Quantitative liquid chromatographic determination of sotalol in human plasma

The analysis of sotalol by a simple and sensitive liquid chromatographic assay is described. Sample preparation involves an extraction by chloroform and isoamyl alcohol (3:1, vol/vol) at pH 9.0 followed by back extraction into 0.05 M sulfuric acid. Analyses are carried out on a reversed-phase chromatographic system using an octadecylsilane stationary phase and a water-methanol-acetic acid-methanesulfonic acid (91.00:8.50:0.50:0.025, vol/vol/vol/vol) mobile phase adjusted at pH 3.3. Sotalol is quantified on the basis of ultraviolet absorption at 235 nm. The precision of the method ranged from 6.3% at 0.16 microM (50 ng/ml) to 3.3% at 5.18 microM (1,600 ng/ml). The limit of quantification was established 0.08 microM (25 ng/ml). This assay provides a suitable method for pharmacokinetic studies.