Magaldrate and Simethicone Tablets
»Magaldrate and Simethicone Tablets contain not less than 90.0percent and not more than 110.0percent of the labeled amount of magaldrate [Al5Mg10(OH)31(SO4)2],and an amount of polydimethylsiloxane [–(CH3)2SiO–]nthat is not less than 85.0percent and not more than 115.0percent of the labeled amount of simethicone.
Packaging and storage— Preserve in well-closed containers.
Labeling— Label the Tablets to indicate that they are to be chewed before being swallowed.
Identification—
A: 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.
B: The IRabsorption spectrum,in the 7-to 11-µm region,determined in a 0.5-mm cell,of the Assay preparationprepared as directed in the Assay for polydimethylsiloxane,exhibits maxima only at the same wavelengths as that of the Standard preparationcontaining about 2mg of USP Polydimethylsiloxane RSper mLprepared as directed in the Assay for polydimethylsiloxane.
Microbial limits á61ñ— Tablets meet the requirements of the test for absence of Escherichia coli.
Uniformity of dosage units á905ñ: meet the requirements for Weight Variationwith respect to magaldrate.
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.
Defoaming activity—
Foaming solution and System suitability tests—Proceed as directed in the test for Defoaming activityunder Magaldrate and Simethicone Oral Suspension.
Procedure— [NOTE—For each test use a clean 250-mLcylindrical jar (50-mm internal diameter ×110-mm internal height)with a 50-mm opening fitted with a tight cap with an inert liner.]Transfer a quantity of finely powdered Tablets,equivalent to 20mg of simethicone,to a 250-mLcylindrical jar containing 50mLof 0.6Nhydrochloric acid that has been warmed to 37,and proceed as directed in the test for Defoaming activityunder Magaldrate and Simethicone Oral Suspension,beginning with “Cap the jar.”Record the time,in seconds,for the foam to collapse to the extent that its thickness,measured from the surface of the liquid,is 1.0cm.The defoaming activity time does not exceed 45seconds.
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.”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 for magaldrate— 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.
Assay for polydimethylsiloxane— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 20mg of simethicone,to a 60-mLseparator.Add 10.0mLof hexanes and 25mLof 6Nhydrochloric acid,cap the separator,and shake by mechanical means for not less than 2hours.Allow to stand for about 10minutes,and drain off as much of the lower,aqueous layer as possible without removing any of the unseparated interphase.Add 25mLof 4Nsodium hydroxide to the separator,cap it,and shake by mechanical means for 1hour.Transfer the mixture from the separator to a 50-mLcentrifuge tube,cap,and centrifuge to obtain clear layers.Transfer not less than 5mLof the clear upper hexanes layer to a test tube containing about 0.5g of anhydrous sodium sulfate.Cap the tube,shake vigorously,and allow to stand to obtain a clear supernatant (Assay preparation).Prepare three Standard preparationsin hexanes having known concentrations of about 1.6,2.0,and 2.4mg of USP Polydimethylsiloxane RSper mL,respectively.Concomitantly determine the absorbances of the Assay preparationand the Standard preparationsin a 0.5-mm cell at the wavelength of maximum absorbance at about 1260-cmwith an IRspectrophotometer,using hexanes as the blank.[NOTE—Between each measurement,rinse the cell with heptane,empty,and dry it.]Plot the absorbances for the Standard preparationsversus concentration,in mg per mL,of USP Polydimethylsiloxane RS,and draw the straight line best fitting the three plotted points.From the graph so obtained,determine the concentration,C,in mg per mL,of polydimethylsiloxane in the Assay preparation.Calculate the quantity,in mg,of [–(CH3)2SiO–]nin the portion of Tablets taken by multiplying Cby 10.
Auxiliary Information— Staff Liaison:Elena Gonikberg,Ph.D.,Scientist
Expert Committee:(PA4)Pharmaceutical Analysis 4
USP28–NF23Page 1165
Pharmacopeial Forum:Volume No.29(6)Page 1919
Phone Number:1-301-816-8251