Identification—
Transfer a portion of powdered Tablets,equivalent to about 40mg of perphenazine,to a 100-mLvolumetric flask containing about 50mLof alcohol.Agitate for 20minutes,add alcohol to volume,mix,and filter or centrifuge.Separately prepare two Standard solutions containing 0.4mg per mLof
USP Perphenazine RSand
USP Amitriptyline Hydrochloride RS,respectively,in alcohol.Separately apply 5µLof the test solution and 5µLof each Standard solution to a thin-layer chromatographic plate (see
Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel mixture.Develop the chromatogram using a solvent system consisting of a mixture of cyclohexane,ethyl acetate,and diethylamine (85:25:5)until the solvent front has moved about 15cm.Remove the plate from the developing chamber,air-dry for 20minutes,and examine the plate under short-wavelength UVlight:the
RFvalues of the principal spots obtained from the test solution correspond to those obtained from the Standard solutions.
Dissolution á711ñ—
Medium:
0.1Nhydrochloric acid;900mL.
Apparatus 2:
50rpm.
Time:
60minutes.
Procedure—
[NOTE—Due to potential decrease in the recovery of perphenazine when multiple injections are made from a vial,no more than two withdrawals should be made from any single vial.
]Determine the amounts of perphenazine and amitriptyline hydrochloride in solution in filtered portions of the solution under test,in comparison with a Standard solution having known concentrations of
USP Perphenazine RSand
USP Amitriptyline Hydrochloride RSin the same medium,as directed for
Procedurein the
Assay.
Tolerances—
Not less than 75%(Q)of the labeled amounts of perphenazine (C21H26ClN3OS)and amitriptyline hydrochloride (C20H23N·HCl)is dissolved in 60minutes.
Assay—
Mobile phase—
Prepare a filtered and degassed mixture of water,acetonitrile,methanol,and methanesulfonic acid (490:310:200:2).Make adjustments if necessary (see
System Suitabilityunder
Chromatography á621ñ).
Standard preparation—
Dissolve an accurately weighed quantity of
USP Perphenazine RSin methanol,and dilute quantitatively with methanol to obtain a solution having a known concentration of about 0.8mg per mL(
Solution P).Transfer 4
Jmg of
USP Amitriptyline Hydrochloride RSto a 50-mLvolumetric flask,
Jbeing the ratio of the labeled amount,in mg,of amitriptyline hydrochloride to the labeled amount,in mg,of perphenazine per Tablet.Add 5.0mLof
Solution Pand 20mLof 0.2Nacetic acid,shake,and sonicate to dissolve the USP Reference Standards.Dilute with methanol to volume,and mix.Pipet 25mLof this solution into a 100-mLvolumetric flask,dilute with a mixture of methanol and 0.04Nacetic acid (3:2)to volume,and mix to obtain a
Standard preparationhaving known concentrations of about 20µg of
USP Perphenazine RSper mLand about 20
Jµg of
USP Amitriptyline Hydrochloride RSper mL.
Assay preparation—
Transfer 10Tablets to a 250-mLvolumetric flask,add 100mLof 0.2Nacetic acid,and shake the mixture until the Tablets have disintegrated.Add methanol to volume,mix,and filter.Dilute an accurately measured volume (VFmL)of the clear filtrate quantitatively with a mixture of methanol and 0.04Nacetic acid (3:2)to obtain a solution (VAmL)containing about 20µg of perphenazine per mL,and filter through a membrane filter.
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 1mLper minute,and is adjusted until the relative retention times for perphenazine and amitriptyline are about 1and 1.5,respectively.Chromatograph the
Standard preparation,and record the peak responses as directed for
Procedure:the relative standard deviation is not more than 2.0%for replicate injections,and the resolution,
R,between perphenazine and amitriptyline is not less than 4.
Procedure—
Separately inject equal volumes (about 20µL)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 perphenazine (C
21H
26ClN
3OS)in each Tablet taken by the formula:
0.25(C/10)(VA/VF)(rU/rS),
in which
Cis the concentration,in µg per mL,of
USP Perphenazine RSin the
Standard preparation,
VAis the volume,in mL,of the
Assay preparation,
VFis the volume,in mL,of the filtrate taken for the
Assay preparation,and
rUand
rSare the responses of the perphenazine peaks obtained from the
Assay preparationand the
Standard preparation,respectively.Calculate the quantity,in mg,of amitriptyline hydrochloride (C
20H
23N·HCl)taken by the same formula,reading amitriptyline hydrochloride instead of perphenazine.