Diatrizoate Sodium
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C11H8I3N2NaO4 635.90

Benzoic acid,3,5-bis(acetylamino)-2,4,6-triiodo-,monosodium salt.
Monosodium 3,5-diacetamido-2,4,6-triiodobenzoate [737-31-5].
»Diatrizoate Sodium contains not less than 98.0percent and not more than 102.0percent of C11H8I3N2NaO4,calculated on the anhydrous basis.
Packaging and storage— Preserve in well-closed containers.Store at room temperature.
Identification—
A: It responds to the Thin-layer Chromatographic Identification Test á201ñ,the test solution and the Standard solution being prepared at a concentration of 1mg of USP Diatrizoic Acid RSper mLin a 0.8in 1000solution of sodium hydroxide in methanol,the solvent mixture being a mixture of chloroform,methanol,and ammonium hydroxide (20:10:2),and short-wavelength UVlight being used to locate the spots.
B: Heat about 500mg in a suitable crucible:violet vapors are evolved.
C: It responds to the flame test for Sodium á191ñ.
Water,Method Iá921ñ: not more than 10.0%.
Free aromatic amine— Transfer 1.0g to a 50-mLvolumetric flask,and add 5mLof water and 10mLof 0.1Nsodium hydroxide.Proceed as directed in the test for Free aromatic amineunder Diatrizoate Meglumine,beginning with “To a second 50-mLvolumetric flask transfer 4mLof water.”
Iodine and iodide—
Test preparation— Transfer 2.0g to a 50-mLcentrifuge tube provided with a stopper,dilute with water to 24mL,and shake to dissolve.
Procedure— Proceed as directed for Procedurein the test for Iodine and iodideunder Diatrizoate Meglumine.
Heavy metals á231ñ— Dissolve 1.0g of Diatrizoate Sodium in 20mLof water and 5mLof 1Nsodium hydroxide,transfer the solution to a 50-mLcolor-comparison tube,dilute with water to 40mL,and mix.Using this as the Test preparation,proceed as directed for Heavy metalsunder Diatrizoate Meglumine:the limit is 0.002%.
Assay— Transfer about 300mg of Diatrizoate Sodium,accurately weighed,to a glass-stoppered,125-mLconical flask,add 30mLof 1.25Nsodium hydroxide and 500mg of powdered zinc,connect the flask to a reflux condenser,and reflux the mixture for 1hour.Cool the flask to room temperature,rinse the condenser with 20mLof water,disconnect the flask from the condenser,and filter the mixture.Rinse the flask and filter thoroughly,adding the rinsings to the filtrate.Add 5mLof glacial acetic acid and 1mLof tetrabromophenolphthalein ethyl ester TS,and titrate with 0.05Nsilver nitrate VSuntil the yellow precipitate just turns green.Each mLof 0.05Nsilver nitrate is equivalent to 10.60mg of C11H8I3N2NaO4.
Auxiliary Information— Staff Liaison:Andrzej Wilk,Ph.D.,Senior Scientific Associate
Expert Committee:(RMI)Radiopharmaceuticals and Medical Imaging Agents
USP28–NF23Page 616
Pharmacopeial Forum:Volume No.29(6)Page 1868
Phone Number:1-301-816-8305