Abstract
•Filgotinib is a selective JAK1 inhibitor; used to treat rheumatoid arthritis and Crohn's disease.•An LC-MS/MS method for the determination of filgotinib (FLG) was developed.•Protein precipitation procedure was used for extract the drug from HLMs.•Optimization and validation of the applied method were performed according FDA guidelines.•The metabolic stability of FLG was evaluated.
Filgotinibis aselective Janus kinase 1 inhibitor drug which is currently under investigation for the treatment of rheumatoid arthritis and Crohn s disease. The aim of the present study was to develop an accurate, simple and sensitive LC-MS/MS method for the determination of filgotinib (FLG) in human liver microsomes (HLMs) and its application to a metabolic stability study. Chromatographic separation was carried on using of a reversed phase C18 column. The mobile phase was mixture of acetonitrile and ammonium formate (10 mM, pH 3.8) (30:70, v/v), under isocratic elution at a flow rate of 0.3 mL/min. Veliparib was used as internal standard. FLG was extracted from HLMs by precipitation. An electrospray ionization source was used to assay of FLG. The assay of FLG at m/z 426 → 358 and 426 → 291 for FLG and IS at 245 → 145 and 245 → 84 was attained through MRM. The linearity of the investigated method was observed from 5 to 500 ng/mL (correlation coefficient r2 = 0.999). The LOD was 1.43 ng/mL, while the LOQ was 4.46 ng/mL. The investigated method exhibited good recovery (98.42–108.6%) and precision (ranged from 0.88% to 4.7%). The investigated method was successfully employed for a metabolic stability study of FLG in the HLMs matrix. The metabolic stability of FLG was evaluated by measuring two parameters, in vitro t1/2 (48.47 min) and intrinsic clearance (14.29μL/min/mg). The results of the metabolic study confirm that FLG is execrated from the human body at a slower rate compared to related tyrosine kinase inhibitors. Therefore, drug plasma levels and kidney function should be monitored due to potential bioaccumulation.