Sulfamethoxazole Tablets
»Sulfamethoxazole Tablets contain not less than 95.0percent and not more than 105.0percent of the labeled amount of C10H11N3O3S.
Packaging and storage— Preserve in well-closed,light-resistant containers.
Identification—
A: Place a quantity of finely powdered Tablets,equivalent to about 100mg of sulfamethoxazole,in a 50-mLcentrifuge tube,and proceed as directed for Identificationtest Aunder Sulfamethoxazole Oral Suspension,beginning with “add 5mLof ammonium hydroxide.”
B: To a portion of finely powdered Tablets,equivalent to about 100mg of sulfamethoxazole,add 2mLof hydrochloric acid,3mLof sodium nitrite solution (1in 100),and 1mLof sodium hydroxide solution (1in 10)containing 10mg of 2-naphthol:a red-orange precipitate is formed.
Dissolution á711ñ—
Medium: dilute hydrochloric acid (7in 100);900mL.
Apparatus 1: 100rpm.
Time: 30minutes.
Procedure— Determine the amount of C10H11N3O3Sdissolved from UVabsorbances at the wavelength of maximum absorbance at about 265nm of filtered portions of the solution under test,suitably diluted with Dissolution Medium,if necessary,in comparison with a Standard solution having a known concentration of USP Sulfamethoxazole RSin the same medium.
Tolerances— Not less than 80%(Q)of the labeled amount of C10H11N3O3Sis dissolved in 30minutes.
Uniformity of dosage units á905ñ: meet the requirements.
Assay— Weigh and finely powder not less than 20Tablets.Weigh accurately a portion of the powder,equivalent to about 500mg of sulfamethoxazole,dissolve in a mixture of 20mLof glacial acetic acid and 40mLof water,and add 15mLof hydrochloric acid.Cool to 15,and titrate immediately with 0.1Msodium nitrite VS,determining the endpoint potentiometrically using a calomel-platinum electrode system.Each mLof 0.1Msodium nitrite is equivalent to 25.33mg of C10H11N3O3S.
Auxiliary Information— Staff Liaison:Behnam Davani,Ph.D.,MBA,Senior Scientist
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 1829
Phone Number:1-301-816-8394