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.

A: Place about 50mg of Fluphenazine Decanoate and about 50mg of USP Fluphenazine Decanoate Dihydrochloride RSin separate,glass-stoppered,small centrifuge tubes,and treat each tube as follows.Add 1.5mLof sodium hydroxide solution (1in 250),and mix.Add 2mLof carbon disulfide,shake vigorously for 2minutes,and centrifuge.Dry the lower,clear layer by filtering through 2g of anhydrous sodium sulfate:the IRabsorption spectrum of the test preparation,determined in a 0.1-mm cell,exhibits maxima only at the same wavelengths as that of the Standard preparation,similarly measured.

B: Use a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel mixture.Impregnate the plate with a 1in 20solution of tetradecane in hexane,and allow to air-dry.Prepare a test solution in alcohol containing 20mg per mL.Apply 1µLeach of the test solution and of a Standard solution of USP Fluphenazine Decanoate Dihydrochloride RSin alcohol,similarly prepared.Allow the spots to dry.Apply to the spot from the Standard solution,1.0µLof 0.1Nsodium hydroxide and allow it to dry.Develop the plate in an equilibrated chamber using a mixture of methanol and water (9:1)as the mobile phase.Examine the plate under short-wavelength UVlight at 254nm:the RFvalue of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.

Test solution: methanol.

Standard solution: methanol.

Eluant :a mixture of acetone,cyclohexane,and ammonium hydroxide (16:6:1).

Visualization: 1;then spray the plate with 50%sulfuric acid.

Interpretation: no individual ordinary impurity observed exceeds 1.0%and the total of any ordinary impurities observed does not exceed 2.0%.