A SENSITIVE HPLC METHOD FOR THE DETERMINATION OF TERFENADINE AND ITS METABOLITE IN HUMAN PLASMA

A sensitive and selective HPLC assay with fluorescence detection was developed for the analysis of terfenadine and its acid metabolite in human plasma. The compounds were isolated from plasma by liquid extraction with methyl-t-butyl ether:isopropyl alcohol (95:5 % v/v). The chromatographic separation was carried on cyanopropylsilane column (15 cm X 4,6 mm) with a mobile phase consisting of 0.001 M acetate buffer, pH 4.0 : acetonitrile (25:75 % v/v). The eluent was monitored at 230 nm excitation and 300 nm emission wavelengths with a 270 nm cut-off filter. The range of quantification was 2 to 1000 ng/ml for terfenadine and 5 to 1000 ng/ml for acid metabolite, respectively. The assay showed linearity over the range of quantification (r(2) > 0.998). This method has been applied to the analysis of human plasma samples.