New and expedient determination of atenolol in biological samples.

A method is described for the GLC determination of atenolol BP in plasma and urine. Extraction is accomplished under dehydrating conditions, and interfering impurities are removed by using an acidified cyclohexane-isopropanol mixture (2:1) and charcoal-treated paper disks. The drug thus isolated appears to react more efficiently with heptafluorobutyric anhydride, increasing the sensitivity of GLC electron-capture analysis. Concentrations as low as 0.02 mug/ml were measured using 0.5-ml aliquots of plasma or 0.1 ml of urine. Amino alcohols such as atenolol may form hydrates or alcoholates, precluding complete derivatization with heptafluorobutyric anhydride.