HPLC quantification of carvedilol in small plasma volumes from children

Summary

A sensitive high-performance liquid chromatographic method has been developed for the determination of the β-receptor blocker carvedilol in small volumes of plasma from pediatric patients. Carvedilol and the internal standard naftopidil were extracted from only 300 μL plasma with solid-phase extraction columns and eluted with a mixture of 80% (v/v) acetonitrile and 20% (v/v) potassium acetate buffer (0.1 M, pH 5). Analysis of the extracts was performed on a Spherisorb C₆ column with a mobile phase of 65% acetonitrile, 35% potassium acetate buffer (0.25 M, pH 4) and fluorescence detection. Carvedilol and the internal standard showed recoveries of 87.0±13.9% and 97.7±18.0% respectively (n=75, each; values are means±standard deviations). The analysis of carvedilol was linear over a range of 0.40–242 ng mL⁻¹, the limit of quantification was 0.40 ng mL⁻¹. As an application of the assay, a profile of plasma concentrations versus time of a six-month-old patient is reported.