Medium: water;900mL.

Apparatus 2: 50rpm.

Time: 2hours.

Potassium stock solution— Prepare as directed in the Assayunder Potassium Chloride Oral Solution.

Standard solutions— Prepare as directed for Standard preparationsin the Assayunder Potassium Chloride Oral Solution.

Procedure— Filter the solution under test,and dilute quantitatively with Dissolution Mediumto obtain a test solution containing about 60µg of potassium chloride per mL.Place 5.0mLof the test solution in a 100-mLvolumetric flask,add 2.0mLof sodium chloride solution (1in 5)and 1.0mLof hydrochloric acid,dilute with water to volume,mix,and proceed as directed for Procedurein the Assayunder Potassium Chloride Oral Solution.Calculate the quantity,in mg,of KCl dissolved by the formula: in which Fis the extent of dilution of the solution under test,and the other terms are as defined therein.

Tolerances— Not more than 35%(Q)of the labeled amount of KCl is dissolved in 2hours.The requirements are met if the quantities dissolved from the Tablets tested conform to the accompanying acceptance table instead of the table shown under Dissolution á711ñ.

Potassium stock solution andStandard preparations— Prepare as directed in the Assayunder Potassium Chloride Oral Solution.

Assay preparation 1— Place not fewer than 20Tablets in a suitable container with 400mLof water,heat to boiling,and boil for 20minutes.Allow to cool,transfer the solution to a 1000-mLvolumetric flask,dilute with water to volume,and mix.Filter,discarding the first 20mLof the filtrate.Transfer an accurately measured volume of the subsequent filtrate,equivalent to about 60mg of potassium chloride,to a 1000-mLvolumetric flask,dilute with water to volume,and mix.

Assay preparation 2(For formulations containing crystals coated with hydrophobic polymers)— Place not fewer than 20Tablets in a 2000-mLvolumetric flask.Add 1200mLof a mixture of acetonitrile and water (1:1),and shake by mechanical means,or stir using a magnetic bar for 90minutes.Dilute with the mixture of acetonitrile and water (1:1)to volume Allow to stand for 90minutes.Pass through a filter having a 0.2-µm porosity.Transfer an accurately measured volume of the filtrate,quantitatively dilute with water to obtain a solution having a concentration of about 0.06mg per mL,and mix.[NOTE—Retain a portion of the filtrate for use in the test for Identification.].Transfer 5.0mLof the resulting solution to a 100-mLvolumetric flask,add 2.0mLof sodium chloride solution (1in 5)and 1.0mLof hydrochloride acid,dilute with water to volume,and mix.

Procedure— Proceed as directed in the Assayunder Potassium Chloride Oral Solution.Calculate the quantity,in mg,of potassium chloride (KCl)in each Tablet taken by the formula: in which Tis the labeled quantity,in mg,of potassium chloride in each Tablet;Dis the concentration,in µg per mL,of potassium chloride in the designated Assay preparation,based on the labeled quantity per Tablet and the extent of dilution;and the other terms are as defined therein.