Add the following:

A:Infrared Absorption á197Kñ.

B: The retention time of the major peak in the chromatogram of theAssay preparation corresponds to that in the chromatogram of theStandard preparation,as obtained in theAssay.

pH7.5Phosphate buffer— Dissolve 6.8g of monobasic potassium phosphate and 1.6g of sodium hydroxide in 1Lof water.Adjust with phosphoric acid or 2Nsodium hydroxide to a pHof 7.5.

Medium— Proceed as directed forMethod BunderDelayed-Release (Enteric-Coated)Articles—General Drug Release Standard,observing the following exceptions.PerformAcid stage testing,using 500mLof 0.1Nhydrochloric acid for 1hour;and performBuffer stage testing,using 500mLofpH7.5Phosphate bufferfor not less than 8hours.

Apparatus 1: 100rpm.

Times: 1,4,6,and 9hours.

Mobile phase— Prepare a filtered and degassed mixture of water,methanol,and glacial acetic acid (72:28:1),containing 0.73g of sodium 1-heptanesulfonate.Make adjustments if necessary (seeSystem Suitability underChromatography á621ñ).

System suitability solution— Dissolve suitable quantities of phenol and USP Morphine Sulfate RSinMobile phase to obtain a solution containing about 0.1mg of each per mL.

Standard solution— Dissolve an accurately weighed quantity of USP Morphine Sulfate RSinpH7.5Phosphate buffer,and dilute quantitatively,and stepwise if necessary,withpH7.5Phosphate buffer to obtain a solution having a known concentration corresponding to that of the solution under test.

Chromatographic system(see Chromatography á621ñ)— The liquid chromatograph is equipped with a 284-nm detector and a 3.9-mm ×30.0-cm column that contains 10-µm packing L1.The flow rate is about 2mLper minute.Chromatograph theSystem suitability solution,and record the peak responses as directed forProcedure:the relative retention times are about 0.8for phenol and 1.0for morphine sulfate;the tailing factor for the morphine sulfate peak is not more than 2.0;the resolution,R,between the phenol and morphine sulfate peaks is not less than 2.0;and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 25µL)of theStandard solution and the filtered portion of the solution under test into the chromatograph,record the chromatograms,and measure the peak responses.Determine the amount of (C17H19NO3)2·H2SO4·5H2Odissolved from the measured peak responses.

Tolerances— The percentage of the labeled amount of (C17H19NO3)2·H2SO4·5H2Odissolved in 1hour conforms toAcceptance Table 2.The percentages of the labeled amount of (C17H19NO3)2·H2SO4·5H2Odissolved at the other times specified conform to Acceptance Table 1.

Standard solution— Prepare as directed in the Assay for Standard preparation.

Diluting solution,Buffer solution,Mobile phase,Resolution solution,and Chromatographic system— Proceed as directed in theAssay.

Test solution— Use theAssay preparation.

Procedure— Separately inject equal volumes (about 30µL)of theDiluting solution and theTest solution into the chromatograph,record the chromatograms,and measure the peak areas,disregarding the peaks corresponding to those obtained in the chromatogram of theDiluting solution.Calculate the percentage of each impurity in the portion of Capsules taken by the formula: in whichFis the relative response factor equal to 0.25for any peak with a relative retention time between 2.2and 2.8and equal to 1.0for all other impurity peaks;riis the peak response for each impurity obtained from theTest solution;andrMis the peak response for morphine sulfate obtained from theTest solution:not more than 1.0%of any individual impurity is found;and not more than 2.0%of total impurities is found.

Diluting solution— Use water,and adjust with phosphoric acid to a pHof 3.60.

Buffer solution— Dissolve 13.8g of monobasic sodium phosphate in 1Lof water.

Mobile phase— Prepare a filtered and degassed mixture of water,Buffer solution,acetonitrile,and triethylamine (874.5:100:25:0.5).Make adjustments if necessary (seeSystem Suitability underChromatography á621ñ).

Resolution solution— Dissolve an accurately weighed quantity of USP Morphine Sulfate RSinDiluting solution to obtain a solution having a known concentration of about 10mg per mL.Transfer 1.0mLof this solution to a 10-mLvolumetric flask containing 2.0mLof 30percent hydrogen peroxide.Heat,with stirring,in a water bath at a temperature of about 80for about 30minutes.Cool to room temperature,dilute withDiluting solution to volume,and mix.

Standard preparation— Dissolve an accurately weighed quantity of USP Morphine Sulfate RSinDiluting solution to obtain a solution having a known concentration of about 1.0mg per mL.

Assay preparation— Accurately weigh and transfer the contents of 10Capsules to a suitable volumetric flask to obtain a solution having a final concentration of about 1mg of morphine sulfate per mL.Add an amount of methanol equivalent to 4.5%of the flask volume.Mix for about 30minutes,gently swirling every 5minutes.AddDiluting solution up to about half of the flask volume,and sonicate for 5minutes to dissolve.Rinse the inner wall and neck of the flask with an amount of methanol equivalent to about 0.5%of the flask volume,dilute withDiluting solution to volume,and mix.Pass through a suitable filter,and use the clear filtrate.

Chromatographic system(see Chromatography á621ñ)— The liquid chromatograph is equipped with a 245-nm detector,a suitable guard column that contains packing L1,and a 3.9-mm ×30.0-cm column that contains 10-µm packing L1.The flow rate is about 2mLper minute.Chromatograph theResolution solution,and record the peak responses as directed forProcedure:the relative retention times are between 1.2and 1.4for morphineN-oxide and between 2.2and 2.8for pseudomorphine;and the resolution,R,between the morphineN-oxide and morphine sulfate peaks is not less than 2.0.Chromatograph theStandard preparation,and record the peak responses as directed forProcedure:the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 30µL)of theStandard preparation and theAssay preparation into the chromatograph,record the chromatograms,and measure the peak responses.Calculate the quantity,in mg,of morphine sulfate pentahydrate (C17H19NO3)2·H2SO4·5H2Oin the portion of Capsules taken by the formula: in whichCis the concentration,in mg per mL,of USP Morphine Sulfate in theStandard preparation;Vis the volume of the volumetric flask used to prepare theAssay preparation;andrUandrSare the peak responses obtained from theAssay preparation and theStandard preparation,respectively.