A high performance liquid chromatographic method for the quantitation of flecainide in plasma.

A routine high performance liquid chromatographic method for the rapid determination of flecaïnide (Flecaine), using a novel internal standard, N-methylflecaïnide, has been developed. After deproteinization of spiked samples, flecaïnide was totally recovered at neutral pH. Flecaïnide and the internal standard were separated on a reversed phase XL 3 microns ODS column using 10 mM phosphate buffer, pH 3.0: acetonitrile (70:30) as mobile phase, in less than 10 min. With spectrofluorometric detection, the limit of quantitation for flecaïnide was 10 ng/mL. Intra- and inter-assay precision variations were 0.24% and 1.4%.