PROPRANOLOL IN SERUM BY HIGH-PRESSURE LIQUID-CHROMATOGRAPHY

A high pressure liquid chromatographic method (HPLC) has been developed to measure therapeutic levels of the beta-blocker and antiarrhythmic drug propranolol in serum. A reverse phase CN column was used with an acetate counter-ion in an aqueous/methanol mobile phase to separate propranolol from an internal standard (protriptyline) and potential interferences such as procainamide and quinidine after a basic ether extraction. Fluorometric detection at 215 nm excitation and 326 nm emission provided sensitivity and selectivity. The linear range was found to be 10-350 ng/mL and was beyond the usual therapeutic ranges. The between-run precision was demonstrated to be 3-7% (CV). The method was compared with a less specific nonchromatographic fluorometric method using patient samples, The results were often higher using the non-chromatographic method. No interferences were found among the over 50 drugs and 5 propranolol metabolites tested. The relationship of dose to peak serum propranolol was examined in 20 patients. © 1979 Oxford University Press.