NOTE—Throughout the following procedures,protect test or assay specimens,the Reference Standard,and solutions containing them,by conducting the procedures without delay,under subdued light,or using low-actinic glassware.

Medium: 0.1Nhydrochloric acid;500mL.

Apparatus 2: 75rpm.

Time: 60minutes.

Procedure— Determine the amount of prochlorperazine (C20H24ClN3S)dissolved from UVabsorbances at the wavelength of maximum absorbance at about 254nm of filtered portions of the solution under test,suitably diluted with Dissolution Medium,if necessary,in comparison with a Standard solution having a known concentration of USP Prochlorperazine Maleate RSin the same Medium.

Tolerances— Not less than 75%(Q)of the labeled amount of C20H24ClN3Sis dissolved in 60minutes.

Ion-pairing solution— Transfer 4.33g of sodium 1-octanesulfonate,accurately weighed,to a 1-liter volumetric flask.Dissolve in 500mLof water,add 4.0mLof glacial acetic acid,dilute with water to volume,and mix.

Mobile phase— Prepare a suitable filtered and degassed mixture of Ion-pairing solution,acetonitrile,and methanol (45:40:15).

Standard preparation— Dissolve an accurately weighed quantity of USP Prochlorperazine Maleate RSin Mobile phaseto obtain a solution having a known concentration of about 0.2mg per mL.

Assay preparation— Weigh and finely powder not less than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 20mg of prochlorperazine maleate,to a 100-mLvolumetric flask.Add 60mLof Mobile phase,sonicate for 3minutes,and shake by mechanical means for 30minutes.Dilute with Mobile phaseto volume,mix,and filter,discarding the first 10mLof filtrate.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 254-nm detector and a 3.9-mm ×30-cm column that contains packing L1.The flow rate is about 2mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the tailing factor for the analyte peak is not more than 2.0;and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 10µL)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 prochlorperazine (C20H24ClN3S)in the portion of Tablets taken by the formula: in which 373.94and 606.09are the molecular weights of prochlorperazine and prochlorperazine maleate,respectively;Cis the concentration,in mg per mL,of USP Prochlorperazine Maleate RSin the Standard preparation;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.