1998 年 24 巻 6 号 p. 624-628
Both low-sensitivity and labor-intensive liquid-liquid extraction have previously limited the use of high-performance liquid chromatography for the therapeutic drug monitoring of cibenzoline. A rapid solid-phase extraction method was developed to minimize the sample workup and provide analytical sensitivity to 0.05μg/ml using 1ml of serum. The serum samples were loaded onto C 18 solid-phase extraction columns, and cibenzoline and an internal standard (di-pmethyl analogue of cibenzoline) were eluted with 5% ammonium hydroxide in methanol, dried and reconstituted in 200μl of the mobile phase. Chromatographic separation was achieved using a Zolbax C 8 column at 40°C and a mobile phase of a mixture of acetonitrile and 0.06% phosphoric acid (40: 60, vol./vol.), at a flow rate of 1 ml/min. UV detection was carried out at 230 nm. The retention times of cibenzoline and the internal standard were 8 and 18 min, respectively. The standard curves were linear over a range of 0.05-1 μg/ml with intra-assay coefficients of variation of 6.4% and 2.9% at 0.05 and 0.5μg/ml, respectively. Fanally, no chromatographic interference from other anti-arrhythmic drugs was observed
