Potassium Bicarbonate and Potassium Chloride Effervescent Tablets for 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)

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1 DEFINITION

Potassium Bicarbonate and Potassium Chloride Effervescent Tablets for Oral Solution contain NLT 90.0% and NMT 110.0% of the labeled amounts of potassium (K) and chloride (Cl).

2 IDENTIFICATION

Change to read:

A. (USP 1-Aug-2022)

Sample: 1 Tablet for Oral Solution

Analysis 1: Dissolve the Sample in 100 mL of water, and collect the gas that evolves.

Acceptance criteria 1: The Sample effervesces when dissolved.

Analysis 2: Proceed as directed in Identication Tests—General 〈191〉, Chemical Identification Tests, Bicarbonate on the gas collected from Analysis 1.

Acceptance criteria 2: Meets the requirements of test A

(USP 1-Aug-2022)

Add the following:

B. The retention time of the potassium peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay, Procedure 1: Potassium. (USP 1-Aug-2022)

Add the following:

C. The retention time of the chloride peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay, Procedure 2: Chloride. (USP 1-Aug-2022)

3 ASSAY

Change to read:

3.1 Procedure 1: Potassium

Use water with a resistivity of NLT 18 megohm-cm to prepare the solutions.

Mobile phase: 4 mM nitric acid

System suitability solution: 30 µg/mL of USP Potassium Chloride RS and 15 µg/mL of magnesium1 in water

Standard solution: 30 µg/mL of USP Potassium Chloride RS in water

Sample stock solution: Nominally 10 mg/mL of potassium chloride prepared as follows. Finely powder NLT 20 Tablets for Oral Solution and transfer an appropriate portion of the powder to a suitable volumetric flask. Add about 10% of the final volume of water, and swirl until effervescence ceases. Dilute with water to volume. [Note—Pass through a suitable filter if necessary.]

Sample solution: Nominally 30 µg/mL of potassium chloride in water from the Sample stock solution

3.1.1 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: Direct conductivity

Columns

Guard: 4-mm × 0.5-cm; 5-µm packing L76

Analytical: 4-mm × 15-cm; 5-µm packing L76

Column temperature: 30°

Flow rate: 0.9 mL/min

Injection volume: 20 µL

Run time: NLT 2 times the retention time of potassium

3.1.2 System suitability

Samples: System suitability solution and Standard solution

[Note—The relative retention times for the potassium and magnesium ions are 1.0 and 1.3, respectively.]

Suitability requirements

Resolution: NLT 3.0 between the potassium and magnesium ions, System suitability solution

Tailing factor: NMT 2.0, Standard solution

Relative standard deviation: NMT 2.0%, Standard solution

3.1.3 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of potassium (K) in the portion of Tablets for Oral Solution taken:

Result = (r_U /r_S ) × (C_S /C_U ) × 100

r_U = peak response of potassium from the Sample solution

r_S = peak response of potassium from the Standard solution

C_S = concentration of USP Potassium Chloride RS in the Standard solution (µg/mL)

C_U = nominal concentration of potassium chloride in the Sample solution (µg/mL) (USP 1-Aug-2022)

Acceptance criteria: 90.0%–110.0%

Change to read:

3.2 Procedure 2: Chloride

[Note—Use water with a resistivity of NLT 18 megohm-cm to prepare the solutions.]

Standard solution, Sample stock solution, and Sample solution: Prepare as directed in Assay, Procedure 1: Potassium. Mobile phase: 15 mM sodium carbonate and 1.5 mM sodium hydroxide in water

System suitability solution: 30 µg/mL of USP Potassium Chloride RS and 20 µg/mL of USP Sodium Nitrite RS in water

3.2.1 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: Conductivity with suppression

Columns

Guard: 4.0-mm × 0.5-cm; 4.6-µm packing L91

Analytical: 4.0-mm × 10-cm; 4.6-µm packing L91

Column temperature: 45°

Flow rate: 0.8 mL/min

Injection volume: 20 µL

Run time: NLT 3 times the retention time of chloride for Standard solution and System suitability solution; NLT 9 times the retention time of chloride for Sample solution

3.2.2 System suitability

Samples: System suitability solution and Standard solution

[Note—The relative retention times for the chloride and nitrite ions are 1.0 and 1.2, respectively.]

Suitability requirements

Resolution: NLT 2.0 between the chloride and nitrite ions, System suitability solution

Tailing factor: NMT 2.0 for the chloride ion, Standard solution

Relative standard deviation: NMT 2.0% for the chloride ion, Standard solution

3.2.3 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of chloride (Cl) in the portion of Tablets for Oral Solution taken:

Result = (r_U /r_S ) × (C_S /C_U ) × 100

r_U = peak response of chloride from the Sample solution

r_S = peak response of chloride from the Standard solution

C_S = concentration of USP Potassium Chloride RS in the Standard solution (µg/mL)

C_U = nominal concentration of potassium chloride in the Sample solution (µg/mL) (USP 1-Aug-2022)

Acceptance criteria: 90.0%–110.0%

4 PERFORMANCE TESTS

Uniformity of Dosage Units 〈905〉: Meet the requirements

5 ADDITIONAL REQUIREMENTS

Change to read:

Packaging and Storage: Preserve in tight containers, and store under cool and dry conditions not exceeding 30°. (USP 1-Aug-2022) Change to read:

Labeling: The label states the potassium and chloride contents in terms of weight and in terms of milliequivalents. Where the Tablets for Oral Solution (USP 1-Aug-2022) are packaged in individual pouches, the label instructs the user not to open until the time of use. Add the following:

USP Reference Standards 〈11〉

USP Potassium Chloride RS

USP Sodium Nitrite RS (USP 1-Aug-2022)