Identification—
A:
Ultraviolet Absorption á197Uñ—
Medium:
methanol and water (75:25).
Solution:
15µg per mL.Obtain the test solution as follows.Mix a volume of Injection,equivalent to 20mg of zidovudine,with 50mLof Mediumin a 200-mLvolumetric flask,and dilute with Mediumto volume.Dilute the resulting solution 15in 100with Medium,and mix.
B:
The retention time of the major peak in the chromatogram of the
Assay preparationcorresponds to that of the
Standard preparation,as obtained in the
Assay.
Related compounds—
Mobile phase
,
Standard stock solution,
Zidovudine related compound Cstandard stock solution,and
Chromatographic system—Proceed as directed in the
Assayunder
Zidovudine.
Standard solution—
Transfer 10.0mLof Standard stock solutionand 1.0mLof Zidovudine related compound Cstandard stock solutionto a 100-mLvolumetric flask,add 25mLof water,mix,dilute with methanol to volume,and mix.
Test solution—
Proceed as directed for
Assay preparationin the
Assay.
Procedure—
Separately inject equal volumes (about 10µL)of the
Standard solutionand the
Test solutioninto the chromatograph,record the chromatograms,and measure the peak responses.Calculate the quantity,in mg,of zidovudine related compound C(thymine)in the volume of Injection taken by the formula:
1000C[(rU/rS)/Q],
in which
Cis the concentration,in mg per mL,of
USP Zidovudine Related Compound C RSin the
Standard solution;
rUand
rSare the peak responses of zidovudine related compound C(thymine)obtained from the
Test solutionand the
Standard solution,respectively;and
Qis the quantity,in mg,of zidovudine in the volume of Injection taken,as determined in the
Assay:not more than 1.0%is found.
Assay—
Mobile phase
,
Standard stock solution,
Zidovudine related compound Cstandard stock solution,and
Chromatographic system—Proceed as directed in the
Assayunder
Zidovudine.
Standard preparation—
Transfer 10.0mLof Standard stock solutionand 2.0mLof Zidovudine related compound Cstandard stock solutionto a 100-mLvolumetric flask,add 25mLof water,mix,dilute with methanol to volume,and mix.
Assay preparation—
Transfer an accurately measured volume of Injection,equivalent to about 25mg of zidovudine,to a 250-mLvolumetric flask,dissolve in and dilute with Mobile phaseto volume,and mix.
Procedure—
Separately inject equal volumes (about 10µL)of the
Standard preparationand the
Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of zidovudine (C
10H
13N
5O
4)in the volume of Injection taken by the formula:
1000C(rU/rS),
in which
Cis the concentration,in mg per mL,of
USP Zidovudine RSin the
Standard preparation;and
rUand
rSare the peak responses obtained from the
Assay preparationand the
Standard preparation,respectively.