Determination of propranolol and carvedilol in urine samples using a magnetic polyamide composite and LC-MS/MS

Aim: beta-blockers are compounds that bind with adrenoreceptors hindering their interaction with adrenalin and noradrenalin. They are clinically relevant and they are also used in some sport as doping agents. Results: A new method based on the combination of dispersive micro-solid phase extraction and LC-MS/MS has been developed to determine propranolol and carvedilol in urine samples. For this purpose a magnetic-polyamide composite is synthesized and used as sorbent. Working under the optimum conditions, the method provides limits of detection and quantification in the range of 0.1-0.15 mu g/l and 0.3-0.5 mu g/l, for carvedilol and propranolol, respectively. The precision, expressed as RSD, was better than 9.6% and the relative recoveries varied between 73.7 and 81.3%. Conclusion: The methodology is appropriate for the determination of beta-blockers in urine samples at the low microgram per liter range for therapeutic purposes.