A: Dilute a volume of Injection,equivalent to about 50mg of diphenhydramine hydrochloride,with 0.03Nsulfuric acid to 25mL,and proceed as directed under Identification—Organic Nitrogenous Bases á181ñ,beginning with “Transfer the liquid to a separator”:the Injection meets the requirements of the test.

B: The retention time of the major peak in the chromatogram of the Assay preparationcorresponds to that in the chromatogram of the Standard preparation,as obtained in the Assay.

Mobile phase, Standard preparation,System suitability solution,and Chromatographic system—Prepare as directed in the Assayunder Diphenhydramine Hydrochloride.

Assay preparation— Transfer an accurately measured volume of Injection,equivalent to about 50mg of diphenhydramine hydrochloride,to a 100-mLvolumetric flask,dilute with water to volume,and mix.

Procedure— Proceed as directed for Procedurein the Assayunder Diphenhydramine Hydrochloride.Calculate the quantity,in mg,of C17H21NO·HCl in each mLof the Injection taken by the formula: in which Cis the concentration,in mg per mL,of USP Diphenhydramine Hydrochloride RSin the Standard preparation,Vis the volume,in mL,of Injection taken,and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.