alcohol and 1 N ammonium hydroxide (88:12).
Visualization:
1.
Organic volatile impurities, Method V 467:
meets the requirements.
Solvent—
Use dimethyl sulfoxide.
Assay—
Dissolve about 200 mg of Acetazolamide, accurately weighed, in a small volume of pyridine in a 10-mL volumetric flask, add the solvent to volume, and mix. Similarly, dissolve an accurately weighed quantity of
USP Acetazolamide RS in pyridine to obtain a Standard solution having a known concentration of about 20 mg per mL. Concomitantly determine the absorbances of both solutions in 0.1-mm cells at the wavelength of maximum absorbance at about 7.38 µm (1350 cm
1), with a suitable IR spectrophotometer, using pyridine as the blank. Calculate the quantity, in mg, of C
4H
6N
4O
3S
2 in the portion of Acetazolamide taken by the formula:
10C(AU / AS),
in which
C is the concentration, in mg per mL, of
USP Acetazolamide RS in the Standard solution; and
AU and
AS are the absorbances of the solution of Acetazolamide and the Standard solution, respectively.
Auxiliary Information—
Staff Liaison :
Feiwen Mao, M.S., Senior Scientific Associate
Expert Committee : (MDOOD05) Monograph Development-Ophthalmics Oncologics and Dermatologicals
USP29–NF24 Page 45
Pharmacopeial Forum : Volume No. 27(3) Page 2500
Phone Number : 1-301-816-8320
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