Determination of a dipeptidyl peptidase IV agonist, β-aminoacyl containing thiazolidine derivatives (KR-66223) in rat plasma by liquid chromatography–tandem mass spectrometry

A sensitive liquid chromatography/tandem mass spectrometry (LC–MS/MS) method was developed for a novel dipeptidyl peptidase IV agonist (DDP-IV) agonist, KR-66223, in rat plasma. It involves liquid-liquid extraction (LLE) followed by HPLC separation and electrospray ionization tandem mass spectrometry. KR-66223 and imipramine (IS) was separated on Gemini-NX C18 column with mixture of acetonitrile–ammonium formate (10 mM) (90:10, v/v) as mobile phase. The ion transitions monitored were m/ z 553.2 → 206.2 for KR-66223, m/ z 281.3 → 86.1 for imipramine in multiple reaction monitoring (MRM) mode. The linear ranges of the assay were 0.003–10 μg/ml with a correlation coefficient ( R 2) greater than 0.99 and the lower limit of quantification was 3 ng/ml. The average recovery was 78.9% and 87.1% from rat plasma for KR-66223 and imipramine, respectively. The coefficients of variation of intra- and inter-assay were 3.9–14.4% and the relative error was 0.8–11.5%. The method was validated and successfully applied to the pharmacokinetic study of KR-66223 in rat.