Polymeric Nanovehicle of α-Tocopheryl Succinate Based on a Methacrylic Derivative of Hydroxychloroquine and Its Cytotoxic Effect on Breast Cancer Cells

This study focuses on the preparation of poly(HCQM-<i>co</i>-VP) copolymeric nanoparticles (NPs) to enhance the aqueous solubility and bioavailability of the hydrophobic and antitumor molecules HCQ (hydroxychloroquine) and α-TOS (α-tocopheryl succinate). HCQ is covalently incorporated into the polymer backbone, while α-TOS is encapsulated within the nanoparticles by non-covalent interactions. Poly(HCQM-<i>co</i>-VP) was synthesized from a vinyl derivative of HCQ (HCQM) and N-vinylpyrrolidone (VP), with a molar composition of 17% HCQM and 83% VP, providing the optimal hydrophobic/hydrophilic balance for forming, via nanoprecipitation, empty nanoparticles (NPs) with a diameter of 123.6 nm and a zeta potential of -5.8 mV. These nanoparticles effectively encapsulated α-TOS within their hydrophobic core, achieving an encapsulation efficiency (%EE) of 78%. These α-TOS-loaded NPs resulted in smaller diameters and more negative zeta potentials (71 nm, -19.2 mV) compared to the non-loaded NPs. The cytotoxicity of these NPs was evaluated using the AlamarBlue assay on MCF-7 breast cancer cells. The empty NPs showed no toxic effects within the tested concentration range, after 72 h of treatment. In contrast, the α-TOS-loaded NPs, exhibited a pronounced cytotoxic effect on MCF-7 cells with an IC₅₀ value of 100.2 μg·mL^-1, thereby demonstrating their potential as controlled drug delivery systems for cancer treatment. These findings contribute to the development of a new HCQ-based polymeric nanocarrier for α-TOS or other hydrophobic drugs for the treatment of cancer and other diseases treatable with these drugs.