Benzoic acid, 3,5-bis(acetylamino)-2,4,6-triiodo-, monosodium salt.
Monosodium 3,5-diacetamido-2,4,6-triiodobenzoate
[
737-31-5].
Packaging and storage—
Preserve in well-closed containers. Store at room temperature.
Identification—
A:
It responds to the
Thin-layer Chromatographic Identification Test 
201
, the test solution and the Standard solution being prepared at a concentration of 1 mg of
USP Diatrizoic Acid RS per mL in a 0.8 in 1000 solution of sodium hydroxide in methanol, the solvent mixture being a mixture of chloroform, methanol, and ammonium hydroxide (20:10:2), and short-wavelength UV light being used to locate the spots.
B:
Heat about 500 mg in a suitable crucible: violet vapors are evolved.
C:
It responds to the flame test for
Sodium 191.
Free aromatic amine—
Transfer 1.0 g to a 50-mL volumetric flask, and add 5 mL of water and 10 mL of 0.1 N sodium hydroxide. Proceed as directed in the test for
Free aromatic amine under
Diatrizoate Meglumine, beginning with “To a second 50-mL volumetric flask transfer 4 mL of water.”
Iodine and iodide—
Test preparation—
Transfer 2.0 g to a 50-mL centrifuge tube provided with a stopper, dilute with water to 24 mL, and shake to dissolve.
Procedure—
Proceed as directed for
Procedure in the test for
Iodine and iodide under
Diatrizoate Meglumine.
Heavy metals 231—
Dissolve 1.0 g of Diatrizoate Sodium in 20 mL of water and 5 mL of 1 N sodium hydroxide, transfer the solution to a 50-mL color-comparison tube, dilute with water to 40 mL, and mix. Using this as the
Test preparation, proceed as directed for
Heavy metals under
Diatrizoate Meglumine: the limit is 0.002%.
Assay—
Transfer about 300 mg of Diatrizoate Sodium, accurately weighed, to a glass-stoppered, 125-mL conical flask, add 30 mL of 1.25 N sodium hydroxide and 500 mg of powdered zinc, connect the flask to a reflux condenser, and reflux the mixture for 1 hour. Cool the flask to room temperature, rinse the condenser with 20 mL of water, disconnect the flask from the condenser, and filter the mixture. Rinse the flask and filter thoroughly, adding the rinsings to the filtrate. Add 5 mL of glacial acetic acid and 1 mL of
tetrabromophenolphthalein ethyl ester TS, and titrate with 0.05 N silver nitrate VS until the yellow precipitate just turns green. Each mL of 0.05 N silver nitrate is equivalent to 10.60 mg of C
11H
8I
3N
2NaO
4.
Auxiliary Information—
Staff Liaison :
Andrzej Wilk, Ph.D., Senior Scientific Associate
Expert Committee : (RMI05) Radiopharmaceuticals and Medical Imaging Agents 05
USP29–NF24 Page 671
Pharmacopeial Forum : Volume No. 29(6) Page 1868
Phone Number : 1-301-816-8305
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