Simethicone Emulsion - USP-NF

1 Interim Revision AnnouncementOfficial January 1, shaker with a radius of (measured from center of shaft to center of bottle) Simethicone Emulsionthat uses an arc of 10 at a frequency of 300 30strokes per min. The recommended shaking time isDEFINITION about 20 min, which can be adjusted as needed.] Simethicone Emulsion is a water-dispersible form ofCentrifuge the mixture. [NOTE The following cen- Simethicone composed of Simethicone , suitable emulsifi-trifuging condition was found suitable: 1500 g forers, preservatives, and water. It may contain suitable vis-30 40 min.] Remove from the centrifuge, and imme-cosity-increasing agents. It contains an amount ofdiately transfer about 5mL of the upper organic (tolu-polydimethylsiloxane ([ (CH3)2 SiO ]n) that is NLT ) layer to a 15-mL screw-capped test tube contain-and NMT of the labeled amount of about 1g of anhydrous sodium sulfate.

2 Close thetube with a screw-cap having an inert liner, agitateIDENTIFICATION vigorously, and centrifuge the mixture until a clearsupernatant is obtained. [NOTE The following cen-Change to read:trifuging condition was found suitable: 1500 g forabout 10 min.]Analysis A. INFRARED ABSORPTION . 197 (IRA 1-Jan-2014)[NOTE Wash the cell with copious amounts of toluene . (IRA 1-Jan-2014) Standard solution and Sample solution:to ensure that there is no carryover or residue.]Prepare as directed in the : Standard solution, Sample solution, and BlankAnalysis: Place a suitable amount of the Sample solu-Calculate the percentage of polydimethylsiloxane tion .in a suitable container, (IRA 1-Jan-2014) and dry it([ (CH3)2 SiO ]n) in the labeled amount of simethiconewith a stream of nitrogen or other appropriate meansin the Emulsion :to evaporate the solvent.

3 Similarly proceed with theStandard solution. Record the spectra of the residuesResult = (AU/AS) (CS/CU) 100using 197A or 197F , and examine the spectra (IRA 1-Jan-2014) in the range between 1400cm-1. and absorbance of the Sample solutionAcceptance criteriaAS= absorbance of the Standard solution .For spectra obtained using 197A : The spectrumCS= concentration of USP Polydimethylsiloxane RSfrom the Sample solution shows strong bands atin the Standard solution (mg/mL)1260 10 cm-1., 1015 15 cm-1., and 795 15 cm-1.,CU= nominal concentration of Simethicone in theand a broad shoulder at 1085 15 cm-1., similar toSample solution (mg/mL)the spectrum from the Standard solution. [NOTE TheAcceptance criteria: maxima of the broad shoulder near differ by up to 15cm-1. for the spectra from theIMPURITIESS ample solution and the Standard solution.]

4 ] HEAVY METALSFor spectra obtained using 197F : The spectrumStandard solution: To 20mL of chloroform addfrom the Sample solution shows a strong band of a freshly prepared solution of1260 10 cm-1. and partially resolved bands neardithizone in chloroform, of Standard Lead Solu-1095 15 cm-1., 1020 15 cm-1., and 800 15 cm-1.,tion (see Heavy Metals 231 ) (containing 10mg/mL ofsimilar to the spectrum from the Standard ), and of a mixture of ammonia TS and a (IRA 1-Jan-2014) solution of hydroxylamine hydrochloride (1:9). Sample solution: of Simethicone Emulsion in10mL of chloroform. Dilute with the same solvent toASSAY20mL. Add of a freshly prepared solu- PROCEDURE tion of dithizone in chloroform, of water, andUse glass apparatus only; avoid use of of a mixture of ammonia TS and a solu-Proper mixing of the Emulsion before sampling andtion of hydroxylamine hydrochloride (1:9).

5 Testing is : Immediately shake both solutions vigorouslyStandard solution: 2mg/mL of USP Polydimethylsilox-for 1 RS in toluene. Treat a aliquot of this solu-Acceptance criteria: NMT 5ppm. Any red color in thetion in the same manner as the Blank, beginning withSample solution is not more intense than that in the add 50mL of dilute hydrochloric acid (2 in 5) .Standard : Equivalent to 50mg of Simethicone from theEmulsionSPECIFIC TESTSS ample solution: To the Sample add of tolu- MICROBIAL ENUMERATION TESTS 61 : The total aerobicene. Treat in the same manner as the Blank, beginningmicrobial count does not exceed 102. add 50mL of dilute hydrochloric acid (2 in DEFOAMING ACTIVITY5) .Foaming solution: 10mg/mL of octoxynol 9 in waterInstrumental conditionsSample solution: Transfer a quantity of Emulsion , (See Spectrophotometry and Light-Scattering 851.)

6 Equivalent to 300mg of Simethicone , to a 60-mL bot-Mode: Infraredtle. Dilute with water to 30g, cap the bottle, andCell: wavelength: Maximum absorbance atAnalysisabout mm (1259cm-1.)[NOTE For each test, use a clean, unused, 250-mLBlank: To of toluene add 50mL of dilute hy-glass jar.]drochloric acid (2 in 5), close the bottle securely withAdd, dropwise, 500mL of the Sample solution to aa cap having an inert liner, vigorously shake by handclean, unused, cylindrical 250-mL glass jar, fitted withfor 5 s, then shake for 5 20 min on a suitable 50-mm cap and containing 100mL of the Foaming[NOTE The following shakers were found suitable: (1)solution. Cap the jar, and clamp it in an upright posi-a reciprocating shaker at a rate of about 200 oscilla-tion on a wrist-action shaker.]

7 Using a radius of tions per min and a stroke of 38 2 mm or (2) (measured from the center of the shaft to the 2013 The United States Pharmacopeial ConventionAll Rights Revision Announcement2 SimethiconeOfficial January 1, 2014center of the bottle), shake for 10 s through an arc ofADDITIONAL REQUIREMENTS10 at a frequency of 300 30 strokes per min. Re- PACKAGING AND STORAGE: Preserve in tight the time, in s, required for the foam to collapse. USP REFERENCE STANDARDS 11 The time for foam collapse is determined at the in-USP Polydimethylsiloxane RSstant the first portion of foam-free liquid surface ap-pears, measured from the end of the shaking criteria: The defoaming activity time doesnot exceed 15 s. 2013 The United States Pharmacopeial ConventionAll Rights Reserved.