Packaging and storage—
Preserve in tight containers, protected from excessive heat.
Labeling—
The label states the potassium and chloride contents in terms of weight and in terms of milliequivalents. Where the Tablets are packaged in individual pouches, the label instructs the user not to open until the time of use.
Identification—
One Tablet dissolves in 100 mL of water with effervescence. The collected gas responds to the test for
Bicarbonate 
191
, and the resulting solution responds to the tests for
Potassium 191 and for
Chloride 191.
Assay for potassium—
Assay preparation—
Transfer 10 Tablets to a 2000-mL volumetric flask, dissolve in 200 mL of water, swirl until effervescence ceases, dilute with water to volume, and mix. Filter, and quantitatively dilute an accurately measured volume of the filtrate with water to obtain a solution containing 30 µg of potassium per mL. Transfer 5.0 mL of the resulting solution to a 100-mL volumetric flask, add 2.0 mL of sodium chloride solution (1 in 5) and 1.0 mL of hydrochloric acid, dilute with water to volume, and mix.
Procedure—
Proceed as directed for
Procedure in the
Assay under
Potassium Chloride Oral Solution. Calculate the quantity, in mg, of K in each Tablet taken by the formula:
L(C / D),
in which
L is the labeled quantity, in mg, of potassium in each Tablet,
C is the concentration, in µg per mL, of potassium in the
Assay preparation, and
D is the concentration, in µg per mL, of potassium in the
Assay preparation on the basis of the labeled quantity in each Tablet and the extent of dilution.
Assay for chloride—
Transfer a number of Tablets, equivalent to about 900 mg of chloride, to a 2000-mL volumetric flask. Add about 200 mL of water, swirl until effervescence ceases, dilute with water to volume, and mix. Transfer 25.0 mL of this solution to a 250-mL conical flask, add 50.0 mL of 0.1 N silver nitrate VS and 15 mL of nitric acid, and boil, with constant swirling, until the supernatant is colorless. Cool to room temperature, add sufficient water to make a volume of about 150 mL, add 5 mL of
ferric ammonium sulfate TS, and titrate the excess silver nitrate with 0.1 N ammonium thiocyanate VS to a permanent faint brown endpoint. Each mL of 0.1 N silver nitrate is equivalent to 3.545 mg of Cl. Calculate the quantity, in mg, of chloride (Cl) in each Tablet by dividing the total amount of chloride in the Tablets taken by the number of Tablets taken.
