Packaging and storage—
Preserve in well-closed containers.
Labeling—
Label the Tablets to indicate that they are to be chewed before being swallowed. Label the Tablets to state the sodium content if it is greater than 5 mg per Tablet. The Tablets 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 0.765 mg of Al(OH)3.
Identification—
Cell:
0.5 mm.
Solution:
prepared as directed in the Assay for polydimethylsiloxane.
B:
To a portion of finely powdered Tablets, equivalent to about 600 mg of magnesium hydroxide, add 25 mL of 3 N hydrochloric acid and 25 mL of water, and mix. Boil gently for 2 minutes. Allow to cool, and filter. Add 5 drops of
methyl red TS, heat to boiling, and add 6 N ammonium hydroxide until the color of the solution just turns to deep yellow. Continue boiling for 2 minutes, and filter: the filtrate so obtained responds to the tests for
Magnesium 
191
.
C:
Wash the precipitate obtained in Identification test B with a hot solution of ammonium chloride (1 in 50), and dissolve the precipitate in hydrochloric acid: the solution so obtained responds to Identification test C under Alumina, Magnesia, and Simethicone Oral Suspension.
Acid-neutralizing capacity 301—
The acid consumed by the minimum single dose recommended in the labeling is not less than 5 mEq, and not less than the number of mEq calculated by the formula:
0.55(0.0385A) + 0.8(0.0343 M),
in which 0.0385 and 0.0343 are the theoretical acid-neutralizing capacities, in mEq, of Al(OH)
3 and Mg(OH)
2, respectively, and
A and
M are the quantities, in mg, of Al(OH)
3 and Mg(OH)
2 in the specimen tested, based on the labeled quantities.
Defoaming activity—
Foaming solution—
Dissolve 500 µg of FD&C Blue No. 1 and 1 g of octoxynol 9 in 100 mL of 0.1 N hydrochloric acid.
Procedure—
[NOTE—For each test, employ a clean, unused, 250-mL glass jar.
] Transfer a quantity of finely powdered Tablets, passed completely through an 80-mesh sieve, equivalent to 20 mg of simethicone, to a clean, unused, cylindrical 250-mL glass jar, fitted with a 50-mm cap, containing 100 mL of
Foaming solution that has been warmed to 37
. Proceed as directed for
Procedure in the test for
Defoaming activity under
Simethicone, beginning with “Cap the jar.” The defoaming activity time does not exceed 45 seconds.
Sodium content—
Potassium chloride solution, Sodium chloride stock solution, and Standard preparations—
Prepare as directed in the test for Sodium content under Alumina, Magnesia, and Simethicone Oral Suspension.
Test preparation—
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to the average weight of 1 Tablet, to a 100-mL volumetric flask. Add 50 mL of 1 N hydrochloric acid, boil for 15 minutes, cool to room temperature, dilute with water to volume, and mix. Filter, discarding the first few mL of the filtrate. Transfer 5.0 mL of the filtrate to a 100-mL volumetric flask containing 10.0 mL of Potassium chloride solution, dilute with water to volume, and mix.
Procedure—
Proceed as directed in the test for
Sodium content under
Alumina,
Magnesia,
and Simethicone Oral Suspension. Calculate the quantity, in mg, of sodium per Tablet taken by the formula:
2C.
Assay for aluminum hydroxide—
Edetate disodium titrant—
Prepare and standardize as directed in the
Assay under
Ammonium Alum.
Assay preparation—
Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 800 mg of aluminum hydroxide, to a 150-mL beaker, add 20 mL of water, stir, and slowly add 30 mL of 3 N hydrochloric acid. Heat gently, if necessary, to aid solution, cool to room temperature, and filter into a 200-mL volumetric flask. Wash the filter with water into the flask, add water to volume, and mix.
Procedure—
Proceed as directed for Procedure in the Assay for aluminum hydroxide under Alumina, Magnesia, and Simethicone Oral Suspension.
Assay for magnesium hydroxide—
Procedure—
Proceed as directed for Procedure in the Assay for magnesium hydroxide under Alumina, Magnesia, and Simethicone Oral Suspension.
Assay for polydimethylsiloxane—
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 33 mg of simethicone, to a suitable round, narrow-mouth, screw-capped, 120-mL bottle, add 40 mL of 0.1 N sodium hydroxide, and swirl to disperse. Add 20.0 mL of toluene, close the bottle securely with a cap having an inert liner, and shake for 30 minutes, accurately timed, on a reciprocating shaker (e.g., about 200 oscillations per minute and a stroke of 38 ± 2 mm). Transfer the mixture to a 125-mL separator, and allow to separate. Remove the upper, organic layer to a screw-capped, centrifuge tube containing about 2 g of anhydrous sodium sulfate. Close the tube with a screw-cap having an inert liner, agitate vigorously, and centrifuge the mixture until a clear supernatant (
Assay preparation) is obtained. Similarly prepare a
Standard preparation, using about 33 mg of
USP Polydimethylsiloxane RS, accurately weighed. Prepare a blank by mixing 10 mL of toluene with about 1 g of anhydrous sodium sulfate and centrifuging to obtain a clear supernatant. Concomitantly determine the absorbances of the solutions in 0.5-mm cells at the wavelength of maximum absorbance at about 7.9 µm (1265.8 cm
1), with a suitable IR spectrophotometer, using the blank to set the instrument. Calculate the quantity, in mg, of [
(CH
3)
2SiO
]
n in the portion of Tablets taken by the formula:
(W)(AU / AS),
in which
W is the weight, in mg, of
USP Polydimethylsiloxane RS used to prepare the
Standard preparation; and
AU and
AS are the absorbances of the
Assay preparation and the
Standard preparation, respectively.
