Identification—
A:
Dissolve about 500 mg in 5 mL of water, add 2 drops of hydrochloric acid, and allow the mixture to stand for about 15 minutes. Filter through a fine sintered-glass funnel, wash with several small portions of water, and dry in vacuum over silica gel for 3 hours: the crystals so obtained respond to the
Identification tests under
Acetazolamide.
Assay—
Dissolve the contents of 1 container of Acetazolamide for Injection in an accurately measured volume of water corresponding to the volume of solvent specified in the labeling. Dilute a portion of the solution quantitatively and stepwise with water to obtain a solution having a concentration of about 500 µg of acetazolamide per mL. Pipet 5 mL of the solution into a 250-mL volumetric flask, add 25 mL of 1 N hydrochloric acid, then add water to volume, and mix. Dissolve an accurately weighed quantity of
USP Acetazolamide RS in sodium hydroxide solution (1 in 100) to obtain a Standard solution having a known concentration of about 100 µg per mL. Dilute 10.0 mL of this solution with 0.1 N hydrochloric acid to 100 mL. Concomitantly determine the absorption of both solutions at the wavelength of maximum absorbance at about 265 nm, with a suitable spectrophotometer, using 0.1 N hydrochloric acid as the blank. Calculate the quantity, in µg, of C
4H
6N
4O
3S
2 in the 5.0-mL portion of the solution of Acetazolamide for Injection taken by the formula:
25C(AU / AS),
in which
C is the concentration, in µg per mL, of
USP Acetazolamide RS in the Standard solution; and
AU and
AS are the absorbances of the solution from the Acetazolamide for Injection and the Standard solution, respectively.
1
, preferably of Type III glass, and store at room temperature.