Clotrimazole Cream contains NLT 90.0% and NMT 110.0% of the labeled amount of clotrimazole (C22H17ClN2).
• The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.
Buffer: 4.35 mg/mL of dibasic potassium phosphate
Mobile phase: Acetonitrile and Buffer (3:1)
[NoteThe ratio of volumes may be changed to obtain the required resolution. ]
Standard solution: 0.5 mg/mL of USP Clotrimazole RS in methanol
System suitability solution: 0.1 mg/mL each of USP Clotrimazole RS and USP Clotrimazole Related Compound A RS in methanol
Sample solution: Transfer the equivalent of 25 mg of clotrimazole from the Cream to a 50-mL screw-capped centrifuge tube. Add 25.0 mL of methanol, and heat at 50 in a water bath for 5 min, with occasional shaking. Remove the tube from the bath, and shake vigorously for 5 min. Cool in a methanolice bath for 15 min, and promptly centrifuge. Transfer the supernatant to a 50-mL volumetric flask. Add 20.0 mL of methanol to the residue in the centrifuge tube, and repeat the extraction starting with heat at 50 in a water bath. Transfer the supernatant to the volumetric flask containing the supernatant from the first extraction, dilute with methanol to volume, and mix.
Detector: UV 254 nm
Column: 4.6-mm × 25-cm; 5-µm packing L1
Flow rate: 1.5 mL/min
Injection size: 25 µL
Samples: Standard solution and System suitability solution
[NoteThe relative retention times for clotrimazole and clotrimazole related compound A are 1.0 and 1.2, respectively. ]
Resolution: NLT 2.0 between clotrimazole and clotrimazole related compound A, System suitability solution
Relative standard deviation: NMT 2.0%, Standard solution
Samples: Standard solution and Sample solution
Calculate the percentage of C22H17ClN2 in the portion of Cream taken:
Result = (rU/rS) × (CS/CU) × 100
Acceptance criteria: 90.0%110.0%
• Packaging and Storage: Preserve in collapsible tubes or tight containers, at a temperature between 2 and 30.
• Labeling: Cream that is packaged and labeled for use as a vaginal preparation shall be labeled Clotrimazole Vaginal Cream.
• USP Reference Standards 11
USP Clotrimazole Related Compound A RS
Auxiliary Information Please check for your question in the FAQs before contacting USP.
USP35NF30 Page 2741Pharmacopeial Forum: Volume No. 35(6) Page 1451