Evaluation of the efiicacy of paclitaxel-loaded hypoxia-sensitive chitosan nanoparticles in a breast cancer cell line

In this thesis, paclitaxel-loaded chitosan nanoparticles modified with hypoxia-sensitive nitroimidazole groups were developed, and their potential for controlled drug release in breast cancer treatment was investigated. The nanoparticles were synthesized using the ionic gelation method, and their key characteristics, such as average particle size, polydispersity index (PDI), and zeta potential, were thoroughly analyzed. Characterization results showed that the nanoparticles had an average particle size between 115-190 nm, PDI values ranging from 0.18 to 0.30, and zeta potential values above +20 mV. These results indicate that the nanoparticles possess suitable stability and homogeneity for biomedical applications. In vitro drug release studies demonstrated that the nanoparticles exhibited enhanced release rates under tumor-specific conditions, including low pH (pH 5.5) and hypoxic environments. Paclitaxel release reached 70-80% under hypoxic conditions, compared to significantly lower levels under normoxic conditions. This suggests that the system can enhance drug efficacy in hypoxic tumor regions. In conclusion, this thesis demonstrates that chitosan-nitroimidazole-based nanoparticles are promising candidates for controlled and targeted drug delivery systems. Future studies involving different cell lines and in vivo models can further support the clinical applicability of this system and contribute to the development of more effective treatment strategies for breast cancer.