Desenvolvimento de hidrogel injetável contendo nanopartículas de zeína para liberação simultânea de doxorrubicina e quercetina

Abstract

Systemic toxicity is one of the major challenges of chemotherapy. Doxorubicin, a first- line drug for breast cancer treatment, is limited by severe adverse effects. The

combined administration of chemotherapeutics, along with drug delivery systems for localized application in malignant tumors, may effectively reduce systemic toxicity. This study developed an injectable hydrogel based on oxidized sodium alginate (OSA) and gelatin (GEL), incorporating zein nanoparticles for the simultaneous release of doxorubicin (DOX) and quercetin (QUE), the latter encapsulated in nanoparticles. The study was structured into five stages: (1) functionalization of sodium alginate by oxidation with sodium periodate (OSA) and characterization using infrared spectroscopy (IR), proton nuclear magnetic resonance (1H NMR), and heteronuclear single quantum coherence (HSQC) correlation; (2) synthesis of hollow zein nanoparticles coated with chitosan using sodium carbonate as a sacrificial template (HNPs), followed by quercetin encapsulation (QNPs). HNPs were characterized in terms of size, zeta potential, X-ray diffraction (XRD), transmission electron microscopy (TEM), and atomic force microscopy (AFM). The encapsulation of quercetin was analyzed via UV-vis spectroscopy; (3) preparation of the injectable hydrogel (OSAG) via Schiff base crosslinking with a 10% (w/v) OSA and 15% gelatin ratio, achieving a gelation time of 2.33 ± 0.03 minutes. The hydrogel was characterized for rheological, morphological, and swelling properties. After confirming the formation of a stable, porous, injectable, and self-healing network, DOX and QNPs were incorporated, resulting in the following systems: hydrogel containing DOX (OSAGX), hydrogel containing quercetin (OSAGQ), and the composite hydrogel containing both therapeutic agents (OSAGC); (4) in vitro release study of DOX and QUE from OSAGX, OSAGQ, and OSAGC; (5) cytotoxicity evaluation of OSAG, OSAGX, OSAGQ, and OSAGC in MCF-7 breast cancer cells. OSA was identified by absorption bands between 1730 and 1739 cm−1 in the IR spectrum, characteristic of aldehydes, further confirmed by the emergence of signals between 5.15 and 5.4 ppm in the 1H NMR spectrum. HNPs had an average size of 195 ± 0.44 nm, while QNPs measured 218.8 ± 2.77 nm, as confirmed by TEM and AFM, which also revealed the spherical morphology of HNPs. The nanoparticles exhibited an encapsulation capacity and efficiency of 4.78 ± 0.00% and 67.32 ± 0.06%, respectively. In vitro release tests of DOX and QUE at pH 6.8 and 7.4 showed distinct release profiles, with 81.2% and 9.7% released, respectively. Cytotoxicity assays revealed a 4.66-fold increase in cytotoxic action with OSAGX. The composite hydrogel OSAGC exhibited an even greater increase, enhancing cytotoxicity by 20.7 times compared to free DOX. Furthermore, the inclusion of QNPs reduced the IC50 of OSAGX from 0.071 ± 0.039 to 0.016 ± 0.014 μg/mL. These results highlight the cytotoxicity-enhancing effect of the hydrogel system, broadening the applications of oxidized alginate–gelatin hydrogels for dual drug delivery. Although localized administration requires further in vivo investigation, in vitro findings suggest strong potential for future therapeutic applications.