A: Dissolve about 100mg in 5mLof water,add 5mLof 1Nsodium hydroxide,cool to about 10,add 1mLof a mixture of absolute ether and benzoyl chloride (2:1),insert the stopper,and shake for 3minutes.Filter the precipitate,wash with about 10mLof cold water,and recrystallize from diluted alcohol:the crystals of the benzoyl derivative of amphetamine so obtained,after drying at 80for 2hours,melt between 131and 135,the procedure for Class Ibeing used (see Melting Range or Temperature á741ñ).

B: Asolution (1in 10)responds to the tests for Sulfate á191ñ.

Change to read:

Diluent— Dilute 3.12mLof phosphoric acid with water to 1000mL.

Buffer solution— Dissolve 2.16g of sodium 1-octanesulfonate in 1000mLof water,and add 1.0mLof triethylamine.USP28Mix,and adjust with phosphoric acid to a pHof 2.5.

Mobile phase— Prepare a filtered and degassed mixture ofBuffer solution,acetonitrile,and methanol (144:37:19).Make adjustments if necessary (seeSystem Suitability underChromatography á621ñ).

Standard stock solution— Dissolve an accurately weighed quantity ofUSP Dextroamphetamine Sulfate RSinDiluent to obtain a solution having a known concentration of about 0.3mg per mL.

Standard solution— Dilute an accurately measured volume ofStandard stock solution inDiluent to obtain a solution having a known concentration of about 0.003mg per mL.

Test solution— Transfer about 30mg of Amphetamine Sulfate,accurately weighed,to a 100-mLvolumetric flask.Dissolve in 50mLofDiluent,sonicate for 5minutes,dilute withDiluent to volume,and mix.

Chromatographic system(see Chromatography á621ñ)— The liquid chromatograph is equipped with a 215-nm detector and a 4.6-mm ×15-cm column that contains 5-µm packing L1.The flow rate is about 1mLper minute.Chromatograph theStandard stock solution,and record the peak responses as directed forProcedure:the tailing factor is not more than 2.0;and the relative standard deviation for replicate injections is not more than 2.0%.Chromatograph theTest solution,and record the peak responses as directed forProcedure:the resolution,R,between the amphetamine peak and any adjacent peak,if any,is not less than 1.5.

Procedure— Separately inject equal volumes (about 50µL)of theStandard solution and theTest solution into the chromatograph,record the chromatograms,and measure the peak responses.Calculate the percentage of each impurity in the portion of Amphetamine Sulfate taken by the formula: in which Cis the concentration,in mg per mL,of USP Dextroamphetamine Sulfate RSin theStandard solution;Wis the weight,in mg,of Amphetamine Sulfate taken to prepare theTest solution;riis the peak response for each impurity obtained from theTest solution;and rSis the peak response for amphetamine obtained from theStandard solution:not more than 0.1%of any individual impurity is found,and not more than 0.5%of total impurities is found.

Standard preparation— Prepare as directed under Amphetamine Assay á331ñ.

Assay preparation— Dissolve about 125mg of Amphetamine Sulfate,previously dried and accurately weighed,in 25mLof hydrochloric acid solution (1in 100)in a 50-mLvolumetric flask,dilute with the solvent to volume,and mix.Pipet 2.0mLof the solution into a 100-mLbeaker containing 3g of purified siliceous earth,and mix until a fluffy mixture is obtained.

Procedure— Proceed as directed under Amphetamine Assay á331ñ.Calculate the quantity,in mg,of (C9H13N)2·H2SO4in the portion of Amphetamine Sulfate taken by the formula: in which Cis the concentration,in µg per mL,of USP Dextroamphetamine Sulfate RSin the Standard preparation,and the other terms are as defined therein.