Liquid chromatographic direct resolution of flecainide and its analogs on a chiral stationary phase based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid.

Flecainide, an antiarrythmic agent, and its analogs were resolved on a high performance liquid chromatographic chiral stationary phase (CSP) based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid with the use of a mobile phase consisting of methanol-acetonitrile-trifluoroacetic acid-triethylamine (80/20/0.1/0.3, v/v/v/v). The chiral resolution was quite successful, the separation factors (alpha) and the resolutions (R(S)) for 20 analytes including flecainide being in the range of 1.19-1.82 and 1.73-6.80, respectively. The ortho-substituent of the benzoyl group of analytes was found to cause decrease in the retention times of analytes probably because of the conformational deformation of analytes originated from the steric hindrance exerted by the ortho-substituent.