Alumina and Magnesia Tablets
»Alumina and Magnesia Tablets contain not less than 90.0percent and not more than 110.0percent of the labeled amounts of aluminum hydroxide [Al(OH)3]and magnesium hydroxide [Mg(OH)2].
Packaging and storage— Preserve in well-closed containers.
Labeling— Tablets prepared with the use of Dried Aluminum Hydroxide Gel may be labeled to state the aluminum hydroxide content in terms of the equivalent amount of dried aluminum hydroxide gel,on the basis that each mg of dried gel is equivalent to 0.765mg of Al(OH)3.
Identification—
A: To a 0.7-g portion of finely powdered Tablets add 10mLof 3Nhydrochloric acid and 5drops of methyl red TS,heat to boiling,and add 6Nammonium hydroxide until the color of the solution changes to deep yellow.Continue boiling for 2minutes,and filter:the filtrate responds to the tests for Magnesium á191ñ.
B: Wash the precipitate obtained in Identificationtest Awith a hot solution of ammonium chloride (1in 50),and dissolve the precipitate in hydrochloric acid:the solution responds to the tests for Aluminum á191ñ.
Disintegration á701ñ: 10minutes,simulated gastric fluid TSbeing substituted for water in the test.
Uniformity of dosage units á905ñ: meet the requirements for Weight Variationwith respect to alumina and to magnesia.
Acid-neutralizing capacity á301ñ— The acid consumed by the minimum single dose recommended in the labeling is not less than 5mEq,and not less than the number of mEq calculated by the formula:
0.55(0.0385A)+0.8(0.0343M),
in which 0.0385and 0.0343are the theoretical acid-neutralizing capacities,in mEq,of Al(OH)3and Mg(OH)2,respectively,and AandMare the quantities,in mg,of Al(OH)3and Mg(OH)2in the specimen tested,based on the labeled quantities.
Assay for aluminum hydroxide—
Edetate disodium titrant— Prepare and standardize as directed in the Assayunder Ammonium Alum.
Assay preparation— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 1200mg of aluminum hydroxide,to a 150-mLbeaker,add 20mLof water,stir,and slowly add 30mLof 3Nhydrochloric acid.Proceed as directed for Assay preparationin the Assay for aluminum hydroxideunder Alumina and Magnesia Oral Suspension,beginning with “Heat gently,if necessary.”
Procedure— Proceed as directed for Procedurein the Assay for aluminum hydroxideunder Alumina and Magnesia Oral Suspension.Each mLof 0.05MEdetate disodium titrantis equivalent to 3.900mg of Al(OH)3.
Assay for magnesium hydroxide—
Assay preparation— Prepare as directed in the Assay for aluminum hydroxide.
Procedure— Proceed as directed for Procedurein the Assay for magnesium hydroxideunder Alumina and Magnesia Oral Suspension.
Auxiliary Information— Staff Liaison:Elena Gonikberg,Ph.D.,Scientist
Expert Committee:(PA4)Pharmaceutical Analysis 4
USP28–NF23Page 78
Pharmacopeial Forum:Volume No.27(3)Page 2515
Phone Number:1-301-816-8251