Procedure
Separately inject equal volumes (about 10 µL) of the
Test solutions and the
Standard piperacillin solution, and proceed as directed in the
Assay. Calculate the percentage of piperacillin related compound A and piperacillin related compound C in the portion of Piperacillin for Injection taken by the formula:
0.1C(P / A)(RRFi)(ri / rSp)
in which
C is the concentration, in mg per mL, of
USP Piperacillin RS in the
Standard piperacillin solution,
P is the designated potency, in µg of piperacillin per mg, of
USP Piperacillin RS,
A is the quantity, in mg, of piperacillin in each mL of
Test solution 1 or
Test solution 2,
RRFi is the response factor of an individual piperacillin related compound relative to the response of piperacillin, specifically 1.4 for piperacillin related compound A and 0.93 for piperacillin related compound C,
ri is the response of each impurity peak, if any, observed in the chromatogram of the
Test solution at a retention time corresponding to piperacillin related compound A or piperacillin related compound C, and
rSp is the peak response of the piperacillin peak in the chromatogram of the
Standard piperacillin solution: not more than 3.5% of piperacillin related compound A and not more than 1.0% of piperacillin related compound C is found.