Design, Synthesis, and Biological Evaluation of Darunavir Analogs as HIV-1 Protease Inhibitors

Darunavir, a frontline treatment for HIV infection, faces limitations due to emerging multidrug resistant (MDR) HIV strains, necessitating the development of analogs with improved activity. In this study, a combinatorial in silico approach was used to initially design a series of HIV-1 PI analogs with modifications at key sites, P1' and P2', to enhance interactions with HIV-1 PR. Fifteen analogs with promising binding scores were selected for synthesis and evaluated for the HIV-1 PR inhibition activity. The variation of P2' substitution was found to be effective, as seen in 5aa (1.54 nM), 5ad (0.71 nM), 5ac (0.31 nM), 5ae (0.28 nM), and 5af (1.12 nM), featuring halogen, aliphatic, and alkoxy functionalities on the phenyl sulfoxide motif exhibited superior inhibition against HIV-1 PR compared to DRV, with minimal cytotoxicity observed in Vero and 293T cell lines. Moreover, computational studies demonstrated the potential of selected analogs to inhibit various HIV-1 PR mutations, including I54M and I84V. Further structural dynamics and energetic analyses confirmed the stability and binding affinity of promising analogs, particularly 5ae, which showed strong interactions with key residues in HIV-1 PR. Overall, this study underscores the importance of flexible moieties and interaction enhancement at the S2' subsite of HIV-1 PR in developing effective DRV analogs to combat HIV and other global health issues.