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

Medium: 0.1Nhydrochloric acid;900mL.

Apparatus 2: 50rpm.

Time: 45minutes.

Procedure— Determine the amount of C21H26ClN3OSdissolved from UVabsorbances at the wavelength of maximum absorbance at about 257nm 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 Perphenazine RSin the same medium.

Tolerances— Not less than 75%(Q)of the labeled amount of C21H26ClN3OSis dissolved in 45minutes.

Acid-alcohol solutionand Palladium chloride solution— Prepare as directed in the Assayunder Perphenazine Injection.

Standard preparation— Prepare as directed in the Assayunder Perphenazine Syrup.

Assay preparation— Weigh and finely powder not less than 20Tablets.Transfer a portion of the powder,equivalent to about 4mg of perphenazine,to a glass-stoppered conical flask,pipet into the flask 25mLof Acid-alcohol solution,shake by mechanical means for 30minutes,and centrifuge a portion of the mixture.The clear supernatant fluid is the Assay preparation.

Procedure— Proceed as directed for Procedurein the Assayunder Perphenazine Injection.Calculate the quantity,in mg,of C21H26ClN3OSin the portion of Tablets taken by the formula: in which Cis the concentration,in µg per mL,of USP Perphenazine RSin the Standard preparation,and AUand ASare the absorbances of the solutions from the Assay preparationand the Standard preparation,respectively.