Abstract: Objective　To establish a method for determining the concentrations of fluoxetine and quetiapine simultaneously in human plasma by high performance liquid chromatography（HPLC）. Methods　The plasma concentrations of fluoxetine and quetiapine were determined by HPLC.The column was Inertsil ODS-C18 column（4.6 mm×150 mm，5 μm），the mobile phase was 0.05 mol/L ammonium acetate-methanol（volume ratio: 22∶78），the flow rate was 0.8 mL/min， the detection wavelength was 254 nm，the column temperature was kept at 40℃，the extractant was ethylacetate-dichloromethane（volume ratio: 77∶23），and the internal standard was carbamazepine. Results　Chromatographic peaks of carbamazepine，quetiapine and fluoxetine were completely separated，and all peak shapes were good.The retention times were 4.91，6.53 and 7.48 min，respectively，and the interference of plasma impurities on the determination did not occur.The calibration curves showed good linearity in range of 10-480 μg/L for fluoxetine and 20-1 600 μg/L for quetiapine（r=0.990 5 and 0.992 9）.When the signal-to-noise ratio（S/N）was 3，the detection limits were 5 and 8 μg/L，respectively.The absolute recoveries of fluoxetine and quetiapine in low，middle and high concentrations were >75％，and the relative recoveries were >95%.The relative standard deviation（RSD） of intra-day and inter-day were <10％. Conclusions　The method is sensitive，accurate and low-cost，and it can be used for clinical drug monitoring and pharmacokinetics studies of fluoxetine and quetiapine.

Key words: Fluoxetine, Quetiapine, High performance liquid chromatography, Plasma drug concentration