pH-sensitive sulfasalazine release from green-synthesized mesoporous Fe3O4@SiO2 nanocomposites using Opuntia ficus-indica extract

Abstract

This study presents the green synthesis of mesoporous Fe₃O₄@SiO₂ nanocomposites using Opuntia ficus-indica extract for pH-sensitive delivery of sulfasalazine. The synthesized nanocomposites exhibited well-defined spherical morphology with particle sizes ranging from 80 to 120 nm and superior superparamagnetic properties with a saturation magnetization of 75.8 emu/g. X-ray diffraction analysis confirmed the formation of a pure magnetite phase with an average crystallite size of 17.37 nm, while nitrogen physisorption revealed a high specific surface area of 165.8 m²/g with uniform mesopores centered at 4.2 nm. The nanocomposites demonstrated exceptional drug loading characteristics with 81.1 % loading efficiency and 23.9 % loading capacity. pH-dependent release studies showed enhanced release under acidic conditions (82 % at pH 3.5) compared to physiological pH (50 % at pH 7.4), indicating potential for targeted drug delivery applications. Cytotoxicity studies using L929 cells and peripheral blood mononuclear cells (PBMCs) revealed remarkable biocompatibility at concentrations up to 200 µg/mL over 72 h. These findings establish the potential of green-synthesized mesoporous Fe₃O₄@SiO₂ nanocomposites as efficient carriers for pH-sensitive drug delivery systems, offering an environmentally friendly approach to developing advanced therapeutic platforms.