Identification
A:
Transfer 1mLof the Injection to a 200-mLvolumetric flask,and dilute with water to volume.To 1mLof this dilution add 2mLof a solution of 0.02%8-hydroxyquinoline in 3Nsodium hydroxide,and add 1mLof 0.1%N-bromosuccinimide solution:an orange color is produced.
Assay
Color reagent
Dissolve 28.0g of potassium hydroxide and 2.0g of potassium sodium tartrate in 100mLof water.Cool,and add,in the order named,100mg of 2,4-dichloro-1-naphthol,180mLof alcohol,and 20.0mLof 0.475%sodium hypochlorite solution.Mix by swirling,and allow to stand at room temperature for 1hour before using.ThisColor reagentmay be stored in a glass-stoppered bottle,in a refrigerator,for 2months.
Standard preparation
Dissolve an accurately weighed quantity of
USP Arginine Hydrochloride RSin water,and dilute quantitatively and stepwise with water to obtain a solution having a known concentration of about 40µg per mL.
Assay preparation
Pipet into a 100-mLvolumetric flask a volume of Injection,equivalent to 200mg of arginine hydrochloride,add water to volume,and mix.Pipet 5mLof this solution into a 250-mLvolumetric flask,add water to volume,and mix.
Procedure
Transfer 2.0-mLportions of the
Assay preparationand the
Standard preparation,respectively,to separate flasks,and treat each as follows.Add 2.0mLof potassium iodide solution (3in 1000),mix,and allow to stand for 15minutes.Add 6.0mLof
Color reagent,mix,and allow to stand for 15minutes.Add 2.0mLof sodium hypochlorite solution (19in 10,000),mix,and allow to stand for 15minutes.Concomitantly determine the absorbances of both solutions in 1-cm cells at the wavelength of maximum absorbance at about 520nm,with a suitable spectrophotometer,using water as the blank.Calculate the quantity,in mg,of C
6H
14N
4O
2·HCl in each mLof the Injection taken by the formula:
5(C/V)(AU/AS),
in which
Cis the concentration,in µg per mL,of
USP Arginine 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.