Calcium Gluconate (C₁₂H₂₂CaO₁₄): Electrolytes Used in Replacement Therapy

Preparation

• Calcium Gluconate Prepared by reacting calcium carbonate or calcium hydroxide with gluconic acid (obtained through the fermentation of glucose by bacteria or fungi, such as Aspergillus niger):

  • CaCO3 + 2C6H12O7 → Ca(C6H11O7)2 + CO2

  • Ca(OH)2 + 2C6H12O7 → Ca(C6H11O7)2 + 2H2O

Properties

• White or off-white, odorless, crystalline powder or granules

• Slightly soluble in water, forming a clear, colorless solution

• Practically insoluble in alcohol and ether

• A salt of gluconic acid and calcium, containing Ca²⁺ and gluconate ions (C₆H₁₁O₇⁻)

Uses

• Used in electrolyte replacement therapy to treat hypocalcemia (low calcium levels in the blood)

• Can be administered orally or intravenously based on the severity of the deficiency

• Used as an antidote for hyperkalemia, magnesium toxicity, and calcium channel blocker overdose in emergency medicine

• Used as a calcium supplement in cases of calcium deficiency, such as osteoporosis, rickets, and hypoparathyroidism

Assay of Calcium Gluconate

• Typically involves complexometric titration using a chelating agent like ethylenediaminetetraacetic acid (EDTA)

• Performed in the presence of an indicator like Eriochrome Black T or Calcon, which changes color at the endpoint

• The calcium ions are chelated with the EDTA solution, and the amount of EDTA consumed is used to calculate the percentage of calcium gluconate in the sample