Packaging and storage
Preserve in single-dose containers,preferably of Type Iglass,protected from light.
Labeling
Label containers of Injection intended for intravascular injection to direct the user to discard any unused portion remaining in the container.Label containers of Injection intended for other than intravascular injection to show that the contents are not intended for intravascular injection.
Identification
Dilute 3mLof Injection with water to 100mL,add an excess of 3Nhydrochloric acid,mix,and filter.Wash the precipitate of iothalamic acid so obtained with four 10-mLportions of water,and dry at 105

for 4hours:the dried iothalamic acid so obtained responds to the following tests.
A:
The IRabsorption spectrum of a potassium bromide dispersion of it exhibits maxima only at the same wavelengths as that of a similar preparation of
USP Iothalamic Acid RS.
B:
Heat about 500mg in a suitable crucible:violet vapors are evolved.
Free aromatic amine
Dilute a suitable volume of Injection with water to yield a solution containing 100mg of the total of iothalamate meglumine and iothalamate sodium per mL.Pipet 5mLof this solution into a 50-mLvolumetric flask,and add 10mLof water.Proceed as directed in the test for
Free aromatic amineunder
Iothalamic Acid,beginning with In another flask place 15mLof water.The absorbance of the solution from the Injection is not greater than that of the Standard solution (0.05%).
Iodine and iodide
Dilute a volume of Injection,equivalent to 2g of the total of iothalamate meglumine and iothalamate sodium,with 20mLof water in a 50-mLbeaker,and proceed as directed for
Procedurein the test for
Iodine under
Iothalamic Acid,beginning with add 5mLof 2Nsulfuric acid.The limit of
Iodine and Iodideis 0.02%of iodide.
Heavy metals á231ñ
In a 50-mLcolor-comparison tube,mix a volume of Injection,equivalent to 1.0g of the total of iothalamate meglumine and iothalamate sodium,with 5mLof 1Nsodium hydroxide,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 for iothalamate meglumine
Pipet 5mLof Injection into a 10-mLvolumetric flask,add water to volume,and mix.Determine the angular rotation (see
Optical Rotation á781ñ)of the diluted Injection,using a 10-cm cell and a suitable polarimeter.Calculate the quantity,in mg per mL,of iothalamate meglumine in the Injection taken by the formula:
2000a/6.01,
in which
ais the observed angular rotation,in degrees,corrected for the blank,and the factor 6.01is the specific rotation,in degrees,of iothalamate meglumine.
Assay for iothalamate sodium
Transfer an accurately measured volume of Injection,equivalent to about 4g of iothalamate meglumine and iothalamate sodium,to a 250-mLvolumetric flask,dilute with water to volume,and mix.Pipet 25mLof this solution into a glass-stoppered,125-mLconical flask,add 12mLof 5Nsodium hydroxide and 1g of powdered zinc,connect the flask to a reflux condenser,and reflux the mixture for 30minutes.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 the filter thoroughly,adding the rinsings to the filtrate.Add 40mLof 2Nsulfuric acid,and titrate immediately with 0.05Nsilver nitrate VS,determining the endpoint potentiometrically,using silvercalomel electrodes and an agarpotassium nitrate salt bridge.Calculate the volume,in mL,consumed by the iothalamate meglumine in the portion of solution taken,using the value found in the Assay for iothalamate meglumine.Each mLof 0.05Nsilver nitrate is equivalent to 13.49mg of C11H9I3N2O4·C7H17NO5.Subtract this volume from the total volume of 0.05Nsilver nitrate consumed.Use the resulting volume to calculate the amount,in mg per mL,of iothalamate sodium in the Injection.Each mLof 0.05Nsilver nitrate is equivalent to 10.60mg of C11H8I3N2NaO4.