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.
Identification—
Shake a quantity equivalent to about 1 g 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 precipitate 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.
pH 
791
:
between 7.0 and 8.0, in a solution (1 in 20).
Assay—
Mobile phase, Standard preparation, and Chromatographic system—
Proceed as directed in the
Assay under
Sulfadimethoxine.
Assay preparation—
Transfer an accurately weighed portion of 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. Protect this solution from light.
Procedure—
Proceed as directed in the
Assay under
Sulfadimethoxine. Calculate the quantity, in mg, of sulfadimethoxine (C
12H
14N
4O
4S) in the portion of Powder taken by the formula:
250C(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Sulfadimethoxine RS in the
Standard preparation; and
rU and
rS are the peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
Auxiliary Information—
Staff Liaison :
Ian DeVeau, Ph.D., Associate Director
Expert Committee : (VET05) Veterinary Drugs 05
USP29–NF24 Page 2028
Pharmacopeial Forum : Volume No. 27(2) Page 2198
Phone Number : 1-301-816-8178
