Magnesium Gluconate Tablets DEFINITION Magnesium Gluconate Tablets contain NLT 95.0% and NMT 105.0% of the labeled amount of magnesium gluconate (C12H22MgO14). IDENTIFICATION • A. Identification TestsGeneral, Magnesium 191 Sample solution: A filtered solution in water from powdered Tablets, equivalent to 100 mg/mL of magnesium gluconate Acceptance criteria: Meet the requirements • B. Thin-Layer Chromatographic Identification Test Standard solution: 10 mg/mL of USP Potassium Gluconate RS Sample solution: Equivalent to 10 mg/mL of magnesium gluconate from a dilution of the Sample solution obtained for the Identification test A Chromatographic system Mode: TLC 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 2 N 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. Analysis Samples: Standard solution and Sample solution Develop the chromatogram until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the chamber, 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 RF value to that of the Standard solution. ASSAY • Procedure Sample: A portion of the powder from NLT 20 finely powdered Tablets, equivalent to 800 mg of magnesium 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 Endpoint detection: Visual Analysis: Transfer the Sample to a 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 min. Filter, rinsing the filter with several portions of water. Dilute the combined filtrate and washings with water to 150 mL. Add ammoniaammonium chloride buffer TS until the solution is neutral to litmus. Add an excess of 5 mL of ammoniaammonium chloride buffer TS and 0.1 mL of eriochrome black TS, and titrate with Titrant to a blue endpoint. Perform a Blank determination. Calculate the percentage of the labeled amount of magnesium gluconate (C12H22MgO14) in the portion of Tablets taken: Result = {[(VS VB) × M × F]/W} × 100
Acceptance criteria: 95.0%105.0% PERFORMANCE TESTS • Dissolution 711 Medium: Water; 900 mL Apparatus 2: 50 rpm Time: 30 min Standard solution: Solution having a known concentration of magnesium in the Medium Sample solution: Filtered portion of the solution under test, suitably diluted with the Medium if necessary Instrumental conditions Mode: Atomic absorption spectrophotometry Analytical wavelength: 285.2 nm Lamp: Magnesium hollow-cathode Flame: Airacetylene Analysis Samples: Standard solution and Sample solution Determine the concentration of magnesium (Mg) in the Sample solution in comparison with a Standard solution. Calculate the percentage of the labeled amount of magnesium gluconate (C12H22MgO14) dissolved: Result = (C × D × V/L) × (Mr/Ar) × 100
Tolerances: NLT 80.0% (Q) of the labeled amount of magnesium gluconate (C12H22MgO14) is dissolved. • Uniformity of Dosage Units 905: Meet the requirements ADDITIONAL REQUIREMENTS • Packaging and Storage: Preserve in well-closed containers. Auxiliary Information Please check for your question in the FAQs before contacting USP.
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