DOUBLE COLUMN-SWITCHING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHOD FOR THE DETERMINATION OF TAK-603 AND ITS METABOLITES IN HUMAN SERUM

A double column-switching high-performance liquid chromatographic (HPL C) method for the determination of concentrations for TAK-603 (T) and its metabolites, T-72258 (M-I) and T-72294 (M-III), in human serum was developed. The analytes were extracted with ethyl acetate from human serum samples treated with triethylamine and injected into the HPLC sy stem. Separation of the analytes was performed on the HPLC system with double column-switching technique. The mobile phases A and B for the first column and the mobile phase C for the second column used were a mixture of methanol-10 mM aqueous ammonium acetate solution (1:1, v/v) , methanol and a mixture of methanol-10 mM aqueous ammonium acetate so lution (11:9, v/v), respectively. The eluate was monitored with a UV d etector at a wavelength of 253 nm. The work-up procedure was reproduci ble and more than 90% of the analytes could be recovered from human se rum. The lower limits of quantitation were all 1 ng/ml for the analyte s when 0.5 ml of human serum was used. Standard curves were linear wit h a correlation coefficient (R) of more than 0.999 in the range of 1-5 00 ng/ml for T, M-I and M-III in human serum. The intra- and inter-day precision of the method for the various analytes were below 4.8%. The accuracy was good with the deviations between spiked and calculated c oncentrations of the analytes being within 11.0%. The method was succe ssfully applied to analyze serum samples after an oral administration of T to healthy male volunteers. (C) 1998 Elsevier Science B.V. All ri ghts reserved.