Quantification of sitagliptin in human plasma and urine by LC-MS/MS method and its application

A rapid and sensitive liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) method for quantification of sitagliptin in human plasma and urine had been developed. This method was applied to the pharmacokinetics study of sitagliptin tablet after single- and multiple-dosing in Chinese population. Plasma samples were prepared by a liquid-liquid extracted method, and urine samples were diluted. Compounds were analyzed by multiple reaction monitoring (MRM) mode with a electrospray ionization (ESI) interface. Mobile phase consisted of methanol and water (85:15, v/v). The linear concentration range of calibration curve was 0.5-1 000 ng·mL^-1 and 0.2-100 μg·mL^-1, intra-run/between-run accuracy was 98.98%-103.69% and 97.63%-102.29%, intra-run/between-run precision was < 5.51% and 4.26% for plasma and urine sample, respectively. The stability of sitagliptin stock solution was tested for 55 days at -30 ℃. Sitagliptin was stable when stored under the following conditions: 24 hours in the autosampler after sample preparation; 24 hours at room temperature, after 3 freeze and thaw cycles (from -30 ℃ to room temperature), 40 days at -30 ℃ for plasma and urine samples. The absolute recovery in plasma was 71.1%, and no matrix effect was founded. This method was proved simple, specific, sensitive, rapid and suitable for pharmacokinetics study of sitagliptin in human being.