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: Infrared Absorption 197K.

B: Ultraviolet Absorption 197U—

C: A solution of Fluphenazine Hydrochloride responds to the tests for Chloride 191.

Test solution: 0.1 M methanolic sodium hydroxide.

Standard solution: 0.1 M methanolic sodium hydroxide.

Eluant: a mixture of acetone, cyclohexane, and diethylamine (40:15:1).

Visualization: 1.

Diluent solution— Prepare a filtered and degassed mixture of 0.05 M monobasic potassium phosphate (adjusted with phosphoric acid to a pH of 2.5), acetonitrile, and methanol (40:30:30). Make adjustments if necessary (see System Suitability under Chromatography 621).

Mobile phase— Prepare a mixture containing 0.2% triethylamine in Diluent solution.

Standard preparation— Dissolve an accurately weighed quantity of USP Fluphenazine Hydrochloride RS in Diluent solution, and dilute quantitatively, and stepwise if necessary, with Diluent solution to obtain a solution having a known concentration of about 0.06 mg per mL.

Assay preparation— Transfer about 120 mg of Fluphenazine Hydrochloride, accurately weighed, to a 100-mL volumetric flask. Dissolve in and dilute with Diluent solution to volume, and mix. Pipet 5.0 mL of this solution into a 100-mL volumetric flask, dilute with Diluent solution to volume, and mix. Filter, discarding the first 5 mL of the filtrate.

Chromatographic system (see Chromatography 621)—The liquid chromatograph is equipped with a 254-nm detector and a 4-mm × 12.5-cm column that contains packing L7. The flow rate is about 1.0 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure : the column efficiency is not less than 2000 theoretical plates, the tailing factor 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 25 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C22H26F3N3OS·2HCl in the portion of Fluphenazine Hydrochloride taken by the formula: in which C is the concentration, in mg per mL, of USP Fluphenazine Hydrochloride RS in the Standard preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.