Calcium Gluconate Tablets

General Notices

Definition

Calcium Gluconate Tablets contain Calcium Gluconate.

The tablets comply with the requirements stated under Tablets and with the following requirements.

Content of calcium gluconate, C12H22CaO14,H2O

95.0 to 105.0% of the stated amount.

Identification

A. Extract five tablets, finely powdered, with two 25-mL quantities of petroleum spirit (boiling range, 40° to 60°), discard the extracts and repeat the extraction with three 10-mL quantities of water, again discarding the extracts. Dissolve the residue as completely as possible in 30 mL of hot water, filter and to 0.5 mL of the filtrate add 0.05 mL of iron(iii) chloride solution R1. An intense yellow colour is produced.
B. To a volume of the filtrate obtained in test A containing 0.5 g of Calcium Gluconate add 0.65 mL of glacial acetic acid and 1 mL of phenylhydrazine, heat on a water bath for 30 minutes, cool and induce crystallisation. Filter, dissolve the residue in 10 mL of hot water, add a few mg of activated charcoal, shake, filter, allow the filtrate to cool and induce crystallisation. A white, crystalline precipitate is produced. The melting point of the crystals, after drying, is about 201°, with decomposition, Appendix V A.
C. The powdered tablets yield the reactions characteristic of calcium salts, Appendix VI.

Tests

Dissolution

Comply with the requirements for Monographs of the British Pharmacopoeia in the dissolution test for tablets and capsules, Appendix XII B1, using Apparatus 2. Use as the medium 900 mL of water and rotate the paddle at 50 revolutions per minute. Withdraw a sample of 20 mL of the medium and filter. Carry out the method for atomic absorption spectrophotometry, Appendix II D, measuring at 422.7 nm using a calcium hollow-cathode lamp as the radiation source, an air-acetylene flame and the following solutions.

Test solutionUse the filtered dissolution medium diluted, if necessary, with water to give a concentration suitable for the instrument used.
Standard solutionsUse calcium standard solution (100 ppm Ca) suitably diluted with water.

Determine the total content of calcium in the dissolution medium and calculate the total content of calcium gluconate taking each mg of calcium to be equivalent to 11.21 mg of C12H22CaO14,H2O.

Assay

Weigh and powder 20 tablets. Ignite a quantity of the powder containing 0.5 g of Calcium Gluconate, cool and dissolve the residue with gentle heat in 5 mL of 2m hydrochloric acid. Filter, wash the residue on the filter with water and dilute the combined filtrate and washings to 50 mL with water. Neutralise with 5m ammonia, using methyl orange solution as indicator, add 5 mL of 8m sodium hydroxide and titrate with 0.05m disodium edetate VS using calconcarboxylic acid triturate as indicator. Each mL of 0.05m disodium edetate VS is equivalent to 22.42 mg of C12H22CaO14,H2O.