Spironolactone Tablets
»Spironolactone Tablets contain not less than 95.0percent and not more than 105.0percent of the labeled amount of spironolactone (C24H32O4S).
Packaging and storage— Preserve in tight,light-resistant containers.
Identification— Mix a quantity of finely powdered Tablets,equivalent to about 100mg of spironolactone,with 25mLof methanol,and filter.Apply 10µLof this solution and 10µLof a solution of USP Spironolactone RSin methanol containing 4mg per mLto a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel mixture.Develop the chromatogram in a solvent system consisting of a mixture of chloroform,ethyl acetate,and methanol (2:2:1)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the developing chamber,mark the solvent front,and allow the solvent to evaporate.Locate the spots on the plate by viewing under short-wavelength UVlight:the RFvalue of the principal spot obtained from the solution under test corresponds to that obtained from the Standard solution.
Dissolution á711ñ—
Medium: 0.1Nhydrochloric acid containing 0.1%of sodium lauryl sulfate;1000mL.
Apparatus 2: 75rpm.
Time: 60minutes.
Procedure— Determine the amount of C24H32O4Sdissolved using UVabsorption at the wavelength of maximum absorbance at about 242nm obtained on filtered portions of the solution under test,diluted with Dissolution Medium,if necessary,in comparison with a Standard solution having a known concentration of USP Spironolactone RSin the same Medium.[NOTE—Avolume of alcohol not exceeding 1%of the final volume of the solution may be used to prepare the Standard solution.]
Tolerances— Not less than 75%(Q)of the labeled amount of C24H32O4Sis dissolved in 60minutes.
Uniformity of dosage units á905ñ: meet the requirements.
Assay—
Mobile phase,Standard preparation,andChromatographic system— Prepare as directed in the Assayunder Spironolactone.
Assay preparation— Accurately weigh 20Tablets,and transfer to a 1000-mLvolumetric flask,add 100mLof water,and sonicate for 15minutes or until the Tablets are disintegrated,and then cool for 10minutes.Add 500mLof acetonitrile,shake for 30minutes,and then sonicate for an additional 30minutes.Cool to room temperature,dilute with water to volume,and mix.Centrifuge a portion of the mixture at about 3000rpm for 10minutes.Dilute an accurately measured portion of the supernatant,expected to contain 25mg of spironolactone,quantitatively,and stepwise if necessary,with a mixture of acetonitrile and water (1:1)to obtain a solution having a concentration of 0.5mg of spironolactone per mL.
Procedure— Proceed as directed for Procedurein the Assayunder Spironolactone.Calculate the quantity,in mg,of spironolactone (C24H32O4S)in the portion of Tablets taken by the formula:
50C(rU/rS),
in which Cis the concentration,in mg per mL,of USP Spironolactone RSin the Standard preparation;and rUand rSare the peak responses obtained for spironolactone from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information— Staff Liaison:Andrzej Wilk,Ph.D.,Senior Scientific Associate
Expert Committee:(PA5)Pharmaceutical Analysis 5
USP28–NF23Page 1800
Pharmacopeial Forum:Volume No.29(4)Page 1080
Phone Number:1-301-816-8305