Cetyl Alcohol
»Cetyl Alcohol contains not less than 90.0percent of cetyl alcohol (C16H34O),the remainder consisting chiefly of related alcohols.
Packaging and storage
Preserve in well-closed containers.
Identification
The retention time of the major peak in the chromatogram of the Assay preparationcorresponds to that of the major peak in the chromatogram of the System suitability solution,as obtained in the Assay.
Acid value á401ñ:
not more than 2.
Iodine value á401ñ:
not more than 5.
Hydroxyl value
Place about 2g,accurately weighed,in a dry,glass-stoppered,250-mLflask,and add 2mLof pyridine,followed by 10mLof toluene.To the mixture add 10.0mLof a solution of acetyl chloride,prepared by mixing 10mLof acetyl chloride with 90mLof toluene.Insert the stopper in the flask,and immerse in a water bath heated at 60
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Assay
System suitability solution
Dissolve accurately weighed quantities of USP Cetyl Alcohol RSand USP Stearyl Alcohol RSin alcohol to obtain a solution having known concentrations of about 9mg per mLand 1mg per mL,respectively.
Assay preparation
Dissolve 100mg of Cetyl Alcohol in 10.0mLof dehydrated alcohol,and mix.
Chromatographic system
(see Chromatography á621ñ)The gas chromatograph is equipped with a flame-ionization detector and a 3-mm ×2-m column packed with 10%liquid phase G2on support S1A.The carrier gas is helium.The column temperature is maintained at about 205
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Procedure
Inject about 2µLof the Assay preparationinto the chromatograph,record the chromatogram,and measure the areas for the major peaks.Calculate the percentage of C16H34Oin the portion of Cetyl Alcohol taken by the formula:
100(rU/rs),
in which rUis the peak area for cetyl alcohol obtained from the Assay preparation;and rsis the sum of the areas of all the peaks except the solvent peak.
Auxiliary Information
Staff Liaison:Daniel K.Bempong,Ph.D.,Scientist
Expert Committee:(EMC)Excipients:Monograph Content
USP28NF23Page 2986
Pharmacopeial Forum:Volume No.30(3)Page 970
Phone Number:1-301-816-8143
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