A: Thin-Layer Chromatographic Identification Test á201ñ—

B: The retention time of the major peak in the chromatogram of the Assay preparationcorresponds to that in the chromatogram of the Standard preparation,as obtained in the Assay.

Medium: 0.01Nhydrochloric acid;900mL.

Apparatus 2: 50rpm.

Time: 60minutes.

Mobile phase,Standard preparation,andChromatographic system— Proceed as directed in the Assay.

Procedure— Inject an appropriate volume (about 20µL)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 60minutes.

Phosphate buffer— Dissolve about 1.15g of monobasic ammonium phosphate in 1liter of water,and adjust with sodium hydroxide to a pHof 6.0.

Mobile phase— Prepare a filtered and degassed mixture of methanol and Phosphate buffer(3:1).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard preparation— Dissolve an accurately weighed quantity of USP Trazodone Hydrochloride RSin 0.01Nhydrochloric acid,and dilute quantitatively,and stepwise if necessary,with 0.01Nhydrochloric acid to obtain a solution having a known concentration of about 0.100mg per mL.

Assay preparation— Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 10mg of trazodone hydrochloride,to a 100-mLvolumetric flask,dilute with 0.01Nhydrochloric acid to volume,and mix.Sonicate for about 30minutes,and pass through a 0.45-µm nylon filter.

Chromatographic system (see Chromatography á621ñ)— 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 1.5mLper 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 900theoretical plates;and the relative standard deviation for replicate injections is not more than 2.0%.

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 trazodone hydrochloride (C19H22ClN5O·HCl)in the portion of Tablets taken by the formula: in which Cis the concentration,in mg per mL,of USP Trazodone Hydrochloride RSin the Standard preparation;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.