Identification—
A:
To a volume of Injection, equivalent to about 50 mg of fluphenazine decanoate, add 2 mL of methanol and 3 mL of palladium chloride solution (1 in 1000): a rust-red color is produced. Add an excess of the palladium chloride solution: the color is intensified to a brownish red.
B:
The retention time of the major peak in the chromatogram of the
Assay preparation corresponds to that in the chromatogram of the
Standard preparation, as obtained in the
Assay.
Chromatographic purity—
From the chromatograms obtained in the
Assay, calculate the percentage of fluphenazine in the portion of
Injection taken by the formula:
3.43(W / V)(rU / rS),
in which
W is the weight, in mg, of
USP Fluphenazine Hydrochloride RS used to prepare the
Standard preparation; V is the amount, in mg, of fluphenazine decanoate in the portion of Injection taken to prepare the
Assay preparation, based on the labeled concentration; and
rU and
rS are the fluphenazine peak responses obtained from the
Assay preparation and the
Standard preparation, respectively. The fluphenazine content is not more than 4% of the labeled amount of fluphenazine decanoate.
[NOTE—Use peak heights where peak responses are indicated.
] Calculate the percentage of each impurity eluting after fluphenazine decanoate in the portion of Injection taken by the formula:
100(ri / rs),
in which
ri is the peak response for each peak eluting after fluphenazine decanoate; and
rs is the sum of the responses for fluphenazine decanoate and all of the peaks eluting after fluphenazine decanoate: the sum of the responses for all of the peaks eluting after fluphenazine decanoate is not more than 2%.
Assay—
Mobile phase—
Prepare a filtered and degassed mixture of methanol, acetonitrile, and 0.05 M ammonium acetate (2:2:1). Make adjustments if necessary (see
System Suitability under
Chromatography 
621
).
Standard preparation—
Accurately weigh about 25 mg of
USP Fluphenazine Hydrochloride RS, and transfer it to a 250-mL volumetric flask. Dissolve in isopropyl alcohol, dilute with isopropyl alcohol to volume, and mix (
Solution A). Accurately weigh about 25 mg of Fluphenazine Decanoate Dihydrochloride RS. Transfer it to a 50-mL volumetric flask, and add 10 mL of
Solution A, quantitatively measured. Add 20 mL of isopropyl alcohol and dissolve sonicating, if necessary. Dilute with isopropyl alcohol to volume, and mix. Quantitatively dilute the resulting solution with acetonitrile (1:5) to obtain a solution having a known concentration of about 0.1 mg of fluphenazine decanoate per mL.
Assay preparation—
Transfer an accurately measured quantity of the Injection, equivalent to about 25 mg of fluphenazine decanoate, to a glass-stoppered, 50-mL volumetric flask. Add about 20 mL of isopropyl alcohol, insert the stopper, and shake vigorously for at least 1 minute. Add 20 mL more of isopropyl alcohol, and repeat the vigorous shaking. Dilute with isopropyl alcohol to volume, and mix. Quantitatively dilute the resulting solution with acetonitrile (1:5) to obtain a solution having a concentration of fluphenazine decanoate of about 0.1 mg per mL.
Chromatographic system
(see
Chromatography 621)—The chromatograph is equipped with a 254-nm detector and a 4.6-mm × 25-cm column containing 10-µm packing L1 preceded by a 4.6-mm × 5-cm pre-column containing similar packing of larger particle size (30–40 µm). The flow rate is about 2 mL per minute. Chromatograph the
Standard preparation and the
System suitability preparation, and record the peak responses as directed for
Procedure: the resolution,
R, between fluphenazine and fluphenazine decanoate in the
System suitability preparation is not less than 3.0; and the relative standard deviation of the fluphenazine decanoate peak for replicate injections of the
Standard preparation does not exceed 2.0. The relative retention times for fluphenazine and fluphenazine decanoate are 0.6 and 1, respectively.
Procedure—
Separately inject equal volumes (about 20 µL) of the
Standard preparation and the
Assay preparation into the chromatograph, continuing the chromatography, in each case, for a time equal to 2.5 times the elution time of fluphenazine decanoate. Record the chromatograms, and measure responses for the major peaks and for the peaks from all substances eluting after fluphenazine decanoate. Calculate the quantity, in mg, of fluphenazine decanoate (C
32H
44F
3N
3O
2S) in each mL of the Injection taken by the formula:
0.890(WS / WU)(rU / rS),
in which
WS is the weight, in mg, of
USP Fluphenazine Decanoate Dihydrochloride RS corrected for its moisture content, used to prepare the
Standard preparation; WU is the volume, in mL, of
Injection taken, and
rU and
rS are the peak responses of fluphenazine decanoate obtained from the
Assay preparation and the
Standard preparation, respectively.
