Isosorbide Dinitrate Tablets
»Isosorbide Dinitrate Tablets contain not less than 90.0percent and not more than 110.0percent of the labeled amount of C6H8N2O8.
Packaging and storage— Preserve in well-closed containers.
Identification— Transfer a suitable quantity of finely powdered Tablets to a glass-stoppered centrifuge tube.Add 10mLof sodium hydroxide solution (1in 250),shake to wet the powder,then add 15mLof solvent hexane,and again shake.Centrifuge the mixture,and transfer the upper phase to a beaker.Evaporate the solvent,and dry the residue in vacuum over anhydrous calcium chloride at room temperature for 16hours:the IRabsorption spectrum of a suitable solution in chloroform of the residue so obtained exhibits maxima only at the same wavelengths as that of a similar preparation from the residue obtained from USP Diluted Isosorbide Dinitrate RS.
Dissolution á711ñ—
Medium: water;1000mL.
Apparatus 2: 75rpm.
Time: 45minutes.
Mobile phase— Prepare a suitable degassed and filtered mixture of pH3.0,0.1Mammonium sulfate and methanol (50:50).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ),using sulfuric acid for any necessary pHadjustment.
Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 220-nm detector and a 4.6-mm ×5-cm column that contains packing L1.The flow rate is about 1.0mLper minute.Chromatograph replicate injections of the Standard solution,and record the peak responses as directed for Procedure:the relative standard deviation is not more than 2.0%,and the tailing factor is not more than 1.5.
Procedure— Separately inject equal volumes (about 20µL)of the Standard solution and a filtered aliquot of the solution under test into the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the amount of C6H8N2O8dissolved in comparison with a Standard solution having a known concentration of USP Isosorbide Dinitrate RS,similarly prepared and chromatographed.
Tolerances— Not less than 70%(Q)of the labeled amount of C6H8N2O8is dissolved in 45minutes.
Uniformity of dosage units á905ñ: meet the requirements.
Assay—
Buffer solution ,Mobile phase,Internal standard solution,Standard preparation,and Chromatographic system—Prepare as directed in the Assayunder Diluted Isosorbide Dinitrate.
Assay preparation— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 12.5mg of isosorbide dinitrate,to a dry,50-mLvolumetric flask,add about 30mLof Mobile phase,and shake the mixture by hand immediately,to prevent clumping.If clumping persists,disperse with the aid of sonication,or break the aggregates with a stirring rod.Shake for 30minutes.Add 8.0mLof Internal standard solution,cool to room temperature,add 8mLof a 1in 10dilution of Buffer solutionin water,dilute with Mobile phaseto volume,and mix.Filter a portion through a disposable ion-exchange filter.
Procedure— Proceed as directed for Procedurein the Assayunder Diluted Isosorbide Dinitrate.Calculate the quantity,in mg,of C6H8N2O8in the portion of Tablets taken by the formula:
50C(RU/RS),
in which Cis the concentration,in mg per mL,of isosorbide dinitrate from the USP Isosorbide Dinitrate RStaken for the Standard preparation,and RUand RSare the ratios of the peak responses obtained 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 1087
Phone Number:1-301-816-8305