A: Infrared Absorption á197Kñ—Obtain the test specimen as follows.Steam-distill a volume of Injection,equivalent to about 250mg of tolazoline hydrochloride,for 5to 10minutes,and discard the distillate.Transfer the remaining solution to a separator,add about 2mLof 1Nsodium hydroxide,and extract with 20mLof ether.Filter the ether extract through cotton into a beaker,evaporate to dryness,and dry the residue in vacuum over silica gel for 4hours.

B: It responds to Identificationtest Bunder Tolazoline Hydrochloride.

C: To 1mLof Injection add 1mLof ammonium reineckate TS:a pink precipitate is formed.

Standard preparation— Transfer about 30mg of USP Tolazoline Hydrochloride RS,accurately weighed,to a 100-mLvolumetric flask,dissolve in and dilute with methanol to volume,and mix.

Assay preparation— Transfer an accurately measured volume of Injection,equivalent to about 150mg of tolazoline hydrochloride,to a 100-mLvolumetric flask,dilute with methanol to volume,and mix.Transfer 20.0mLof this solution to a second 100-mLvolumetric flask,dilute with methanol to volume,and mix.

Procedure— Transfer 3.0mLeach of the Standard preparation,the Assay preparation,and methanol to provide the blank,to separate 25-mLvolumetric flasks.To each flask add 1mLof 0.5Nsodium hydroxide and 1mLof dilute sodium nitroferricyanide TS(1in 2),mix,and allow to stand for 10minutes.Add 3mLof sodium bicarbonate solution (1in 12)to each flask,dilute with water to volume,mix,and allow to stand for 10minutes.Concomitantly determine the absorbances of the solutions in 1-cm cells at the wavelength of maximum absorbance at about 565nm,with a suitable spectrophotometer,against the blank.Calculate the quantity,in mg,of C10H12N2·HCl in each mLof the Injection taken by the formula: in which Cis the concentration,in µg per mL,of USP Tolazoline Hydrochloride RSin the Standard preparation,Vis the volume,in mL,of Injection taken,and AUand ASare the absorbances of the solutions from the Assay preparationand the Standard preparation,respectively.