Magaldrate Oral Suspension
»Magaldrate Oral Suspension contains 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 tight containers.
Identification—
A: Dissolve an amount of Oral Suspension,equivalent to about 800mg of magaldrate,in 20mLof 3Nhydrochloric acid,dilute with water to about 50mL,add 3drops of methyl red TS,and proceed as directed in Identificationtest Aunder Magaldrate,beginning with “and heat to boiling.”
B: It responds to Identificationtest Bunder Magaldrate.
C: Transfer an amount of Oral Suspension,equivalent to about 1g 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 of the residue with three 60-mLportions of water.Transfer the residue to a 250-mLbeaker,and heat on a steam bath to dryness:the X-ray diffraction pattern (see X-ray Diffraction á941ñ),in the d-spacings region below 2.57angstrom units,of the residue so obtained conforms to that of USP Magaldrate RS.
Microbial limits á61ñ— Its total aerobic microbial count does not exceed 100cfu per mL,and it meets the requirements of the test for absence of Escherichia coli.
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— Transfer an accurately measured quantity of Oral Suspension,equivalent to about 1g of magaldrate,to a 100-mLvolumetric flask,add 30mLof dilute hydrochloric acid (1in 10),shake to dissolve,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.
Other requirements— Evaporate a volume of Oral Suspension,equivalent to about 5g of magaldrate,on a steam bath to dryness:the residue so obtained meets the requirements of the tests for Arsenicand Heavy metalsunder Magaldrate.
Assay— Transfer an accurately measured quantity of Oral Suspension,equivalent to about 3g of magaldrate,to a beaker.Add 100.0mLof 1Nhydrochloric acid VS,and mix,using a magnetic stirrer to achieve dissolution.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 1Nhydrochloric acid is equivalent to 35.40mg 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