Spectral range: 250 to 400 nm.

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

Medium: 0.075 N hydrochloric acid; 900 mL.

Apparatus 2: 50 rpm.

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

Procedure— Determine the amount of C17H20F6N2O3·C2H4O2 dissolved from UV absorbances at the wavelength of maximum absorbance at about 296 nm 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 RS in the same Medium.

Tolerances— Not less than 70% (Q) of the labeled amount of C17H20F6N2O3·C2H4O2 is dissolved from 50-mg Tablets in 30 minutes; or from 100-, 150-, or 200-mg Tablets in 60 minutes.

Procedure for content uniformity— Transfer 1 Tablet to a volumetric flask of such capacity that the concentration of flecainide acetate should be in the range of 0.1 to 1 mg per mL, dilute with lactic acid solution (2 mg per mL) to volume, mix, and sonicate for about 30 minutes, 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 (2 mg per mL) to obtain a test solution having a concentration of about 0.1 mg of flecainide acetate per mL. Dissolve an accurately weighed quantity of USP Flecainide Acetate RS in the lactic acid solution (2 mg per mL), sonicating if necessary to achieve dissolution, to obtain a Standard solution having a known concentration of about 0.1 mg per mL. Concomitantly determine the absorbances of both solutions at the wavelength of maximum absorbance at about 296 nm, with a spectrophotometer, using the lactic acid solution (2 mg per mL) as the blank. Calculate the quantity, in mg, of C17H20F6N2O3·C2H4O2 in the Tablet taken by the formula: in which C is the concentration, in mg per mL, of USP Flecainide Acetate RS in the Standard solution; T is the labeled quantity, in mg of flecainide acetate per Tablet; D is 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 AU and AS are the absorbances of the test solution and the Standard solution, respectively.

(Official January 1, 2007)

Mobile phase— Prepare a mixture of water, acetonitrile, glacial acetic acid, and 1.0 N tetrabutylammonium hydroxide in methanol (710:290:10:5). Make adjustments if necessary (see System Suitability under Chromatography 621).

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

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

Resolution solution— Prepare a solution in Diluent containing about 2 mg of USP Flecainide Acetate RS and 0.8 mg of USP Flecainide Related Compound A RS per mL.

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

Chromatographic system (see Chromatography 621)—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 2 mL per minute. Chromatograph the Resolution solution, and record the responses as directed forProcedure: the relative retention times are 1.0 for flecainide and about 1.5 for flecainide related compound A; and the resolution, R, between flecainide and the flecainide related compound A is 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 10 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 flecainide acetate (C17H20F6N2O3·C2H4O2) in each Tablet taken by the formula: in which C is the concentration, in mg per mL, of USP Flecainide Acetate RS in the Standard preparation; T is the labeled quantity, in mg, of flecainide acetate per Tablet; D is the concentration, in mg per mL, of flecainide acetate in the Assay preparation on the basis of the labeled quantity per Tablet and the extent of dilution; and rU and rS are the flecainide peak responses obtained from the Assay preparation and the Standard preparation, respectively.