Abstract
Among the available chemotherapeutic agents, gemcitabine (GEM) has demonstrated significant efficacy against various cancers. Nevertheless, its clinical application is restricted due to its poor pharmacokinetic properties, highlighting the need for improved drug delivery strategies. Here, Dual stimuli-responsive hybrid polymeric nanoparticles conjugating GEM have been developed using a chitosan alginate biopolymer. The polymers anchored GEM via hydrazone and disulfide linkers, enabling dual stimuli-responsive drug release in tumors by leveraging pH variations and elevated glutathione (GSH) levels. This innovative nanoplatform enhances GEM systemic exposure, stability, and therapeutic efficacy while minimizing systemic toxicity. The Alg/Chi-GEM nanoparticles (NPs) were comprehensively characterized for their physicochemical properties via (1)H NMR, infrared spectroscopy, GPC, DSC, and particle size analysis, along with stimuli-responsive drug release and hemolysis studies to confirm their robustness. The therapeutic potential of the nanoplatform was rigorously assessed in various breast cancer cell lines, including 4T1, MCF-7, and MDA-MB-231 cells, where the NPs demonstrated superior cellular uptake, enhanced cytotoxicity, and efficient apoptosis induction through DNA fragmentation, ROS generation, mitochondrial depolarization, and G2/M phase arrest. In vivo studies using 4T1-Luc tumor-bearing mice further validated their antitumor efficacy, showing significant tumor growth inhibition at a 10 mg/kg GEM equivalent dose with reduced toxicity compared to free GEM. These findings indicated that Alg/Chi-GEM NPs, as a next-generation nanomedicine, offer a safer, more effective approach to overcoming gemcitabine resistance and enhancing breast cancer therapy.