Simultaneous solid-phase extraction combined with liquid chromatography with ultraviolet absorbance detection for the determination of remifentanil and its metabolite in dog plasma

To establish pharmacokinetic/pharmacodynamic relationships, a selective and specific high-performance liquid chromatographic method was developed for the quantitation of remifentanil and its metabolite in dog plasma. The assay involves a solid-phase extraction and a reversed-phase chromatographic separation with ultraviolet detection (λ=210 nm). The calibration curves are linear in the range of 7.89–1500 ng ml−1. Intra-day assay variability is less than 7% for all standards evaluated. Good recovery, linearity, accuracy, and precision were achieved with the assay that proved readily applicable to pharmacokinetic studies in dogs.