(spir on'' oh lak' tone).
Pregn-4-ene-21-carboxylic acid, 7-(acetylthio)-17-hydroxy-3-oxo-, -lactone, (7,17)-;
17-Hydroxy-7-mercapto-3-oxo-17-pregn-4-ene-21-carboxylic acid -lactone acetate [52-01-7].
Spironolactone contains NLT 97.0% and NMT 103.0% of C24H32O4S, calculated on the dried basis.
Change to read:• A. Infrared Absorption 197KUSP35
• B. Ultraviolet Absorption 197U
Sample solution: 10 µg/mL in methanol
Analytical wavelength: 238 nm
Acceptance criteria: Absorptivities, calculated on the dried basis, do not differ by more than 3.0%.
Sample solution: Add 100 mg to a mixture of 10 mL of water and 2 mL of 1 N sodium hydroxide.
Analysis: Boil the mixture for 3 min, cool, and add 1 mL of glacial acetic acid and 1 mL of lead acetate TS.
Acceptance criteria: A brown-to-black precipitate of lead sulfide is formed.
Mobile phase: Methanol and water (60:40)
Standard solution: 0.5 mg/mL of USP Spironolactone RS in a mixture of acetonitrile and water (1:1)
Sample solution: 0.5 mg/mL of Spironolactone in a mixture of acetonitrile and water (1:1)
Detector: UV 230 nm
Column: 4.6-mm × 15-cm; packing L1
Flow rate: 1 mL/min
Injection size: 20 µL
Sample: Standard solution
Tailing factor: NMT 2.0
Relative standard deviation: NMT 1.5%
Samples: Standard solution and Sample solution
Calculate the percentage of spironolactone (C24H32O4S) in the portion of sample taken:
Result = (rU/rS) × (CS/CU) × 100
Acceptance criteria: 97.0%103.0% on the dried basis
• Limit of Mercapto Compounds
Sample solution: Shake 2.0 g with 30 mL of water, and filter.
Analysis: To 15 mL of the filtrate add 3 mL of starch TS, and titrate with 0.010 N iodine. Perform a blank determination, and make any necessary correction.
Acceptance criteria: NMT 0.10 mL of 0.010 N iodine is consumed.
• Ordinary Impurities 466
Standard solution: Chloroform
Test solution: Chloroform
Eluant: Butyl acetate
Change to read:• Optical Rotation, Specific Rotation 781S: 41 to 45USP35
Sample solution: 10 mg/mL in alcoholUSP35
• Loss on Drying 731: Dry a sample at 105 for 2 h: it loses NMT 0.5% of its weight.
• Packaging and Storage: Preserve in well-closed containers.
• USP Reference Standards 11
Auxiliary Information Please check for your question in the FAQs before contacting USP.
USP35NF30 Page 4680Pharmacopeial Forum: Volume No. 37(1)