Dichlorphenamide
;)
1,3-Benzenedisulfonamide,4,5-dichloro-.
4,5-Dichloro-m-benzenedisulfonamide [120-97-8].
»Dichlorphenamide contains not less than 98.0percent and not more than 101.0percent of C6H6Cl2N2O4S2,calculated on the dried basis.
Packaging and storage—
Preserve in well-closed containers.
Identification—
A:
To 10mLof a 1in 10,000solution in sodium hydroxide solution (1in 2500)add 0.1mLof hydrochloric acid:it exhibits absorption maxima at 295±2nm and at 286±2nm.The ratio A295/A286is between 0.90and 1.00.
B:Infrared Absorption á197Mñ.
Loss on drying á731ñ—
Dry it at a pressure not exceeding 5mm of mercury at 100
to constant weight:it loses not more than 1.0%of its weight.
to constant weight:it loses not more than 1.0%of its weight.
Residue on ignition á281ñ:
not more than 0.2%.
Chloride á221ñ—
To 100mg add 25mLof 8Nnitric acid,and warm on a steam bath to dissolve.Cool to room temperature:the solution shows no more chloride than corresponds to 0.28mLof 0.020Nhydrochloric acid (0.20%).
Selenium á291ñ:
0.003%,a 100-mg test specimen,mixed with 100mg of magnesium oxide,being used.
Heavy metals,Method IIá231ñ:
0.001%.
Organic volatile impurities,Method Vá467ñ:
meets the requirements.
Solvent—
Use dimethyl sulfoxide.
Assay—
Mobile solvent—
Prepare a suitable solution of 0.02Mmonobasic sodium phosphate and 0.02Mdibasic sodium phosphate in acetonitrile and water (approximately 1:1)such that the retention time of Dichlorphenamide is approximately 6minutes.
Standard preparation—
Dissolve an accurately weighed quantity of USP Dichlorphenamide RSin Mobile solventto obtain a solution containing about 1mg per mL.
Assay preparation—
Accurately weigh about 50mg of Dichlorphenamide,and prepare as directed for Standard preparation.
Procedure—
Introduce separately 20-µLportions of the Assay preparationand the Standard preparationinto a high-pressure liquid chromatograph (see Chromatography á621ñ)operated at 25,by means of a suitable microsyringe or sampling valve,adjusting the operating parameters such that the peak obtained with the Standard preparationis full-scale.Typically,the apparatus is fitted with a 4-mm ×30-cm column,packed with packing L1,is equipped with an UVdetector capable of monitoring absorption at 280nm and a suitable recorder,and is capable of operating at a column pressure of up to 3500psi.Five replicate injections of the Standard preparationshow a relative standard deviation of not more than 1.5%.Calculate the quantity,in mg,of C6H6Cl2N2O4S2in the portion of Dichlorphenamide taken by the formula:
,by means of a suitable microsyringe or sampling valve,adjusting the operating parameters such that the peak obtained with the Standard preparationis full-scale.Typically,the apparatus is fitted with a 4-mm ×30-cm column,packed with packing L1,is equipped with an UVdetector capable of monitoring absorption at 280nm and a suitable recorder,and is capable of operating at a column pressure of up to 3500psi.Five replicate injections of the Standard preparationshow a relative standard deviation of not more than 1.5%.Calculate the quantity,in mg,of C6H6Cl2N2O4S2in the portion of Dichlorphenamide taken by the formula:
50C(AU/AS),
in which Cis the concentration,in mg per mL,of USP Dichlorphenamide RSin the Standard preparation;and AUand ASare the area responses obtained at equivalent retention times from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information—
Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist
Expert Committee:(PA6)Pharmaceutical Analysis 6
USP28–NF23Page 625
Pharmacopeial Forum:Volume No.29(4)Page 1025
Phone Number:1-301-816-8389