Acetazolamide
;)
Acetamide,N-[5-(aminosulfonyl)-1,3,4-thiadiazol-2-yl]-.
N-(5-Sulfamoyl-1,3,4-thiadiazol-2-yl)acetamide [59-66-5].
»Acetazolamide contains not less than 98.0percent and not more than 102.0percent of C4H6N4O3S2,calculated on the anhydrous basis.
Packaging and storage—
Preserve in tight containers,and store at room temperature.
Identification—
A:Infrared Absorption á197Kñ.
B:
Dissolve about 100mg in 5mLof 1Nsodium hydroxide.Add 5mLof a solution made by dissolving 100mg of hydroxylamine hydrochloride and 80mg of cupric sulfate in 10mLof water.Mix,and heat the resulting pale yellow solution on a steam bath for 5minutes:a clear,bright yellow solution is produced.No heavy precipitate or dark brown color results after the mixing or heating.
Water,Method Iá921ñ:
not more than 0.5%.
Residue on ignition á281ñ:
not more than 0.1%.
Chloride á221ñ—
Digest 1.5g with 75mLof water at about 70
for 5minutes.Cool to room temperature,and filter:a 25-mLportion of the filtrate shows no more chloride than corresponds to 0.10mLof 0.020Nhydrochloric acid (0.014%).
for 5minutes.Cool to room temperature,and filter:a 25-mLportion of the filtrate shows no more chloride than corresponds to 0.10mLof 0.020Nhydrochloric acid (0.014%).
Sulfate á221ñ—
A25-mLportion of the filtrate prepared in the test for Chlorideshows no more sulfate than corresponds to 0.20mLof 0.020Nsulfuric acid (0.04%).
Selenium á291ñ:
0.003%,a 200-mg specimen being used.
Heavy metals,Method IIá231ñ:
0.002%.
Silver-reducing substances—
Thoroughly wet 5.0g with alcohol.Add 125mLof water,10mLof nitric acid,and 5.0mLof 0.1Nsilver nitrate VS.Stir with a mechanical stirrer for 30minutes.Filter,add 5mLof ferric ammonium sulfate TSto the filtrate,and titrate with 0.1Nammonium thiocyanate VSto a reddish-brown endpoint:not less than 4.8mLof 0.1Nammonium thiocyanate is required.
Ordinary impurities á466ñ—
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 1Nammonium hydroxide (88:12).
Visualization:
1.
Organic volatile impurities,Method Vá467ñ:
meets the requirements.
Solvent—
Use dimethyl sulfoxide.
Assay—
Dissolve about 200mg of Acetazolamide,accurately weighed,in a small volume of pyridine in a 10-mLvolumetric flask,add the solvent to volume,and mix.Similarly,dissolve an accurately weighed quantity of USP Acetazolamide RSin pyridine to obtain a Standard solution having a known concentration of about 20mg per mL.Concomitantly determine the absorbances of both solutions in 0.1-mm cells at the wavelength of maximum absorbance at about 7.38µm (1350cm-1),with a suitable IRspectrophotometer,using pyridine as the blank.Calculate the quantity,in mg,of C4H6N4O3S2in the portion of Acetazolamide taken by the formula:
10C(AU/AS),
in which Cis the concentration,in mg per mL,of USP Acetazolamide RSin the Standard solution;and AUand ASare the absorbances of the solution of Acetazolamide and the Standard solution,respectively.
Auxiliary Information—
Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist
Expert Committee:(PA6)Pharmaceutical Analysis 6
USP28–NF23Page 41
Pharmacopeial Forum:Volume No.27(3)Page 2500
Phone Number:1-301-816-8389