Calcium and Magnesium Carbonates Tablets
DEFINITION
Calcium and Magnesium Carbonates Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of calcium carbonate (CaCO3) and NLT 85.0% and NMT 115.0% of the labeled amount of magnesium carbonate (MgCO3).
IDENTIFICATION
• A. Identification Tests—General, Calcium 
191
:
The addition of 1 N hydrochloric acid to 1 Tablet produces effervescence, and the resulting solution, after having been filtered, meets the requirements of the tests.
191:
The addition of 1 N hydrochloric acid to 1 Tablet produces effervescence, and the resulting solution, after having been filtered, meets the requirements of the tests.
• B. Identification Tests—General, Magnesium 191
191
Sample solution:
Heat 2 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:
Meet the requirements
ASSAY
• Calcium Carbonate
Sample solution:
Finely powder NLT 20 Tablets. Transfer a portion of the powder, equivalent to 400 mg of calcium carbonate, to a beaker with the aid of 25 mL of water, and add 10 mL of 1 N hydrochloric acid. Heat on a steam bath for 30 min, allow to cool, and transfer to a 100-mL volumetric flask with the aid of water. Dilute with water to volume, mix, filter, and use the filtrate. [Note—Reserve a portion of the filtrate for the Sample solution in the Magnesium Carbonate test. ]
Analysis:
Transfer 20.0 mL of Sample solution to a suitable container. Dilute with water to 100 mL, and add 15 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. Each mL of 0.05 M edetate disodium is equivalent to 5.004 mg of CaCO3.
Acceptance criteria:
90.0%–110.0%
• Magnesium Carbonate
Sample solution:
Use a portion of the filtrate from the Sample solution in the Calcium Carbonate test.
Analysis:
Transfer the Sample solution equivalent to 120 mg of calcium carbonate and magnesium carbonate combined to a suitable container. Dilute with water to 100 mL, and add 10 mL of ammonia–ammonium 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. From the volume of 0.05 M edetate disodium consumed, subtract the volume of 0.05 M edetate disodium corresponding to the content of calcium carbonate in the portion of the Sample solution taken. The difference is the volume of 0.05 M edetate disodium equivalent to the quantity of magnesium carbonate present. Each mL of 0.05 M edetate disodium is equivalent to 4.216 mg of MgCO3.
Acceptance criteria:
85.0%–115.0%
PERFORMANCE TESTS
• Disintegration 701
701
Time:
NMT 10 min, except that where Tablets are labeled as gelatin-coated, the time is NMT 30 min, simulated gastric fluid TS being substituted for water in the test
• Uniformity of Dosage Units 905:
Meet the requirements for Weight Variation with respect to calcium carbonate and to magnesium carbonate
905:
Meet the requirements for Weight Variation with respect to calcium carbonate and to magnesium carbonate
SPECIFIC TESTS
• Acid-Neutralizing Capacity 301
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:
Result = [(FM × M) × 0.8] + [(FC × C) × 0.9]
| FM | = | = theoretical acid-neutralizing capacity of MgCO3, 0.024 mEq |
| M | = | = quantity of MgCO3 in the specimen tested, based on the labeled quantity (mg) |
| FC | = | = theoretical acid-neutralizing capacity of CaCO3, 0.02 mEq |
| C | = | = quantity of CaCO3 in the specimen tested, based on the labeled quantity (mg) |
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers.
• Labeling:
Tablets that are gelatin-coated are so labeled.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Elena Gonikberg, Ph.D.
Principal Scientific Liaison 1-301-816-8251 |
(SM32010) Monographs - Small Molecules 3 |
| 701 |
Margareth R.C. Marques, Ph.D.
Senior Scientific Liaison 1-301-816-8106 |
(GCDF2010) General Chapters - Dosage Forms |
USP35–NF30 Page 2449
Pharmacopeial Forum: Volume No. 27(6) Page 3256