» Sulfapyridine Tablets contain not less than 95.0 percent and not more than 105.0 percent of the labeled amount of C11H11N3O2S.
Packaging and storage Preserve in well-closed, light-resistant containers.
Identification Triturate a quantity of finely powdered Tablets, equivalent to about 500 mg of sulfapyridine, 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 sulfapyridine is formed. Collect the precipitate on a filter, wash it well with cold water, and dry at 105 for 1 hour: the sulfapyridine so obtained melts between 189 and 192 as determined by the method for Class Ia under Melting Range or Temperature 741, and responds to the Identification tests under Sulfapyridine.
Medium: 0.01 N hydrochloric acid; 900 mL.
Apparatus 2: 50 rpm.
Time: 60 minutes.
Procedure Determine the amount of C11H11N3O2S 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 Sulfapyridine RS in the same media.
Tolerances Not less than 70% (Q) of the labeled amount of C11H11N3O2S is dissolved in 60 minutes.
Uniformity of dosage units 905: meet the requirements.
Assay Weigh and finely powder not less than 20 Tablets. Weigh accurately a portion of the powder, equivalent to about 500 mg of sulfapyridine, and proceed as directed under Nitrite Titration 451, beginning with and transfer to a suitable open vessel. Each mL of 0.1 M sodium nitrite is equivalent to 24.93 mg of C11H11N3O2S.
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USP32NF27 Page 3630