Cytotoxic Evaluation of Niclosamide via Saccharin-Based Multicomponent Crystal: Insights from in Vitro MTT Assay

Abstract

Breast cancer remains a major health burden among women globally. While targeted therapies continue to evolve, affordable and effective alternatives are still needed. Niclosamide, an FDA-approved anthelmintic, shows promise for drug repurposing due to its anticancer activity, though its poor solubility and bioavailability limit clinical use. To address this, cocrystallization with saccharin, a GRAS-status coformer, was employed to enhance niclosamide’s physicochemical properties without altering its pharmacological effect. This study evaluates the cytotoxic effect of pure niclosamide and the niclosamide–saccharin cocrystal on T47D breast cancer cells, synthesized via the solvent drop grinding (SDG) method and assessed using the MTT assay with microplate spectrophotometric analysis. The results demonstrated that both pure niclosamide and its multicomponent crystal exhibited cytotoxic effects on T47D cells. Notably, the niclosamide–saccharin crystal showed a lower IC₅₀ value (0.90 µg/mL) compared to that of pure niclosamide (1.39 µg/mL), indicating enhanced potency. A significant decrease in T47D cell viability was observed, suggesting that the multicomponent crystal formulation may augment the anticancer efficacy of niclosamide. In conclusion, the formation of a niclosamide–saccharin multicomponent crystal significantly enhances its cytotoxic activity against breast cancer cells in vitro. These findings underscore the potential of cocrystallization as a strategic formulation approach to improve the therapeutic performance of repurposed drugs in cancer treatment.