Magnesium Gluconate Tablets
» Magnesium Gluconate Tablets contain not less than 95.0 percent and not more than 105.0 percent of the labeled amount of magnesium gluconate (C12H22MgO14).
Packaging and storage— Preserve in well-closed containers.
Identification— A filtered solution of Tablets, equivalent to magnesium gluconate solution (1 in 10), diluted with water where necessary, responds to the Identification tests under Magnesium Gluconate.
Dissolution 711
Medium: water; 900 mL.
Apparatus 2: 50 rpm.
Time: 30 minutes.
Procedure— Determine the amount of C12H22MgO14 dissolved, employing atomic absorption spectrophotometry at a wavelength of about 285.2 nm, in filtered portions of the solution under test, suitably diluted with water, in comparison with a Standard solution having a known concentration of magnesium in the same Medium.
Tolerances— Not less than 80% (Q) of the labeled amount of C12H22MgO14 is dissolved in 30 minutes.
Uniformity of dosage units 905: meet the requirements.
Assay— Weigh and finely powder not fewer than 20 Tablets. Weigh accurately a portion of the powder, equivalent to about 800 mg of magnesium gluconate, transfer to a suitable crucible, and ignite, gently at first, until free from carbon. Cool the crucible, add 25 mL of water and 5 mL of hydrochloric acid, and stir. Heat on a steam bath for 5 minutes, and filter, rinsing the filter with several portions of water. Dilute the combined filtrate and washings with water to about 150 mL. Add ammonia–ammonium chloride buffer TS until the solution is neutral to litmus. Add 5 mL of ammonia–ammonium chloride buffer TS and 0.1 mL of eriochrome black TS, and titrate with 0.05 M edetate disodium VS to a blue endpoint. Each mL of 0.05 M edetate disodium is equivalent to 20.73 mg of magnesium gluconate (C12H22MgO14).
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Topic/Question Contact Expert Committee
Monograph Curtis Phinney

(DSN05) Dietary Supplements - Non-Botanicals
Reference Standards Lili Wang, Technical Services Scientist
711 Margareth R.C. Marques, Ph.D.
Senior Scientist
(BPC05) Biopharmaceutics05
USP32–NF27 Page 2834