Procedure
Proceed as directed in
Chromatographic purity for
Gemcitabine Hydrochloride. Calculate the amount of cytosine expressed as a percentage of Gemcitabine Hydrochloride by the formula:
0.1(263.20/299.66)(CcV/L)(rt / rs )
in which 263.20 and 299.66 are the molecular weights of gemcitabine and gemcitabine hydrochloride, respectively;
Cc is the concentration of USP Cytosine RS in the
Standard solution, in µg per mL;
V is the volume, in mL, of water used to reconstitute the vial;
L is the labeled amount of gemcitabine in the vial, in mg;
rt is the peak response for cytosine in the
Test solution; and
rs is the response for cytosine in the
Standard solution: not more than 0.1% of cytosine is found. Similarly, calculate the amount of each impurity other than cytosine, expressed as a percentage of gemcitabine hydrochloride, by the formula:
0.1(263.20/299.66)(CsV/L)(ri / rs)
in which 263.20 and 299.66 are the molecular weights of gemcitabine and gemcitabine hydrochloride, respectively;
Cs is the concentration of
USP Gemcitabine Hydrochloride RS in the
Standard solution, in µg per mL;
V is the volume, in mL, of water used to reconstitute the vial,
L is the labeled amount of gemcitabine in the vial, in mg;
ri is the response for gemcitabine
-anomer or any other individual impurity; and
rs is the peak response for gemcitabine in the
Test solution. Not more than 0.1% of gemcitabine
-anomer is found; not more than 0.2% each of any other impurity is found; and the sum of all impurities is not more than 0.3%. Exclude from the sum of all impurities any peaks that are below the limit of quantitation (0.02%).