Enhancing Giardicidal Activity and Aqueous Solubility through the Development of "RetroABZ", a Regioisomer of Albendazole: In Vitro, In Vivo, and In Silico Studies.

Parasitic diseases, including giardiasis caused by (), present a considerable global health burden. The limited effectiveness and adverse effects of current treatment options underscore the necessity for novel therapeutic compounds. In this study, we employed a rational design strategy to synthesize retroalbendazole (), aiming to address the limitations associated with albendazole, a commonly used drug for giardiasis treatment. exhibited enhanced in vitro activity against trophozoites, demonstrating nanomolar potency (IC = 83 nM), outperforming albendazole (189 nM). Moreover, our in vivo murine model of giardiasis displayed a strong correlation, supporting the efficacy of , which exhibited an eleven-fold increase in potency compared to albendazole, with median effective dose (ED) values of 5 µg/kg and 55 µg/kg, respectively. A notable finding was 's significantly improved water solubility (245.74 µg/mL), representing a 23-fold increase compared to albendazole, thereby offering potential opportunities for developing derivatives that effectively target invasive parasites. The molecular docking study revealed that displays an interaction profile with tubulin similar to albendazole, forming hydrogen bonds with Glu198 and Cys236 of the β-tubulin. Additionally, molecular dynamics studies demonstrated that has a greater number of hydrophobic interactions with the binding site in the β-tubulin, due to the orientation of the propylthio substituent. Consequently, exhibited a higher affinity compared to albendazole. Overall, our findings underscore 's potential as a promising therapeutic candidate not only for giardiasis but also for other parasitic diseases.