Determination of concentrations of flecainide in human serum by high-performance liquid chromatography on a fluorocarbon-bonded silica gel column

An optimized method for the determination of flecainide in serum is present ed. Extraction using a solid-phase C-18 column and chromatography on a stab ilized fluorocarbon-bonded silica gel column effectively separate flecainid e from an internal standard (a positional isomer of flecainide). The HPLC a pparatus and conditions were as follows: analytical column, Fluofix 120N: s ample solvent, 20 mu l; column temperature, 40 degrees C; detector, Shimadz u RF-5000 fluorescence spectrophotometer (excitation wavelength=300 nm, emi ssion wavelength=370 mm); mobile phase, 0.06% phosphoric acid containing 0. 1% tetra-n-butyl ammonium bromide-acetonitrile (75:25, v/v); flow-rate, 1.0 ml/min. The standard curves for flecainide were linear in the concentratio n range examined (10-2000 ng/ml). The regression equation was y=0.08+0.0078 x (r=0.9998). The minimum detectable amount of flecainide was approximately 5 ng/ml. In the within-day study, the precision coefficients of variation were 2.66, 2.18, 2.54, 2.72, 2.88, 2.24, and 3.29% for the 10, 50, 100, 200 , 500, 1000, and 1500 ng/ml standards, respectively. The absolute recovery rates of flecainide at each concentrations were 94-100%. The method describ ed provides analytical sensitivity, specificity and reproducibility suitabl e for both biomedical research and therapeutic drug monitoring. (C) 1999 El sevier Science B.V. All rights reserved.