Lidocaine Topical Aerosol
»Lidocaine Topical Aerosol is a solution of Lidocaine in a suitable flavored vehicle with suitable propellants in a pressurized container equipped with a metering valve.It contains not less than 90.0percent and not more than 110.0percent of the labeled amount of C14H22N2O,and it delivers not less than 85.0percent and not more than 115.0percent of the labeled amount of C14H22N2Oper actuation.
Packaging and storage— Preserve in nonreactive aerosol containers equipped with metered-dose valves.
Identification—
A: To about 5mLof Aerosol spray,collected in a separator,add about 10mLof water and 3mLof dilute hydrochloric acid (1in 2),wash with two 15-mLportions of chloroform,and discard the chloroform washings.Render the solution in the separator alkaline with 5to 6mLof ammonium hydroxide,and extract with three 20-mLportions of chloroform,filtering the chloroform extracts through a pledget of cotton previously moistened with chloroform.Evaporate the combined chloroform extracts with the aid of gentle heat to dryness,and dry the residue in vacuum over silica gel for 24hours:a potassium bromide dispersion of the lidocaine so obtained exhibits maxima only at the same wavelengths as that of a similar preparation of USP Lidocaine RS.
B: To about 2mLof Aerosol spray,collected in a test tube,add 10to 15drops of cobaltous chloride TS,and shake for about 2minutes:a bright green color develops,and a fine precipitate is formed (lidocaine).
C: To about 2mLof Aerosol spray,collected in a test tube,add 5mLof water,1mLof 2Nnitric acid,and 3mLof mercuric nitrate TS:a light yellow color develops (lidocaine).
Microbial limits á61ñ— It meets the requirements of the tests for absence of Staphylococcus aureusand Pseudomonas aeruginosa.
Other requirements— It meets the requirements for Total Number of Discharges per Containerand Delivered Dose Uniformityfor Topical Aerosolsunder Aerosols,Nasal Sprays,Metered-Dose Inhalers,and Dry Powder Inhalers á601ñ.
Assay— Accurately weigh 1Aerosol container and actuator.Transfer a counted number of not less than 10doses to a 125-mLconical flask by carefully discharging the doses in a manner such as to avoid loss of material,and take precautions to protect the specimen from absorption of atmospheric moisture.Accurately weigh the container and actuator to obtain the specimen weight.To the specimen add 20mLof chloroform,mix,and add 10mLof dioxane and 2drops of crystal violet TS.Titrate with 0.1Nperchloric acid in dioxane VSto a blue endpoint.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nperchloric acid is equivalent to 23.43mg of C14H22N2O.
Auxiliary Information— Staff Liaison:Kahkashan Zaidi,Ph.D.,Senior Scientific Associate
Expert Committee:(AER)Aerosols
USP28–NF23Page 1129
Phone Number:1-301-816-8269