Packaging and storage—
Preserve in tight, light-resistant containers.
Labeling—
Label the container to indicate that the contents are not intended for parenteral use.
Identification—
A:
Dilute a volume of Solution, if necessary, with an 0.8 in 1000 solution of sodium hydroxide in methanol, to obtain a test solution having a concentration of 1 mg per mL. The test solution responds to the
Thin-Layer Chromatographic Identification Test 
201
, 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:
Evaporate a volume of Solution, equivalent to about 500 mg of diatrizoate meglumine and diatrizoate sodium, to dryness, and heat the residue so obtained in a crucible: violet vapors are evolved.
Iodine and iodide—
Using as the
Test preparation a volume of Solution equivalent to about 2 g of diatrizoate meglumine and diatrizoate sodium and diluting it with water to 24 mL in a 50-mL centrifuge tube provided with a stopper, proceed as directed for
Procedure in the test for
Iodine and iodide under
Diatrizoate Meglumine.
Assay for diatrizoate meglumine—
Pipet a volume of Solution, equivalent to about 1.5 g of diatrizoate meglumine and diatrizoate sodium, into a 250-mL volumetric flask, dilute with water to volume, and mix. Pipet 10 mL of the solution so obtained into a glass-stoppered, 250-mL flask. Add 4 mL of 2 N sulfuric acid and 20 mL of sodium metaperiodate solution (1 in 200). Insert the stopper, and set aside in the dark for 1 hour. Add 50 mL of water, mix, and add 10 mL of
potassium iodide TS. Insert the stopper quickly, mix by swirling for 20 seconds, and immediately titrate with 0.1 N sodium thiosulfate VS, using 3 mL of starch TS. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N sodium thiosulfate is equivalent to 10.11 mg of C
11H
9I
3N
2O
4·C
7H
17NO
5.
Assay for iodine—
Transfer an accurately measured volume of Solution, equivalent to about 4 g of the total of diatrizoate meglumine and diatrizoate sodium, to a 50-mL volumetric flask, dilute with water to volume, and mix. Pipet 5 mL of this solution into 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 6.345 mg of iodine.
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. 27(6) Page 3273
Phone Number : 1-301-816-8305
