Clobetasol Propionate Topical Solution
Clobetasol Propionate Topical Solution contains NLT 90.0% and NMT 110.0% of the labeled amount of clobetasol propionate (C25H32ClFO5).
• A. Thin-Layer Chromatographic Identification Test 201
Standard solution: 0.75 mg/mL of USP Clobetasol Propionate RS in chloroform
Test solution: Nominally 0.75 mg/mL of clobetasol propionate. Transfer a portion of Topical Solution equivalent to 1.5 mg of clobetasol to a 50-mL separatory funnel. Add 5 mL of water, and extract with 5 mL of chloroform. Collect the lower layer through a cotton wool plug, and evaporate with the aid of a stream of nitrogen to dryness. Dissolve the residue in 2 mL of chloroform.
Developing solvent system: Chloroform, acetone, and alcohol (100:10:5)
Acceptance criteria: The RF value of the principal spot obtained from the Test solution corresponds to that from the Standard solution.
Buffer: 0.05 M monobasic sodium phosphate. Adjust with 85% phosphoric acid to a pH of 2.5.
Mobile phase: Acetonitrile, methanol, and Buffer (95:20:85)
Internal standard solution: 0.2 mg/mL of beclomethasone dipropionate in methanol
System suitability solution: 0.001 mg/mL of USP Clobetasol Propionate Related Compound A RS and 0.1 mg/mL of USP Clobetasol Propionate RS in Mobile phase
Standard solution: 0.04 mg/mL of USP Clobetasol Propionate RS and 0.08 mg/mL of beclomethasone dipropionate prepared as follows. Transfer 1.0 mg of USP Clobetasol Propionate RS to a 25-mL volumetric flask, add 10.0 mL of the Internal standard solution, and dilute with methanol to volume.
Sample solution: Nominally 0.04 mg/mL of clobetasol propionate. Transfer a portion of Topical Solution equivalent to 1.0 mg of clobetasol propionate to a 25-mL volumetric flask, add 10.0 mL of the Internal standard solution, and dilute with Mobile phase to volume.
Detector: UV 240 nm
Column: 4.6-mm × 15-cm; packing L1
Flow rate: 1 mL/min
Injection size: 10 µL
Sample: System suitability solution
[NoteThe relative retention times for clobetasol propionate and clobetasol propionate related compound A are 1.0 and 1.1, respectively. ]
Resolution: NLT 1.5 between clobetasol propionate and clobetasol propionate related compound A
Column efficiency: NLT 5000 theoretical plates for the clobetasol propionate peak
Tailing factor: NMT 2.0 for the clobetasol propionate peak
Relative standard deviation: NMT 2.0% for the clobetasol propionate peak
Samples: Standard solution and Sample solution
[NoteThe relative retention times for clobetasol propionate and beclomethasone dipropionate are 1.0 and 1.6, respectively. ]
Calculate the percentage of clobetasol propionate (C25H32ClFO5) in the portion of Topical Solution taken:
Result = (RU/RS) × (CS/CU) × 100
Acceptance criteria: 90.0%110.0%
• Minimum Fill 755: Meets the requirements
• Microbial Enumeration Tests 61 and Tests for Specified Microorganisms 62: The total aerobic microbial count does not exceed 102 cfu/g. It meets the requirements of the tests for absence of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Salmonella species.
• pH 791: 4.56.0
• Packaging and Storage: Preserve in tight containers. Store at controlled room temperature. Do not refrigerate.
• USP Reference Standards 11
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USP35NF30 Page 2715