Identification
B:
Place in a small separator a volume of Injection,equivalent to about 30mg of edrophonium chloride,add 15mLof pH9.6alkaline borate buffer (see
Buffer Solutionsin the section
Reagents,Indicators,and Solutions)and 5mLof a 1in 1000solution of thymol blue in pH9.6alkaline borate buffer,and mix.Add 10mLof chloroform,shake thoroughly,and allow to settle:a yellow color is produced in the chloroform layer.
C:
It responds to the tests for Chloride á191ñ.
Assay
Pipet a volume of Injection,equivalent to about 50mg of edrophonium chloride,into a glass-stoppered,50-mLcentrifuge tube.Add 5mLof pH8.0phosphate buffer (see
Buffer Solutionsin the section
Reagents,Indicators,and Solutions)and 5g of sodium chloride.Wash the solution with four 20-mLportions of a mixture of equal volumes of solvent hexane and ether.Transfer the aqueous phase to a 100-mLvolumetric flask,add 0.1Nhydrochloric acid to volume,and mix.Transfer a 5-mLaliquot of this solution to a 50-mLvolumetric flask,add 0.1Nhydrochloric acid to volume,and mix test solution.Dissolve an accurately weighed quantity of
USP Edrophonium Chloride RSin 0.1Nhydrochloric acid,and dilute quantitatively and stepwise with the acid to obtain a Standard solution having a known concentration of about 50µg per mL.Concomitantly determine the absorbances of both solutions in 1-cm cells at the wavelength of maximum absorbance at about 273nm,with a suitable spectrophotometer,using 0.1Nhydrochloric acid as the blank.Calculate the quantity,in mg,of C
10H
16ClNOin each mLof the Injection taken by the formula:
(C/V)(AU/AS),
in which
Cis the concentration,in µg per mL,of
USP Edrophonium Chloride RSin the Standard solution;
Vis the volume,in mL,of Injection taken;and
AUand
ASare the absorbances of the test solution and the Standard solution,respectively.