Calcium Gluconate Tablets

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

Calcium Gluconate Tablets contain NLT 95.0% and NMT 105.0% of the labeled amount of calcium gluconate (C₁₂H₂₂CaO₁₄).

2 IDENTIFICATION

2.1 A. IDENTIFICATION TESTS-GENERAL, Calcium(191)

Sample stock solution: A warm, filtered solution in water, equivalent to 100 mg/mL of calcium gluconate from powdered Tablets

Sample solution: Equivalent to 20 mg/mL of calcium gluconate from a dilution of the Sample stock solution

Acceptance criteria: Meet the requirements

2.2 B. THIN-LAYER CHROMATOGRAPHIC IDENTIFICATION TEST

Standard solution: 10 mg/mL of USP Potassium Gluconate RS

Sample solution: Equivalent to 10 mg/mL of calcium gluconate from a dilution of the Sample stock solution obtained from Identification test A

2.2.1 Chromatographic system

(See Chromatography (621), Thin-Layer Chromatography.)

Adsorbent: 0.25-mm layer of chromatographic silica gel

Application volume: 5 µL

Developing solvent system: Alcohol, ethyl acetate, ammonium hydroxide, and water (50:10:10:30)

Spray reagent: Dissolve 2.5 g of ammonium molybdate in 50 mL of 2N sulfuric acid in a 100-mL volumetric flask, add 1.0 g of ceric sulfate, swirl to dissolve, and dilute with 2 N sulfuric acid to volume.

2.2.2 Analysis

Samples: Standard solution and Sample solution

Develop until the solvent front has moved about three-fourths of the length of the plate. Remove the plate, and dry at 110° for 20 min. Allow to cool, and spray with Spray reagent. Heat the plate at 110° for about 10 min.

Acceptance criteria: The principal spot of the Sample solution corresponds in color, size, and R, value to that of the Standard solution.

3 ASSAY

PROCEDURE

Sample: A portion of the powder from NLT 20 finely powdered Tablets, equivalent to 500 mg of calcium gluconate

Blank: Proceed as directed in the Analysis, without the Sample.

Titrimetric system (See Titrimetry (541).)

Mode: Direct titration

Titrant: 0.05 M edetate disodium VS

Indicator: Hydroxy naphthol blue, 300 mg

Endpoint detection: Visual

Analysis: Transfer the Sample to a suitable crucible. Ignite, gently at first, until free from carbon. Cool the crucible. Add 10 mL of water, and dissolve the residue by adding sufficient 3 N hydrochloric acid, dropwise, to achieve complete solution. Transfer the solution to a suitable container, and add about 150 mL of water. While stirring, preferably with a magnetic stirrer, add 20 mL of Titrant from a 50-mL. buret. Add 15 mL of 1 N sodium hydroxide, then add the Indicator. Continue the titration to a blue endpoint. Perform a Blank determination. Calculate the percentage of the labeled amount of calcium gluconate (C₁₂H₂CaO) in the portion of Tablets taken:

Result ={[(V_S-V_B) x MxF]/W} x 100

V_S = Titrant volume consumed by the Sample (mL)

V_B = Titrant volume consumed by the Blank (mL)

M actual molarity of the Titrant (mM/mL)

F = equivalency factor, 430.4 (mg/mM)

W nominal weight of calcium gluconate in the Sample (mg)

Acceptance criteria: 95.0%-105.0%

4 PERFORMANCE TESTS

4.1 DISSOLUTION (711).

Medium: Water; 900 mL

Apparatus 2: 50 rpm

Time: 45 min

Standard solution: Solution having a known concentration of calcium in Medium

Sample solution: Filtered portion of the solution under test, suitably diluted with Medium if necessary

Instrumental conditions

(See Atomic Absorption Spectroscopy (852).)

Mode: Atomic absorption spectrophotometry

Analytical wavelength: 422.8 nm

Lamp: Calcium hollow-cathode

Flame: Air-acetylene

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of calcium gluconate (C₁₂H₂₂CaO₁₄) dissolved:

Result = (A_U/A_S) x (C_SxDxV/L) x (M_r/A_r) x 100

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

C_s = concentration of calcium in the Standard solution (mg/mL)

D = dilution factor for the Sample solution

V = volume of Medium, 900 mL

L = label claim (mg/Tablet)

M_r = molecular weight of calcium gluconate, 430.4

A_r = atomic weight of calcium, 40.078

Tolerances: NLT 75% (Q) of the labeled amount of calcium gluconate (C₁₂H₂₂CaO₁₄,) is dissolved.

4.2 UNIFORMITY OF DOSAGE UNITS (905)

Meet the requirements

5 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in well-closed containers.

USP REFERENCE STANDARDS (11),

USP Potassium Gluconate RS