DETERMINATION OF ?-BLOCKERS BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY COUPLED WITH SOLID PHASE MICROEXTRACTION FROM URINE AND PLASMA SAMPLES

The solid phase microextraction (SPME) method was applied to drug monitoring of ?blockers in human urine and plasma. Six ?-blockers (alprenolol, atenolol, oxprenolol, pindolol, ?-propranolol, and timolol) were extracted from urine and plasma samples by SPME fiber coated with 85-µm polyacrylate for 2 h at 30°C. The ?-blockers extracted were separated by Capcell PackTM SG120 (4.6 × 150 mm, 5 µm) with 0.05 M phospholic acidmethanol (55 + 45, v/v) and detected by photometric detection (280 nm) and fluorometric detection (excitation wavelength 220 nm, emission wavelength at 360 nm). The recoveries of ?-blockers (500 µg/ml) from urine were 84.3 to 88.4%, and from plasma they were 86.4 to 90.2%. The detection limits were 2 to 25 µg/ml by the photometric detection, 0.4 µg/ml of ?propranolol by fluorescence detection. The relative standard deviations were 10.1 to 15.3% for 500 µg/ml ?-blockers in urine, 9.9 to 13.2% for 5 µg/ml of ?-blockers in plasma, respectively.