Development and validation of bioanalytical method for the determination of asulacrine in plasma by liquid chromatography

Asulacrine (9-[(2-methoxy-4-methylsulphonylamino)phenylamino]-N,5-dimethyl-4-acridinecarboxamide), an analogue of the antileukaemia drug amsacrine, has high antitumour activity in mice and has also shown clinical activity. A simple method is described for the quantitation of asulacrine in plasma by liquid chromatography. Chromatographic separation was achieved on a reversed phase C 18 column (250 mm × 4.6 mm, particle size 5 μm, Gemini) using isocratic elution (acetonitrile and 0.01 M sodium acetate buffer pH 4.0, 45/55, v/v) at a flow rate of 1 ml/min. Asulacrine and internal standard (the ethylsulphonanilide analogue) were measured using UV detection at 254 nm. The total chromatographic run-time was 8 min with asulacrine and internal standard eluting at ∼4.7 and ∼6.5 min, respectively. Limit of quantification was 0.1 μg/ml. The linearity range of the method was 0.1–10 μg/ml (r2 = 0.9995). Mean recoveries from plasma were 100–105%. Intra-batch and inter-batch precision was 7.1 and 7.8%, respectively, and intra-batch and inter-batch accuracy (relative error) was 4.9 and 8.4%, respectively (n = 8 in all cases). The bench top, freeze thaw, short-term storage and stock solution stability evaluation indicated no evidence of degradation of asulacrine. The validated method is simple, selective and rapid and can be used for pharmacokinetic studies in mice.