Liquid chromatographic high-throughput analysis of the new ultra-short acting hypnotic 'HIE-124' and its metabolite in mice serum using a monolithic silica column

For the first time, a fast, high-performance liquid chromatography (HPLC) method was developed and validated for the simultaneous determination of the new ultra-short hypnotic HIE-124 and its metabolite in mice serum. Each compound, together with carbamazepine (internal standard) was extracted from the serum matrix using liquid-liquid extraction (LLE). Chromatographic resolution of the analytes was performed on a Chromolith Speed Rod monolithic silica column (100 mm x 4.6 mm i.d.) under isocratic conditions using a mobile phase of 65 : 35 (v/v), 20 mM phosphate buffer (pH 7.0 adjusted with phosphoric acid)-acetonitrile. The elution of the analytes were monitored at 240 nm and conducted at ambient temperature. Because of high column efficiency the mobile phase was pumped at a flow rate of 2.5 mL min(-1). The total run time of the assay was 2 min. The method was validated over the range of 60-2000 ng mL(-1) for HIE-124 and 200-1600 ng mL(-1) for the metabolite (r(2) = 0.99). The limit of detection (LOD) for HIE-124 and its metabolite were 20 ng mL(-1) and 65 ng mL(-1), respectively. The proposed method was validated in compliance with ICH guidelines, in terms of accuracy, precision, limits of detection and quantitation and other aspects of analytical validation. The developed method could be used for the trace analyses of HIE-124 and its metabolite in serum and was finally used for the pharmacokinetic study investigation of HIE-124 in mice serum.