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Benzenesulfonamide, 4-amino-N-(2,6-dimethoxy-4-pyrimidinyl)-, monosodium salt.
N1-(2,6-Dimethoxy-4-pyrimidinyl)sulfanilamide monosodium salt [1037-50-9].
» Sulfadimethoxine Sodium contains not less than 98.0 percent and not more than 102.0 percent of C12H13N4NaO4S, calculated on the dried basis.
Packaging and storage Preserve in tight, light-resistant containers, and store at controlled room temperature.
Labeling Label it to indicate that it is for veterinary use only.
USP Reference standards 11
A: To about 100 mg, add 50 mL of water, mix until dissolved, and dilute with water to 100 mL. To about 5 mL of this solution add 100 mg of phenol, and heat to boiling. Cool the solution, and add 0.5 mL of sodium hypochlorite TS and 3 drops of 2.5 N sodium hydroxide: a yellow color is produced.
B: The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.
C: Dissolve 10 mg in 2 mL of diluted hydrochloric acid, add 3 drops of sodium nitrite solution (1 in 100), and dilute with water to 4 mL: the solution turns yellow. Add 1 mL of 2.5 N sodium hydroxide containing 10 mg of 2-naphthol: a red-orange precipitate is formed.
pH 791: between 8.0 and 9.5, in a solution (1 in 20).
Loss on drying 731 Dry it at 125 for 3 hours: it loses not more than 5.0% of its weight.
Heavy metals Dissolve 1.0 g in 25 mL of water, and add 5 drops of freshly prepared sodium sulfide TS: any color produced is not darker than that of a control made with 23 mL of water, 2.0 mL of Standard Lead Solution (see Heavy Metals 231), and 5 drops of freshly prepared sodium sulfide TS (0.002%).
Mobile phase, Standard preparation, and Chromatographic system Proceed as directed in the Assay under Sulfadimethoxine.
Assay preparation Transfer about 60 mg of Sulfadimethoxine Sodium, accurately weighed, to a 250-mL volumetric flask, add about 200 mL of Mobile phase, and swirl to dissolve. Dilute with Mobile phase to volume, and mix. Protect this solution from light.
Procedure Proceed as directed in the Assay under Sulfadimethoxine. Calculate the quantity, in mg, of C12H13N4NaO4S in the portion of Sulfadimethoxine Sodium taken by the formula:
(332.31/310.34)(250C)(rU / rS)in which 332.31 and 310.34 are the molecular weights of sulfadimethoxine sodium and sulfadimethoxine, respectively; and the other terms are as defined therein.
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USP35NF30 Page 4711Pharmacopeial Forum: Volume No. 33(2) Page 254