Sulfadimethoxine
;)
Benzenesulfonamide,4-amino-N-(2,6-dimethoxy-4-pyrimidinyl)-.
N1-(2,6-Dimethoxy-4-pyrimidinyl)sulfanilamide [122-11-2].
»Sulfadimethoxine contains not less than 98.0percent and not more than 102.0percent of C12H14N4O4S,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.
Identification—
A:
Infrared Absorption á197Kñ.
B:
Ultraviolet Absorption á197Uñ—
Solution:
1in 100,000.
Medium:
alcohol.
Absorptivities,calculated on the dried basis,at 272nm do not differ by more than 3.0%.
C:
To about 100mg,add 3mLof 2.5Nsodium hydroxide and 50mLof water,mix until dissolved,and dilute with water to 100mL.To about 5mLof this solution,add 100mg of phenol,and heat to boiling.Cool the solution,and add 0.5mLof sodium hypochlorite TSand 3drops of 2.5Nsodium hydroxide:a yellow color is produced.
D:
To about 10mg dissolved in 2mLof diluted hydrochloric acid,add 3drops of sodium nitrite solution (1in 100),and dilute with water to 4mL:the solution turns yellow.Add 1mLof 2.5Nsodium hydroxide containing 10mg of 2-naphthol:a red-orange precipitate is formed.
Loss on drying á731ñ:
Dry it at 105
for 3hours:it loses not more than 0.5%of its weight.
for 3hours:it loses not more than 0.5%of its weight.
Residue on ignition á281ñ:
not more than 0.1%.
Heavy metals,Method IIá231ñ:
0.002%.
Assay—
Mobile phase—
Dissolve 6g of monobasic sodium phosphate in water to make 1000mL.Adjust with 50%(w/v)sodium hydroxide solution to a pHof 7.0.Prepare a mixture of this solution and methanol (300:100).Make adjustments if necessary (seeSystem Suitability under Chromatography á621ñ).
Standard preparation—
Quantitatively dissolve an accurately weighed quantity of USP Sulfadimethoxine RSinMobile phase to obtain a solution having a known concentration of about 0.2mg per mL.Protect this solution from light.
Assay preparation—
Transfer about 20mg of Sulfadimethoxine,accurately weighed,to a 100-mLvolumetric flask,add about 75mLof Mobile phase,and swirl to dissolve.Dilute this solution with Mobile phaseto volume,and mix.Protect this solution from light.
Chromatographic system(see Chromatography á621ñ)—
The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm ×25-cm column that contains packing L1.The flow rate is about 1mLper minute.Chromatograph theStandard preparation,and record the peak responses as directed forProcedure:the tailing factor is not more than 1.5;and the relative standard deviation for replicate injections is not more than 1.0%.
Procedure—
Separately inject equal volumes (about 10µL)of theStandard preparation and theAssay preparation into the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C12H14N4O4Sin the portion of Sulfadimethoxine taken by the formula:
100C(rU/rS),
in whichCis the concentration,in mg per mL,of USP Sulfadimethoxine RSin theStandard preparation;and rUand rSare the peak responses obtained from theAssay preparation and theStandard preparation,respectively.
Auxiliary Information—
Staff Liaison:Ian DeVeau,Ph.D.,Senior Scientist
Expert Committee:(VET)Veterinary Drugs
USP28–NF23Page 1823
Pharmacopeial Forum:Volume No.28(6)Page 1871
Phone Number:1-301-816-8178