Identification—
A:
Thin-Layer Chromatographic Identification Test 
201
—
Test solution—
Place a number of Tablets, equivalent to about 150 mg of trazodone hydrochloride, in a clean scintillation vial, add about 7.5 mL of methanol, and sonicate until the Tablets have disintegrated. Shake the vials, by hand, for a few seconds to mix, and filter to obtain the test solution.
Standard solution:
20 mg per mL, in methanol.
Application volume:
1 µL.
Developing solvent system:
a mixture of cyclohexane, alcohol, toluene, and diethylamine (80:30:20:20).
Procedure:
Proceed as directed in the chapter except locate the spots on the plate by examination under long-wavelength UV light.
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.
Dissolution 711—
Medium:
0.01 N hydrochloric acid; 900 mL.
Apparatus 2:
50 rpm.
Time:
60 minutes.
Determine the amount of C19H22ClN5O·HCl dissolved by employing the following method.
Mobile phase, Standard preparation, and Chromatographic system—
Proceed as directed in the
Assay.
Procedure—
Inject an appropriate volume (about 20 µL) of a portion of the solution under test, previously passed through a 0.45-µm nylon filter, into the chromatograph, record the chromatogram, and measure the response for the major peak. Calculate the quantity of C19H22ClN5O·HCl dissolved by comparing this peak response with the major peak response similarly obtained from the Standard preparation.
Tolerances—
Not less than 80% (Q) of the labeled amount of C19H22ClN5O·HCl is dissolved in 60 minutes.
Assay—
Phosphate buffer—
Dissolve about 1.15 g of monobasic ammonium phosphate in 1 L of water, and adjust with sodium hydroxide to a pH of 6.0.
Mobile phase—
Prepare a filtered and degassed mixture of methanol and
Phosphate buffer (3:1). Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Standard preparation—
Dissolve an accurately weighed quantity of
USP Trazodone Hydrochloride RS in 0.01 N hydrochloric acid, and dilute quantitatively, and stepwise if necessary, with 0.01 N hydrochloric acid to obtain a solution having a known concentration of about 0.100 mg per mL.
Assay preparation—
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 10 mg of trazodone hydrochloride, to a 100-mL volumetric flask, dilute with 0.01 N hydrochloric acid to volume, and mix. Sonicate for about 30 minutes, and pass through a 0.45-µm nylon filter.
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a 246-nm detector and a 5-mm × 10-cm column that contains packing L1. The flow rate is about 1.5 mL per minute. Chromatograph the
Standard preparation, and record the peak responses as directed for
Procedure: the capacity factor,
k¢, is not less than 1.5; the column efficiency is not less than 900 theoretical plates; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 20 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 trazodone hydrochloride (C
19H
22ClN
5O·HCl) in the portion of Tablets taken by the formula:
100C(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Trazodone Hydrochloride RS in the
Standard preparation; and
rU and
rS are the peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
