ABSTRACT
Objective To provide a specific,sensitive,reproducible HPLC method for the determination of doxepin in urine and whole blood with doxapram as the internal standard.Methods The sample preparation was simple and time-saving by using an Oasis pretreatment cartridge.Separations were achieved by a Lichrospher 100 RP-18e (250mm?4.0mm,5?m)column kept at 50 ℃,and the DAD detector was set at 230nm and 250nm.Results The detection limit was 2 ng/ml in urine and whole blood.The results showed excellent linearity.The relative standard deviation of between-day and within-day assay was Less than 6.75%,and absolute recoveries were higher than 85%.Conclusion The method for determination of doxepin in urine and whole blood is effective,simple and reliable,which may be applicable to the practical cases.