Identification—
A:
The UVabsorption spectrum,measured in the region between 250and 350nm,of a dilution of Injection in 0.01Nmethanolic sodium hydroxide containing ketamine hydrochloride equivalent to about 800µg of ketamine per mL,exhibits maxima and minima at the same wavelengths as that of a similar preparation of
USP Ketamine Hydrochloride RS,concomitantly measured.
B:
The UVabsorption spectrum of the solution employed for measurement of absorbance of the assay solution,prepared as directed in the
Assay,exhibits maxima and minima at the same wavelengths as that of the Standard solution,prepared as directed in the
Assay.
Assay—
Transfer an accurately measured volume of Injection,equivalent to about 500mg of ketamine hydrochloride,to a 200-mLvolumetric flask,dilute with water to volume,and mix.Transfer 20.0mLof this solution to a 125-mLseparator,add 3mLof 0.1Nsodium hydroxide,and extract with three 15-mLportions of chloroform.Collect the chloroform extracts in a second 125-mLseparator,and extract with three 30-mLportions of 0.1Nsulfuric acid,collecting the acid extracts in a 200-mLvolumetric flask.Dilute with 0.1Nsulfuric acid (saturated with chloroform)to volume,and mix.Concomitantly determine the absorbances of this solution and a Standard solution of
USP Ketamine Hydrochloride RSin the same medium having a known concentration of about 250µg per mL,in 1-cm cells at the wavelength of maximum absorbance at about 269nm,with a suitable spectrophotometer,using 0.1Nsulfuric acid (saturated with chloroform)as the blank.Calculate the quantity,in mg,of ketamine (C
13H
16ClNO)in each mLof the Injection taken by the formula:
(237.73/274.19)(2C/V)(AU/AS),
in which 237.73and 274.19are the molecular weights of ketamine and ketamine hydrochloride,respectively,
Cis the concentration,in µg per mL,of
USP Ketamine Hydrochloride RSin the Standard solution,
Vis the volume,in mL,of Injection taken,and
AUand
ASare the absorbances of the solution from the Injection and the Standard solution,respectively.