» Simethicone Capsules contain an amount of polydimethylsiloxane ([(CH3)2SiO]n) that is not less than 85.0 percent and not more than 115.0 percent of the labeled amount of simethicone.
Packaging and storage Preserve in well-closed containers.
USP Reference standards 11
Identification, Infrared Absorption 197S [noteUse the procedural blank, prepared as directed in the Assay, to set the instrument. ]
Test solution Prepare as directed for the Assay preparation in the Assay.
Standard solution Prepare as directed for the Standard preparation in the Assay.
Cell size: 0.5 mm.
For hard gelatin capsules: 30 minutes, determined using water.
For soft gelatin capsules: 30 minutes, determined using 1.0% w/w octoxynol-9 in water, using the disks.
Uniformity of dosage units 905: meet the requirements.
Assay [notePerform this procedure on at least 3 individual Capsules. The mean of the assay values obtained is the assay value. ] Transfer 1 Capsule to a round, narrow-mouth, screw-capped, 120-mL bottle, add about 20 mL of 6 N hydrochloric acid, and allow to stand, with frequent swirling, until the Capsule has dissolved. Add 10.0 mL of toluene, accurately measured, for each 25 mg of the labeled amount of simethicone in the Capsule, close the bottle securely with a cap having an inert liner, and shake by mechanical means for 5 minutes. Allow the phases to separate, draw off 10 mL of the upper organic (toluene) layer to a test tube containing 0.5 g of anhydrous sodium sulfate, agitate vigorously for 30 seconds, and allow the mixture to settle. If necessary, centrifuge the mixture to obtain a clear solution (Assay preparation). Prepare a Standard preparation by similarly treating a solution of USP Polydimethylsiloxane RS in toluene having a known concentration of about 2.5 mg per mL. Prepare a procedural blank by similarly treating 10.0 mL of toluene. Concomitantly determine the absorbances of the solutions in 0.5-mm cells at the wavelength of maximum absorbance at about 7.9 µm, with an IR spectrophotometer, using the blank to set the instrument. Calculate the quantity, in mg, of [(CH3)2SiO]n in the Capsule taken by the formula:
VC(AU / AS)in which V is the volume, in mL, of toluene taken to prepare the Assay preparation; C is the concentration, in mg per mL, of USP Polydimethylsiloxane RS in the Standard solution; and AU and AS are the absorbances of the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 4637Pharmacopeial Forum: Volume No. 33(5) Page 948