Comprehensive identification and characterization of in vitro and in vivo metabolites of the novel GLP-1 receptor agonist danuglipron using UHPLC-QToF-MS/MS

Small-molecule glucagon-like peptide-1 receptor (GLP-1R) agonists are emerging as promising therapeutic agents for type 2 diabetes mellitus (T2DM) and obesity. Danuglipron, a novel investigational GLP-1R agonist, has demonstrated notable efficacy in clinical trials. This study aimed to evaluate the in vitro metabolic stability of danuglipron and to identify its metabolites both in vitro and in vivo. Metabolite profiling was conducted using ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC-QToF-MS/MS). In vitro studies were performed in human liver microsomes (HLM), rat liver microsomes (RLM), and human S9 (HS9) fractions, while in vivo metabolites were identified from rat plasma, urine, and faeces. Seven novel phase I and phase II metabolites were characterized through high-resolution MS data, employing both data-dependent and data-independent acquisition, alongside in silico prediction tools. Key biotransformations included hydroxylation, O-dealkylation, oxetane ring hydrolysis followed by acetylation and methylation. The in vitro half-life (t₁/₂) of danuglipron was 208 ± 31 min in HLM and 81 ± 16 min in RLM, with corresponding intrinsic clearance (CL_int) values of 7.49 µL/min/mg and 35.57 µL/min/mg, respectively, indicating moderate hepatic metabolism and low clearance in both species. Molecular docking suggested that certain metabolites (M-1, M-2, M-7) may have stronger GLP-1R binding affinity than the parent compound, implying potential bioactivity. This comprehensive analysis offers valuable insights into danuglipron metabolic fate and supports further investigation of its metabolites in the treatment of T2DM and obesity.