A sensitive column-switching HPLC method for aripiprazole and dehydroaripiprazole and its application to human pharmacokinetic studies

A simple and sensitive column-switching HPLC-UV method was developed for the simultaneous determination of aripiprazole, a novel atypical antipsychotic drug, and its active metabolite, dehydroaripiprazole in human plasma. Aripiprazole, its active metabolite and 7-[5-[4-(3-chloro-2-methylphenyl)-1-piperazinyl]pentyloxy]-3,4-dihydro-2(1H)quinolinone (OPC-14558) as an internal standard were extracted from 1 mL of plasma using a mixture of chloroform/n-heptane (3:7, v/v), and the extract was injected into a column I (TSK BSA-ODS/S precolumn, 5 mm) for cleanup and column II (C-18 STR ODS-II analytical column, 5 mm) for separation. Peaks were detected with an UV detector set at a wavelength of 254 nm, and the total time for chromatographic separation was similar to 20 min. Mean absolute recoveries were 74.0 and 74.7% for aripiprazole and dehydroaripiprazole, respectively. Intra-and inter-day CVs were less than 7.5 and 7.1% for aripiprazole concentrations ranging from 2 to 600 ng/mL, and 9.2 and 4.5% for dehydroaripiprazole concentrations ranging from 2 to 160 ng/mL. The validated concentration ranges for this method were 1-500 ng/mL and the limits of detection were 0.5 ng/mL for both aripiprazole and dehydroaripiprazole. This method was applied to pharmacokinetic study in human volunteers and patients taking aripiprazole.