Identification
A:
Transfer a volume of Injection,equivalent to about 500mg of phenylbutazone,to a 250-mLconical flask,add 100mLof solvent hexane,and heat the mixture under reflux for 15minutes.Filter the hot mixture,and allow the filtrate to cool.Separate the crystals thus formed by filtration,and dry in vacuum at 80

for 30minutes:the phenylbutazone so obtained responds to
Identificationtest
Aunder
Phenylbutazone.
B:
The retention time of the phenylbutazone peak in the chromatogram of the
Assay preparationcorresponds to that in the chromatogram of the
Standard preparationas obtained in the
Assay.
Assay
Acetate buffer,Mobile phase,Internal standard solution,Standard preparation,and Chromatographic system
Proceed as directed in the
Assayunder
Phenylbutazone.
Assay preparation
Transfer an accurately measured volume of Injection,equivalent to about 200mg of phenylbutazone,to a 100-mLvolumetric flask.Dilute with acetonitrile to volume,and mix.Transfer 7.0mLof this solution to a 50-mLvolumetric flask,add 10.0mLof Internal standard solution,dilute with acetonitrile to volume,and mix.[NOTEUse this solution within 8hours of its preparation.]
Procedure
Proceed as directed for
Procedurein the
Assayunder
Phenylbutazone.Calculate the quantity,in mg,of C
19H
20N
2O
2in each mLof the Injection taken by the formula:
350(C/V)(RU/RS),
in which
Cis the concentration,in mg per mL,of
USP Phenylbutazone RSin the
Standard preparation,Vis the volume,in mL,of Injection taken to prepare the
Assay preparation,and
RUand
RSare the ratios of the peak responses of phenylbutazone to that of the internal standard obtained from the
Assay preparationand the
Standard preparation,respectively.