BTK inhibitor 17 is a potent and orally active irreversible BTK inhibitor with an IC50 of 2.1 nM. BTK inhibitor 17 can be used for rheumatoid arthritis research[1].

BTK inhibitor 17 (compound 8) could covalently bind to Cys481 and formed an HB network with hinge key residues Met477, Glu475, and gatekeeper Thr474[1].

BTK inhibitor 17 (compound 8; 3-10 mg/kg; oral gavage; daily; for 28 days) treatment inhibits the significant progression of the disease and exhibits a clear dose-dependent reduction per paw clinical scores, and no significant body weight loss is observed for all different dosages[1].BTK inhibitor 17 (compound 8) shows >95% plasma protein binding across three species of human, rat, and mouse. After an intravenous injection, the half-life (rat, 0.32 h; mice, 0.42 h), clearance (rat, 54.6 mL/min/kg; mice, 31.3 mL/min/kg), volume of distribution (rat, 1.55 L/kg; mice, 0.82 L/kg), and AUC exposure (rat, 604 ng.h/mL; mice, 576 ng.h/mL) are observed in two species. After oral administration, BTK inhibitor 17 exhibits higher Cmax (rat, 466 ng/mL; mice, 252 ng/mL) and plasma exposure (rat, 642 ng.h/mL; mice, 128 ng.h/mL) with a favorable oral bioavailability (rat, 23.7%; mice, 11.2%)[1].

[1]. Xuejun Zhang, et al. Discovery and Evaluation of Pyrazolo[3,4- d]pyridazinone as a Potent and Orally Active Irreversible BTK Inhibitor. ACS Med Chem Lett. 2019 Dec 11;11(10):1863-1868.