Assay preparation—
Transfer about 1000 mg of Cream, accurately weighed, to a 100-mL volumetric flask, dissolve in 60 mL of methanol, mix vigorously for 2 minutes, and dilute with methanol to volume. Heat at 45
for 5 minutes, and cool to room temperature.
Procedure—
Separately inject equal volumes (about 15 µL) of the
Standard preparation and the
Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C
21H
21N·HCl in the portion of Cream taken by the formula:
100C(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Naftifine Hydrochloride RS in the
Standard preparation, and
rU and
rS are the peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
61
—
It meets the requirements of the tests for absence of Staphylococcus aureus and Pseudomonas aeruginosa.