Calcium Carbonate and Magnesia Chewable Tablets
DEFINITION
Calcium Carbonate and Magnesia Chewable Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of calcium carbonate (CaCO3) and NLT 90.0% and NMT 115.0% of the labeled amount of magnesium hydroxide [Mg(OH)2].
IDENTIFICATION
• A. Identification TestsGeneral, Calcium 191:
The addition of 3 N hydrochloric acid to the Chewable Tablets produces effervescence. The resulting solution, after being boiled to expel carbon dioxide and neutralized with 6 N ammonium hydroxide, meets the requirements of the tests.
• B. Identification TestsGeneral, Magnesium 191
Sample solution:
Heat 2 Chewable Tablets in 20 mL of 1 N sulfuric acid. Cool, add 20 mL of alcohol, mix, and allow to stand for 30 min. Filter this solution, and add 2 mL of 1 N hydrochloric acid to the filtrate.
Acceptance criteria:
The solution meets the requirements.
ASSAY
• Calcium Carbonate
Sample solution:
Finely powder NLT 20 Chewable Tablets. Transfer a portion of the powder, equivalent to 400 mg of calcium carbonate, to a beaker with 25 mL of water. Add 40 mL of 1 N hydrochloric acid. Heat on a steam bath for 30 min, allow to cool, and transfer with the aid of water to a 100-mL volumetric flask. Dilute with water to volume, mix, filter, and use the filtrate. [NoteReserve a portion of it for the test for Magnesium Hydroxide. ]
Analysis:
Transfer 20.0 mL of the Sample solution to a suitable container, dilute with water to 100 mL, and add 30 mL of 1 N sodium hydroxide, 5 mL of triethanolamine, and 100 mg of hydroxy naphthol blue. Titrate with 0.05 M edetate disodium VS until the solution is deep blue in color. Each mL of 0.05 M edetate disodium is equivalent to 5.004 mg of CaCO3.
Acceptance criteria:
90.0%110.0%
• Magnesium Hydroxide
Sample solution:
Use the Sample solution from the test for Calcium Carbonate.
Analysis:
Transfer a portion of the Sample solution, equivalent to 120 mg of calcium carbonate and magnesium hydroxide combined, to a suitable container. Dilute with water to 100 mL, and add 10 mL of ammoniaammonium chloride buffer TS, 5 mL of triethanolamine, and 0.3 mL of eriochrome black TS. Titrate with 0.05 M edetate disodium VS to a blue endpoint. The volume, in mL, of 0.05 M edetate disodium consumed, less the volume of 0.05 M edetate disodium corresponding to the content of calcium carbonate in the volume, in mL, of the Sample solution taken, represents the volume, in mL, of 0.05 M edetate disodium equivalent to the quantity of magnesium hydroxide present. Each mL of 0.05 M edetate disodium is equivalent to 2.916 mg of Mg(OH)2.
Acceptance criteria:
90.0%115.0%
PERFORMANCE TESTS
• Uniformity of Dosage Units 905:
Meet the requirements for Weight Variation with respect to calcium carbonate and to magnesia
SPECIFIC TESTS
• Acid-Neutralizing Capacity 301
Analysis:
NLT 5 mEq of acid is consumed by the minimum single dose recommended in the labeling, and NLT the number of mEq calculated by the formula:
Result = [0.8 × (FM × M)] + [0.9 × (FC × C)]
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers.
• Labeling:
Label the Chewable Tablets to indicate that they must be chewed before being swallowed.
Auxiliary Information
Please check for your question in the FAQs before contacting USP.
USP35NF30 Page 2446
Pharmacopeial Forum: Volume No. 33(2) Page 212
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