Procedure
Separately inject equal volumes (about 20 µL) of the
Standard solution and the
Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the vasopressin activity in USP Vasopressin Unit per USP Corticotropin Unit by the formula:
C(rU / rS)/2,
in which
C is the concentration, in USP Vasopressin Units per mL, of the
Standard solution; and
rU and
rS are the peak responses obtained from the
Test solution and the
Standard solution, respectively. The vasopressin activity is not more than 0.05 USP Vasopressin Unit per USP Corticotropin Unit.