Packaging and storage— Preserve in tight containers.

USP Reference standards 11— USP Lidocaine RS.

Identification— Transfer a quantity of Oral Topical Solution, equivalent to about 250 mg of lidocaine, to a separator with 20 mL of water, and extract with 20 mL of chloroform. Wash the chloroform extract with 20 mL of water, and evaporate the chloroform extract with the aid of a current of warm air. Dissolve the residue in hexane, evaporate with the aid of a current of warm air, and dry the residue in vacuum over silica gel for 24 hours: the crystalline precipitate so obtained responds to Identification test A under Lidocaine.

Residual solvents 467: meets the requirements.

Assay— Transfer an accurately measured volume of Oral Topical Solution, equivalent to about 150 mg of lidocaine, to a 125-mL conical flask, and protect from atmospheric moisture with a stopper fitted with a tube containing silica gel. Add 20 mL of glacial acetic acid and 2 drops of crystal violet TS. Titrate immediately with 0.1 N perchloric acid VS to a blue endpoint. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 23.43 mg of C14H22N2O.

Expert Committee : (MDPS05) Monograph Development-Pulmonary and Steroids

USP29–NF24 Page 1252

Phone Number : 1-301-816-8143