Potassium Gluconate 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 Gluconate Oral Solution contains NLT 95.0% and NMT 105.0% of the labeled amount of potassium gluconate (C₆H₅K₃O₇).

2 IDENTIFICATION

A. Oral Solution imparts a violet color to a nonluminous flame. The presence of small quantities of sodium can mask the color unless the yellow color produced by sodium is screened out by viewing through a blue filter that blocks emission at 589 nm (sodium), but is transparent to emission at 404 nm (potassium). [Note - Traditionally, cobalt glass has been used, but other suitable filters are commercially available.]

B.

Analysis: Evaporate 5 mL on a steam bath to dryness.

Acceptance criteria: A Mineral oil dispersion of the residue exhibits an IR absorption maximum in the spectral region of 6.2–6.25 μm (carboxylic acid salt).

3 ASSAY

Procedure

Standard stock solution: Transfer 190.7 mg of potassium chloride, previously dried at 105° for 2 h, to a 1000-mL volumetric flask, add sufficient water to dissolve, and dilute with water to volume. Transfer 100.0 mL of this solution to a 1000-mL volumetric flask, and dilute with water to volume. This solution contains 10 μg/mL of potassium (equivalent to 19.07 μg/mL of potassium chloride).

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

Sample solution: Transfer an accurately measured volume of Oral Solution, equivalent to 1.8 g of potassium gluconate, to a 1000-mL volumetric flask, dilute with water to volume, and mix. Transfer 10.0 mL of the solution to a 100-mL volumetric flask, dilute with water to volume, and mix. 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.

Blank: Water

Instrumental conditions

(See Atomic Absorption Spectroscopy 〈852〉.)

Mode: Atomic absorption spectrophotometry

Analytical wavelength: 766.5 nm

Lamp: Potassium hollow-cathode

Flame: Air–acetylene

Analysis

Samples: Standard solutions and Sample solution

Determine the absorbances of the Standard solutions and the Sample solution. Plot the absorbances of the Standard solutions versus their concentrations, in μg/mL, of potassium, and draw the straight line best fitting the three plotted points. From the graph so obtained, determine the concentration, C , in μg/mL, of potassium in the Sample solution.

Calculate the percentage of the labeled amount of potassium gluconate (C₆H₅K₃O₇) in the portion of Oral Solution taken:

Result = (C_K/C_U) × (M_r/A_r) × 100

C_K = determined concentration of potassium in the Sample solution, (μg/mL)

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

M_r = molecular weight of potassium gluconate, 234.25

A_r = atomic weight of potassium, 39.10

Acceptance criteria: 95.0%–105.0%

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4 SPECIFIC TESTS

Alcohol Determination 〈611〉, Method I (ERR 1-Feb-2023) - Distillation Method: 4.5%–5.5% of alcohol (C H OH)

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight, light-resistant containers.