Add the following:
Sildenafil Tablets
DEFINITION
Sildenafil Tablets contain sildenafil citrate equivalent to NLT 90% and NMT 110% of the labeled amount of sildenafil (C22H30N6O4S).
IDENTIFICATION
• A. Infrared Absorption 〈197K〉
Solution A: Ammonium hydroxide and water (10:90)
Standard solution: 1.4 mg/mL of USP Sildenafil Citrate RS in Solution A
Sample solution: Grind 1 Tablet and add a sufficient amount of Solution A to obtain nominally 1 mg/mL of sildenafil. Sonicate for 2 min, shake well, and centrifuge. U the supernatant.
Analysis: For each of the Standard solution and the Sample solution, prewash a 6-cc C18 solid pha
extraction cartridge with 10 mL of methanol followed by
10 mL of Solution A, discarding both washings. Apply 5 mL each of the
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Standard solution and the Sample solution to parate prewashed cartridges and draw each solution through the cartridge. Wash each cartridge with 10 mL of water and allow the cartridge to dry under vacuum. Elute the sildenafil from each cartridge with 5 mL of methanol, collecting the eluant in a
suitable container. Add about 200 mg of potassium bromide to each container, mix well, and evaporate to dryness. To about 70 mg of each dried mixture, add about 140 mg of potassium bromide and mix.
Acceptance criteria: Meet the requirements
• B. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.
ASSAY
• Procedure
Buffer: Dilute 7 mL of triethylamine with water to 1 L. Adjust with phosphoric acid to a pH of 3.0.
Mobile pha: Buffer, methanol, and acetonitrile (58:25:17)
Diluent: Acetonitrile and water (90:10)
Standard solution: 0.028 mg/mL of USP Sildenafil Citrate RS in Mobile pha Sample stock solution: Disper 1 Tablet in at least 5 mL of Diluent with the aid of sonication. Once the Tablet is fully disperd, dilute with Mobile
pha to 250.0 mL while swirling. Centrifuge and u the supernatant.
Sample solution: Nominally 0.02 mg/mL of sildenafil prepared by diluting a
suitable portion of the Sample stock solution with Mobile pha
如何缓解孕吐Chromatographic system
(See Chromatography 〈621〉, System Suitability.)
Mode: LC
Detector: UV 290 nm
Column: 3.9-mm × 15-cm; 5-µm packing L1脐橙上火吗
Column temperature: 30°
Flow rate: 1 mL/min
Injection volume: 20 µL
Run time: NLT 1.5 times the retention time of sildenafil
System suitability
Sample: Standard solution
Suitability requirements
Tailing factor: NMT 1.3
Relative standard deviation: NMT 3.0%
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of the labeled amount of sildenafil (C22H30N6O4S) in the portion of Tablets taken:
Result = (rU/rS) × (CS/CU) × (Mr1/Mr2) × 100 rU=peak respon of sildenafil from the Sample solution
rS=peak respon of sildenafil from the Standard solution
CS=concentration of USP Sildenafil Citrate RS in the Standard solution (mg/mL) CU=nominal concentration of sildenafil in the Sample solution (mg/mL)
Mr1=molecular weight of sildenafil, 474.58
Mr2=molecular weight of sildenafil citrate, 666.70
Acceptance criteria: 90%–110%
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PERFORMANCE TESTS
• Dissolution 〈711〉
Medium: 0.01 N hydrochloric acid; 900 mL
Apparatus 1: 100 rpm
Time: 15 min
Standard solution: 0.03 mg/mL of USP Sildenafil Citrate RS in Medium
分辨率有哪几种Sample solution: A filtered portion of the solution under test, suitably
diluted with Medium, if necessary
Instrumental conditions
Mode: UV-Vis
Analytical wavelength: Maximum at about 290 nm
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of the labeled amount of sildenafil (C22H30N6O4S)
dissolved:
Result = (AU/AS) × CS × D × V × (1/L) × (Mr1/Mr2) × 100 AU=absorbance of the Sample solution
AS=absorbance of the Standard solution
CS=concentration of USP Sildenafil Citrate RS in the Standard solution (mg/mL) D=dilution factor for the Sample solution, if needed
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V=volume of Medium, 900 mL
L=label claim (mg/Tablet)
Mr1=molecular weight of sildenafil, 474.58
Mr2=molecular weight of sildenafil citrate, 666.70
Tolerances: NLT 80% (Q) of the labeled amount of sildenafil (C22H30N6O4S) is dissolved.
• Uniformity of Dosage Units 〈905〉: Meet the requirements
IMPURITIES
• Organic Impurities
Buffer, Mobile pha, Diluent, and Chromatographic system: Proceed as directed in the Assay, except for Run time.
Run time: NLT 3 times the retention time of sildenafil
System suitability solution: A mixture of sildenafil and sildenafil N-oxide in Mobile pha, prepared as follows. Dissolve 70 mg of USP Sildenafil Citrate RS in 1 mL of a solution of hydrogen peroxide and formic acid (2:1), allow to stand for NMT 10 min, and then dilute with Mobile pha to 250.0 mL.
Standard solution: 0.0014 mg/mL of USP Sildenafil Citrate RS in Mobile pha Sensitivity solution: 0.00035 mg/mL of USP Sildenafil Citrate RS in Mobile
pha from the Standard solution
Sample stock solution: Transfer 5 Tablets to a 250-mL volumetric flask and
disper in 25 mL of Diluent with the aid of sonication. Dilute with Mobile pha to volume. Sonicate, if necessary. Centrifuge and u the supernatant.
Sample solution: Nominally 0.5 mg/mL of sildenafil prepared by diluting a
suitable portion of the Sample stock solution with Mobile pha
System suitability
Samples: System suitability solution, Standard solution, and Sensitivity
solution
[Note—See Table 1 for the relative retention times.]
Suitability requirements
Resolution: NLT 2.6 between sildenafil N-oxide and sildenafil, System
猪的网名suitability solution
Tailing factor: NMT 1.3, Standard solution
Relative standard deviation: NMT 3.0%, Standard solution
Signal-to-noi ratio: NLT 10, Sensitivity solution
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of any individual degradation product in the portion of Tablets taken:
Result = (rU/rS) × (CS/CU) × (Mr1/Mr2) × 100
rU=peak respon of any individual degradation product from the Sample solution
rS=peak respon of sildenafil from the Standard solution
CS=concentration of USP Sildenafil Citrate RS in the Standard solution (mg/mL) CU=nominal concentration of sildenafil in the Sample solution (mg/mL)
Mr1=molecular weight of sildenafil, 474.58
Mr2=molecular weight of sildenafil citrate, 666.70
Acceptance criteria: See Table 1. Disregard any peak less than 0.05%.
Table 1
Name
Relative
Retention
Time
Acceptance
Criteria,
NMT (%)
Sildenafil 1.0—Sildenafil N-oxide a 1.20.20
Any individual degradation product —
0.20
Total degradation products—0.50
a 1-{[3-(6,7-Dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-5-
yl)-4-ethoxyphenyl]sulfonyl}-4-methylpiperazine N4-oxide.
ADDITIONAL REQUIREMENTS
• Packaging and Storage: Prerve in well-clod containers. Store at controlled room temperature.
• USP Reference Standards 〈11〉
USP Sildenafil Citrate RS
1S (USP39)
Auxiliary Information— Plea check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Ren-Hwa Yeh, Ph.D.
Senior Scientific Liaison
(301) 998-6818(CHM52015) Chemical Medicines Monographs 5
Margareth R.C. Marques, Ph.D.
我与地坛赏析Principal Scientific Liaison (GCDF2015) General Chapters-Dosage Forms 2015
〈711〉
(301) 816-8106
Reference Standards RS Technical Services 1-301-816-8129
rstech@usp
USP39–NF34 Supplement: No. 1 Page 8146
Pharmacopeial Forum: Volume No. 41(3)
Chromatographic Column—
SILDENAFIL TABLETS
Chromatographic columns text is not derived from, and not part of, USP 39 or NF
34.
