Clobetasol Propionate Cream
DEFINITION
Clobetasol Propionate Cream is Clobetasol Propionate in a suitable cream base. It contains NLT 90.0% and NMT 115.0% of the labeled amount of clobetasol propionate (C25H32ClFO5).
IDENTIFICATION
• A. Thin-Layer Chromatographic Identification Test 
201
201
Standard solution:
0.6 mg/mL of USP Clobetasol Propionate RS in chloroform
Test solution:
Transfer a portion of Cream equivalent to 0.75 mg of clobetasol propionate to a 25-mL, plastic-stoppered centrifuge tube. Add 10 mL of methanol, and cap. Heat in a 60
water bath for 4 min, remove the tube from the bath, and shake vigorously. Repeat the heating and shaking. Cool to room temperature, add 3.5 mL of water, and mix. Centrifuge at 3500 rpm for 10 min. Transfer 5 mL of the supernatant to a 100-mL separator, add 1 g of sodium chloride and 10 mL of water, and mix. Extract with 5 mL of chloroform by shaking for 1 min, collect the lower layer, and evaporate with the aid of a stream of nitrogen to dryness. Dissolve the residue in 0.5 mL of chloroform.
water bath for 4 min, remove the tube from the bath, and shake vigorously. Repeat the heating and shaking. Cool to room temperature, add 3.5 mL of water, and mix. Centrifuge at 3500 rpm for 10 min. Transfer 5 mL of the supernatant to a 100-mL separator, add 1 g of sodium chloride and 10 mL of water, and mix. Extract with 5 mL of chloroform by shaking for 1 min, collect the lower layer, and evaporate with the aid of a stream of nitrogen to dryness. Dissolve the residue in 0.5 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.
ASSAY
• Procedure
Buffer:
0.05 M monobasic sodium phosphate. Adjust with 50% sodium hydroxide solution to a pH of 5.5.
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. In a suitable flask, dissolve a portion of Cream equivalent to 1.0 mg of clobetasol propionate in 10.0 mL of the Internal standard solution and 15.0 mL of methanol, and shake vigorously to disperse the Cream. Centrifuge at about 3500 rpm for 10 min, and pass a portion of the supernatant through a filter of 0.45-µm pore size.
Chromatographic system
Mode:
LC
Detector:
UV 240 nm
Column:
4.6-mm × 15-cm; packing L1
Flow rate:
1 mL/min
Injection size:
10 µL
System suitability
Sample:
System suitability solution
[Note—The relative retention times for clobetasol propionate and clobetasol propionate related compound A are 1.0 and 1.1, respectively. ]
Suitability requirements
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
Analysis
Samples:
Standard solution and Sample solution
[Note—The 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 Cream taken:
Result = (RU/RS) × (CS/CU) × 100
| RU | = | = ratio of the clobetasol propionate peak area to the internal standard peak area from the Sample solution |
| RS | = | = ratio of the clobetasol propionate peak area to the internal standard peak area from the Standard solution |
| CS | = | = concentration of USP Clobetasol Propionate RS in the Standard solution (mg/mL) |
| CU | = | = nominal concentration of clobetasol propionate in the Sample solution (mg/mL) |
Acceptance criteria:
90.0%–115.0%
PERFORMANCE TESTS
• Minimum Fill 755:
Meets the requirements
755:
Meets the requirements
SPECIFIC TESTS
• 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.
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:
4.5–7.0
791:
4.5–7.0
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in collapsible tubes or in tight containers. Store at controlled room temperature. Do not refrigerate.
• USP Reference Standards 11
11
USP Clobetasol Propionate RS 
') + '&img=../../images/v35300/cas-25122-46-7.gif',600,500);)
USP Clobetasol Propionate Related Compound A RS
9
-Fluoro-11
-hydroxy-16-methyl 3-oxo-androsta-1,4-diene-17(R)-spiro-2¢-[4¢-chloro-5¢-ethylfuran-3¢(2¢H)-one].
C25H30ClFO4 448.96
') + '&img=../../images/v35300/c11rs288.gif',600,500);)
9
-Fluoro-11-hydroxy-16-methyl 3-oxo-androsta-1,4-diene-17(R)-spiro-2¢-[4¢-chloro-5¢-ethylfuran-3¢(2¢H)-one].
C25H30ClFO4 448.96
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Domenick Vicchio, Ph.D.
Senior Scientific Liaison 1-301-998-6828 |
(SM42010) Monographs - Small Molecules 4 |
| 61 |
Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison 1-301-816-8339 |
(GCM2010) General Chapters - Microbiology |
| 62 |
Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison 1-301-816-8339 |
(GCM2010) General Chapters - Microbiology |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 2714