Magnesium Oxide Tablets
» Magnesium Oxide Tablets contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of magnesium oxide (MgO).
Packaging and storage— Preserve in well-closed containers.
Dissolution 711
Medium: 0.1 N hydrochloric acid; 900 mL.
Apparatus 2: 75 rpm.
Time: 45 minutes.
Procedure— Determine the amount of MgO dissolved, employing atomic absorption spectrophotometry at a wavelength of about 285.2 nm using filtered portions of the solution under test, suitably diluted with Medium if necessary, in comparison with a standard solution having a known concentration of magnesium in the same Medium.
Tolerances— Not less than 75% (Q) of the labeled amount of MgO is dissolved in 45 minutes.
Uniformity of dosage units 905: meet the requirements.
Acid-neutralizing capacity 301 (where Tablets are labeled as intended for antacid use): not less than 5 mEq of acid is consumed by the minimum single dose recommended in the labeling, and not less than 85.0% of the expected mEq value calculated from the results of the Assay is obtained. Each mg of MgO has an expected acid-neutralizing capacity value of 0.0492 mEq.
Other requirements— One powdered Tablet responds to the Identification test under Magnesium Oxide Capsules.
Assay— Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 500 mg of magnesium oxide, to a beaker. Proceed as directed in the Assay under Magnesium Oxide Capsules beginning with “add 20 mL of water.” Each mL of 0.05 M edetate disodium consumed is equivalent to 2.015 of mg of magnesium oxide (MgO).
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Topic/Question Contact Expert Committee
Monograph Elena Gonikberg, Ph.D.
Senior Scientist
(MDGRE05) Monograph Development-Gastrointestinal Renal and Endocrine
711 Margareth R.C. Marques, Ph.D.
Senior Scientist
(BPC05) Biopharmaceutics05
USP32–NF27 Page 2836