Spectral range: 250to 400nm.

Solution: Use the test solution obtained in the test for Uniformity of dosage units.

Medium: 0.075Nhydrochloric acid;900mL.

Apparatus 2: 50rpm.

Time: 30minutes for Tablets each containing 50mg of flecainide acetate,or 60minutes for 100-,150-,or 200-mg Tablets.

Procedure— Determine the amount of C17H20F6N2O3·C2H4O2dissolved from UVabsorbances at the wavelength of maximum absorbance at about 296nm on filtered portions of the solution under test,suitably diluted with Dissolution Medium,if necessary,in comparison with a Standard solution having a known concentration of USP Flecainide Acetate RSin the same Medium.

Tolerances— Not less than 70%(Q)of the labeled amount of C17H20F6N2O3·C2H4O2is dissolved from 50-mg Tablets in 30minutes;or from 100-,150-,or 200-mg Tablets in 60minutes.

Procedure for content uniformity— Transfer 1Tablet to a volumetric flask of such capacity that the concentration of flecainide acetate should be in the range of 0.1to 1mg per mL,dilute with lactic acid solution (2mg per mL)to volume,mix,and sonicate for about 30minutes,shaking at about 10-minute intervals.Allow to cool,and pass a portion of this stock solution through a glass-fiber filter.If necessary,quantitatively dilute an accurately measured volume of the clear filtrate with the lactic acid solution (2mg per mL)to obtain a test solution having a concentration of about 0.1mg of flecainide acetate per mL.Dissolve an accurately weighed quantity of USP Flecainide Acetate RSin the lactic acid solution (2mg per mL),sonicating if necessary to achieve dissolution,to obtain a Standard solution having a known concentration of about 0.1mg per mL.Concomitantly determine the absorbances of both solutions at the wavelength of maximum absorbance at about 296nm,with a spectrophotometer,using the lactic acid solution (2mg per mL)as the blank.Calculate the quantity,in mg,of C17H20F6N2O3·C2H4O2in the Tablet taken by the formula: in which Cis the concentration,in mg per mL,of USP Flecainide Acetate RSin the Standard solution;Tis the labeled quantity,in mg of flecainide acetate per Tablet;Dis the concentration,in mg per mL,of flecainide acetate in the test solution on the basis of the labeled quantity per Tablet and the extent of dilution;and AUand ASare the absorbances of the test solution and the Standard solution,respectively.

Mobile phase— Prepare a mixture of water,acetonitrile,glacial acetic acid,and 1.0Ntetrabutylammonium hydroxide in methanol (710:290:10:5).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Diluent— Prepare a mixture of water and lactic acid (980:20).

Standard preparation— Quantitatively dissolve an accurately weighed quantity of USP Flecainide Acetate RSin Diluentto obtain a solution having a known concentration of about 2mg per mL.

Resolution solution— Prepare a solution in Diluentcontaining about 2mg of USP Flecainide Acetate RSand 0.8mg of USP Flecainide Related Compound A RSper mL.

Assay preparation— Transfer not fewer than 20Tablets,accurately counted,to a volumetric flask of such capacity that the concentration of flecainide acetate is about 2mg per mLafter dilution to volume as directed below.Fill the flask to about 90%of its capacity with Diluent,and sonicate for about 30minutes,swirling periodically.Allow to cool,dilute with Diluentto volume,and mix.Pass a portion of this solution through a filter having a of 0.5-µm or finer porosity,discarding the first 2mLof the filtrate.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm ×15-cm column that contains 5-µm packing L7.The flow rate is about 2mLper minute.Chromatograph the Resolution solution,and record the responses as directed forProcedure:the relative retention times are 1.0for flecainide and about 1.5for flecainide related compound A;and the resolution,R,between flecainide and the flecainide related compound Ais not less than 2.0.Chromatograph the Standard preparation,and record the responses as directed for Procedure:the relative standard deviation for replicate injections is not more than 1.5%.

Procedure— [NOTE—Use peak areas where peak responses are indicated.]Separately inject equal volumes (about 10µL)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 flecainide acetate (C17H20F6N2O3·C2H4O2)in each Tablet taken by the formula: in which Cis the concentration,in mg per mL,of USP Flecainide Acetate RSin the Standard preparation;Tis the labeled quantity,in mg,of flecainide acetate per Tablet;Dis the concentration,in mg per mL,of flecainide acetate in the Assay preparationon the basis of the labeled quantity per Tablet and the extent of dilution;and rUand rSare the flecainide peak responses obtained from the Assay preparationand the Standard preparation,respectively.