Sulfachlorpyridazine
;)
N1-(6-Chloro-3-pyridazinyl)sulfanilamide [80-32-0].
»Sulfachlorpyridazine contains not less than 97.0percent and not more than 103.0percent of C10H9ClN4O2S,calculated on the dried basis.
Packaging and storage—
Preserve in well-closed,light-resistant containers.
Labeling—
Label it to indicate that it is for veterinary use only.
Identification—
A:
Infrared Absorption á197Mñ.
Clarity and color of solution—
Dissolve 1.0g of it in 50mLof 0.1Nmethanolic hydrochloric acid prepared by diluting 8.6mLof hydrochloric acid with methanol to obtain 1000mLof solvent:a clear solution is produced that is not deeper in color than pale yellow.
Acidity—
Prepare a suspension of 3.0g of it in 150.0mLof carbon dioxide-free water,and heat at 70
for 5minutes,maintaining the suspension.Cool rapidly in an ice bath to 20±0.5,stirring by mechanical means.Filter the suspension using vacuum,and collect the filtrate.Titrate 25.0mLof the clear filtrate with 0.1Nsodium hydroxide VS,using 2drops of thymolphthalein TSas the indicator.Transfer a second 25.0-mLportion of the clear filtrate to a 250-mLconical flask,add 10mLof hydrochloric acid,and cool in an ice bath to 15.Add about 25g of crushed ice,prepared from frozen purified water,and titrate with 0.1Msodium nitrite VS,stirring vigorously,until the titrated solution produces an immediate,stable,blue color on starch-iodide paper.The volume of 0.1Nsodium hydroxide consumed in the titration of the first 25.0-mLportion of the filtrate does not exceed the volume of 0.1Msodium nitrite consumed in the titration of the second 25.0-mLportion of the filtrate by more than 0.5mL.
for 5minutes,maintaining the suspension.Cool rapidly in an ice bath to 20±0.5,stirring by mechanical means.Filter the suspension using vacuum,and collect the filtrate.Titrate 25.0mLof the clear filtrate with 0.1Nsodium hydroxide VS,using 2drops of thymolphthalein TSas the indicator.Transfer a second 25.0-mLportion of the clear filtrate to a 250-mLconical flask,add 10mLof hydrochloric acid,and cool in an ice bath to 15.Add about 25g of crushed ice,prepared from frozen purified water,and titrate with 0.1Msodium nitrite VS,stirring vigorously,until the titrated solution produces an immediate,stable,blue color on starch-iodide paper.The volume of 0.1Nsodium hydroxide consumed in the titration of the first 25.0-mLportion of the filtrate does not exceed the volume of 0.1Msodium nitrite consumed in the titration of the second 25.0-mLportion of the filtrate by more than 0.5mL.
Loss on drying á731ñ:
Dry it at 105for 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—
pH2.5phosphate buffer—
Dissolve 14g of monobasic potassium phosphate in 1600mLof water,adjust with phosphoric acid to a pHof 2.5±0.1,dilute with water to 2000mL,and mix.
Mobile phase—
Prepare a filtered and degassed mixture of pH2.5phosphate bufferand methanol (700:300).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).
Standard preparation—
Prepare a stock solution of USP Sulfachlorpyridazine RSin methanol having a known concentration of about 0.5mg per mL.Transfer 3.0mLof this stock solution to a 100-mLvolumetric flask,dilute with Mobile phaseto volume,and mix.Filter this solution through a nylon filter having a porosity of 0.5µm or finer,and use the filtrate as the Standard preparation.The Standard preparationcontains about 15µg of USP Sulfachlorpyridazine RSper mL.
Assay preparation—
Transfer about 50mg of Sulfachlorpyridazine,accurately weighed,to a 100-mLvolumetric flask.Dissolve in and dilute with methanol to volume,and mix.Transfer 3.0mLof this solution to a second 100-mLvolumetric flask,dilute with Mobile phaseto volume,and mix.Filter this solution through a filter having a porosity of 0.5µm or finer,and use the filtrate as the Assay preparation.
Chromatographic system
(see Chromatography á621ñ)—The liquid chromatograph is equipped with a 265-nm detector,a 4.6-mm ×25-cm analytical column containing 5-µm packing L1,and a guard column containing 5-µm packing L1,and is maintained at about 40.The flow rate is about 1mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the relative standard deviation for replicate injections is not more than 2.0%.
.The flow rate is about 1mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 20µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C10H9ClN4O2Sin the portion of Sulfachlorpyridazine taken by the formula:
(10/3)(C)(rU/rS),
in which Cis the concentration,in µg per mL,of USP Sulfachlorpyridazine RSin the Standard preparation;and rUand rSare the sulfachlorpyridazine peak area responses obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information—
Staff Liaison:Ian DeVeau,Ph.D.,Senior Scientist
Expert Committee:(VET)Veterinary Drugs
USP28–NF23Page 1819
Phone Number:1-301-816-8178