Reference
Sutar, Y., Fulton, S., Paul, S., Altamirano, S., Mhatre, S., Saeed, H., Patel, P., Mallick, S., Bhat, R., Patravale, V., Chauhan, D., Nielsen, K., & Date, A. (2021). Docusate-Based Ionic Liquids of Anthelmintic Benzimidazoles Show Improved Pharmaceutical Processability, Lipid Solubility, and Activity against . 7(9). https://doi.org/10.1021/acsinfecdis.1c00063
Abstract

As the existing therapeutic modalities for the treatment of cryptococcal meningitis (CM) have suboptimal efficacy, repurposing existing drugs for the treatment of CM is of great interest. The FDA-approved anthelmintic benzimidazoles, albendazole, mebendazole, and flubendazole, have demonstrated potent but variable activity against , the predominant fungal species responsible for CM. We performed molecular docking studies to ascertain the interaction of albendazole, mebendazole, and flubendazole with a β-tubulin structure, which revealed differential binding interactions and explained the different efficacies reported previously and observed in this investigation. Despite their promising efficacy, the repurposing of anthelmintic benzimidazoles for oral CM therapy is significantly hampered due to their high crystallinity, poor pharmaceutical processability, low and pH-dependent solubility, and drug precipitation upon entering the intestine, all of which result in low and variable oral bioavailability. Here, we demonstrate that the anthelmintic benzimidazoles can be transformed into partially amorphous low-melting ionic liquids (ILs) with a simple metathesis reaction using amphiphilic sodium docusate as a counterion. efficacy studies on a laboratory reference and a clinical isolate of showed 2- to 4-fold lower IC values for docusate-based ILs compared to the pure anthelmintic benzimidazoles. Furthermore, using a strain with green fluorescent protein (GFP)-tagged β-tubulin and albendazole and its docusate IL as model candidates, we showed that the benzimidazoles and their ILs reduce the viability of by interfering with its microtubule assembly. Unlike pure anthelmintic benzimidazoles, the docusate-based ILs showed excellent solubility in organic solvents and >30-fold higher solubility in bioavailability-enhancing lipid vehicles. Finally, the docusate ILs were successfully incorporated into SoluPlus, a self-assembling biodegradable polymer, which upon dilution with water formed polymeric micelles with a size of <100 nm. Thus, the development of docusate-based ILs represents an effective approach to improve the physicochemical properties and potency of anthelmintic benzimidazoles to facilitate their repurposing and preclinical development for CM therapy.