Amrinone and N-acetylamrinone assay in human plasma using solid-phase extraction and reversed-phase chromatography

A simple and sensitive liquid chromatographic assay for simultaneous quantitation of amrinone and N-acetylamrinone in human plasma was developed. The method involves extraction of samples via activated solid-phase extraction Bond Elut C18 disposable columns, followed by chromatographic separation on a reversed-phase phenyl column using isocratic condition and UV detection. The assay can measure concentrations of both compounds over the range 0.075-10 micrograms ml-1. The injection interval is 11 min. The inter-day relative standard deviation (RSD) for replicate analysis of spiked samples is less than 10% and the accuracy more than 94% for both compounds over the standard curve range. The assay has been successfully applied to pharmacokinetic studies in humans.