Bioanalysis of thiocoraline, a new marine antitumoral depsipeptide, in plasma by high-performance liquid chromatography and fluorescence detection

A sensitive bioanalytical assay for thicoraline, an investigational marine anticancer agent, in plasma, based on reversed-phase liquid chromatography and fluorescence detection, is reported. The proteins in the sample are precipitated by the addition of acetonitrile. After centrifugation, the supernatant is injected directly into the chromatograph. The analyte is quantified by fluorescence detection with excitation and emission at 365 and 540 nm, respectively. The method has been validated in the 1-100 ng/ml range, 1 ng/ml being the lower limit of quantification. Precision and accuracy both meet the current requirements for a bio-analytical assay and are <15% at 1 ng/ml and < or =5% in the 5-100 ng/ml range. Plasma samples can be stored for at least 4 months at -80 degrees C. Finally, the usefulness of this method for pharmacological research was shown in a pilot study of the pharmacokinetics of thiocoraline in rats.