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 90.0 percent and not more than 110.0 percent of the labeled amounts of benzocaine (C9H11NO2), butamben (C11H15NO2), and tetracaine hydrochloride (C15H24N2O2·HCl).
Packaging and storage Preserve in tight containers, and avoid freezing.
USP Reference standards 11
Identification The retention times of the major peaks in the chromatogram of the Assay preparation correspond to those in the chromatogram of the Standard preparation, as obtained in the Assay.
Minimum fill 755: meets the requirements.
Diluent , Mobile phase, Standard preparation, and Chromatographic systemProceed as directed in the Assay under Benzocaine, Butamben, and Tetracaine Hydrochloride Topical Solution.
Assay preparation Transfer an accurately weighed portion of Ointment, equivalent to about 1400 mg of benzocaine, to a 100-mL volumetric flask. Add about 75 mL of methanol, and mix. Sonicate for about 1 minute, dilute with methanol to volume, and mix. Transfer 10.0 mL of this solution to a second 100-mL volumetric flask, add about 75 mL of Diluent, shake, dilute with Diluent to volume, and mix.
Procedure Proceed as directed for Procedure in the Assay under 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 C is the concentration, in mg per mL, of the appropriate Reference Standard in the Standard preparation; and rU and rS are the peak responses of the corresponding analyte obtained from the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 2323