Related compounds
TEST A(EARLY-ELUTING IMPURITIES)
Mobile phase
Prepare as directed in the Assay.
System suitability solution
Prepare as directed for
System suitability solutionin
Chromatographic purity Test Aunder
Fludarabine Phosphate.
Sensitivity check solution
Dilute the Standard solutionwith Mobile phaseto obtain a solution having a concentration of 0.0005mg per mL.
Test solution
Inject 2.0mLof water into each of 5vials of Fludarabine Phosphate for Injection.Quantitatively transfer the contents of the vials into a single 250-mLvolumetric flask,using water rinses.Dilute the volumetric flask with Mobile phaseto volume,and mix to obtain a solution having a concentration of about 1mg of fludarabine phosphate per mL.
Chromatographic system
Proceed as directed for
Chromatographic systemin
Chromatographic purity Test Aunder
Fludarabine Phosphate.
Procedure
Separately inject equal volumes (about 10µL)of the
Standard solutionand the
Test solution,record the chromatograms,and measure all of the peak responses up to and including the fludarabine phosphate peak.Calculate the percentage of each early-eluting impurity present in the portion of Fludarabine Phosphate taken by the formula:
100F1(ru/rs),
in which
F1is a relative response factor equal to the values given in
Table 1,and equal to 1.0for any other individual early-eluting degradation product not appearing in
Table 1;rUis the response for each individual impurity in the
Test solution;and
rSis the response for the fludarabine phosphate peak in the
Test solution.In addition to meeting the limits for the individual degradation products given in
Table 1,not more than 0.2%of any other early-eluting fludarabine phosphate degradation peak is found.
Table 1.
Relative Retention Time |
Relative Response Factor (F1) |
Relative Response Factor (F2) |
Impurity Name |
Limit (w/w%) |
| 0.26 |
4.0 |
|
Iso-ara-guanine-monophosphate |
1.0 |
| 0.34 |
2.5 |
|
Isoguanine |
0.2 |
| 1.5 |
|
0.5 |
2-fluoroadenine |
0.2 |
| 1.9 |
|
0.6 |
2-fluoro-ara-adenine |
0.2 |
TEST B(LATE-ELUTING-IMPURITIES)
Mobile phase
Prepare a mixture of filtered,degassed 10mMmonobasic potassium phosphate and methanol (4:1).
Standard solution,System suitability solution,and Sensitivity check solution
Prepare as directed for
Chromatographic purity Test Aunder
Fludarabine Phosphate.
Test solution
Prepare as directed for Related compounds Test A.
Chromatographic system
Proceed as directed for
Chromatographic purity Test Bunder
Fludarabine Phosphate.
Procedure
Separately inject equal volumes (about 10mL)of the
Standard solution and the
Test solution,record the chromatograms at 260nm,and measure all of the peak responses starting with the fludarabine phosphate peak.Calculate the percentage of each late-eluting impurity present in the portion of Fludarabine Phosphate taken by the formula:
100F2(rU/rS),
in which
F2is a relative response factor equal to the values given in
Table 1,and 1.0for any other individual late-eluting degradation peak not appearing in
Table 1;rUis the response for each individual impurity in the
Test solution;and
rSis the response for the fludarabine phosphate peak in the
Test solution.In addition to meeting the limits for the individual degradation products given in
Table 1,not more than 0.2%of any other late-eluting fludarabine phosphate degradation product is found;and the sum of all fludarabine phosphate degradation products found in
Test Aand
Test Bis not more than 2.0%.
Assay
Mobile phase
Prepare a mixture of filtered,degassed 10mMmonobasic potassium phosphate and methanol (47:3).
Standard preparation
Dissolve an accurately weighed quantity of
USP Fludarabine Phosphate RSin
Mobile phase,and dilute quantitatively,and stepwise if necessary,in
Mobile phaseto obtain a solution having a known concentration of 0.02mg per mL.
Assay preparation
Inject 2.0mLof Mobile phaseinto each of 5vials of Fludarabine Phosphate for Injection.Quantitatively transfer the contents of the vials into a 250-mLvolumetric flask,using Mobile phaserinses.Dilute with Mobile phaseto volume,and mix.Transfer 5.0mLof the solution to a 250-mLvolumetric flask,dilute with Mobile phaseto volume,and mix to obtain a solution having a concentration of about 0.02mg of fludarabine phosphate per mL.
Chromatographic system
The liquid chromatograph is equipped with a 260-nm detector and a 4.6-mm ×15-cm column containing 5-µm packing L1.The flow rate is 1.0mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the relative standard deviation for replicate injections is not more than 2.0%.
Procedure
Separately inject equal volumes (about 10µL)of the
Standard preparationand
Assay preparationinto the chromatograph,record the chromatograms,and measure the response for the fludarabine phosphate peak.Calculate the quantity,in mg,of C
10H
13FN
5O
7Pin the portion of Fludarabine Phosphate for Injection taken by the formula:
2500C(rU/rS),
in which
Cis the concentration,in mg per mL,of
USP Fludarabine Phosphate RSin the
Standard preparation;and
rUand
rSare the peak responses for fludarabine in the
Assay preparationand the
Standard preparation,respectively.