Procedure
Separately inject equal volumes (about 20µL)of the appropriate
Assay preparationand the
Standard preparationinto the chromatograph,record the chromatograms,and measure the peak responses for insulin and A-21desamido insulin.Calculate the potency,in USP Insulin Human Units per mL,of the Injection taken by the formula:
(CD)(SrU/SrS),
in which
Cis the concentration,in USP Insulin Human Units per mL,of USP Insulin Human RSin the
Standard preparation;Dis the dilution factor;and
SrUand
SrSare the sums of the areas of the insulin and A-21desamido insulin peaks obtained from the chromatograms of the
Assay preparationand the
Standard preparation,respectively.