Simple and sensitive method for the quantitative analysis of lometrexol in plasma using high-performance liquid chromatography with electrochemical detection

Previously described methods for the determination of lometrexol in plasma used either fluorescence or ultraviolet detection. An alternative method for the determination of lometrexol utilizing electrochemical detection is described, having comparable sensitivity to fluorometric methods but no requiring pre-analytical oxidation. Following sample clean-up, separation is achieved on a phenyl column with a mobile-phase of 8% acetonitrile in 50 mM sodium acetate buffer, pH 4.0. The calibration curve in plasma is linear from 10 to 200 ng/ml, with inter- and intra-day precision of 5.4 and 5.5%, respectively. The recovery of lometrexol from plasma is 81 ± 1.5%, and the lower limit of detection is 5 ng/ml, using a signal-to-noise ratio of 3.