HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHOD FOR DETERMINATION OF ATENOLOL FROM HUMAN PLASMA AND URINE - SIMULTANEOUS FLUORESCENCE AND ULTRAVIOLET DETECTION

A rapid, reliable analytical method was required to study the disposition of atenolol following oral administration in subjects in various stages of pregnancy. Available methods showed wide variability due to matrix interference. A simple HPLC method is reported for the determination of atenolol in human blood and urine. Atenolol and the internal standard, albuterol, were isolated using solid phase extraction and separated isocratically on a C-18 analytical column with a mobile phase consisting of a mixture of an aqueous solution of mono-basic ammonium phosphate and N,N-dimethyloctylamine, and acetonitrile (93:7 v/v). Atenolol and the I.S. were monitored in the effluent using both fluorescence (228/310 nm, excitation/emission) and ultraviolet (224 nm) detection. Within-run and between-run precision showed a c.v. <5% for concentration of 50-400 ng/ml with an error <5%. Recovery following solid phase extraction ranged from 72.8% at 50 ng/ml to 95.5% at 500 ng/ml. The method is linear over a range of 50-750 ng/ml. The assay has been applied for quantification of atenolol plasma levels for the determination of pharmacokinetic parameters following oral dosing.