Automated high-performance liquid chromatography method for the determination of rosiglitazone in human plasma

A robust, fully automated assay procedure for the determination of rosiglitazone (I, BRL-49653) in human plasma has been developed. Plasma concentrations of I were determined using automated sequential trace enrichment of dialysates (ASTED) coupled to reversed-phase high-performance liquid chromatography. Sequential automated dialysis of human plasma samples was followed by concentration of the dialysate by trace enrichment on a C18 cartridge. Drug and internal standard, SB-204882 (II) were eluted from the trace enrichment cartridge by mobile phase (0.01 M ammonium acetate, pH 8–acetonitrile, 65:35, v/v) onto the HPLC column (a Novapak C18, 4 μm, 100×5 mm radial compression cartridge) protected by a Guard-Pak C18 cartridge. The compounds were detected by fluorescence detection, using an excitation wavelength of 247 nm, and emission wavelength of 367 nm. The lower limit of quantitation of the method was 3 ng/ml (200 μl aliquot) with linearity demonstrated up to 100 ng/ml. Within- and between-run precision and accuracy of determination were better than 10% across the calibration range. There was no evidence of instability of I in human plasma following three complete freeze–thaw cycles and samples can be safely stored for at least 7 months at −20°C. This method has been successfully utilised to provide pharmacokinetic data throughout the clinical development of rosiglitazone.