Packaging and storage—
Preserve in well-closed, light-resistant containers.
Identification—
Triturate a quantity of finely powdered Tablets, equivalent to about 500 mg of sulfadiazine, with 5 mL of chloroform, and transfer to a small filter. Wash with another 5-mL portion of chloroform, and discard the filtrate. Triturate the residue with 10 mL of 6 N ammonium hydroxide for 5 minutes, add 10 mL of water, and filter. Warm the filtrate until most of the ammonia is expelled, cool, and add 6 N acetic acid until the reaction is distinctly acid: a precipitate of sulfadiazine is formed. Collect the precipitate on a filter, wash it with cold water, and dry at 105
for 1 hour: the sulfadiazine so obtained melts between 250
and 254
, as determined by the method for
Class Ia under
Melting Range or Temperature 
741
and responds to
Identification test
A under
Sulfadiazine.
Dissolution 711—
Medium:
0.1 N hydrochloric acid; 900 mL.
Apparatus 2:
75 rpm.
Time:
90 minutes.
Procedure—
Determine the amount of C
10H
10N
4O
2S dissolved by employing UV absorption at the wavelength of maximum absorbance at about 254 nm on filtered portions of the solution under test, suitably diluted with 0.01 N sodium hydroxide, in comparison with a Standard solution having a known concentration of
USP Sulfadiazine RS in the same media.
Tolerances—
Not less than 70% (Q) of the labeled amount of C10H10N4O2S is dissolved in 90 minutes.
Assay—
Mobile phase
and Standard preparation—Prepare as directed in the Assay under Sulfadiazine.
Assay preparation—
Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 100 mg of sulfadiazine, to a 100-mL volumetric flask, add 75 mL of 0.025 N sodium hydroxide, shake for 30 minutes, dilute with 0.025 N sodium hydroxide to volume, mix, and centrifuge.
Chromatographic system
and
Procedure—Proceed as directed for
Chromatographic system and for
Procedure in the
Assay under
Sulfadiazine. Calculate the quantity, in mg, of C
10H
10N
4O
2S in the portion of Tablets taken by the formula:
100C(rU / rS),
in which the terms are as defined therein.
