Sulfadimethoxine Tablets

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

DOWNLOAD PDF HERE

Sulfadimethoxine Tablets contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of sulfadimethoxine.

1 Packaging and storage

Preserve in tight, light-resistant containers, and store at controlled room temperature.

2 Labeling

Label the Tablets to indicate that they are for veterinary use only.

USP Reference standards 〈11〉—

USP Sulfadimethoxine RS

3 Identification

Shake a quantity of finely powdered Tablets, equivalent to about 1 g of sulfadimethoxine, with 5 mL of diluted hydrochloric acid and 10 mL of water. Filter, and to the filtrate add 2.5 N sodium hydroxide dropwise until a precipitate forms and redissolves. Add diluted hydrochloric acid dropwise until a precipitate forms. Collect the filtrate on a very fine filter, and wash it with water and with ether: the sulfadimethoxine so obtained meets the requirements for the Identification tests under Sulfadimethoxine.

Disintegration 〈701〉: 30 minutes.

Uniformity of dosage units 〈905〉: meet the requirements.

4 Assay

Mobile phase, Standard preparation, and Chromatographic system—Proceed as directed in the Assay under Sulfadimethoxine.

Assay preparation—Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 50 mg of sulfadimethoxine, 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. Filter if necessary to obtain a clear solution. Protect this solution from light.

Procedure—Proceed as directed in the Assay under Sulfadimethoxine. Calculate the quantity, in mg, of sulfadimethoxine in the portion of Tablets taken by the formula:

250C(r_U/r_S)

in which the terms are as defined therein.