Development and evaluation of sulfadiazine-loaded gastric floating microsponge for repurposed cancer therapy

Abstract

Sulfadiazine has gained renewed interest as a repurposed anticancer agent owing to its ability to inhibit folate-dependent metabolic pathways and disrupt tumor cell proliferation. However, its therapeutic potential is hindered by poor aqueous solubility, short gastric residence time, and limited absorption from the gastrointestinal tract. This study aimed to develop a gastro-retentive floating microsponge system to enhance gastric retention and sustain release of sulfadiazine for improved absorption. Microsponges were prepared using the quasi-emulsion solvent diffusion method with Eudragit RS 100 as the polymer matrix. Three formulations (F-1, F-2, F-3) were evaluated for production yield, drug content, entrapment efficiency, floating behavior, in-vitro drug release, surface morphology, thermal characteristics, and short-term stability. All formulations appeared as white, free-flowing microsponge powders with high production yields (91.11–97.72%). Entrapment efficiency ranged from 57.65% to 80.14%, increasing with polymer concentration. All formulations remained buoyant for more than 12 hours, confirming effective floating behavior. SEM analysis revealed spherical, porous structures, while DSC thermograms indicated reduced crystallinity of the encapsulated drug. In-vitro drug release demonstrated sustained release over 8 hours, with F-1 showing the fastest release and F-2 the most controlled profile. Stability studies showed no changes in appearance and minimal variation in drug content over three months. The results suggest that sulfadiazine-loaded gastric floating microsponges can enhance gastric residence, support sustained delivery, and improve the therapeutic potential of sulfadiazine as a repurposed anticancer agent.