Isolation and characterization of pseudo degradation products of acalabrutinib using ESI-HRMS/MS and NMR: Formation of possible geometrical isomers.

A forced degradation study of acalabrutinib (ACB), used to treat relapsed mantle cell lymphoma, was performed to identify and characterize all possible major degradation products formed under different stress conditions. The degradation products (DP) were separated using reverse phase UHPLC system on Kinetex EVO C18 column. Major DPs formed were isolated using semi-preparative HPLC and characterized by LC-ESI-HRMS/MS and NMR. ACB degraded to form seven major degradants (DP-I to DP-VII). DP-I and DP-V were formed under alkaline stress condition, whereas DP-II, DP-III, DP-VI and DP-VII were formed under both acidic and basic conditions. Further, DP-IV was formed when ACB drug was exposed to hydrogen peroxide stress condition. ACB was found to be stable when subjected to aqueous (neutral pH), thermal and UV radiation of 254 nm, as it has not shown any significant degradation under these conditions. Interestingly, two pairs of pseudo geometrical isomeric DPs (DP-II and DP-III, DP-VI and DP-VII) were observed. The plausible degradation pathway of ACB and fragmentation patterns of both ACB and major DPs were discussed.

Optimization of Nicotinamides as Potent and Selective IRAK4 Inhibitors with Efficacy in a Murine Model of Psoriasis.

IRAK4 is an attractive therapeutic target for the treatment of inflammatory conditions. Structure guided optimization of a nicotinamide series of inhibitors has been expanded to explore the IRAK4 front pocket. This has resulted in the identification of compounds such as 12 with improved potency and selectivity. Additionally 12 demonstrated activity in a pharmacokinetics/pharmacodynamics (PK/PD) model. Further optimization efforts led to the identification of the highly kinome selective 21, which demonstrated a robust PD effect and efficacy in a TLR7 driven model of murine psoriasis.