COMPARISON OF TWO DIFFERENT APPROACHES OF SAMPLE PRETREATMENT FOR STEREOSELECTIVE DETERMINATION OF (R,S)-PROPRANOLOL IN HUMAN PLASMA

A column-switching chromatographic system using the teicoplanin chiral stationary phase for stereoselective determination of the β-blocker (R,S)-propranolol in human plasma has been developed and validated. A conventional, off-line liquid–liquid extraction procedure was used for pretreatment of plasma samples and compared to an on-line sample preparation method employing a special type of packing material (LiChrospher RP-8 ADS). The HPLC-integrated sample pretreatment (on-line liquid–solid extraction) allows higher precision, accuracy, and sensitivity. Detailed validation parameters are discussed.