Metabolite Identification of HIV-1 Capsid Modulators PF74 and 11L in Human Liver Microsomes

PF74and11L, as potent modulators of the HIV-1 capsid protein, have been demonstrated to act at both early and late stages in the HIV-1 life cycle. However, their clearance is high in human liver microsomes (HLMs). The main goal of this study was to clarify the metabolism ofPF74and11Lin HLMs, and provide guidance for future structural optimization. To accomplish this, the phase-I metabolites ofPF74and11L, resulting from in vitro incubation with HLMs, were investigated via ultra-performance liquid chromatography–ultraviolet–high-resolution mass spectrometry (UPLC–UV–HRMS). The results show that 17 phase-I metabolites were putatively annotated forPF74, whereas 16 phase-I metabolites were found for11L. The main metabolic pathways ofPF74in HLMs were oxidation and demethylation, and the secondary metabolic pathway was hydrolysis; thus, the di-oxidation and demethylation products (M7,M9,M11, andM14) were found to be major metabolites ofPF74in HLMs. In comparison, the main metabolic pathways of11Lin HLMs were oxidation, demethylation, dehydrogenation, and oxidative deamination, withM6′,M11′,M15′, andM16′as the main metabolites. We suggest that the indole ring andN-methyl group ofPF74, and the aniline group, benzene ring R1′,N-methyl, and methoxy group of11L, were the main metabolic soft spots. Therefore, our research illuminates structural optimization options in seeking improved HIV-1 CA modulators.Keywords:PF74;11L;capsid modulators;human liver microsomes;UPLC–UV–HRMS;metabolite identification