Packaging and storage—
Preserve in well-closed containers.
Identification—
A warm, filtered solution of Tablets, equivalent to calcium gluconate solution (1 in 10), diluted with water, where necessary, responds to the
Identification tests under
Calcium Gluconate.
Dissolution 
711
—
Medium:
water; 900 mL.
Apparatus 2:
50 rpm.
Time:
45 minutes.
Procedure—
Determine the amount of C12H22CaO14 dissolved, employing atomic absorption spectrophotometry at a wavelength of about 422.8 nm on filtered portions of the solution under test, suitably diluted with water, in comparison with a Standard solution having a known concentration of calcium in the same Medium.
Tolerances—
Not less than 75% (Q) of the labeled amount of C12H22CaO14 is dissolved in 45 minutes.
Assay—
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 500 mg of calcium gluconate, to a suitable crucible, and 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, dilute with water to 150 mL, and while stirring, preferably with a magnetic stirrer, add about 20 mL of 0.05 M edetate disodium VS from a 50-mL buret. Add 15 mL of 1 N sodium hydroxide and 300 mg of hydroxy naphthol blue, and continue the titration to a blue endpoint. Each mL of 0.05 M edetate disodium is equivalent to 21.52 mg of calcium gluconate (C12H22CaO14).
Auxiliary Information—
Staff Liaison :
Lawrence Evans, III, Ph.D., Scientist
Expert Committee : (DSN05) Dietary Supplements - Non-Botanicals
USP29–NF24 Page 355
Pharmacopeial Forum : Volume No. 27(6) Page 3258
Phone Number : 1-301-816-8389
