NOTE—Throughout the following procedures,protect test or assay specimens,the Reference Standard,and solutions containing them,by conducting the procedures without delay,under subdued light,or using low-actinic glassware.

A: Place a volume of Injection,equivalent to about 100mg of triflupromazine hydrochloride,in a test tube,add 5mLof 8Nnitric acid,and mix:a peach to amber color develops,quickly turns dark brown,and then changes to a clear solution having a yellow tint.

B: Avolume of Injection,equivalent to about 50mg of triflupromazine hydrochloride,meets the requirements under Identification—Organic Nitrogenous Bases á181ñ.

C: The UVabsorption spectrum of the Assay preparation,prepared as directed in the Assay,exhibits maxima and minima at the same wavelengths as that of the Standard preparation,prepared as directed in the Assay.

Standard preparation— Transfer about 50mg of USP Triflupromazine Hydrochloride RS,accurately weighed,to a 50-mLvolumetric flask,dissolve in 0.5Nsulfuric acid,dilute with 0.5Nsulfuric acid to volume,and mix.Proceed as directed under Assay preparation,beginning with “Transfer 10.0mLof this solution to a 100-mLvolumetric flask.”The concentration of USP Triflupromazine Hydrochloride RSin the Standard preparationis about 5µg per mL.

Assay preparation— Transfer an accurately measured volume of Injection,equivalent to about 50mg of triflupromazine hydrochloride,to a 50-mLvolumetric flask,dilute with 0.5Nsulfuric acid to volume,and mix.Transfer 10.0mLof this solution to a 100-mLvolumetric flask,dilute with the same acid to volume,and mix.Transfer 10.0mLof this solution to a glass-stoppered,50-mLcentrifuge tube containing 10mLof ether previously chilled in an ice bath,insert the stopper,shake for 3minutes,and centrifuge at 1500rpm for 5minutes.Transfer 5.0mLof the aqueous layer to a 100-mLvolumetric flask,dilute with 0.5Nsulfuric acid to volume,and mix.

Procedure— Concomitantly determine the absorbances of the Assay preparationand the Standard preparationin 1-cm cells at the wavelength of maximum absorbance at about 255nm,with a suitable spectrophotometer,using 0.5Nsulfuric acid as the blank.Calculate the quantity,in mg,of C18H19F3N2S·HCl in each mLof the Injection taken by the formula: in which Cis the concentration,in µg per mL,of USP Triflupromazine Hydrochloride RSin the Standard preparation,Vis the volume,in mL,of Injection taken,and AUand ASare the absorbances of the Assay preparationand the Standard preparation,respectively.