Magnesium Oxide Tablets
»Magnesium Oxide Tablets contain not less than 90.0percent and not more than 110.0percent of the labeled amount of magnesium oxide (MgO).
Packaging and storage— Preserve in well-closed containers.
Dissolution á711ñ—
Medium: 0.1Nhydrochloric acid;900mL.
Apparatus 2: 75rpm.
Time: 45minutes.
Procedure— Determine the amount of MgOdissolved,employing atomic absorption spectrophotometry at a wavelength of about 285.2nm using filtered portions of the solution under test,suitably diluted with Mediumif 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 MgOis dissolved in 45minutes.
Uniformity of dosage units á905ñ: meet the requirements.
Acid-neutralizing capacity á301ñ(where Tablets are labeled as intended for antacid use): not less than 5mEq 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 Assayis obtained.Each mg of MgOhas an expected acid-neutralizing capacity value of 0.0492mEq.
Other requirements— One powdered Tablet responds to the Identificationtest under Magnesium Oxide Capsules.
Assay— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 500mg of magnesium oxide,to a beaker.Proceed as directed in the Assayunder Magnesium Oxide Capsulesbeginning with “add 20mLof water.”Each mLof 0.05Medetate disodium consumed is equivalent to 2.015of mg of magnesium oxide (MgO).
Auxiliary Information— Staff Liaison:Elena Gonikberg,Ph.D.,Scientist
Expert Committee:(PA4)Pharmaceutical Analysis 4
USP28–NF23Page 1173
Phone Number:1-301-816-8251
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