Magaldrate Tablets
»Magaldrate Tablets contain not less than 90.0percent and not more than 110.0percent of the labeled amount of magaldrate [Al5Mg10(OH)31(SO4)2].
Packaging and storage— Preserve in well-closed containers.
Labeling— Label the Tablets to indicate whether they are to be swallowed or to be chewed.
Identification— Transfer a quantity of powdered Tablets,equivalent to about 2g of magaldrate,to a 100-mLcentrifuge tube.Add about 60mLof water,cap,and shake for 3minutes.Centrifuge the suspension,and discard the supernatant.Repeat the washing with three more 60-mLportions of water.Transfer the residue to a 250-mLbeaker,and heat on a steam bath to dryness:the residue so obtained meets the requirements of the Identificationtests under Magaldrate.
Microbial limits á61ñ— Tablets meet the requirements of the test for absence of Escherichia coli.
Disintegration á701ñ: 2minutes,for Tablets labeled to be swallowed.
Uniformity of dosage units á905ñ: meet the requirements for Weight Variation.
Acid-neutralizing capacity— Proceed as directed under 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:
0.8(0.0282M),
in which 0.0282is the theoretical acid-neutralizing capacity,in mEq per mg,of magaldrate;andMis the quantity,in mg,of the labeled amount of magaldrate.
Magnesium hydroxide content—
Test preparation— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 1g of magaldrate,to a 100-mLvolumetric flask,add 30mLof dilute hydrochloric acid (1in 10),shake for 15minutes,dilute with water to volume,and mix.
Procedure— Transfer 10.0mLof Test preparationto a 400-mLbeaker,and proceed as directed in the test for Magnesium hydroxide contentunder Magaldrate,beginning with “and dilute with water to about 200mL.”Not less than 492mg and not more than 666mg of magnesium hydroxide [Mg(OH)2]per g of the labeled amount of magaldrate is found.
Aluminum hydroxide content—
Edetate disodium titrant— Prepare and standardize as directed in the Assayunder Ammonium Alum.
Test preparation— Prepare as directed in the test for Magnesium hydroxide content.
Procedure— Transfer 10.0mLof Test preparationand 20mLof water to a 250-mLbeaker,and proceed as directed for Procedurein the test for Aluminum hydroxide contentunder Magaldrate,beginning with “Add,with stirring,25.0mLof Edetate disodium titrant.”Not less than 321mg and not more than 459mg of aluminum hydroxide [Al(OH)3]per g of the labeled amount of magaldrate is found.
Assay— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 6g of magaldrate,to a 200-mLvolumetric flask.Add 100.0mLof 2Nhydrochloric acid VS,and swirl by mechanical means for 30minutes.Dilute with water to volume,mix,and filter.Transfer 100.0mLof the filtrate to a beaker.Titrate the excess acid with 1Nsodium hydroxide VSto a pHof 3.0,determined potentiometrically.Perform a blank determination (see Residual Titrationsunder Titrimetry á541ñ).Each mLof 2Nhydrochloric acid is equivalent to 70.80mg of Al5Mg10(OH)31(SO4)2.
Auxiliary Information— Staff Liaison:Elena Gonikberg,Ph.D.,Scientist
Expert Committee:(PA4)Pharmaceutical Analysis 4
USP28–NF23Page 1163
Phone Number:1-301-816-8251