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 disposit ion of atenolol following oral administration in subjects in various s tages of pregnancy. Available methods showed wide variability due to m atrix interference. A simple HPLC method is reported for the determina tion of atenolol in human blood and urine. Atenolol and the internal s tandard, albuterol, were isolated using solid phase extraction and sep arated isocratically on a C-18 analytical column with a mobile phase c onsisting of a mixture of an aqueous solution of mono-basic ammonium p hosphate and N,N-dimethyloctylamine, and acetonitrile (93:7 v/v). Aten olol and the I.S. were monitored in the effluent using both fluorescen ce (228/310 nm, excitation/emission) and ultraviolet (224 nm) detectio n. Within-run and between-run precision showed a c.v. <5% for concentr ation of 50-400 ng/ml with an error <5%. Recovery following solid phas e 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 appl ied for quantification of atenolol plasma levels for the determination of pharmacokinetic parameters following oral dosing.