Medium: water;900mL.

Apparatus 2: 50rpm.

Time: 45minutes.

Mobile phase— Prepare a filtered and degassed mixture of dilute perchloric acid (1in 20)and acetonitrile (7:3).

Standard solution— Dissolve an accurately weighed quantity of USP Methamphetamine Hydrochloride RSin water to obtain a solution having a known concentration similar to the one expected in the Test solution.Dilute 2:1with 0.15Mperchloric acid.

Test solution— Use filtered aliquots of the solution under test.Dilute 2:1with 0.15Mperchloric acid.

Procedure— The liquid chromatograph is equipped with a 211-nm detector and a 3.9-mm ×30-cm column that contains packing L1.The flow rate is about 2.5mLper minute.Chromatograph the Standard solution(about 100µL),record the chromatogram,and measure the response for the major peak:the tailing factor is not more than 1.5;and the relative standard deviation for replicate injections is not more than 3.0%.Inject an equal volume of the Test solutioninto the chromatograph,record the chromatogram,and measure the response of the major peak.Calculate the quantity of C10H15N·HCl dissolved by comparison with the Standard solution.

Tolerances— Not less than 75%(Q)of the labeled amount of C10H15N·HCl is dissolved in 45minutes.

PROCEDURE FOR CONTENT UNIFORMITY—

Chloroform-saturated 0.1Nsulfuric acid— Shake 250mLof 0.1Nsulfuric acid with 25mLof chloroform for 10minutes.Allow to stand for 1hour with occasional shaking.Drain off the chloroform,and retain the chloroform-saturated sulfuric acid in a stoppered flask.

Standard preparation— Dissolve an accurately weighed quantity of USP Methamphetamine Hydrochloride RSin Chloroform-saturated 0.1Nsulfuric acid,and mix to obtain a solution having a known concentration of about 0.5mg per mL.

Test preparation— Place 1Tablet in a 125-mLseparator,add 15mLof water,and shake by mechanical means for 15minutes to dissolve.Add 2.5mLof 1Nsodium hydroxide,and shake.Extract the liberated methamphetamine with four 10-mLportions of chloroform,collecting the chloroform extracts in a second 125-mLseparator.Transfer 10.0mLof Chloroform-saturated 0.1Nsulfuric acidto the second separator,and shake by mechanical means for 10minutes.Allow the layers to separate,and collect the aqueous layer.

Procedure— Concomitantly determine the absorbances of the Test preparationand the Standard preparationin 1-cm cells,at the wavelength of maximum absorbance at about 257nm,with a suitable spectrophotometer,using Chloroform-saturated 0.1Nsulfuric acidas the blank.Calculate the quantity,in mg,of C10H15N·HCl in the Tablet taken by the formula: in which Cis the concentration,in mg per mL,of USP Methamphetamine Hydrochloride RSin the Standard preparation;and AUand ASare the absorbances of the Test preparationand the Standard preparation,respectively.

Mobile phase,Standard preparation,and Chromatographic system— Proceed as directed in the Assayunder Methamphetamine Hydrochloride.

Assay preparation— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 10mg of methamphetamine hydrochloride,to a 50-mLvolumetric flask.Add 20mLof 0.12Mphosphoric acid,and sonicate for 5minutes.Dilute with 0.12Mphosphoric acid to volume,mix,and filter.

Procedure— Separately inject equal volumes (about 20µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of methamphetamine hydrochloride (C10H15N·HCl)in the portion of Tablets taken by the formula: in which Cis the concentration,in mg per mL,of USP Methamphetamine Hydrochloride RSin the Standard preparation;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.