Column-switching high-performance liquid chromatographic analysis of fluvastatin in rat plasma by direct injection

A column-switching high-performance liquid chromatographic (HPLC) method has been developed and validated for quantification of fluvastatin in rat plasma. Plasma samples were diluted with an equal volume of mobile phase, i.e. acetonitrile-5 mM potassium phosphate buffer (pH 6.8) (15:85, v/v), and the mixture was directly injected onto the HPLC system. The analyte was enriched in a pre-treatment column, while endogenous components were eluted to waste. The analyte was then back-flushed onto an analytical column and quantified with fluorescence detection (λ_ex = 305 nm; λ_em = 390 nm). The standard curve for the drug was linear in the range 0.5-100 ng mL^-1 in rat plasma. The limit of quantitation for plasma was found to be 0.5 ng mL^-1. This method has been fully validated and shown to be specific, accurate and precise. The method is simple and rapid because of a minimized sample preparation and appears to be useful for the pharmacokinetic study of fluvastatin.