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Naftifine Hydrochloride Gel
» Naftifine Hydrochloride Gel contains not less than 90.0 percent and not more than 110.0 percent of Naftifine Hydrochloride (C21H21N·HCl) in a water-miscible base.
Packaging and storage
Preserve in tight containers.
Identification
The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that of the Standard preparation as obtained in the Assay.
Microbial enumeration tests
Minimum fill
pH
Content of alcohol
Internal standard solution
Transfer 10.0 mL of n-propyl alcohol to a 200-mL volumetric flask, dilute with water to volume, and mix.
Standard solution
Prepare a mixture containing an accurately weighed quantity of alcohol in water having a known concentration of about 10.0 mg of alcohol per mL. Transfer 3.0 mL of Internal standard solution to a 10-mL volumetric flask, dilute with the alcohol solution, and mix.
Test solution
Transfer about 250 mg of Gel, accurately weighed, to a suitable container. Add 14.0 mL of water and 6.0 mL of Internal standard solution, and shake for 15 minutes.
Chromatographic system
(see Chromatography
Procedure
Inject equal volumes (about 1 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 quantity, in mg, of C2H5OH in the portion of Gel taken by the formula:
5.6C(RU / RS)
in which C is the concentration, in mg per mL, of C2H5OH in the Standard solution, and RU and RS are the ratios of the peak responses for alcohol to those of the internal standard obtained from the Test solution and the Standard solution, respectively: the content of C2H5OH is between 40% and 45%.
Assay
Mobile phase, Standard preparation, and Chromatographic system
Proceed as directed in the Assay under Naftifine Hydrochloride.
Assay preparation
Transfer about 1000 mg of Gel, 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
Procedure
Separately inject equal volumes (about 20 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 C21H21N·HCl in the portion of Gel 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.
Auxiliary Information
Please check for your question in the FAQs before contacting USP.
USP35NF30 Page 3983
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