Benzocaine,Butamben,and Tetracaine Hydrochloride Ointment
»Benzocaine,Butamben,and Tetracaine Hydrochloride Ointment is Benzocaine,Butamben,and Tetracaine Hydrochloride in a suitable ointment base.It contains not less than 90.0percent and not more than 110.0percent of the labeled amounts of benzocaine (C9H11NO2),butamben (C11H15NO2),and tetracaine hydrochloride (C15H24N2O2·HCl).
Packaging and storage— Preserve in tight containers,and avoid freezing.
Identification— The retention times of the major peaks in the chromatogram of the Assay preparationcorrespond to those in the chromatogram of the Standard preparation,as obtained in the Assay.
Minimum fill á755ñ: meets the requirements.
Assay—
Diluent ,Mobile phase,Standard preparation,and Chromatographic system—Proceed as directed in the Assayunder Benzocaine,Butamben,and Tetracaine Hydrochloride Topical Solution.
Assay preparation— Transfer an accurately weighed portion of Ointment,equivalent to about 1400mg of benzocaine,to a 100-mLvolumetric flask.Add about 75mLof methanol,and mix.Sonicate for about 1minute,dilute with methanol to volume,and mix.Transfer 10.0mLof this solution to a second 100-mLvolumetric flask,add about 75mLof Diluent,shake,dilute with Diluentto volume,and mix.
Procedure— Proceed as directed for Procedurein the Assayunder Benzocaine,Butamben,and Tetracaine Hydrochloride Topical Solution.Calculate the individual quantities,in mg,of benzocaine (C9H11NO2),butamben (C11H15NO2),and tetracaine hydrochloride (C15H24N2O2·HCl)in the portion of Ointment taken by the formula:
1000C(rU/rS),
in which Cis the concentration,in mg per mL,of the appropriate Reference Standard in the Standard preparation;and rUand rSare the peak responses of the corresponding analyte obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information— Staff Liaison:Karen A Russo,Ph.D.,Scientist
Expert Committee:(PA1)Pharmaceutical Analysis 1
USP28–NF23Page 231
Phone Number:1-301-816-8379
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