Packaging and storage—
Preserve in tight containers.
Identification—
Afiltered solution of powdered Tablets responds to the tests for Potassium á191ñand for Iodide á191ñ.
Dissolution á711ñ—
FORUNCOATEDTABLETS
—
Medium:
water;900mL.
Apparatus 2:
50rpm.
Time:
15minutes.
Procedure—
Determine the amount of KIdissolved from UVabsorbances at the wavelength of maximum absorbance at about 227nm of filtered portions of the solutions under test,suitably diluted with Dissolution Medium,if necessary,in comparison with a Standard solution having a known concentration of potassium iodide in the same medium.
Tolerances—
Not less than 75%(Q)of the labeled amount of KIis dissolved in 15minutes.
Assay—
Weigh and finely powder not less than 20Tablets.Transfer a portion of the powder,equivalent to about 1.2g of potassium iodide,to a 250-mLvolumetric flask,add 100mLof water,shake for 20minutes,dilute with water to volume,and mix.Filter through paper,discarding the first 20mLof the filtrate.Transfer 100.0mLof the filtrate,25mLof alcohol,and 1.0mLof 1Nnitric acid to a 200-mLbeaker.Titrate with 0.1Nsilver nitrate VS,determining the endpoint potentiometrically,using silver-calomel electrodes and a salt bridge containing 4percent agar in a saturated potassium nitrate solution.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nsilver nitrate is equivalent to 16.60mg of KI.