Benzocaine, Butamben, and Tetracaine Hydrochloride Topical Aerosol
» Benzocaine, Butamben, and Tetracaine Hydrochloride Topical Aerosol is Benzocaine, Butamben, and Tetracaine Hydrochloride Topical Solution packaged in a pressurized container with a suitable inert propellant. 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 pressurized containers, and avoid exposure to excessive heat.
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Identification—
The retention times of the major peaks in the chromatograms of the Assay preparation correspond to those in the chromatogram of the Standard preparation, as obtained in the Assay.
Other requirements—
It meets the requirements for Pressure Test, Minimum Fill, and Leakage Test under Aerosols, Nasal Sprays, Metered-Dose Inhalers, and Dry Powder Inhalers 
601
.
601.
Assay—
Diluent,
Mobile phase, Standard preparation, and Chromatographic system—Proceed as directed in the Assay under Benzocaine, Butamben, and Tetracaine Hydrochloride Topical Solution.
Assay preparation—
Fit the valve of the Topical Aerosol container with a cannula, and expel the contents of the container into a 100-mL, glass-stoppered round-bottom flask. Attach the flask to a rotary evaporator, and evaporate under a vacuum of about 600 mm of mercury for about 2.5 hours. Transfer an accurately weighed portion of the material in the round-bottom flask, 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 the residue of Topical Aerosol taken from the round-bottom flask 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.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Ravi Ravichandran, Ph.D.
Principal Scientific Liaison 1-301-816-8330 |
(SM42010) Monographs - Small Molecules 4 |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 2322