NOTE—When performing assays and tests,store all standard,system suitability,and sample solutions in a cool place,protected from light.

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: 0.1Nhydrochloric acid;500mL,deaerated.

Apparatus 1: 100rpm.

Times: 15minutes.

Procedure— Determine the amount of C17H25N3O2Sdissolved from the difference between first derivative absorbance values at the wavelengths of maximum and minimum in the range from 226nm to 236nm on filtered portions of the solution under test,suitably diluted with Medium,if necessary,in comparison with a Standard solution having a known concentration of USP Naratriptan Hydrochloride RSin the same Medium.[Note—Do not sonicate the Standard solution to dissolve.Dissolve the USP Reference Standard with Mediumat about 37.]

Tolerances— Not less than 80%(Q)of the labeled amount of C17H25N3O2Sis dissolved in 15minutes.

0.05M Ammonium phosphate buffer and Resolution solution— Prepare as directed in the test for Chromatographic purityunder Naratriptan Hydrochloride.

Solution A— Use filtered and degassed 0.05M Ammonium phosphate buffer.

Solution B— Use filtered and degassed acetonitrile.

Mobile phase— Use variable mixtures of Solution Aand Solution Bas directed for Chromatographic system.Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Test solution— Transfer 5Tablets into a suitable amber flask.Add 20.0mLof 0.1Nsodium hydroxide,and allow to stand for 10minutes.Sonicate for 10minutes with regular vigorous swirling of the flask.Add 30.0mLof 0.05M Ammonium phosphate buffer,and mix well.Centrifuge a portion of this solution at 3500rpm for about 10minutes,and pass through a suitable filter having a 0.45-µm porosity,discarding the first 3mLof the filtrate.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 225-nm detector and a 4.6-mm ×15-cm column that contains packing L1.The column temperature is maintained at 40.The flow rate is about 1.5mLper minute.The chromatograph is programmed as follows. Chromatograph the Resolution solution,and record the peak responses as directed for Procedure:the relative retention times are about 1.07for naratriptan related compound Band 1.0for naratriptan;and the resolution,R,between naratriptan and naratriptan related compound Bis not less than 1.5.

Procedure— Inject a volume (equivalent to about 5µg of naratriptan hydrochloride)of the Test solutioninto the chromatograph,record the chromatogram,and measure the areas for all the peaks.Calculate the percentage of each impurity in the portion of Tablets taken by the formula: in which Fis the relative response factor (see the accompanying table for values)for each impurity;riis the peak response for each impurity;and rNis the naratriptan peak response (see the accompanying table for limits). In addition to not exceeding the limits listed in the accompanying table,not more than 0.2%of any other individual impurity is found;and not more than 1.5%of total impurities is found.

0.01M Triethylamine phosphate buffer,Mobile phase,and Resolution solution— Prepare as directed in the Assayunder Naratriptan Hydrochloride.

Standard preparation— Dissolve an accurately weighed quantity of USP Naratriptan Hydrochloride RSin 0.1Nsodium hydroxide to obtain a solution having a known concentration of about 0.2mg per mL.Dilute an accurately measured volume of this solution in 0.01M Triethylamine phosphate bufferto obtain a solution having a known concentration of about 20µg per mL.

Assay preparation— Transfer 5Tablets into an amber 250-mLvolumetric flask,add 30mLof 0.1Nsodium hydroxide,and shake on a wrist-action shaker for at least 30minutes.Sonicate for 10minutes with regular vigorous swirling of the flask.Add about 170mLof 0.01M Triethylamine phosphate buffer,and mix well.Allow to cool to room temperature,dilute with 0.01M Triethylamine phosphate bufferto volume,and mix.Centrifuge a portion of this solution at 3500rpm for about 10minutes,and pass through a suitable filter having a 0.45-µm porosity,discarding the first 3mLof the filtrate.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 224-nm detector and a 4.6-mm ×15-cm column that contains 5-µm packing L11.The flow rate is about 1.3mLper minute.Chromatograph the Resolution solution,and record the peak responses as directed for Procedure:the relative retention times are about 0.9for naratriptan related compound A,1.0for naratriptan,and 1.1for naratriptan related compound B;and the resolution,R,between naratriptan related compound Aand naratriptan and between naratriptan related compound Band naratriptan is not less than 1.5.Chromatograph the Standard preparation,record the chromatogram,and measure the peak response as directed for Procedure:the relative standard deviation for replicate injections is not more than 1.5%.

Procedure— Separately inject volumes (equivalent to about 1µg of naratriptan hydrochloride)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 naratriptan (C17H25N3O2S)in the portion of Tablets taken by the formula: in which 335.47and 371.93are the molecular weights of naratriptan and naratriptan hydrochloride,respectively;Cis the concentration,in mg per mL,of USP Naratriptan Hydrochloride RSin the Standard preparation;Dis the concentration,in mg per mL,of naratriptan in the Assay preparation,based upon the labeled quantity of naratriptan in the portion of Tablets taken and the extent of dilution;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.