Direct and fast determination of paclitaxel, morphine and codeine in urine by micellar electrokinetic chromatography.

A micellar electrokinetic chromatography (MEKC) method was developed for the determination of paclitaxel, morphine and codeine in human urine from patients under cancer treatment. The background electrolyte consisted of a borate buffer (pH 9.2; 20 mM) with sodium dodecyl sulfate (60 mM) and 5% MeOH. The applied voltage was 25 kV, temperature was 20 °C and the sample injection was performed in the hydrodynamic mode. All analyses were carried out in a fused silica capillary with an internal diameter of 75 μm and a total length of 57 cm. The detection of target compounds was performed at 212 nm. Under these conditions, a complete separation of paclitaxel, morphine and codeine was achieved in less than 15 min. According to the validation study, the developed method was proved to be accurate, precise, sensitive, specific, rugged and robust. This method was applied to the analysis of six urines samples from different cancer patients undergoing treatment with paclitaxel or/and codeine. In all the urine paclitaxel determination were done.