A novel bioanalytical method for the quantification of pemigatinib in rat plasma by UPLC-MS/MS

Pemigatinib is an oral, selective, potent, competitive inhibitor acting on fibroblast growth factor receptor (FGFR)1, FGFR2, and FGFR3, which has obtained accelerated approval in the USA through a test approved by the USA FDA. It is not only significant in the therapy of adult recurrent, unresectable, metastatic or locally advanced cholangiocarcinoma, but also plays an important role in treating adult patients with FGFR2 fusion or other rearrangements. The aim of our research was to establish and verify a reliable and quick ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) assay to determine the level of pemigatinib in rat plasma. The analyte was prepared using a simple and convenient approach with acetonitrile for protein crash, and then separated from the matrix on a Waters Acquity UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) in a gradient elution program, where the mobile phase was consisted of acetonitrile and 0.1 % formic acid in water and was set at 0.40 mL/min flow rate. Selective reaction monitoring (SRM) was used to conducted for UPLC-MS/MS dectection with ion transitions at m/z 488.01 → 400.98 for pemigatinib and m/z 447.00 → 361.94 for erdafitinib (Internal standard, IS), respectively. This method had good linearity in a 0.5-1000 ng/mL calibration range for pemigatinib, where the lower limit of quantification (LLOQ) was validated at 0.5 ng/mL. The precision of pemigatinib for intra- and inter-day was less than 13.3 %, and the accuracy was determined to be from -4.8%-11.2%. During the assay in plasma samples, the analyte was found to be stable. Besides, matrix effect and recovery of the analyte and IS were acceptable. The novel optimized UPLC-MS/MS assay was also suitable for determining the concentration level of pemigatinib in a pharmacokinetic study after a single dose of 1.35 mg/kg pemigatinib orally to the rats.