Abstract:

Tofacitinib citrate is a kinase inhibitor that alleviates symptoms such as joint swelling, pain, and deformity by modulating signal transduction in the immune system and it has been applied in the treatment of rheumatoid arthritis. In this study, the structure of tofacitinib citrate was analyzed by ultraviolet absorption spectroscopy, infrared absorption spectroscopy, mass spectrometry, nuclear magnetic resonance spectroscopy (¹H NMR, ¹³C NMR, DEPT, ¹H-¹H COSY, ¹H-¹³C HSQC, ¹H-¹³C HMBC and 1D-TOCSY) and single crystal diffraction. The ¹H and ¹³C NMR signals of tofacitinib citrate were assigned. In addition, the crystal form of tofacitinib citrate was studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and powder X-ray diffraction (PXRD).

Key words: tofacitinib citrate, nuclear magnetic resonance (NMR), structural elucidation, infrared absorption spectroscopy