Packaging and storage— Preserve in pressurized containers,and avoid exposure to excessive heat.

Identification— Spray a portion of Topical Aerosol into a beaker,and heat on a steam bath for a few minutes to expel residual propellant.Aportion of this solution,equivalent to about 5mg of benzocaine,responds to the Identificationtest under Benzocaine Topical Solution.

Other requirements— It meets the requirements for Pressure Test,Minimum Fill,and Leakage Testunder Aerosols,Nasal Sprays,Metered-Dose Inhalers,and Dry Powder Inhalers á601ñ.

Assay— Spray a portion of Topical Aerosol into a beaker,and heat on a steam bath for a few minutes to expel residual propellant.Cool,and transfer an accurately weighed portion of the solution,equivalent to about 200mg of benzocaine,to a 250-mLbeaker.Add 50mLof water and 5mLof hydrochloric acid,and stir.Cool the solution in an ice bath to about 10,and titrate slowly with 0.1Msodium nitrite VS,determining the endpoint potentiometrically,using a calomel-platinum electrode system.Perform a blank determination,and make any necessary correction.Each mLof 0.1Msodium nitrite is equivalent to 16.52mg of C9H11NO2.

Expert Committee:(AER)Aerosols

USP28–NF23Page 229

Phone Number:1-301-816-8269