Potassium Chloride Oral Solution

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

DOWNLOAD PDF HERE

1 DEFINITION

Potassium Chloride Oral Solution contains NLT 95.0% and NMT 105.0% of the labeled amount of potassium chloride (KCl). It may contain alcohol.

2 IDENTIFICATION

A. Identification Tests - General, Potassium〈191〉

Sample solution: Carefully evaporate 5 mL to dryness, and ignite the residue at dull-red heat to remove all organic matter. Cool, dissolve the residue in 10 mL of water, and filter.

Acceptance criteria: Meets the requirements

B. Identification Tests - General, Chloride〈191〉

Sample solution: Carefully evaporate 5 mL to dryness, and ignite the residue at dull-red heat to remove all organic matter. Cool, dissolve the residue in 10 mL of water, and filter.

Acceptance criteria: Meets the requirements

3 ASSAY

Procedure

Standard stock solution: 19.07 μg/mL of potassium chloride, previously dried at 105° for 2 h, in water. This solution contains 10 μg/mL of potassium.

Standard solutions: To separate 100-mL volumetric flasks transfer 10.0, 15.0, and 20.0 mL, respectively, of Standard stock solution. To each flask add 2.0 mL of sodium chloride solution (200 mg/mL) and 1.0 mL of hydrochloric acid, and dilute with water to volume. The Standard solutions contain, respectively, 1.0, 1.5, and 2.0 μg/mL of potassium.

Sample stock solution: Transfer a volume of Oral Solution, equivalent to 600 mg of potassium chloride, to a 500-mL volumetric flask, and dilute with water to volume. Transfer 5.0 mL of the solution to a 100-mL volumetric flask, and dilute with water to volume.

Sample solution: Transfer 5.0 mL of Sample stock solution to a 100-mL volumetric flask, add 2.0 mL of sodium chloride solution (200 mg/mL) and 1.0 mL of hydrochloric acid, and dilute with water to volume.

Instrumental conditions

(See Atomic Absorption Spectroscopy 〈852〉.)

Mode: Atomic absorption spectrophotometry

Analytical wavelength: Potassium emission line at 766.5 nm

Lamp: Potassium hollow-cathode

Flame: Air–acetylene

Blank: Water

Analysis

Samples: Standard solutions, Sample solution, and Blank

Plot the absorbance of the Standard solutions versus the concentration of potassium, in μg/mL, and draw the straight line best fitting the three plotted points. From the graph so obtained, determine the concentration of potassium in the Sample solution (μg/mL).

Calculate the percentage of the labeled amount of potassium chloride (KCI) in the portion of Oral Solution taken:

Result = (C/C_U) × (M_r/A_r) × 100

C = concentration of potassium in the Sample solution as determined in this test (μg/mL)

C_U = nominal concentration of potassium chloride in the Sample solution (μg/mL)

M_r = molecular weight of potassium chloride, 74.55

A_r = atomic weight of potassium, 39.10

Acceptance criteria: 95.0%–105.0%

4 SPECIFIC TESTS

Alcohol Determination, Method II 〈611〉(if present): NLT 90.0% and NMT 115.0% of the labeled amount, the labeled amount being NMT 7.5% of C₂H₅OH, acetone being used as the internal standard

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers.