Analysis of the recent antipsychotic aripiprazole in human plasma by capillary electrophoresis and high performance liquid chromatography with diode array detection

Two methods, based on the use of Capillary Electrophoresis (CE) and High Performance Liquid Chromatography (HPLC), respectively, were developed for the analysis of the atypical antipsychotic aripiprazole in plasma of schizophrenic patients for therapeutic drug monitoring purposes. Good analytical performances were obtained with the CE method, using uncoated fused silica capillaries and a background electrolyte composed of 50 mM phosphate buffer at pH 2.5. With 20 kV voltage, aripiprazole was detectable at 214 nm within 5 minutes. The second analytical method, based on HPLC with diode array detection, employed a C8 reversed phase column and a mixture of a 12.5 mM phosphate buffer, pH 3.5, containing triethylamine and acetonitrile as the mobile phase. Aripiprazole was detected at 254 nm and a complete chromatographic run lasted about 10 minutes. For both analytical methods loxapine was used as the internal standard and the same plasma sample pre-treatment by means of solid-phase extraction on cyano cartridges was carried out, with extraction yield values always higher than 91.3%. Linear responses for aripiprazole were obtained between 70 and 700 ng/mL and precision assays (expressed as relative standard deviation values) were lower than 7.0%. After validation, both methods were successfully applied to human plasma samples drawn from schizophrenic patients undergoing therapy with Abilify® tablets. Accuracy was satisfactory, with recovery value higher than 91.0%.