Packaging and storage
Preserve in well-closed, light-resistant containers.
Clarity and color of solution
Dissolve 1 g in a mixture of 20 mL of water and 5 mL of 1 N sodium hydroxide. The solution is clear and not more deeply colored than pale yellow.
Carefully melt about 50 mg in a small test tube: a reddish brown color develops. The fumes evolved during the decomposition do not discolor moistened lead acetate test paper (distinction from sulfathiazole).
Gently heat about 1 g in a small test tube until a sublimate is formed. Collect a few mg of the sublimate with a glass rod, and mix in a test tube with 1 mL of a 1 in 20 solution of resorcinol in alcohol. Add 1 mL of sulfuric acid, and mix by shaking: a deep red color appears at once. Cautiously dilute the mixture with 25 mL of ice-cold water, and add an excess of 6 N ammonium hydroxide: a blue or reddish blue color is produced.
Digest 2.00 g with 100 mL of water at about 70
for 5 minutes. Cool at once to room temperature, and filter. To 25.0 mL of the filtrate add 2 drops of phenolphthalein TS, and titrate with 0.10 N sodium hydroxide: not more than 0.20 mL is required to produce a pink color.
Ordinary impurities 466
8.3 mg per mL, in a mixture of toluene and dimethylformamide (2:1).
0.008, 0.041, 0.08, and 0.17 mg per mL, in a mixture of toluene and dimethylformamide (2:1).
a mixture of chloroform, methanol, and ammonium hydroxide (30:12:1).
Prepare a suitable degassed solution of water, acetonitrile, and glacial acetic acid (87:12:1).
Dissolve an accurately weighed quantity of USP Sulfadiazine RS
in 0.025 N sodium hydroxide to obtain a solution having a known concentration of about 1 mg per mL.
Transfer about 100 mg of Sulfadiazine, accurately weighed, to a 100-mL volumetric flask, add 0.025 N sodium hydroxide to volume, and mix.
(see Chromatography 621
)The liquid chromatograph is equipped with a 254-nm detector and a 4-mm × 30-cm column that contains packing L1. The flow rate is about 2 mL per minute. Chromatograph five replicate injections of the Standard preparation
, and record the peak responses as directed for Procedure:
the relative standard deviation is not more than 2.0%, and the tailing factor for sulfadiazine is not more than 1.5.
Separately inject equal volumes (about 10 µL) of the Standard preparation
and the Assay preparation
into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C10
S in the portion of Sulfadiazine taken by the formula:
100C(rU / rS)
in which C
is the concentration, in mg per mL, of USP Sulfadiazine RS
in the Standard preparation;
are the peak responses for sulfadiazine obtained from the Assay preparation
and the Standard preparation