Development of a gas chromatography-mass spectrometry method for the analysis of sitagliptin in human urine

A new, simple and rapid gas chromatography-mass spectrometry (GC-MS) method for the determination of sitagliptin (STG) in human urine was developed and fully validated. STG was derivatized by N-methyl-trimethylsilyltrifluoroacetamide prior to GC-MS analysis and converted to its N-TMS amine derivative. It was extracted from urine by using carbonate buffer (pH 9.0) and ether. The method was validated in terms of specificity, limit of quantitation (LOQ), linearity, accuracy, precision, stability, recovery, robustness and ruggedness. LOQ was found to be 50 ng mL(-1). The calibration curve was linear in the range of 50-600 ng mL(-1) with a coefficient of determination (r(2)) above 0.997. The intra- and inter-day precisions were less than 8.76%, and the intra- and inter-day accuracies were found between 0.83 and 4.53%. The method was successfully applied to urine samples obtained from diabetic patients.