Mobile phase— Dissolve 5.5g of sodium 1-heptanesulfonate in 700mLof water.Add 300mLof methanol and 10mLof glacial acetic acid,mix,filter,and degas.Make adjustments if necessary (seeSystem SuitabilityunderChromatography á621ñ).

Standard preparation— Dissolve an accurately weighed quantity of USP Morphine Sulfate RSinMobile phase,and dilute quantitatively,and stepwise if necessary,withMobile phase to obtain a solution having a known concentration of about 0.5mg per mL.[NOTE—Prepare this solution fresh daily.]

System suitability preparation— Prepare a solution inMobile phase containing,in each mL,about 0.24mg of USP Morphine Sulfate RSand 0.15mg of phenol.

Assay preparation— Transfer 1Suppository to a 60-mLseparator containing 20mLof chloroform and 20mLof 0.01Nhydrochloric acid,and shake to dissolve the Suppository.Transfer the chloroform layer to a 250-mLseparator.Extract the aqueous layer with a second 20-mLportion of chloroform,and combine the chloroform extracts in the 250-mLseparator.Wash the chloroform extracts with two additional 20-mLportions of 0.01Nhydrochloric acid,combine the aqueous layers in a 100-mLvolumetric flask,dilute withMobile phase to volume,and mix.Pass this solution through a filter having a 0.45-µm or finer porosity,discarding the first 4mLof the filtrate.

Chromatographic system(see Chromatography á621ñ)— The liquid chromatograph is equipped with a 284-nm detector and a 4.6-mm ×25-cm column that contains packing L1.The column temperature is maintained at 30.The flow rate is about 1.5mLper minute.Chromatograph theStandard preparation and theSystem suitability preparation,and record the peak responses as directed forProcedure:the relative retention times are about 0.7for phenol and 1.0for morphine;the resolution,R,between phenol and morphine is not less than 2.0;the tailing factor for the morphine peak is not more than 2.0;and the relative standard deviation for replicate injections of theStandard preparation is not more than 2.0%.

Procedure— Separately inject equal volumes (about 20µL)of theStandard preparation and theAssay preparation into the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of morphine sulfate pentahydrate [(C17H19NO3)2·H2SO4·5H2O]in the Suppository taken by the formula: in which 758.83and 668.77are the molecular weights of morphine sulfate pentahydrate and anhydrous morphine sulfate,respectively;Cis the concentration,in mg per mL,of anhydrous morphine sulfate in theStandard preparation,as determined from the concentration of USP Morphine Sulfate RScorrected for moisture content by a titrimetric water determination;andrUandrSare the peak responses obtained from theAssay preparation and theStandard preparation,respectively.

Morphine Sulfate	50mg
Silica Gel	25mg
Polyethylene Glycol Base,a sufficient quantity to make one suppository

Mobile phase,Standard preparation,System suitability preparation,and Chromatographic system— Proceed as directed in theCompliance assay for suppositories compounded in fatty acid base.

Assay preparation— Transfer 1Suppository to a 100-mLvolumetric flask,and add about 70mLofMobile phase.Sonicate for 15minutes to dissolve the Suppository,cool,dilute withMobile phase to volume,and mix.Pass a 10-mLportion of the solution through a filter having a 0.45-µm or finer porosity,discarding the first 4mLof the filtrate.

Procedure— Proceed as directed in theCompliance assay for suppositories compounded in fatty acid base.Calculate the quantity,in mg,of morphine sulfate pentahydrate [(C17H19NO3)2·H2SO4·5H2O]in the Suppository taken by the formula: in which the terms are as defined therein.