Procedure
Separately inject equal volumes (about 10 µL) of the
Standard preparation and the
Assay preparation into the chromatograph, record the chromatograms, and measure the areas for the major peaks. Calculate the quantity, in mg, of clindamycin (C
18H
33ClN
2O
5S) in each mL of the Oral Solution taken by the formula:
0.1(CP / V)(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Clindamycin Hydrochloride RS in the
Standard preparation; P is the potency, in µg of clindamycin per mg, of
USP Clindamycin Hydrochloride RS;
V is the volume, in mL, of Oral Solution taken to prepare the
Assay preparation; and
rU and
rS are the clindamycin peak area responses obtained from the
Assay preparation and the
Standard preparation, respectively.