Medium: water; 900 mL.

Apparatus 1: 100 rpm.

Time: 2 hours.

Potassium stock solution and Standard preparations— Prepare as directed in the Assay under Potassium Chloride Oral Solution.

Procedure— Filter the solution under test, and dilute quantitatively with Dissolution Medium to obtain a test solution containing about 60 µg of potassium chloride per mL. Add 5.0 mL of the test 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, mix, and proceed as directed for Procedure in the Assay under Potassium Chloride Oral Solution. Calculate the quantity, in mg, of KCl dissolved by the formula: in which F is 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 2 hours. The requirements are met if the quantities dissolved from the Capsules tested conform to the accompanying acceptance table instead of the table shown under Dissolution 711.

Potassium stock solution and Standard preparations— Prepare as directed in the Assay under Potassium Chloride Oral Solution.

Assay preparation— Place not less than 20 Capsules in a suitable container with 400 mL of water, heat to boiling, and boil for 20 minutes. Allow to cool, transfer the solution to a 1000-mL volumetric flask, dilute with water to volume, and mix. Filter, discarding the first 20 mL of the filtrate. Transfer an accurately measured volume of the subsequent filtrate, equivalent to about 60 mg of potassium chloride, to a 1000-mL volumetric flask, dilute with water to volume, and mix. (Retain a portion of the filtrate for use in the Identification test.) 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 KCl in each Capsule taken by the formula: in which T is the labeled quantity, in mg, of potassium chloride in each Capsule, D is the concentration, in µg per mL, of potassium chloride in the Assay preparation, based on the labeled quantity per Capsule and the extent of dilution, and the other terms are as defined therein.