A Rapid Liquid Chromatographic Method for Determination of Flecainide in Human Blood Plasma Using Ultraviolet Detection

Abstract

A liquid chromatographic method for the assay of the antiarrhythmic drug flecainide in plasma has been developed. The method is rapid, simple and with sufficient detection sensitivity to render it suitable for therapeutic drug monitoring. Flecainide and added internal standard, a non-fluorinated analogue, were extracted by a single ether extraction from alkalinized plasma followed by a back-extraction of the ether with dilute phosphoric acid. A portion of the acid extract was then applied directly to a 30 cm ODS column eluting isocratically with 30% acetonitrile in water containing 0.01M dibutylamine phosphate. Monitoring was by ultraviolet detection at 214 nm and the total run time was 8 min. This method is specific and can quantitate plasma levels to less than 30 ng/ml (free base) from 0.5 ml of plasma without interference from antiarrhythmic drugs commonly used in therapy.