Mobile phase
Prepare a mixture of water, acetonitrile, glacial acetic acid, and 1.0 N tetrabutylammonium hydroxide in methanol (710:290:10:5). Adjust with ammonium hydroxide to a pH of 5.8 ± 0.05. Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Chromatographic system
(see
Chromatography 621)The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm × 15-cm column containing 5-µm packing L7. The flow rate is about 2 mL per minute. Chromatograph the
Standard preparation, and record the responses as directed for
Procedure: the relative retention times are 1.0 for flecainide and about 1.7 for flecainide related compound A; the resolution,
R, between flecainide and e flecainide related compound A is not less than 2; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure
[NOTEUse peak areas where peak responses are indicated.
] Separately inject equal volumes (about 20 µL) of the
Standard solution and the
Test solution into the chromatograph, record the chromatograms, and measure the responses for all the peaks. Calculate the percentage of flecainide related compound A in the portion of Flecainide Acetate taken by the formula:
2500(CA / WU)(rUA / rSA),
in which
CA is the concentration, in mg per mL, of
USP Flecainide Related Compound A RS in the
Standard solution; WU is the weight, in mg, of Flecainide Acetate taken to prepare the
Test solution; and
rUA and
rSA are the flecainide related compound A peak responses obtained from the
Test solution and the
Standard solution, respectively. Not more than 0.5% is found. Calculate the percentage of any other impurity in the portion of Flecainide Acetate taken by the formula:
2500(CF / WU)(ri / rF),
in which
CF is the concentration, in mg per mL, of USP Flecainide RS in the
Standard solution;WU is the weight, in mg, of Flecainide Acetate taken to prepare the
Test solution; ri is the peak response for any individual impurity observed in the chromatogram obtained from the
Test solution; and
rF is the flecainide peak response obtained from the
Standard solution. Not more than 0.5% is found, and the sum of all impurities found is not greater than 2.0%.