High-performance liquid chromatographic determination of the insulin sensitizing agent DRF-2189 in rat plasma

A high-performance liquid chromatographic method for the determination of DRF-2189, using troglitazone as internal standard, is described. A dichloromethane-ethyl acetate solvent mixture (6:4, v/v) was used as the extraction solvent. A Kromasil C18 column with a mobile phase consisting of 0.05 M phosphate buffer-acetonitrile-methanol (22.5:37.5:40) (pH 5.0) was used at a flow-rate of 1.0 ml/min. The eluate was monitored by using fluorescence detection with excitation and emission wavelengths at 292 nm and 325 nm, respectively. Ratio of peak area of analyte to internal standard was used for quantification of plasma samples. Using this method, the absolute recovery of DRF-2189 from rat plasma was >95% and the limit of quantitation was 50 ng/ml. The intra-day relative standard deviation (R.S.D.) ranged from 1.74 to 7.24% at 1 microg/ml and 1.86 to 3.83% at 10 microg/ml. The inter-day R.S.D.s were 8.34 and 4.91% at 1 and 10 microg/ml, respectively. The method was applied to measure plasma concentrations of DRF-2189 in pharmacokinetic studies in Wistar rats.